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Sequence of events following addition of a surround stimulus to a center stimulus in an inhibition-stabilized network model of primary visual cortex. The
circuit consists of a population of excitatory neurons (E) that recurrently excite one another, and a population of inhibitory neurons (I) that recurrently inhibit
one another (red/pink synapses are excitatory, black/grey synapses are inhibitory). The excitatory cells excite the inhibitory neurons, which in turn provide
feedback inhibition to the excitatory cells. Stronger colors indicate higher levels of activity of a neuron or synapse. At all times the network receives a
steady input driven by a steady center stimulus (not shown). The plot below is a continuous-time plot of excitatory and inhibitory firing rates. The points in
time at which conditions A–D occur are indicated. (Adapted, with permission, from Ozeki et al. 2009.)
Source: Theoretical Approaches to Neuroscience: Examples from Single Neurons to Networks, Principles of Neural Science, Fifth Editon
A. The circuit before the addition of the surround input. The populations are firing at steady rates in response to the center stimulus. The surround input is
Citation: Kandel ER, Schwartz JH, Jessell TM, Siegelbaum SA, Hudspeth AJ, Mack S. Principles of Neural Science, Fifth Editon; 2012 Available
not yet activated.
at: http://mhmedical.com/ Accessed: May 10, 2017
B. After the surround
is activated
at 50Education.
ms, inhibitory
firing reserved
rates initially increase.
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C. This additional inhibitory input drives down excitatory firing rates, resulting in withdrawal of recurrent excitation from both excitatory and inhibitory