Journal of Neuroscience, Vol 7, 2488-2492, Copyright © 1987 by Society for Neuroscience
Synaptic responses of cortical pyramidal neurons to light stimulation in the isolated turtle visual system
AR Kriegstein
The resistance of the turtle brain to hypoxic injury permits a unique in
vitro preparation in which the organization and function of visual cortex
can be explored. Intracellular recordings from cortical pyramidal neurons
revealed biphasic responses to flashes of light, consisting of an early
phase (50-100 msec) of concurrent inhibitory and excitatory activation,
followed by a longer, inhibitory phase (250-600 msec) composed of summated
Cl- -dependent postsynaptic potentials mediated by GABA. This response
sequence results from the coactivation of pyramidal and GABAergic
non-pyramidal cells, followed by feed- forward and possibly feed-back
pyramidal cell inhibition, and is partly dependent on differences in the
membrane properties of pyramidal and non-pyramidal neurons.