Biology subjects

Ciceri, S.

Publications and source records attributed to Ciceri, S..

3 recordsLinked to original sources

bioRxiv2026

Memory consolidation and representational drift

Memory consolidation is the process by which temporary, malleable memories are transformed into more stable, longer-lasting forms. On a coarse anatomical scale, consolidation redistributes memories in the brain, but it remains poorly understood how these changes manifest themselves on the finer, cellular scale of neuronal engrams and how they relate to the cognitive level. In this study, we developed a phenomenological model of engram dynamics under systems consolidation. The model describes consolidation as a brain-wide phenomenon, where memories deterministically follow a trajectory through a space of patterns distributed among brain regions. It captures a broad range of features of memory consolidation, including selective consolidation, semantization, and power-law forgetting. In the model, consolidation is accompanied by population-level changes in neuronal representations that resemble the widely observed phenomenon of representational drift. When only a subset of neurons is observed, the deterministic dynamics of the model can appear stochastic, and a readout of task features deteriorates over time even when a stable readout exists for the full system. Our model offers a dynamical systems perspective on memory consolidation as a distributed process, moving beyond the classic region-centered view, and provides a functional interpretation of drift as a means of redistributing engrams for improved memory retention.

neuroscience↗

bioRxiv2026

Innate development of cognitive functions and motor programs by chemoaffinity

Humans and animals are equipped with a rich innate repertoire of cognitive and behavioral skills [1-3]. Yet, the developmental programs that establish the underlying neural structures are unknown. During early development, neural connectivity is shaped by molecular axon guidance and cell adhesion programs that connect neurons based on the affinity between presynaptic receptors and postsynaptic ligands [4, 5]. Here, we show how such chemoaffinity-based connectivity rules can also establish innate cognitive functions and motor programs by structuring recurrent neuronal networks prior to experience. Different networks develop depending on the statistics of receptor and ligand expression. We illustrate this mechanism in computational models of chemoaffinity-based development that establish i) continuous attractor networks for path integration [6] with a toroidal grid cell topology [7], ii) networks with an exponentially large number of discrete attractors and sequences [8] as categorical, hierarchical, or temporal priors [9, 10], and iii) networks for arbitrary innate motor trajectories. Hence, chemoaffinity may shape not only the anatomical organization of the brain but also its innate cognitive and motor functions.

neuroscience↗

bioRxiv2023

The neural and computational architecture of feedback dynamics in mouse cortex during stimulus report

Conscious reportability of visual input is associated with a bimodal neural response in primary visual cortex (V1): an early-latency response coupled to stimulus features and a late-latency response coupled to stimulus report or detection. This late wave of activity, central to major theories of consciousness, is thought to be driven by prefrontal cortex (PFC), responsible for "igniting" it. Here we analyzed two electrophysiological studies in mice performing different stimulus detection tasks, and characterize neural activity profiles in three key cortical regions: V1, posterior parietal cortex (PPC) and PFC. We then developed a minimal network model, constrained by known connectivity between these regions, reproducing the spatio-temporal propagation of visual-and report-related activity. Remarkably, while PFC was indeed necessary to generate report-related activity in V1, this occurred only through the mediation of PPC. PPC, and not PFC, had the final veto in enabling the report-related late wave of V1 activity.

neuroscience↗