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Synapses & Circuits


Neurons are highly specialized for communicating with each other. This communication takes place mostly at a unique anatomical structure: the synapse. Synapses are formed by a presynaptic nerve terminal, which releases chemical neurotransmitter in response to the arrival of an electrical action potential from the axon; the postsynaptic cell, in which neurotransmitter receptors, signaling molecules, and ion channels are concentrated; and the processes of glial cells, which participate in the uptake and metabolism of neurotransmitters and maintain ion homeostasis. Information is processed in the brain through vast networks of neurons that are specifically wired into synaptic circuits by the synapses among them. As many as 10,000 synaptic inputs from thousands of other neurons converge on a typical neuron and are then integrated by the postsynaptic cell. The result of this integration, action potentials, are then transmitted down the axon to the thousands of cells to which the neuron is synaptically coupled.

Members of the Synapses and Circuits focus group are engaged in research devoted to understanding how individual nerve cells communicate with each other at synapses and how the behavior of populations of synaptically connected cells is determined by this communication. Synapses and synaptic circuits in the healthy brain are essential for the functions of learning and memory formation, processing of sensory information, and determination of stereotypical behaviors. When the elements of certain synapses or synaptic circuits become abnormal or injure, there is considerable evidence that several important neurological diseases arise, including epilepsy, Alzheimer's disease, schizophrenia, chronic pain, mental retardation, and sensory deficits.

With the full decoding of the human genome, the biggest challenge has shifted to understanding what the function of the many gene products is and how these gene products work together to produce both the complex structure of the nervous system and the delicate web of molecular signals that underlie our impressive cognitive abilities. The members of this focus group are committed to unraveling these mysteries and to minimizing the devastating impact of the many neurological diseases in which synaptic dysfunction has been implicated.