Poster Session

Location

Roberts G02 Foyer
Engineering Building
Torrington PI, London, WC 1E 6 EQ

Poster Session I

Thursday, 13 July , 17:00-18:00

Poster Number

1st Author

Title with abstract

Action, Perception, and Motor Cognition

I-01

Ragni, F.

An eccentricity effect for different stimulus categories during visual imagery

Participants respond faster to stimuli presented at small in comparison to larger eccentricities. This eccentricity effect (EE) has been suggested to be due to cortical magnification present in early visual cortex (EVC). Similar EEs have been obtained for visual imagery of simple shapes, and were interpreted as a sign of EVC involvement. Here we asked whether this EE is present also for different imagined stimulus categories, and if so, which stimulus category yields the strongest EE. N=12 participants imagined six stimulus categories (checkerboards, gratings, invented shapes, lowercase letters, objects, simple shapes) at 4 different locations (2° and 8° of visual angle from the central fixation point, to the left or right side), indicated by 4 placeholders. Each block started with the presentation of the stimulus exemplar to be imagined; an auditory cue indicated at which location to imagine the stimulus. Participants pressed a button when they reached a vivid imagery. Reaction times (RTs) were recorded, and eye movements monitored using eye tracking. We obtained a robust EE for each of our stimulus categories, characterized by shorter RTs at smaller compared to higher eccentricities. This finding confirmed the theoretical premises of our study. The analysis of subjective reports highlighted a strong inverse correlation between vividness and difficulty ratings, suggesting how lowercase letters, objects and simple shapes could be imagined more easily and led to vivid mental images in comparison to checkerboards, gratings, and invented shapes. For this reason, the former three categories might be better suited for our future fMRI studies.

I-02

Darda, K.

Sex differences in automatic imitation

Automatic imitation, or an involuntary tendency to copy the behaviour of others, is an important part of social interaction. Although situational and contextual antecedents of imitation have been studied, research on how processes underlying imitation vary across individuals, especially between sexes, is limited. Recent evidence suggests that when using a reaction-time measure of automatic imitation, females showed a greater level of interference when inhibiting automatic imitative tendencies than males (Butler, Ward, & Ramsey, 2015). However, whether this difference between the sexes is domain-general or solely tied to imitative control is as yet unclear. Using a large sample (N = 217; 113 females), the current study tested whether performance on a non-social inhibitory control task (i.e. the Flanker task) and an automatic imitation task differed between the sexes. Further, in order to minimise the contribution of spatial compatibility in the automatic imitation task, we positioned the stimuli orthogonal to the response hand. Results demonstrated a larger interference effect for females as compared to males in the imitation task, but not in the Flanker task. In addition, a correlational analysis showed no evidence for a relationship between the interference effects of the two tasks. Taken together, these results provide evidence for partially distinct mechanisms of inhibitory control between the flanker and the automatic imitation task as a function of sex. To extend and complement this behavioural research, an fMRI experiment (N=50) is currently exploring the interplay between domain-general and domain-specific neural architectures in automatic imitation and how these differ between the sexes.

I-03

Malfatti, G.

Decoding "concrete" and "abstract" action representations within the tool network

Dorsal and ventral streams underlie the perceptual processes and sensorimotor transformations necessary to manipulate a tool. Lesion and neuroimaging studies have shown similar action-related processing within both pathways, suggesting their possible interaction. Pantomimes of tool actions engage regions within both streams providing a window through which similarities and differences in action encoding can be investigated. The aim of this study is to investigate how “concrete” action information (i.e. performing different actions with the same tool) and “abstract” goal information (i.e. achieving the same goal irrespective of the adopted tool) are encoded within the regions of the fronto-parietal motor system (SMG, aIPS, PMv, SPOC, PMd) and within the ventral stream (MTG). The study considered a 2x2 factorial design. In the MR scanner, participants pantomimed a ‘grasp-to-move’ or a ‘grasp-to-use’ action (factor “action type”), either with a pair of scissors or an axe (factor “object”). ROI-based MVPA approach was adopted to investigate the encoding of “concrete” action information (decoding: move vs use with a specific tool) and of “abstract” goal information (cross-decoding: move vs use across tools). Our results showed significant encoding for “concrete” action information in all the considered ROIs. “Abstract” goal cross-decoding was significant within the aIPS (dorsal stream) and in the MTG (ventral stream). Overall, these findings showed the processing of “abstract” information about the action’s goal within both streams, suggesting a possible interaction between these two visual pathways .

I-04

Orlandi, A.

Perceiving the exertion: The role of visuomotor expertise

The observation and imagination of human actions requiring a great muscular effort is known to increase autonomic responses. In addition TMS evidences have been provided of a greater muscle-specific cortical excitability during the observation of heavy vs. light objects lifting, while electrophysiological studies have shown an increase in late ERP potentials during observation of dynamic vs. static gestures. In the present study, the neural correlates of perceiving effortful vs. effortless dance movements were investigated, by means of the EEG/ERP technique. 15 professional female ballet dancers and 15 female naïve controls were recruited. They were shown hundreds of video clips displaying a male dancer performing a standard step from ballet technique, that could be either effortful or relatively effortless. Participants were asked to observe each clip and to imagine themselves physically executing the same movement. The observation of effortful compared to effortless movements resulted in a greater P300 over frontal sites in professionals than controls, suggesting that probably a resonance process occurred allowing them to encore more accurately the action complexity. Moreover, a larger Late Positivity over parietal and occipital sites was observed in response to effortful stimuli in both groups. SwLoreta source reconstruction performed on such LP showed a greater involvement of mirror neuron regions in dancers (BA 40, 6) during the observation of effortful-minus-effortless movements. Contrarily, an enhanced activity in frontal (BA 10), body and motion related visual regions (BA 19, 20, 21, 37) was found in controls.

