Methods for studying the conductance changes associated with synaptic activation of forebrain slices: the interpretation of field potentials using CSD profiles

Abstract

In this report the cortical slice preparation and an array electrode that instantaneously records laminar field potentials are used to evaluate issues related to the interpretation of cortical CSD profiles. The major issues are: (1) what cell types are responsible for producing the source/sink pairs seen in CSD profiles; (2) what neurotransmitters are responsible for producing the sinks/sources seen in the CSD profile and do the sinks/sources reflect activation of receptors that produce inward currents, outward currents, or both; (3) can active and passive currents be distinguished; (4) do action potentials contribute to the CSD profile; and (5) can synaptic population with different kinetics and onset latencies be distinguished? Methods for analyzing neuronal circuits and analyzing CSDs quantitatively are discussed.