Figure 7.

Understanding how SK channels affect both spike frequency adaptation in tuning to second-order stimulus attributes. (A) Schematic showing a simple mathematical model based on the leaky integrate-and-fire formalism. Adaptation is implemented by feeding back a current whose time course decays after each action potential (i.e., the adaptation kernel). (B) Left: varying the adaptation strength in the model leads to tuning curves that are more and more high-pass. Right: when considering natural stimuli for which spectral power decays with increasing frequency, increasing adaptation strength initially leads to a progressive whitening of the response (i.e., the response power spectrum becomes more and more independent of frequency). There is then a given value of adaptation strength for which the response is white. Further increasing adaptation strength leads to a response whose spectral power will increase more and more steeply with increasing frequency (i.e., will not be white). (C) The white index displays a maximum when increasing adaptation strength.