I-05

Pares, E.

Ambushing the will: A new method for studying conscious intention in voluntary action

An important aspect of voluntary action is the conscious experience of intention to move that precedes action execution. The Readiness Potential (RP) is an increasing negativity over motor cortical areas that is thought to reflect voluntary motor preparation and starts before the conscious intention to move spontaneously arises (Libet, Gleason, Wright & Pearl, 1983). However, it has been suggested that this ongoing preparation may be accessible before it becomes spontaneously conscious (Matsuhashi & Hallet, 2008). In order to test this hypothesis we designed a task where participants performed self-paced actions and were sometimes interrupted by cues that prompted them to introspect and evaluate whether or not they were preparing to move at that moment. They were told to respond to the cue by pressing a key if they were or to ignore it if they were not. We show that people are able to correctly detect motor preparation at early stages. In particular, we detect a negative trend over motor areas corresponding to an incipient RP preceding the cues that elicited a response, whereas no such trend is found preceding the cues that were ignored.

Clinical Neuroscience

I-06

Albrecht, F.

Proposing an imaging biomarker for progressive supranuclear palsy by combined gray & white matter meta-analysis using ALE and SDM

Progressive supranuclear palsy (PSP) shows clinical features of vertical gaze palsy and postural instability. PSP belongs to the atypical parkinsonian syndromes. Although, midbrain atrophy has been suggested as a pathognomic marker, it has not been validated systematically. To identify disease-specific regional atrophy in PSP, we conducted a systematic and quantitative meta-analysis on structural magnetic resonance imaging (MRI) data. Based on strict inclusion criteria 18 studies were identified in PubMed including 315 patients compared with 393 healthy controls. The included studies were separated into studies reporting either gray or white matter atrophy. To ensure consistent results, we used a unique approach by combining two widely used meta-analytical algorithms. In a conjunction analysis the results of anatomical likelihood estimation (ALE) and seed-based D mapping (SDM) were superimposed. The gray matter analysis revealed that clusters in the bilateral thalamus, bilateral anterior insulae, midbrain and bilateral caudate nuclei were consistently identified as effected by both methods, SDM and ALE. White matter analyses showed consistent atrophy in the bilateral superior cerebellar/cerebral pedunculi, and midbrain. Considering previous meta-analyses studying neurodegenerative diseases, our meta-analyses identify gray matter loss in the midbrain and in the white matter loss in the cerebral/cerebellar pedunculi and midbrain as disease-specific in PSP. Atrophy in these brain regions is recommended to be included into new revised diagnostic criteria for PSP. The design of our study enabled high validity and statistical power. We combined two meta-analytic methods, combined analyses in white and gray matter, and included the biggest cohort of PSP patients to date.

I-07

Filchenko, I.

Neuroprotective effect of liraglutide in transient focal brain ischemia in rats with type 2 diabetes mellitus

Ischemic stroke is a severe complication of type 2 diabetes mellitus (T2DM). Glucagon-like peptide-1 receptors (GPL-1R) are present in brain, thus GLP-1R agonists may be used not only to decrease glycaemia but also for neuroprotection. In present study we evaluated neuroprotective effect of GLP-1R agonist liraglutide in experimental stroke in Wistar rats without T2DM and with T2DM. In the first phase of the study experimental animals were treated with liraglutide for 7 days, while control ones received NaCl. Then transient focal brain ischemia was modelled in all rats and infarct volume was measured. Garcia scale was used to determine neurological deficit. In the second phase of the study T2DM was induced. In 14 days after T2DM induction the first and the second groups of experimental animals started to receive liraglutide and metformin for 7 days, respectively, while control animals were treated with NaCl. Then transient focal brain ischemia was modelled in all rats, neurological deficit and infarct volume were measured. In the first phase liraglutide-treated rats had significantly smaller infarct volume and neurological deficit in comparison with control animals. In the second phase liraglutide-treated rats had significantly smaller infarct volume and neurological deficit in comparison both with animals that received isotonic NaCl and with metformin-treated animals. There were no significant differences in infarct volume and neurological deficit between the groups of metformin-treated and control rats. Liraglutide has an independent neuroprotective effect in experimental stroke, not related to glycemic control improvement. GLP-1R agonists may be promising in stroke prevention in T2DM.

I-08

Garcia-Gorro, C.

Association between white matter tracts and symptomatic profiles in Huntington's disease

Huntington’s disease (HD) is a neurodegenerative disease that involves motor, cognitive and psychiatric disturbances. There is great variability regarding the prominence of each type of clinical sign. The aim of the present study was to study the relationship between the different clinical symptoms of HD and the microstructure integrity of different white matter tracts. Thirty-two HD patients were clinically assessed and scanned using structural and diffusion-weighted MRI. The behavioural measures consisted of questionnaires and neurological, neuropsychological and psychiatric assessments. Nineteen white matter tracts were virtually segmented using diffusion-based deterministic tractography. Radial diffusivity (RD) was chosen a measure of microstructural integrity. Age and disease burden were included as nuisance variables. Three Canonical Correlation Analyses (CCAs) were carried out, one for each symptomatic domain. Regarding the cognitive domain, one significant covariance mode was found (p = .027). Fifteen tracts showed a significant correlation with the mode. In the psychiatric domain, there was one mode with a significance of p = .053. In this case, five tracts significantly correlated with the mode. Regarding the motor domain, no significant modes were found. When repeating this analysis without including disease burden as a variable of no interest, one significant mode was found (p = .036). In this case, 11 tracts were significantly correlated with the mode. These results suggest that whereas there is no specificity in the white matter tracts in relation with cognitive and motor deficits in HD, psychiatric symptoms present a more specific pattern of white matter degeneration.

I-09

Kikkert, S.

