Download program: LABMAN Program
Leonardo Cohen (NIH, USA), Valeria Della-Maggiore (UBA, Argentina, Maximo Zimmerman (INECO, Argentina), Claudia Vargas (UFRJ, Brazil)
“Neural and Neurophysiological Correlates of Motor Learning and Consolidation”
Julien Doyon (University of Montreal, Canada)
Nikolaas Oosterhof (CIMeC, Italy), Edson Amaro (USP, Brazil), Daniel Fraiman (Universidad San Andrés, Argentina), Patricio Donelly-Kehoe (CONICET, Argentina)
“Educators are natural neurocognitive enhancers. Moving on from research to practice”
Vivian Reigosa (Cuban Center for Neuroscience, Cuba)
Pablo Barttfeld (University Torcuato di Tella, Argentina), Eugenio Rodriguez (PCUC, Chile), Tristan Bekinschtein (Cambridge, UK), María Antonieta Bobes (CNEURO, Cuba)
“The connectome: Structure, Function and Evolution”
Yaniv Assaf (University of Tel Aviv, Israel)
German Campos Arteaga (PCUC, Chile), Silvia Kochen (IBCN, Argentina), Sergio Ruiz (PCUC, Chile), Tom Schonberg (University of Tel Aviv, Israel), Jorge Armony (Douglas Institute & McGill University, Canada)
Human Cortical Physiology and Neurorehabilitation Section, NINDS, NIH, USA
Effects of Reward on skill acquisition: Implications for Rehabilitation
Learning and retention of motor memories are dynamic processes that evolve over multiple behavioral stages: online learning, consolidation, and long-term retention. In humans, training under rewarded conditions is more effective than training under punished or neutral conditions in eliciting lasting motor learning. Interindividual differences in the effects of reward on performance are prevalent and poorly understood. In one study, we tested the relationship between reward dependence in a motor learning task and brain structure in healthy humans. Reward dependence was defined as the statistical trial-by-trial relation between reward and subsequent performance. We reported that regional gray-matter volume predicted reward dependence but not feedback alone. Multivoxel pattern analysis confirmed the anatomical specificity of this relationship. In ecologically valid settings, complex skills are acquired when mapping between actions and rewarding outcomes is not continuous and fixed but, rather, when it is variable and unknown. This results in reinforcement schedules of a stochastic nature or uncertain. In a second study, subjects trained on a motor task, as we manipulated reinforcement schedules (higher, lower or no stochasticity). The high stochasticity group learned more than the low stochasticity and the fixed reward groups, indicating that the enhancing effects of reinforcement on skill acquisition depend on reinforcement schedules. Thus, contrary to what might be assumed from normative models of valuation, humans who learn new motor skills do not maximally benefit from training schedules where successful performance is continuously reinforced. Rather, training with high levels of stochastic reinforcement benefits skill learning more strongly. These studies identified structural substrates of rewarded performance and suggest levels of stochastic reinforcement best fit to induce successful learning. More generally, this work suggests more successful reinforcement schedules that could impact neurorehabilitation.
IFIBIO Houssay – Department of Physiology, School of Medicine, University of Buenos Aires, Argentina
Functional and structural reorganization induced by sensorimotor adaptation
One of the most striking properties of the adult central nervous system is its ability to undergo changes in function and/or structure. In mammals, learning is a major inducer of adaptive plasticity. Sensorimotor adaptation is a type of procedural –motor- learning that allows maintaining accurate movements in the presence of environmental or internal perturbations by adjusting motor output. In this work I will present experimental evidence from longitudinal studies conducted at different time scales pointing to possible sites of plasticity associated with consolidation and near perfect long-term memory retention associated with this type of learning.
Institute of Cognitive Neurology, INECO, Buenos Aires, Argentina
Recovery of motor function and Brain Plasticity: New concepts in Neurorehabilitation
Relearning of motor skills is a fundamental process for recovering motor function after neurological injury. In this context, non-invasive brain stimulation (NIBS) techniques provide a powerful means to modulate the function of specific neural structures, and show potential for future application in the rehabilitation of eurological patients. Transcranial direct current stimulation (tDCS) is a well tolerated method that can be applied while the patient receives occupational or physical therapy and has been shown to induce prolonged excitability changes in cortical regions, resulting in LTP/LTD-like synaptic modifications, a cellular correlate of learning and memory.
Federal University of Rio de Janeiro, Brazil.
