Computational model

…All experimental models for seizure generation are based on the administration of drugs (e.g. pilocarpine), on artificial increase in the concentrations of extracellular K+ (Ko) or on direct electric stimulation, to name a few. However, all these approaches may not accurately reflect the in vivo conditions, where otherwise normal neuronal activity can generate occasional seizures. It is thus important to better understand the pathological changes that may be

Astrocytes play a crucial role in regulating synaptic strength and orchestrating synaptic plasticity, which is fundamental for learning and memory. However, the specific mechanisms by which astrocytes and their neuroactive transmitters, like D-serine, control these processes remain largely unexplored. D-serine, a co-agonist for the NMDA receptor, has garnered increasing interest as a potential regulatory molecule in synaptic plasticity. Given its activity-dependent release mediated by astrocytes, D-serine is a key player in balancing long-term synaptic depression (LTD) and potentiation (LTP) d

…our research, we employed a detailed computational model of a CA1 pyramidal neuron, considering both its morphology and biophysics. We aimed to elucidate how, and under what circumstances, such a neuron could encode a specific location based on the self-orga

Humans tend to repeat past actions, with habits as extreme case. With each execution of an action this repetition bias increases the probability to repeat this action. However, there is a lack of experiments investigating repetition bias.To test for the presence of a repetition bias, we developed a new sequential decision-making task (see Figure). For this task, participants had to collect points with four moves and meet a trial-specific goal as closely as possible. To ensure frequent repetition of at least one sequence of actions, we informed participants about a default action sequence that

…This study proposes a computational model to study how the mammalian brainstem implements sound localization: the ability to identify an acoustic source in the surrounding space. The main actors in sound localization are two brainstem nuclei: the medial and the lateral superior olive. We have reconstructed a model made of thousands of spiking

…To this end, a computational model of the retino-thalamic pathway was combined with an in-vitro model of cortical input layer 4. The latter was either a primary culture of cortical neurons or an acute horizontal brain slice of primary visual cortex. The two stages were interfaced optogenetically by e

…Here we present a computational model of two interconnected cortical areas and use it to study the impact of inter-areal connectivity on sensory processing. The model integrates a multitude of data from rodent primary somatosensory cortex and reproduces biological features across multiple scales: from tens of ion channel models and electrical types, to thousands of morphologically detailed neurons, to millions of stochastic synapses mediating local and long-r

…experiments aiming to build a computational model comprised of interconnected functional units, each performing a specific task-independent operation. The interaction between units and the readout of the system can be

Explicit similarity judgments tend to emphasize relational information more than do difference judgments. In this talk, I propose and test the hypothesis that this asymmetry arises because human reasoners represent the relation different as the negation of the relation same (i.e., as not-same). This proposal implies that processing difference is more cognitively demanding than processing similarity. Both for verbal comparisons between word pairs, and for visual comparisons between sets of geometric shapes, participants completed a triad task in which they selected which of two options was eith

During foraging, changes in sensory cues such as food odor drive changes in locomotor statistics, shifting animal behavior from dispersal to local search. While cue-evoked changes in locomotor statistics have been observed across species, the neural circuit mechanisms that govern locomotor statistics remain unclear. Here, we explore the neural encoding of locomotor statistics in Drosophila melanogaster. Analysis of walking trajectories following loss of an attractive food odor revealed multiple changes in locomotor statistics relative to baseline: a shift towards lower forward and higher an

The capacities to learn and to store memories are two of the most important functions of the brain, but these abilities are inherently at odds with each other. On one hand, a neuronal network must be flexible enough to quickly store new information, but on the other it must be stable enough to prevent old memories from being constantly overwritten. Metaplasticity in which the timescale of synaptic modifications made by an individual neuron changes could resolve this flexibility-stability tradeoff. We propose that this strategy may be implemented in the olfactory bulb (OB). A striking, characte

…We developed a computational model of human time perception based on tracking changes in neural activity across brain regions involved in sensory processing, using fMRI. By measuring changes in brain activity patterns across these regions, our approach accommodates the

Human behavior is known to be idiosyncratic, yet research in neuroscience typically assumes a universal brain-behavior relationship. Here we test this assumption by estimating the level of idiosyncrasy by compare two different aspects of brain function: task- and behavior-based activation. Human subjects (N=50) perform a perceptual task with confidence inside an MRI scanner. For each subject, task-based activation strength is estimated from blocks of 8 trials. We first show that task-based activation maps are both stable within an individual (r = 0.99) and similar across people (r = 0.59). Beh

…a full-blown developmentally plausible computational model of reading acquisition that has been implemented in English, French, Italian and German. The model can simulate individual learning trajectories and intervention outcomes on the basis of three component skills: orthography, phonology, and vocabulary. I will use the model to show how cross-language diffe

…We began by using a normative computational model of hearing to exami

Selection is the hallmark of attention: processing improves for attended items but is relatively impaired for unattended items. It is well known that visual spatial attention changes sensory signals and perception in this selective fashion. In the work I will present, we asked whether and how attentional selection happens across time. First, our experiments revealed that voluntary temporal attention (attention to specific points in time) is selective, resulting in perceptual tradeoffs across time. Second, we measured small eye movements called microsaccades and found that directing voluntary t

Current computational models of visual salience accurately predict the distribution of fixations on isolated visual stimuli. It is not known, however, whether the global salience of a stimulus, that is its effectiveness in the competition for attention with other stimuli, is a function of the local salience or an independent measure. Further, do task and familiarity with the competing images influence eye movements? In this talk, I will present the analysis of a computational model of the global salience of natural images. We trained a machine learning algorithm to learn the direction of the f