Non-invasive brain stimulation relieves phantom limb pain in amputees; an fMRI study

Following arm amputation individuals frequently report experiencing vivid, and often painful sensations of the missing limb (phantom limb pain, PLP). PLP is an intractable chronic neuropathic pain syndrome. We previously showed that chronic PLP positively associates with maintained activation in the cortical territory of the missing hand (hereafter deprived sensorimotor cortex). This study was aimed at alleviating PLP using non-invasive brain stimulation, in a within-subject, double-blind, counterbalanced and sham-controlled design. Fifteen arm amputees suffering from chronic PLP underwent twenty minutes of excitatory (anodal, 1mA) brain stimulation (transcranial direct current stimulation; tDCS) over deprived sensorimotor cortex while performing PLP-inducing phantom hand movements. Subjective pain ratings and functional neuroimaging scans were obtained prior to, during, and post brain stimulation. Subjective pain ratings were also obtained in the week following each session. While PLP was increased in the sham condition immediately after brain stimulation, excitatory stimulation over deprived sensorimotor cortex averted this pain increase. Further, excitatory stimulation decreased transient PLP at ninety minutes following stimulation. This PLP relief lasted at least one week, while no long-term change in PLP was observed in the sham condition. Functional neuroimaging analysis revealed that amputees with less pain after stimulation showed less activation in the deprived sensorimotor cortex after stimulation, as well as modulated activation in ipsilateral insula during stimulation. Our results suggest non-invasive brain stimulation as a promising tool for inducing lasting relief of PLP and highlight the role of pain-related networks in mediating PLP.

Language, Music and Communication

I-10

Beese, C.

The benefit of syntactic chunking for language comprehension in the aging brain

Language comprehension declines with age, crucially due to an age-related decline in working memory capacity. One possible way to overcome the age-related memory decline is to chunk single words into phrases, which reduces the number of discrete memory representations that have to be encoded into memory. Previous studies have suggested that while older adults’ language comprehension deteriorates overall, they benefit from syntactic chunking relatively more than younger adults. Moreover, compared to young adults, older adults could additionally use their enriched semantic knowledge to compensate for their memory decline. In this behavioral study, we compared young and older adults in a design crossing sentence structure with sentence meaning. We found that across age groups, syntactic chunking facilitated language comprehension. We also found that across age groups, meaningful sentences were processed easier than non-meaningful sentences. An interaction effect between structure and meaning showed that meaning only contributed to a performance increase when the sentences were structured; yet, none of the effects interacted with age. In sum, contradictory to our hypothesis, the results show that syntactic chunking plays the same facilitatory role in young and older adults during sentence processing. Possibly, syntactic chunking is only differentially beneficial for older adults when sentence processing is even more working memory demanding, which we will test in our next study.

I-11

Cheung, V.

The neurocognition of nested hierarchical sequences in music

Relating remote elements beyond their temporal order enables cognitive abilities such as music and language. Previous studies investigating hierarchical processing of music have mainly employed irregular harmonic cadences; these can, however, be processed serially by auditory short-term memory alone, without necessarily requiring hierarchical processing. Therefore we conducted an fMRI experiment where participants with prior exposure to an atonal nested grammar discriminated between grammatical and ungrammatical musical sequences. To assess the processing of violations in the grammar, we manipulated the grammaticality (grammatical vs. ungrammatical) of the sequences; To ensure the process was general to nested sequences of different lengths, we also manipulated their level of embedding (LoE) (1 vs. 2). Results from 17 musicians (11 females) revealed increased activity in right inferior frontal gyrus, bilateral dorsolateral prefrontal cortex, anterior insular cortex, and the pre-supplementary motor area for ungrammatical sequences, and increased activity in bilateral inferior parietal lobules and the dorsolateral prefrontal cortex for increased LoE. Our findings establish the functional neuroanatomy of processing nested hierarchical sequences in music and suggest that the functional neuroanatomy of hierarchical processing in music is a mirror image of that in language.

I-12

Graessner, A.

Interactions in the semantic network in understanding minimal word combinations

The ability to combine single words to form complex new meanings (i.e., semantic composition) is a core feature of the highly productive human language faculty. Despite growing interest in the neural correlates of semantic composition, little is known about the functional neuroanatomy at the most basic combinatorial level, such as the processing of two-word phrases. The few studies that focused on such minimally complex phrases found task-related activation in the left anterior inferior frontal gyrus (IFG, BA45), left anterior temporal lobe (ATL) and left angular gyrus (AG). In order to scrutinize the role of the AG in the processing of minimal combinatoric phrases, we conducted a preliminary meta-analysis on two-word studies and found a differential involvement of anterior and posterior portions of the AG, with the anterior part being more engaged by the processing of two-word versus one-word stimuli. The purpose of the planned project is to describe the interactions in the semantic network involved in understanding minimal word combinations by means of functional MRI. Participants will perform a picture-matching task on auditorily presented adjective-noun pairs (e.g. red car) compared to a single-word control condition, with unintelligible speech preceding the noun (e.g. XXX car). We expect to find a left-hemispheric temporo-fronto-parietal network comprising BA45, ATL and AG. Moreover, we aim at delineating task-specific interactions within this network by employing effective connectivity analyses. Based on our meta-analysis, we cautiously hypothesize that the anterior AG will increase its functional connectivity with the other semantic core regions during the processing of two-word combinations.

I-13

Lanzoni, L.