Mechanisms of brain plasticity induced by injury of the Brachial Plexus
In the study I will be presenting the effects of traumatic brachial plexus lesion with root avulsions (BPA) on the organization of the primary motor cortex (M1). Nine right-handed patients with a right BPA in whom an intercostal to musculocutaneous (ICN-MC) nerve transfer was performed had post-operative resting state fMRI scanning. The analysis of empirical functional correlations between neighboring voxels revealed faster correlation decay as a function of distance in the M1 region corresponding to the arm in BPA patients as compared to the control group. No differences between the two groups were found in the face area. We also investigated whether such larger decay in patients could be attributed to a gray matter diminution in M1. Structural imaging analysis showed no difference in gray matter density between groups. Our findings suggest that the faster decay in neighboring functional correlations without significant gray matter diminution in BPA patients could be related to a reduced activity in intrinsic horizontal connections in M1 responsible for upper limb motor synergies.
Functional Neuroimaging Unit, University of Montreal, Canada
Neural and Neurophysiological Correlates of Motor Learning and Consolidation
For the last 20 years, research in my laboratory has focused on investigating the behavioral, neuronal and neurophysiological determinants of motor skill learning and consolidation. During this presentation, I will first review some of our work focusing on motor sequence learning (MSL), which refers to the process by which movement elements come to be performed effortlessly as a unitary sequence through multiple sessions of practice. I will summarize the results of studies, which demonstrate that interactions between the cortico-striatal and cortico-cerebellar systems, as well as the the spinal cord, are critical for establishing the motor routines used to acquire new sequence of movements. I will then briefly discuss our studies, which show that the consolidation of such a memory trace depends upon greater functional integration of the cortico-striatal system and N-REM sleep spindle activity measured during the night following the initial training session.
Center for Mind and Brain Sciences, University of Trento, Rovereto, Italy
Aplication of machine learning to the analysis of Neuroimaging and Electrophysiological data: CoSMoMVPA
Recent years have seen an increase in the popularity of multivariate pattern (MVP) analysis of functional magnetic resonance (fMRI) data, and, to a much lesser extent, magneto- and electro-encephalography (M/EEG) data. To make analyses in these modalities more accessible to cognitive neuroscientists, I will present CoSMoMVPA, a lightweight MVPA (MVP analysis) toolbox implemented in the intersection of the Matlab and GNU Octave languages.
CoSMoMVPA can be used to address questions about neural organization and representations through state-of-the-art MVP analysis techniques, supporting various machine-learning techniques including classification and representational similarity analysis. It can read and write data in various data formats uses by popular cognitive neuroscience analysis packages. Exploratory data-driven analyses are supported in various dimensions (time, space, frequency), with generalized multiple comparison correction that combines Threshold-Free Cluster Enhancement with Monte Carlo-based permutation techniques. During the talk I will describe the history and key characteristics of CoSMoMVPA, and illustrate how CoSMoMVPA can be used to answer specific questions about neural representations.
School of Medicine, Department of Radiology, University of São Paulo
Using post-mortem modern imaging techniques to investigate human brain diseases
Since ancient times, autopsy has shown to be a very rich source of material and inspiration for the advancement of scientific knowledge. Latest technology development of in medical imaging techniques has resulted in an increase in spatial, contrast and functional resolution enabling researchers to look at the brain with previously unimaginable precision. Although it seems logical that the increased capacity to observe biological alterations results in better correlation, validations are, in general, based on technical image capabilities and proof-of-concept studies based on daily routine during clinical use of imaging equipment. There is a need for studying in depth the clinical correlation and notably, histological validation. We have established a program based in imaging, guided biopsies and image-processing techniques at the School of Medicine of the University of Sao Paulo (FMUSP). The PISA Project is a core-facility including natural death cases from the Death Verification Service to the city of São Paulo community, performing over 13,000 autopsies each year. In this talk we’ll show how PISA (a test-bed platform for validation) is helping us to understand new imaging technologies integrate them with molecular and pathological analysis. We will cover a few relevant points to disclosure the potential of this platform in the field of neuroscience and the main clinical applications from the findings will be explored and illustrated with examples of both normal and diseased human brain. In particular, preliminary results from a recent multicenter initiative illustrating the potential to translate results from this platform to in vivo neurological markers of white matter hyperintensities (WMH) will be depicted. We have used diffusion-tensor (DTI) images to probe white matter properties from both short postmortem interval brain specimens imaged in cranium. In this talk we will present the current results obtained by a method for point-to-point correlation allowing precise spatial matching between histology (including molecular and immunochemistry-based methods) and high resolution MRI. I’ll also highlight the main features of PISA and emphasize its potential for providing the histological basis for modern medical imaging, especially ultra-high field Magnetic Resonance Imaging. Finally, we will comment on the perspectives of PISA as a core-facility in Brazil equipped with a Multi-slice Computed Tomography, 7T MR whole body system and ultrasound installed at one of the Worlds largest autopsy centers in Latin America.
