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Identifier

000400411

Title

A computational study of place cell formation by grid cell convergence in a CA1 pyramidal neuron

Alternative Title

Μελέτη σχηματισμού "place" κυττάρου από τη σύγκλιση "grid" κυττάρων σε μοντέλο CA1 πυραμιδικού νευρώνα

Author

Πολλάλη, Ευαγγελία

Thesis advisor

Ποϊράζη , Παναγιώτα

Abstract

Pyramidal cells in the hippocampus, which are known as place cells, have been found to display a specific firing pattern which covers a restricted location of the environment. A plausible model for the formation of these cells is the convergence of multiple grid cells, from the Entorhinal Cortex, in the distal dendrites of CA1pyramidal neurons. The convergence of these grid cells and the formation of place cells depend on the interplay between a number of factors, such as the proportion of excitation and inhibition and theta rhythm. In order to examine the effect of these different factors, we used a biophysically constrained compartmental CA1 model neuron. We stimulated the neuron using grid-like patterns and studied the properties of the resulting firing fields. In addition, we examined the firing of the neuron under different levels of inhibition or excitation related to the timing of theta. We show that the presence and magnitude of inhibition, its modulation by theta rhythm and its relative firing phase compared to the theta rhythm determine place cell formation. Specifically, we found that inhibition can balance excitation, in a way that spikes occur mainly in a restricted location of the environment, the place field. Additionally, inhibition had greater effect when it was applied in the distal dendrites than when applied in proximal dendrites. Also, we found that in presence of theta modulation in all synapses it was more likely to form place fields. Thus, the theta rhythm coordinates excitation and inhibition in favor of place cell formation.

Language

English

Subject

Hippocampus

Δενδρίτες

Διάμεσοι νευρώνες

Issue date

2015-03-31

Collection

School/Department--School of Medicine--Department of Medicine--Post-graduate theses

Type of Work--Post-graduate theses

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