Barcelona Computational, Cognitive and Systems Neuroscience (BARCCSYN 2026)

We recently proposed that the beta rhythm (15–30 Hz) provides a key aspect of routing information through the brain, namely, the formation of flexible, transient neural ensembles. We tested this hypothesis using spike and LFP recordings in non-human primates and MEG/EEG in healthy human participants performing a categorical decision-making task. We found that beta-band frequency shifts in frontal cortex signal categorical decision outcomes, with activity in these bands predicting the behavioral response. These results further substantiate the idea that beta provides the scaPolding for the formation of neural ensembles. We argue that beta frequency shifts arise from changes in connectivity between weakly coupled oscillators and that, more than a spectral fingerprint, they reflect an active mechanism to (re)-activate behaviorally relevant communication channels in the brain.

To understand adaptive behavior, we must understand how decisions are computed and updated through experience. For example, when facing a potential threat, animals may initially rely on instinctive responses, such as escape, yet with experience they can suppress these reactions as the environment is reinterpreted. In this talk, I will show how these transformations arise from interactions between cortical and subcortical circuits that dynamically reshape decision variables in aversive contexts.
Using an ethologically grounded paradigm in which mice escape from an overhead looming stimulus that mimics an aerial predator, I will show that repeated exposure leads to suppression of this instinctive response. We find that higher visual areas instruct this learning through projections to the inhibitory ventrolateral geniculate nucleus (vLGN). Neural population recordings reveal that specific vLGN neurons increase their activity across learning and are necessary for the expression of escape suppression, indicating that cortical inputs instruct learning, while plasticity within vLGN implements the learned behavioral change.
I will then extend this framework to show how vLGN integrates inputs from retrosplenial cortex and hypothalamic circuits to regulate decisions between safety and exploration. These pathways carry distinct signals related to prior experience and internal state, and their coordinated activity shapes when animals decide to leave safety. ogether, these results reveal circuit mechanisms through which experience reshapes decision-making in aversive environments.
Finally, I will present ongoing work showing how acute stress induces persistent changes in hippocampal dynamics, linking experience-dependent updating of threat with longer-lasting circuit adaptations that may be relevant for anxiety and PTSD.

Change is ubiquitous in living beings. In particular, the connectome and neural representations can change. Nevertheless, behaviors and memories often persist over long times. In a standard model, associative memories are represented by assemblies of strongly interconnected neurons. For faithful storage these assemblies are assumed to consist of the same neurons over time. We propose a contrasting memory model with complete temporal remodeling of assemblies, based on experimentally observed changes of synapses and neural representations. The assemblies and thus the memory engrams drift freely as noisy autonomous network activity and spontaneous synaptic turnover induce neuron exchange. The gradual exchange allows plasticity to conserve the representational structure and keep inputs, outputs, and assemblies consistent. This leads to persistent memory. We develop statistical physics-inspired descriptions to quantitatively model the drift of assemblies in single brain regions and throughout the brain. This allows to predict the future dynamics of the neurobiologically observed initial drift of memory representations. The results suggest that the brain operates in a regime where engrams drift, both deterministically and randomly, to induce their emergent redistribution and thereby the consolidation of memories.