Department of Science and Mathematics, University of San Andres, Buenos Aires, Argentina
Statistical methods for the analysis of brain networks
The study of random graphs and networks had an explosive development in the last couple of decades. Meanwhile, techniques for the statistical analysis of these networks were less developed. In this work we focus on brain networks and study some statistical problems in a nonparametric framework. We address the following questions: Given one or more samples of brain networks, How to calculate a representative brain network? How to define a notion of variability for networks? How to identify a network outlier? How to test if two or more groups of networks have the same probability law? How to perform classification? Answers to these questions provide an important step in the development of potential neuroimaging-based tools for diagnosis. Finally, we show some applications to EEG and fMRI data.
Multimedia Signal Processing Group – Neuroimage Division at CIFASIS – CONICET
Using whole-brain modelling and brain dynamics to generate consistent functional metrics
Resting state fMRI has been the primary tool for studying the functional organization of the human brain. Most conventional resting state quantification techniques, based on Pearson correlations, have shown low test-retest reproducibility, making them unusable for clinical applications. Here we show an imaging-based technique capable of portraying information of local dynamics at a single-subject level reliably by using a whole-brain model that estimates a local bifurcation parameter, which reflects if a brain region presents stable, asynchronous or transitory oscillations. Here, I will show how this approach allows to examine individual global and local brain dynamics with high consistency and how it is possible to estimate the optimal scanning time. I will also show that brain hubs exhibit specific dynamics and that frontal areas have larger variations compared to other regions. Finally, I will demonstrate how this framework can be used to address clinical questions using as an example the effect of deep brain stimulation in Parkinson’s Disease. This framework can be used to study functional brain dynamics on an individual level, opening new avenues for possible clinical applications.
IBRO Keynote Speaker: Vivian Reigosa
Cuban Center for Neuroscience, La Habana, Cuba
Educators are natural neurocognitive enhancers. Moving on from research to practice.
Currently is widely accepted the existence of specific brain networks responsible to basic capacities which are close related with learning maths and reading. These capacities are observed early in the human infants and they are part of the “starter kit” for understanding numbers or written words. My talk will be focused in three main issues: 1) neurocognitive capacities and academic competence in typical and atypical development, 2) tools for screening, profiling and training the neurocognitive capacities, 3) new school-based programs for enhancing the neurocognitive development in K-12 learners. The implication of these issues for educational practices and policies will be discussed.
University Torcuato di Tella, INECO, Buenos Aires, Argentina.
Factoring the brain signatures of anesthesia concentration and level of arousal across individuals
Combining resting-state functional magnetic resonance imaging (fMRI) connectivity and behavioral analysis during sedation we factored out general effects of the anaesthetic propofol and a specific index of conscious report, participants’ level of responsiveness. The factorial analysis shows that increasing concentration of propofol in blood specifically decreases the strength of fronto-parietal cortical loops. In contrast, loss of responsiveness is indexed by a functional disconnection between the thalamus and the frontal cortex, balanced by an increase in connectivity strength of the thalamus to occipital and temporal regions of the cortex.
Pontifical Catholic University of Chile.
Mapping the mind on the brain: Past results and present research of the ‘Laboratorio de Neurodinamica Básica & Aplicada’
During the last years we have been trying to understand mind states as subserved by mechanisms of brain large-scale self-organization. Here I will summarize some of these results showing the theoretical reasons to believe that neural synchrony is involved in neural self-organization, along with a few experiments showing the involvement of neural synchrony in a) visual perception, b) conscious awareness, c) impaired perception in schizophrenia and d) the maturation of neural networks during normal development. Finally I will present the new lines of research conducted by other members of the lab.