The impact of context in flexible semantic retrieval: Exploring the role of contextual cueing in shaping retrieval of ambiguous words in semantic aphasia

Spatial contexts and emotion are known to be powerful retrieval cues in episodic memory, but their contribution to the accessibility of conceptual knowledge has not been widely investigated. We examined the effect of such cues in both healthy participants and patients with multimodal semantic deficits who have deficient control over semantic retrieval following left prefrontal and temporo-parietal infarcts. We characterised the effects of emotional facial expressions (Experiment 1), emotional prosody (Experiment 2) and visuo-spatial context images (Experiment 3) on the retrieval of dominant and subordinate meanings of ambiguous words. Consistent with previous findings, the patients showed greater deficits when the subordinate meaning of ambiguous words was probed, and they also showed stronger effects of cueing and miscuing: i.e., better semantic retrieval when the face, voice or context image was consistent with the relevant interpretation of the ambiguous word, and poorer retrieval when the cue matched the alternative meaning. These findings are consistent with the proposal that external constraints on semantic retrieval reduce the control demands of semantic tasks. They reveal an important role for visuo-spatial contextual information and emotional signals across modalities in verbal semantic retrieval. Moreover, they indicate that people with semantic control deficits rely on such cues to guide their semantic interpretations: these patients will be vulnerable to misinterpretations when meaning is not grounded in the physical environment and when emotional expressions are at odds with the message being communicated

Memory, Sleep, and Executive Function

I-14

Balduin, S.

Speeding up recognition: Effects of tDCS on the dominant hand in a verbal memory task

Anodal tDCS of temporal areas facilitates memory and recognition processes in participants with memory deficits (Boggio et al., 2008; Ross, McCoy, Wolk, Coslett, & Olson, 2010). We explored the influence of 20 minutes of anodal tDCS on the left temporal cortex in a single session in a group of right-handed healthy young subjects (16f, 12m; 20-33y, ∅=24.9y). Participants were to memorize auditorily presented words in a learning phase. After that, they were to recognize single words out of several distractors (semantically or phonologically related words) via button press. The button press to signal the recognition of words or refusal of distractors was balanced between hands. Reaction times in the memory task varied depending on the answer the dominant hand gave (F(1;20) = 6.9; p = .016). While the recognition of stimuli indicated by a reaction with the dominant right hand led to a tDCS induced facilitation of recognition, this is not true for the left hand. Furthermore, the refusal of distractors with the right hand led to longer reaction times, while the refusal with the left hand led to shorter ones. One possible explanation for the divergence in reaction times could be a preference of each hand for specific tasks. Studies show a preference of right-handers to associate positive values with their right hand side, which is also reflected in increased reaction times (Casasanto, 2009; de la Vega, Graebe, Härtner, Dudschig, & Kaup, 2015). The application of tDCS might strengthen this preference.

I-15

Busack, I.

How do worms think when they sleep?

Little is known about the functions of sleep and the mechanisms behind those. Sleep seems to be important for memory storage and consolidation (Nguyen et al., 2013), the immune system (Zager et al., 2007) and other biological processes. It is highly conserved among species (Cirelli, Tononi, 2008). This research uses the nematode Caenorhabditis elegans as a model system to study the regulation and functions of sleep. C. elegans sleep four times during their development, every time before molting into the next developmental stage (Raizen et al., 2008). Furthermore, they sleep upon starvation or stress induction (You et al., 2008). Their nervous system is comprised of 302 neurons and easily accessible due to their transparency (Altun, Hall, 2011). The GABAergic, peptidergic interneuron RIS is a known sleep-active neuron (Turek et al., 2016). Worms for which RIS was ablated do not show quiescence (Turek et al., 2013). In addition, a mutant of the aptf-1 gene, which is expressed in RIS, does not sleep and transcriptome analysis of this mutant allowed identification of FLP-11 neuropeptides to be involved in sleep regulation through RIS (Turek et al., 2016). Calcium imaging was done to determine the overall neuronal activity for worms. Wild type neuronal activities for sleep and wake times were compared to the neuronal activities of sleep-impaired worms to show what effects sleep has on the nervous system. This may lead to more insights about the function of sleep in C. elegans and its regulation, which are likely to be conserved in other species.

I-16

Cerrato, A.

E-BTT: An integrative tool to assess unilateral spatial neglect with tangible interfaces and AI

Neuropsychological tests tend to be laborious and time-consuming, not motivating participants enough; these problems can be overcome recreating digitalized versions of original tests, favouring higher engagement level of the participants. A neuropsychological disease that can be evaluated with digitalized tests, is the Unilateral Spatial Neglect (USN), a visuospatial cognition impairment. A sensitive task to assess USN is The Baking Tray Task (BTT), a test well-suited to be reproduced in a digital version; BTT consists in disposing 16 small cubes, “as if they were buns on a baking tray” (Tham & Tegner, 1996). In this respect, we developed our Enhanced BTT version (E-BTT) using the STELT (Smart Technologies to Enhance Learning and Teaching) platform, a software developed for the implementation of augmented reality modules based on RFID/NFC technology (Miglino et al., 2014). This methodology, adopting tangible interfaces (in our case: the real manipulation of cubes to spread over a board), allows, in unique manner, to connect the physical perspective and the digitalized one. The project is divided in three stages: the development of the software, the evaluation of the E-BTT made by clinicians (required to provide digital prototype patterns of BTT disposition), the administration of E-BTT to patients. Moreover, we aim to develop an Expert System, comprising of AI and Machine Learning modules, analyzing the patterns of the cubes, as placed by participants of the E-BTT. Ultimately, the system will be able to discriminate between: the absence of any visuospatial disorder, the presence of USN, the existence of other visuospatial impairment.

Neuroanatomy and Connectivity

I-17

Qi, T.

