Biology subjects

Rezaei, Z.

Publications and source records attributed to Rezaei, Z..

4 recordsLinked to original sources

bioRxiv2026

Refinement and Retrospective Shift of the CA1 Place Code during Food-Carrying Decisions

Food carrying is an adaptive component of foraging that integrates resource evaluation with home-directed navigation, providing a naturalistic model for investigating how the brain organizes goal-directed behaviour. Despite extensive work on hippocampal coding during navigation and homing, how CA1 representations are reorganized when animals spontaneously transport acquired food home remains largely unexplored. We recorded dorsal CA1 population activity using one-photon calcium imaging with a V4 Miniscope while mice performed a self-paced foraging task in which food could be consumed at the acquisition site followed by a homeward return or carried to the home for consumption. Mice preferentially carried larger pellets, indicating that transport behaviour was sensitive to resource value. CA1 spatial coding differed systematically across behavioural outcomes. During carry-homeward runs, spatial representations were sparser, conveyed more spatial information, and showed greater trial-to-trial stability than during eat-inward runs, indicating a more precise and reliable place code during home-directed transport. Place fields also shifted forward during carrying, consistent with a retrospective bias toward recently traversed locations. By linking a self-generated food-handling decision to coordinated changes in the precision, stability, and temporal organization of CA1 activity, these findings extend hippocampal spatial-coding frameworks from trained navigation to ecologically grounded foraging behaviour.

neuroscience↗

bioRxiv2026

Ecological Suboptimality in Naturalistic Foraging: Amplified Deviation from Optimality in a Mouse Model of Alzheimer Disease

Adaptive decision-making extends beyond selecting among discrete alternatives. It requires the dynamic organization of actions as costs, opportunities, and goals evolve over time. Foraging captures this complexity in an evolutionarily conserved behavior that integrates spatial, temporal, and reward-related information across successive actions. These demands make foraging an ecologically grounded framework for investigating Alzheimer disease, in which spatial cognition, temporal organization, cost evaluation, and behavioral flexibility are frequently disrupted. We examined foraging-related action selection in control C57BL/6J mice and APPNL-G-F knock-in mice using a controlled task in which travel distance, food texture, and pellet size altered the costs and benefits of available strategies. Bayesian multinomial modeling showed that control mice flexibly redistributed their behavior across conditions, whereas APPNL-G-F mice showed impaired cost integration, increased withdrawal, and reduced behavioral flexibility rather than a generalized performance impairment. Comparison with a classical reward-rate-maximization benchmark revealed substantial suboptimality in both groups. Control mice achieved 53% of the predicted optimal reward rate, whereas APPNL-G-F mice achieved 45%. These systematic departures suggest that behavior was shaped by cognitive, motivational, or contextual constraints not represented in the normative model, with Alzheimer-disease-relevant dysfunction associated with greater suboptimality. Group differences were greatest when optimal behavior was highly sensitive to competing costs. By preserving the distribution of behavior across strategies, this study establishes foraging-related action selection as a sensitive framework for detecting disease-associated disruptions that may be obscured by conventional measures of choice or overall task performance.

neuroscience↗

bioRxiv2022

Inhibition is a prevalent mode of activity in the neocortex around awake hippocampal ripples

Coordinated peri-ripple activity in the hippocampal-neocortical network is essential for mnemonic information processing in the brain. Hippocampal ripples likely serve different functions in sleep and awake states. Thus, the corresponding neocortical activity patterns may differ in important ways. We addressed this possibility by conducting voltage and glutamate wide-field imaging of the neocortex with concurrent hippocampal electrophysiology in awake mice. Contrary to our previously published sleep results, deactivation and activation were dominant in post-ripple neocortical voltage and glutamate activity, respectively, especially in the agranular retrosplenial cortex (aRSC). Additionally, the spiking activity of aRSC neurons, estimated by two-photon calcium imaging, revealed the existence of two subpopulations of excitatory neurons with opposite peri-ripple modulation patterns: one increases and the other decreases firing rate. These differences in peri-ripple spatiotemporal patterns of neocortical activity in sleep versus awake states might underlie the reported differences in the function of sleep versus awake ripples.

neuroscience↗

bioRxiv2020

Prenatal Stress Dysregulates Resting-State Functional Connectivity and Sensory Motifs

Prenatal stress (PS) can impact fetal brain structure and function and contribute to higher vulnerability to neurodevelopmental and neuropsychiatric disorders. To understand how PS alters evoked and spontaneous neocortical activity and intrinsic brain functional connectivity, mesoscale voltage imaging was performed in adult C57BL/6NJ mice that had been exposed to auditory stress on gestational days 12-16, the age at which neocortex is developing. PS mice had a four-fold higher basal corticosterone level and reduced amplitude of cortical sensory-evoked responses to visual, auditory, whisker, forelimb, and hindlimb stimuli. Relative to control animals, PS also led to a general reduction of resting-state functional connectivity, as well as reduced inter-modular connectivity, enhanced intra-modular connectivity, and altered frequency of auditory and forelimb spontaneous sensory motifs. These resting-state changes resulted in a cortical connectivity pattern featuring disjoint but tight modules and a decline in network efficiency. The findings demonstrate that cortical connectivity is sensitive to PS and exposed offspring may be at risk for adult stress-related neuropsychiatric disorders.

neuroscience↗