Department of Psychology, University of Cambridge, UK
Cognitive fragmentation or change of processing mode? Taking decision while falling asleep
Cognitive Neuroscience is the attempt to integrate neurophysiology (nervous system physiology) and cognition (Psychology) in a single wide theoretical framework. In a series of experiments we have explored the physiological and cognitive changes of human participants during the transition from wake to sleep. TMS-EEG, bistable perception and metacognitive judgements experiments will be presented to illustrate the framework at hand. The perturbation with an electromagnetic pulse to the motor cortex elicits a cortical excitability change that, if strong enough, triggers a hand movement (through specific muscle activations). Our participants were instructed to press a button with the other hand to signal if they felt the muscle move or not (they knew it might be only a sound and not the pulse happening or also the TMS pulse). A behavioural curve per subject revealed that both threshold and slope change in when people when drowsy, and that there is a reduction in long-distance information sharing and brain integration on the process of falling asleep. IN the case of bistable perception, the same train of sounds feels (is perceived) sometimes like a horse galloping or as a “morse” signal. We found that both percepts showed different brain markers of information sharin g and complexity (measures of integration) but no differences in power amplitude of the brain EEG signals or the synchrony between brain areas. These specific changes reflecting the content of consciousness reported by the person are entirely driven by internal perception, with no change in the external stream of sounds. Finally, we showed that the performance of a perceptual discrimination task diminishes with drowsiness but the confidence on that performance remains the same. We coined it the “drunk effect”. The fragmentation of cognition and physiology in the transition to sleep shows variable patterns that seem to depend on the cognitive demands, and the individual differences. The method reveals itself as a good framework to study neurocognitive processes while keeping the external stimuli constant.
María Antonieta Bobes
Cuban Neuroscience Center, La Habana, Cuba
Dissociation of neural circuitry for conscious and unconscious processing of personally significant faces
Face recognition models postulate two independent streams of processing, one for personal semantic information and another for affective reaction to this identity. This idea comes mainly from double dissociation between conscious identity recognition (overt) and unconscious emotional response (covert) to familiar faces present in prosopagnosia and Capgras syndrome. However, the neural circuitry underlying overt and covert face recognition is still barely unknown. Two pathways, one (ventral) linking the Occipital and Fusiform Face Areas (OFA/FFA) and Anterior-Inferior Temporal (AIT) cortex and another (dorsal) linking OFA/FFA with more anterior areas of the emotional system, such as insula and orbitofrontal cortex could be candidates for underlying these processes. Here we use multimodal neuroimaging (VBM, fMRI and DTI tractography) to explore the integrity of the neural pathways underlying face processing system both in typical observers and in two patients: one case with prosopagnosia (showing signs of covert recognition), and another patient exhibiting Capgras syndrome, in whom the affective responses to consciously recognized familiar faces was absent. In the prosopagnosic patient, the ventral path was impaired, whereas the dorsal path to pre-frontal regions were preserved. The opposite pattern was present in the Capgras patient. These dissociated pathways could respectively support conscious and unconscious processes in these patients and possibly in normal face recognition. Finally, multivoxel pattern analysis (MVPA) was used in typical observers to decode emotional valences and familiarity in target areas of the two pathways. Valence was decoded accurately in areas of the posited covert pathway, whereas familiarity was decode accurately in areas of the posited overt pathway. These results provided neurophysiologic support t for dual path model of face processing.
Department of Neurobiology, University of Tel Aviv, Israel
The Connectome: structure, function and evolution
At every aspect of our lives – function determines structure. Just as new roads are built between developing cities, network wires are laid to adjust to faster communication demand and social networks are formed under a common goal of individuals, also the brain needs to remodel it’s connectome to adapt to the daily and continuous change in functional demands. The connectome refers to several functional and structural characteristics of brain connectivity that span from the micron level (neural circuits) to the macroscopic level (long scale pathways). This complex network (which includes the white matter but not only) is responsible for the information passage through different regions. If the integrity of the connectome is affected, the brain functions abnormally. Hence, the connectome is intrinsic to everything that the brain does.Without the ability to explore the connectome in-vivo, it was traditionally considered to be stable and fixed. Indeed, most effort in white matter research was invested in describing the geographical appearance of the network and the areas it connects.Magnetic resonance imaging (MRI) and specifically diffusion MRI opened, for the first time, a window into the in-vivo physiology of white matter and the connectome. By measuring micro-structural features of white matter there is a new opportunity to explore also its physiology and dynamics. In the presentation we will demonstrate how the connectome can be measured and what are its macro and micro-structural features, we will describe its evolutional characteristics by comparing connectomes of 100 different mammals and we will the role of the connectome in brain plasticity and how dynamic this feature is.
Germán Campos Arteaga
Pontifical Catholic University of Chile.