Gray matter structural covariance changes in brain development

This study analyzed structural covariance networks in children and adults, comparing 4 age groups from age 5 years until adulthood with a special focus on language-associated cortical regions and their covariance networks. Language comprehension, especially the processing of the complex sentences, is associated with neural activation in the left inferior frontal gyrus (IFG) and the superior temporal cortex (STG). Little is known so far about the structural covariance (SC) of these cortical regions and their changes during brain development. Here, structural magnetic resonance imaging (sMRI) data of 65 five-year-old children, 24 six-year-old children, 27 adolescents (age range 9-13) and 34 adults (age range 19 to 33) were collected. Structural covariance analysis was performed to examine the SC changes from preschool children to adults and whether SC is modulated by behavioral language performance. Our findings show that, first of all, age was associated with increased SC in the left IFG and the left insular in children. Furthermore, the language relevant seed-based SC results demonstrated that increasing age was associated with greater structural co-variation in fronto-temporal regions. This finding was further supported by a group comparison of SC between adults and children. Finally, SC between left IFG and left STG was positively modulated by sentences comprehension scores already at preschool age. These findings provide anatomical evidences for developmental changes in fronto-temporal brain structural co-variation that is furthermore associated with language development.

I-18

Baczkowski, B.M.

Beyond the salience network: Threat-induced brain activation unfolds from salience to default mode regions

An adaptive response to threat requires the brain to flexibly adjust large-scale patterns of its activity. Human threat-conditioning studies carried out with functional magnetic resonance imaging (fMRI) have associated an immediate response to threat with activation of the salience network. However, its subsequent impact on other brain systems is less known. To characterize how the brain responds to threat in a time-varying fashion, we performed a Pavlovian threat-conditioning task in 29 healthy individuals and estimated whole-brain fMRI activity over a fifteen-second epoch after the onset of a stimulus. We found that, in contrast to safety cues, threat-related cues induced a typical and early activation in cingulo-opercular regions of the salience network. Late activation was observed in regions of the default mode network, specifically the dorso-medial/-lateral prefrontal and temporal cortex. The transient shift between the two networks was accompanied by the intermediate activation of right dorso-lateral prefrontal and parietal regions, which belong to the cognitive control network. We conclude that threat triggers a coordinated brain response that unfolds temporally over multiple large-scale functional systems. Such flow of activation might progressively integrate internal and external information to promote adaptive behaviour in the face of environmental challenges.

I-19

Ballarini, T.

Brain connectivity changes induced by dopaminergic therapy in Parkinson’s disease

Introduction: Dopamine therapy (DT) is the most common treatment for Parkinson’s Disease (PD). Our aim was to investigate the still unclear effects of prolonged DT on brain connectivity. Methods: Thirty-one PD patients (age: 64.74±7.76 years mean±SD) under DT for several years were assessed through structural and resting-state functional MRI, both under their optimal treatment (PD-ON) and after withdrawal (PD-OFF). Thirty age and gender matched healthy controls (HC) were also included. Eigenvector Centrality Mapping was used to identify brain nodes with high connectivity that are in turn linked to central nodes in the network. Then, to investigate specific pattern of region-to-region connectivity, seed-based analysis was performed. Statistical comparisons revealed connectivity changes within the patient group and between patients and controls (p<0.05 FWE at cluster level). Results: DT effectively improved clinical symptoms. PD-OFF patients, compared to HC (i.e. disease effect), showed increased connectivity in cortical sensorimotor areas, extending to the cerebellar-thalamo-cortical pathway and parietal and frontal cortex. DT suppressed this abnormal increased connectivity. PD-ON patients showed less functional connectivity as compared to PD-OFF (i.e. treatment effect) in the lentiform nuclei, precuneus, supplementary motor and sensorimotor areas bilaterally. Similarly, decreased connectivity was found comparing PD-ON with HC, with maximum overlap in the lentiform nuclei. Seed-based analysis revealed that DT reduced connectivity in both motor and default mode networks. Conclusion: Prolonged DT administration mainly decreases the connectivity of key structures of the motor and default mode networks that are abnormally elevated in the OFF state. MLS and RJ equally contributed to this work.

I-20

Chiappini, E.

Grounding motor resonance in PMv-M1 connectivity

Years of research on the putative human mirror neuron system (MNS) has shown that watching other’s actions induces “motor resonance” (MR) phenomena in the observers’ motor system. Compelling evidence from TMS studies showed that seeing actions increases the amplitude of motor-evoked potentials (MEPs) for those muscles that would be recruited when performing the same action. Such MR phenomenon is highly plastic and reflects the facilitatory influence that the ventral premotor cortex (PMv, a core region of the MNS) exerts over the primary motor cortex (M1). Yet, it is still unknown whether MR is amenable to changes driven by exogenous plastic modifications of PMv-M1 effective connectivity. To address this issue, we used a novel TMS protocol named cortico-cortical paired associative stimulation (ccPAS) to induce Hebbian-like plastic strengthening of the PMv-to-M1 connectivity and verified its effect on MR. Specifically, we tested whether MEPs recorded by M1 stimulation during action observation changed after ccPAS. 45 participants were randomly assigned to 2 different ccPAS active conditions (aimed at either increasing or decreasing PMv-to-M1 connectivity) or a sham ccPAS. Enhanced MR, intended as increased M1 sensitivity to the observed action, was selectively evidenced in the ccPAS group with optimal parameters to increase PMv-to-M1 connectivity and returned to baseline values 20 minutes after ccPAS. No similar effects were observed in the other groups. These findings highlight the functional relevance of PMv-to-M1 connectivity in MR, and suggest that neuroplastic changes induced by ccPAS can disclose neural functioning within the motor nodes of the putative human MNS.

Neuroimaging Physics and Signal Processing

I-21

Georgi, J.

