Publication

Structure and function of the olfactory bulb microcircuit

Michele Pignatelli
2009
Theses

Abstract

The aim of this study is to contribute to understand the physiology of the Olfactory System through detailed microcircuit investigation, adopting advanced electrophysiological and anatomical techniques. Multiple patch clamp recordings allow understanding the structural foundations supporting the network architecture, the biophysical rules adopted by the microcircuit connectivity and the fine dynamic of the synaptic transmission. The study focuses on the Olfactory Bulb microcircuit as a first neuronal processor of sensory inputs. The excitatory elements of the Olfactory Bulb microcircuit are anatomically defined by affiliation to the same receptive field: the Glomerulus. A correlated subthreshold activity between microcircuit elements defines the physiological signature of the microcircuit. We experimentally addressed three fundamental issues: origin of the correlated subthreshold activity, connectivity rules and dynamic of the synaptic transmission. In the first study we attribute the origin of correlated subthreshold activity to a class of pacemaker cells responsible for the synchronization of the population onset and acting therefore as a timer of the microcircuit response. In the second study we investigated the connectivity rules supporting the interaction between excitatory cells. The tight apposition between gap junctions and chemical synapses on the excitatory cells dendrites allows gap junctions to propagate postsynaptic potentials toward surrounding compartments. The result of the propagation is represented by an enhancement in the amplification of the sensory information and an increase in the speed of the reaction time. In the third study we extensively analyzed the mechanisms of the synaptic transmission and the activity dependent properties of synapses, revealing a potential role for the short-term plasticity in the development of the sensory processing. The results of our investigation are going to constitute the foundation of a database available for high definition multi-compartmental modeling of the Olfactory Bulb network.

Official source

https://infoscience.epfl.ch/entities/publication/a9cb0de5-abb1-4710-9aff-a4712338a7ff

Michele Pignatelli
2009
Theses

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/a9cb0de5-abb1-4710-9aff-a4712338a7ff

Ontological neighbourhood

Biology

Cell biology: Neurotransmission

Related concepts (32)

Synapse

In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. Synapses are essential to the transmission of nervous impulses from one neuron to another. Neurons are specialized to pass signals to individual target cells, and synapses are the means by which they do so. At a synapse, the plasma membrane of the signal-passing neuron (the presynaptic neuron) comes into close apposition with the membrane of the target (postsynaptic) cell.

Sensory nervous system

The sensory nervous system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory neurons (including the sensory receptor cells), neural pathways, and parts of the brain involved in sensory perception and interoception. Commonly recognized sensory systems are those for vision, hearing, touch, taste, smell, balance and visceral sensation. Sense organs are transducers that convert data from the outer physical world to the realm of the mind where people interpret the information, creating their perception of the world around them.

Chemical synapse

Chemical synapses are biological junctions through which neurons' signals can be sent to each other and to non-neuronal cells such as those in muscles or glands. Chemical synapses allow neurons to form circuits within the central nervous system. They are crucial to the biological computations that underlie perception and thought. They allow the nervous system to connect to and control other systems of the body. At a chemical synapse, one neuron releases neurotransmitter molecules into a small space (the synaptic cleft) that is adjacent to another neuron.

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