Biology subjects

Chenani, A.

Publications and source records attributed to Chenani, A..

3 recordsLinked to original sources

bioRxiv2026

Comparison of place field detection methods and their effect on place field stability and drift in mouse dCA1.

BackgroundHippocampal place cells (PCs) undergo representational drift, i.e., a gradual change in their place fields despite unaltered behavior. While Ca2+ imaging enables long-term tracking of PC populations, distinct PC detection methods have been shown to yield different subpopulations of PCs, with only a few systematic comparisons between methods, especially in open arenas. New MethodWe provide an analysis protocol for one-photon PC data obtained during free foraging in two-dimensional arenas that allows us to compare two widely used PC detection methods, significance of spatial information (SI), and split-half correlation (SHC), and their effect on representational drift. The analysis is demonstrated on previously published Ca2+ data from dorsal CA1 of freely foraging mice, with cells tracked for 10 consecutive days. ResultsBoth criteria, SI and SHC, yielded proportions of approx. 17% PCs with only 40% overlap. SI-identified PCs demonstrated higher stability, higher rate map correlations, and a slower rate of representational drift than SHC-PCs. Comparison with existing methodsPrevious studies comparing SI and SHC PC detection methods in Ca2+ data did not focus on either open field behavior or representational drift. ConclusionOur results indicate that the choice of PC detection method significantly affects the estimate of representational drift in Ca2+ imaging studies.

neuroscience↗

bioRxiv2020

Aberrant structural synaptic dynamics precede disorganization of temporal and spatial coding in the hippocampus upon repeated stress exposure

Stress exposure strongly contributes to the pathophysiology of psychiatric diseases such as depression, schizophrenia, anxiety, and post-traumatic stress disorder. It also affects both function and structure of hippocampal CA1, leading to episodic memory impairment. Here, we used deep-brain optical imaging to elucidate the effects of stress on CA1 pyramidal neuron structural connectivity and activity. We tracked dynamics of dendritic spines during repeated stress and found decrease in spinogenesis followed by decrease in spine stability. In contrast to repeated stress, acute stress led to stabilization of the spines born in temporal proximity to the stressful event. To investigate the link between structural plasticity and activity patterns upon repeated stress, we studied the activity of thousands of CA1 pyramidal neurons in freely-moving. We found an increase in activity and loss of temporal organization followed by a disruption in temporal and spatial coding. Our data suggest that stress-induced sustained increase in activity leads to loss of structural connectivity and subsequent temporal and spatial coding impairments.

neuroscience↗

bioRxiv2019

Stability of excitatory structural connectivity predicts the probability of CA1 pyramidal neurons to become engram neurons

Neurons undergoing activity-dependent plasticity represent experience and are functional for learning and recall thus they are considered cellular engrams of memory. Although increase in excitability and stability of structural synaptic connectivity have been implicated in the formation and persistance of engrams, the mechanisms bringing engrams into existence are still largely unknown. To investigate this issue, we tracked the dynamics of structural excitatory synaptic connectivity of hippocampal CA1 pyramidal neurons over two weeks using deep-brain two-photon imaging in live mice. We found that neurons that will prospectively become part of an engram display higher stability of connectivity than neurons that will not. A novel experience significantly stabilizes the connectivity of non-engram neurons. Finally, the density and survival of dendritic spines negatively correlates to freezing to the context but not to the tone in a trace fear conditioning learning paradigm.

neuroscience↗