Validation of the two-pool diffusion model in post-mortem white matter using the CLARITY method

Water diffusivity in brain tissue is sensitive to the underlying microstructure but its biophysical basis is not yet completely understood. In previous MRI studies using high diffusion weightings, the signal attenuation was well described by a bi-exponential function, with two diffusion regimes of water assigned to a ‘fast’ bulk-like compartment and a ‘slow’ pool in contact with macromolecules. To more directly assess the influence from myelin membranes on the MR-diffusion signal, we performed experiments in post-mortem white matter samples exposed to the CLARITY technique. This method removes lipid-based structures in the tissue, which are replaced by a hydrogel mesh linked to proteins and nucleic acids while the brain structure is kept intact. The strong deviation from mono-exponential behavior despite ultra-short diffusion times of 2 ms in the native samples as well as the observation of two distinct signal fractions with activation energies differing by a factor of two is in line with previous reports and with the assumption of a two-pool diffusion model. The increase in water mobility after lipid removal indicates a strong interaction between water and membrane compounds. The slow diffusion pool disappears upon CLARITY treatment, allowing to assign this fraction to water between myelin lamellae. Our observations indicate that the effect of non-Gaussian behavior in experiments employing high magnetic field gradients and short diffusion times is strongly affected by the existence of two separate water pools.

I-22

Metere, R.

Effects of coil combination algorithms on quantitative susceptibility mapping

Purpose: Quantitative susceptibility mapping (QSM) estimates the relative magnetic susceptibility from phase images. If a coil array is used, data from multiple channels need to be combined using non-trivial algorithms, which can degrade the phase information when a reference scan is unavailable. Particularly, some coil combination methods produce pole artifacts. Here, we investigated how QSM results are affected by such image degradations. Methods: Complex gradient-echo images of the full brain were obtained at 3T from 22 healthy volunteers. The individual channel data were combined using: (i) the adaptive coil combination algorithm; (ii) a recently proposed virtual coil combination algorithm (based on singular value decomposition and ESPIRiT). The phase images from each method were used as input of the same QSM pipeline, and the resulting susceptibility maps were compared. Results: The phase images and the QSM results mostly differed around the pole artifacts, but some deviations were observed globally. This finding persisted for the group average. Conclusion: This study indicates that the coil combination algorithm can significantly affect QSM results, and images without pole artifacts are required for accurate group studies.

I-23

Kalloch, B.

Investigation of the influence of white matter lesions on the distribution of the electrical field during tDCS – an application of tDCS computer simulation

Transcranial direct current stimulation (tDCS) is a brain stimulation technique that employs two electrodes, which are non-invasively mounted onto a subject’s scalp, to apply a weak direct current stimulating certain brain areas to induce specific neurologic effects. However, general problems of utilizing tDCS as a brain stimulation technique are the relatively weak observable effects of the tDCS application and a high inter-subject variability of the effect strength due to individual anatomical characteristics. It is known that for a successful stimulation effect, the distribution of the electrical field within the patient’s head induced by the electrodes is vital. For these reasons, recent research tries to numerically calculate the distribution of the individual electrical field in the subject’s head during tDCS through computer simulations. A considerable amount of research effort is spent on further improving the detail of the models underlying the simulation. We have previously established a simulation pipeline for tDCS. This pipeline covers the whole process from preprocessing the MRI data to visualizing the resulting electrical field. Using this pipeline, we investigate the influence of lesions of the white matter which are common in elderly people on the distribution of the electrical field during a tDCS application. The simulation pipeline was extended by a semi-automated segmentation approach for segmenting the white matter lesions. To investigate their influence the electrical properties of the lesions are systematically varied. First results show a clear influence on the field strength in the areas proximal to the lesions sites, but only a weak effect on cortical regions.

I-24

Waschke, J.

Visualization, exploration, and comparison of DTI tractograms using edge bundling

Diffusion tensor imaging is a non-invasive in-vivo imaging technique that can provide insight into macroscopic brain connectivity, but the output data is rather complex and not intuitively comprehensible. These difficulties of understanding are exacerbated when two datasets, like pre and post treatment screenings, should be compared. Comparing two datasets based on their tractograms is hardly possible as thousands of streamlines must be considered. Typical problems are navigation and orientation difficulties caused by occlusion. We present a method to facilitate the navigation through streamline sets and enable comparison of two datasets in one image. We minimize occlusion by clustering the streamlines based on magnet-like forces, resulting in a skeleton-like representation, and allow the user to interactively explore regions of interest in detail.

I-25

Zarubin, G.

Development of a tACS-EEG closed loop system in order to understand and utilize the neuromodulatory role of tACS

Introduction

We develop a closed loop EEG-tACS system in order to better understand mechanisms of tACS and further increase effects by tuning adaptively parameters such as onset time, phase, amplitude, frequency and duration of the stimulation to each individual. Here we present our initial model and preliminary results from offline data, which prove, that concept can be developed and applied for adaptive stimulation.

Methods

The system consist of following elements: EEG device (different amplifiers, BCI2000), application in C++, DAQ device for transmitting stimulation signal, tACS device. Taking into account fast dynamics of alpha phase changes, we consider short intervals (<=1 sec) of imaging and stimulation. The system runs in cycles: getting EEG data (imaging interval), extraction phase values and determining optimal phase shift for stimulation (optimization interval), sending signal (stimulation interval) through DAQ device on stimulator. We use and evaluate several methods for prediction of stimulation, two modes of stimulation are currently implemented – “In Phase”, “Opposite Phase”.

Results

Preliminary results are represented in terms of following measures: optimization time (ms), (for offline data): relative accuracy (based on relation to optimally possible stimulation), phase difference (Euclidean distance between instantaneous phase values), Phase Locking Value.

Discussion

Closed loop tACS is essential for tuning stimulation parameters and investigation of stimulation effects. Presented model is ready for basic adaptive stimulation experiments, however, there are many critical issues, which should be considered and solved such as choice of electrodes, preprocessing and filtering data, number of optimization parameters, length of intervals, compensation of different delays.

