Biology subjects

Kurth, A. C.

Publications and source records attributed to Kurth, A. C..

4 recordsLinked to original sources

bioRxiv2026

Spike-history gating of plateau potentials enables closed-loop rewriting of CA1 representations

Behavioral time scale synaptic plasticity (BTSP) allows hippocampal CA1 neurons to form or shift place fields after a single plasticity-inducing plateau potential, but what determines when individual neurons become eligible for another plasticity event remains unclear. Here we propose that recent somatic spike history provides a cell-specific gate for plateau initiation, making neurons sensitive to rising activity after relative silence while suppressing repeated plasticity during sustained firing. In a two-compartment spiking model of CA1, this gate interacts with entorhinal input to create a feedback loop in which existing representations bias subsequent plateau locations. The resulting dynamics produce gradual place-field drift, reward-associated overrepresentation, recovery of environment-specific representations after remapping, and cross-day reinstatement. Our model further predicts that stronger residual activity biases subsequent plateaus toward previous field locations, a relationship we identify by reanalyzing experimental data. Thus, the expression of neural representations can help determine when and where they are subsequently rewritten.

neuroscience↗

bioRxiv2025

Retinotopy constrains the topology of neural manifolds in macaque visual cortex

Cortical population activity often evolves along low-dimensional manifolds, shaped by external activity, task-demands and the underlying neuronal network structure. The structure of population activity has been studied across many brain areas and species. However, the influence of retinotopic organization in the structure of population activity of the primate visual cortex in vivo remains understudied. Here, we show that retinotopy in primary visual cortex (V1) determines the topological structure in neural population activity in the macaque. We analysed large-scale extracellular recordings from two macaques implanted with 896-channel Utah arrays in V1 performing a receptive field mapping task, with high-contrast moving bars. Isometric Mapping (isomap) applied to the neural population activity revealed a loop-like manifold. Persistent homology on 10-dimensional embeddings confirmed a single dominant one-dimensional loop. To test whether retinotopy alone can account for this structure, we constructed a minimal neural response model and simulated activity with the same stimuli as the macaque neural data. The model reproduced the loop-like topology observed in the brain. Taken together, the experimental and simulated data show that retinotopic maps naturally induce loop-like neural manifolds in response to moving stimuli, directly linking travelling waves and rotational dynamics. Our results provide a basis for further analysis on how neuronal populations encode and process visual information at the population level.

neuroscience↗

bioRxiv2024

Cell-type specific projection patterns promote balanced activity in cortical microcircuits

The structure of neural networks provides the stage on which their activity unfolds. Models of cerebral cortex linking connectivity to dynamics have primarily relied on probabilistic estimates of connectivity derived from paired electrophysiological recordings or single-neuron morphologies obtained by light microscopy (LM) studies. Only recently have electron microscopy (EM) data sets been processed and made available for volumes of cortex on the cubic millimeter scale, exposing the actual connectivity of neurons. Here, we construct a population-based, layer-resolved connectivity map from EM data, taking into account the spatial scale of local cortical connectivity. We compare the obtained connectivity with a map based on an established LM data set. Simulating spiking neural networks constrained by the derived microcircuit architectures shows that both models allow for biologically plausible ongoing activity when synaptic currents caused by neurons outside the network model are specifically adjusted for every population. However, differentially varying the external current onto excitatory and inhibitory populations reveals that only the EM-based model robustly exhibits biologically plausible dynamics. Our work confirms the long-standing hypothesis that a preference of excitatory neurons for inhibitory targets, not present in the LM-based model, promotes balanced activity in cortical microcircuits.

neuroscience↗

bioRxiv2023

Neural manifolds in V1 change with top-down signals from V4 targeting the foveal region

High-dimensional brain activity is often organized into lower-dimensional neural manifolds. However, the neural manifolds of the visual cortex remain understudied. Here, we study large-scale multielectrode electrophysiological recordings of macaque (Macaca mulatta) areas V1, V4 and DP with a high spatio-temporal resolution. We find, for the first time, that the population activity of V1 contains two separate neural manifolds, which correlate strongly with eye closure (eyes open/closed) and have distinct dimensionalities. Moreover, we find strong top-down signals from V4 to V1, particularly to the foveal region of V1, which are significantly stronger during the eyes-open periods, a previously unknown effect. Finally, in silico simulations of a balanced spiking neuron network qualitatively reproduce the experimental findings. Taken together, our analyses and simulations suggest that top-down signals modulate the population activity of V1, causing two distinct neural manifolds. We postulate that the top-down modulation during the eyes-open periods prepares V1 for fast and efficient visual responses, resulting in a type of visual stand-by state.

neuroscience↗