How the Cortex Controls Thalamically-Generated Oscillations

Thursday, January 22, 1998 - 2:00pm - 3:00pm
Keller 3-180
Alain Destexhe (Laval University)
Since the forties, it has become clear that the thalamus is essential in the genesis of sleep spindle oscillations in the 10-14 Hz frequency range. In 1962, Andersen and Eccles identified for the first time one essential property of thalamic neurons: the ability to produce a burst of action potentials in response to inhibitory inputs. It was proposed that the interaction between thalamic cells and inhibitory neurons makes an oscillator, a principle still valid today. With the more recent and more precise data from intracellular recordings in vivo and it in vitro, thalamic oscillations have been thoroughly explored and dissected in detail. The underlying ionic currents and their biophysical properties were characterized, allowing to build computational models of thalamic circuits. The complex interactions that take place in these circuits, implying a variety of ionic currents and synaptic receptors, will be reviewed here.

The focus of the present research is directed to thalamocortical interactions. The questions that will be discussed are:

Can corticothalamic feedback control thalamic oscillations?

How is large-scale synchrony generated in the thalamocortical system

Can a similar mechanism be applied to explain the genesis of pathological behavior, such as epilepsy ?

What possible physiological roles can be drawn for these oscillations?