CHATTERING CELLS - SUPERFICIAL PYRAMIDAL NEURONS CONTRIBUTING TO THE GENERATION OF SYNCHRONOUS OSCILLATIONS IN THE VISUAL-CORTEX

In response to visual stimulation, a subset of neurons in the striate and prestriate cortex displays synchronous rhythmic firing in the gamm a frequency band (20 to 70 hertz). This finding has raised two fundame ntal questions: What is the functional significance of synchronous gam ma-band activity and how is it generated? This report addresses the se cond of these two questions. By means of intracellular recording and s taining of single cells in the cat striate cortex in vivo, a biophysic ally distinct class of pyramidal neuron termed ''chattering cells'' is described. These neurons are located in the superficial layers of the cortex, intrinsically generate 20- to 70-hertz repetitive burst firin g in response to suprathreshold depolarizing current injection, and ex hibit pronounced oscillations in membrane potential during visual stim ulation that are largely absent during periods of spontaneous activity . These properties suggest that chattering cells may make a substantia l intracortical contribution to the generation of synchronous cortical oscillations and thus participate in the recruitment of large populat ions of cells into synchronously firing assemblies.