Social Cognition and Emotions

I-26

Belham, F. S.

Brain activity related to emotional reinterpretation in younger and older adults

Evaluative conditioning refers to the transfer of valence from emotional to neutral stimuli by pairing the two. This emotional reinterpretation has been related to memory, with literature suggesting reinterpretation only occurs when the pairing can be remembered. It is, however, unclear what processes underlie evaluative conditioning. Here, we tested the effects of ageing on brain activity associated with the emotional reinterpretation of neutral information, since older adults are better at adding positive valence to events. Electrical brain activity was recorded while participants created positive or neutral sentences from neutral words on the basis of preceding cues. Participants then performed a source memory task, followed by a likeability task involving explicit ratings for each word. For both age groups, words used in positive sentences were better remembered and rated as more likeable than words used in neutral sentences. The creation of positive and neutral sentences was also associated with different brain activity over posterior scalp sites. This activity occurred between 150-250ms after word onset for younger adults, but persisted until 800ms for older adults. These duration differences may indicate the times during which emotional information captures attention in the two age groups. In younger adults, successful retrieval of positive valence elicited a larger late posterior negativity in comparison with retrieval of neutral valence. This may reflect a need to reconstruct the study episode to recollect valence. Together, our results support the idea that neutral information can take on positive valence, influencing behavior and brain activity differentially in younger and older adults.

I-27

Bitsch, F.

Neural basis of a social prediction error: Right temporo-parietal junction detects competitive intentions during social interaction

Inferring other humans’ goals and intentions can enhance the prediction of their subsequent behavior significantly. Such Theory of Mind (ToM) processes would then be functional when they inform decision making once a person’s intentions are highly important for oneself, as another cheats during a social exchange. This could be an evolutionary beneficial detection mechanism of competitive intents in order to avoid unequal payoffs and thus exploitation. Therefore, we predicted that during the detection of repeated selfish behavior brain regions within the ToM network, particularly the right temporo-parietal junction (rTPJ), are strongly activated. We tested our hypotheses using fMRI and a modified prisoner’s dilemma game where 20 participants interacted with three fictive counterparts who behaved according to three stable strategies either competitively, cooperatively or randomly during seven interaction blocks. The rTPJ and the posterior medial prefrontal cortex were stronger activated during the competitive compared to the cooperative interaction. Only the rTPJ showed a high response in the early and reduced responses in later interaction phases, indicating a detection mechanism of the person’s competitive intents. Enhanced functional connectivity between the rTPJ and the left hippocampus, suggests that ToM processes are closely linked with social memory processes within this early period. Furthermore, a higher rTPJ-hippocampus connectivity in the early compared to the late phase was associated with participants' beneficial social learning during the experiment. Thus, the rTPJ may function as a social prediction error module that facilitates adaptive social behavior with its hippocampus coupling.

I-28

Canigueral, V.

Cognitive mechanisms behind the audience effect: Self, gaze and prosocial behaviour

The audience effect is a change in the behaviour of people caused by the belief that someone else is watching them. Previous research has shown that the belief of being watched increases pro-social behaviour and decreases eye-contact compared to the belief of not being watched. The recently proposed Watching Eyes effects model suggests that these changes take place due to a self-referencing effect when being watched by other people. However, a challenge when studying the audience effect is to build an experimental setting that allows for well-matched control and test conditions, which has been hardly accomplished before. Our aims are three-fold: 1) to develop a new paradigm that meets such requirement, 2) to test the effect of the belief of being watched on pro-social and eye-gaze behaviour, and 3) to test whether self-reference mediates this audience effect. In Experiment 1, participants performed two tasks measuring pro-social behaviour while they were recorded with eye-tracking. To complete the tasks, they used a fake video-chat interface: in one condition they believed the interaction was real, whereas in the other they were told the videos were pre-recorded. We found that “being watched” increased pro-social responses and decreased the percentage of looking time to the person in the video. In Experiment 2 (in progress) participants will use the same fake video-chat interface to complete two tasks measuring self-reference and pro-social behaviour. We hypothesize self-reference will be higher under the belief of being watched, and that it will correlate with the level of pro-social behaviour.

I-29

Fuhrmann, D.

Neural predictors of schoolwork-related impulsivity in adolescence

Impulsivity is thought to be higher in adolescence than in childhood or adulthood, which may in part be due to the protracted development of frontal brain regions implementing cognitive control during the second decade of life. There is a large degree of individual variation during adolescence both in terms of brain maturation and impulsivity, however. To better understand such individual differences we investigated whether schoolwork-related impulsivity predicts functional activation when inhibiting responses, particularly to appetitive social cues. We recruited 37 typically developing girls aged 14-15 and measured functional activation during an emotional go-no-go inhibition task using functional Magnetic Resonance Imaging. This task required participants to inhibit pre-potent responses to appetitive cues (happy faces). School-work related impulsivity was measured in self-report and in an out-of-scanner task. This task measured the ability to resist procrastination when completing schoolwork. We found that individuals with higher levels of schoolwork-related impulsivity showed higher inferior frontal activation when resisting responding to appetitive cues, highlighting the need to consider individual differences in development.

I-30

Langeloh, M.