Neural signatures of modified declarative memories as result of reconsolidation process
It has been demonstrated that consolidated memories – when reactivated by the presentation of retrieval cues – can return to a labile state from which they must be re-stabilized during a process known as reconsolidation. During this phase, memories are susceptible to modifications, thus giving a unique opportunity for memory modulation. Despite the behavioral evidence, little research has been done on the brain mechanisms underlying memory reconsolidation in humans. Here, I will discuss about the neural signatures of disrupted and strengthened declarative memories as result of behavioral modulation of reconsolidation process, showing analysis of evoked potentials as psychophysiological memory markers.
IBCN, University of Buenos Aires, Center of Epilepsy El Cruce, Buenos Aires, Argentina.
Emotional memory: behavioral aspects and intracerebral recordings in humans
Several studies suggest that highly emotional information could facilitate long-term memory encoding and consolidation processes via an amygdala-hippocampal network. Our aim was to assess emotional perception and episodic memory for emotionally arousing material in patients with temporal lobe epilepsy (TLE) who are candidates for surgical treatment. We did this by using an audiovisual paradigm. Forty-six patients with medically resistant TLE (26 with left TLE and 20 with right TLE) and 19 healthy controls were assessed with a standard narrative test of emotional memory. The experimental task consisted of sequential picture slides with an accompanying narrative depicting a story that has an emotional central section. Subjects were asked to rate their emotional arousal reaction to each stimulus after the story was shown, while emotional memory (EM) wasassessed a week later with a multiple choice questionnaire and a visual recognition task. Our results showed that ratings for emotional stimuli for the patients with TLE were significantly higher than for neutral stimuli (p=0.000). It was also observed that patients with TLE recalled significantly less information from each slide compared with controls, with a trend to lower scores on the questionnaire task for the group with LTLE, as well as poorer performance on the visual recognition task for the group with RLTE. Emotional memory was preserved in patients with RTLE despite having generally poorer memory performance compared with controls, while it was found to be impaired in patients with LTLE. In this talk I will present data from a current single unit recordings study carried out in these patients showing individual responses associated with emotional memory.
Pontifical Catholic University of Chile. Santiago de Chile, Chile.
Brain Machine Interfaces based on fMRI and its application to Neuropsychiatric disorders.
Brain Machine Interfaces (BMI) refer to neurotechnologies and proceedings in which neuronal activity is measured and displayed in real time to allow the modulation of brain activity associated with a specific behavior or pathology. The physiological consequences of training with BMI could be considered as a form of endogenous neuronal stimulation for the modulation of behaviorally relevant neural networks (Birbaumer, Ruiz & Sitaram 2013 Trends in Cognitive Sciences, Sulzer, Sitaram et al 2013 Neuroimage, Ruiz et al., 2014 Biological Psychology). The relatively high resolution of functional MRI, has enabled the modulation of specific brain regions through BMI. My presentation summarizes some of the main achievements in BMI based on hemodynamic brain activity and its potential application to the study and treatment of developmental disorders and some neuropsychiatric disorders such as psychosis and anxiety.
School of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
New behavioral and imaging findings on a non-reinforced mechanism of behavior change
We recently developed a manipulation named the cue-approach task to influence choices of snack food items relying on non-reinforced mechanisms. In the task, a neutral tone and a button press are repeatedly associated with specific pictures of items in a session lasting less than 1 hour. In a subsequent probe phase participants choose between pairs of items where only one of the items in each pair was previously associated with the cue and button press. Replicated results show that this training leads to preference changes favoring the previously cued item and that these changes last up to several months. Functional MRI results show a value change signature in the ventro-medial prefrontal cortex during the choice phase. In this talk I will discuss new new studies where we were able to change preferences towards other stimuli such as faces and fractals which attest to the generality of the effect. I will discuss new imaging findings that reveal the putative mechanisms underlying this effect.
Douglas Institute & McGill University, Montreal, Canada
Neural correlates of recognition memory for emotional expressions
In this talk I will present a series of fMRI studies exploring the neural correlates of memory performance (accuracy and bias) in tasks involving emotional facial expressions in health individuals. I will also show how these paradigms can be used to study emotional function and dysfunction, as well as recovery, in psychiatric populations, specifically schizophrenia and post-traumatic stress disorder (PTSD). Finally, I will briefly discuss the similarities and differences in the emotional modulation of episodic memory across sensory modalities (visual and auditory) and domains within a modality (e.g., voice and music).