Are we on the same wavelength? Brain-to-brain coupling during dyadic interaction between adults and infants

From very early on infants are sensitive to contingent social interactions (Striano & Reid, 2006). Recent EEG research found increased mu desynchronization associated with the mirror neuron system in 14-month-olds during a social imitation game with an adult (Reid et al., 2011). What makes contingent social interactions special and what happens in both brains during interaction? Adult research indicates that both parties mutually adapt their behavior to each other in an interaction. Phases of behavioral synchronization of hand movements were associated with increased interbrain synchronization in the mu band (Dumas et al., 2010). We aim to investigate whether there is brain-to-brain synchrony during phases of behavioral synchrony also between adult experimenters and infants. Fourteen-month-olds (N=22; 11 girls) will be tested in a within-subjects design with three conditions: Baseline, Contingent Imitation (CI) and Non-Contingent Action (NCA). Infants will sit opposite the experimenter while EEG of both parties will be recorded. In the Baseline condition, adult and infant will not see each other but observe the same moving toy. In the CI condition, the experimenter will contingently imitate salient elements of the infant’s movements and body posture. In contrast, in the NCA condition, the experimenter will incontinently show other random actions. We predict increased brain-to-brain coupling in the CI condition compared to Baseline and NCA and increased mu suppression in the infant’s brain on central channels in response to CI compared to Baseline and NCA. Possible implications of the results for adult-infant-interactions will be discussed.

I-31

Dirupo, G.

When pain appraisal is not based only on the patient. The role of social conformity in medical environment

Medical practitioners often underestimate pain in others, sometimes regardless of patients’ self-reports. We run four experiments (total N=120 participants) to assess whether this effect could be explained through the psychological mech- anisms underlying social conformity, according to which individuals adjust their opinions and behaviors according to those of their peers. Medical students and controls watched videos of facial expressions of pain and were requested to rate the pain unpleasantness felt by the person in the video. Subsequently, they were exposed to two independent social cues: the rating reported by the protagonist of the video and the average judgement of 20 emer - gency doctors on the same expression. 30 minutes after this session, participants were unexpectedly required to rate the same expressions again without seeing any social cue. Our measure of interest was difference between the first and the second rating. We found that participants adjusted their evaluation towards the social cue sig- naling the highest pain (regardless of whether it was from the protagonist or doctors: b = 0.17, t(3075) = 3.09, p = 0.002). This tendency, was significantly smaller in older medical students (Controls vs. OLD_Med b = -0.18, t(3073) = 2.41, p = 0.016; Controls vs. Young_Med: n.s.). Our data suggest that medical practitioners, when diagnosing pain, tend to take weight more the more conservative social cues. This effect is in the opposite direction as compared to the controls and medical education seems to play a central role. fMRI experiments are currently conducted to explore the neural mechanisms underlying this effect.

Poster Session II

Thursday, 13 July, 18:00-19:00

Poster Number

1st Author

Title with abstract

Action, Perception, and Motor Cognition

II-01

Schliephake, L.

The effect of direct gaze on the mechanisms of action control

II-02

Stuckenberg, M.V.

Stimulus probability modulates visually induced auditory expectations whereas task requirements have only minor impact

II-03

Bono, D.

Feeling space with teeth: A psychophysical study

II-04

Poyo Solanas, M.

Looking at the face and seeing the whole body. Neural correlates of face-body compounds

II-05

Hassanpour, S.M.

Foot somatosensory information contributes to quiet stance

Clinical Neuroscience

II-06

Schulz, C.C.

Neurobiological stress reactivity in youth: Relevance of maltreatment and social support

II-07

Grigoryan, K.A.

Neural signatures of sensorimotor performance: Characterisation and modulation via neurofeedback approaches

High-field Neuroimaging

II-08

Haenelt, D.

Layer-dependent BOLD of M1 during observed and actual finger tapping

II-09

Sanders, Z.

Malleability of cortical hand map following single digit nerve block

Language, Music, and Communication

II-10

Rocca, R.

Here and there around the brain: The role of extra-linguistic spatial representations in the comprehension of spatial deictics

II-11

van der Burght, C.L.

Processing syntactic and prosodic information during sentence comprehension

II-12

Vassileiou, B.

Syntax is the key to memorizing long sentences: The role of brain oscillations

Memory, Sleep, and Executive Function

II-13

Meyer, A.-K.

Intentional forgetting - caused by the disruption of suppressed memory traces?

II-14

Paulus, P.

Affective representations in medial prefrontal cortex

II-15

Reichert, M.

Executive Functions: Training and transfer effects

Neuroanatomy and Connectivity

II-16

Berger, P.

Personality modulates amygdala connectivity during humor appreciation: An event-related fMRI study

II-17

Mohavedian-Attar, F.

Identification and characterisation of short cortico-cortical association fibres in humans in vivo using diffusion MRI

II-18

Oligschläger, S.

Primary and limbic regions anchor the layout of long-range projections in the macaque monkey cortex
II-19

Zaragoza Jimenez, N.I.

Relationship between the sulcal pattern of the inferior frontal gyrus and individual tractography based parcellation

Neuroplasticity

II-20

Chien, S.-C.

Excitatory-to-inhibitory plasticity for sequence learning

II-21

Patel, D.

Repeated social stress in rats leads to contrasting patterns of structural plasticity in the amygdala and hippocampus

II-22

Paul, K.I.

Brain plasticity related to psychomotor skills in catheter-based interventions

II-23

Shih, P.-C.

Kinematic profiles and EEG-coherence differentiate mirror- from non-mirror movements in a bilateral circle drawing task

II-24

Uhlig, M.

Rapid brain changes in cortical midline structures after acute psychosocial stress

Social Cognition and Emotions

II-25

Mishor, E.

A putative social chemosignal may modulate aggression in humans

II-26

Puhlmann, L.

Longitudinal contemplative mental training differentially influences change in inflammatory cytokines and the neurotrophic factor BDNF

II-27

Schleihauf, H.

Overimitation - imitation for object-learning or imitation for social interaction - an fMRI study

II-28

Linz, R.

When your daily mental content resonates in your stress-system: Evidence for the association of stress-related thought patterns and cortisol levels in an everyday experience sampling study

II-29

Delplanque, J.

Repetition suppression of groups and stereotypes

II-30

Stojić, S.

Recognition of facial expressions: Can performance be dictated by levels of sex hormones?

 
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