The role of the parafascicular complex (CM-Pf) of the human thalamus in the neuronal mechanisms of selective attention.

The reactions of 93 neurons in the parafascicular complex (CM-Pf) of the human thalamus were studied by microelectrode recording during stereotaxic neurosurgical operations in patients with spastic torticollis. High reactivity was demonstrated for two previously classified types of neurons with identical irregular (type A) and bursting Ca2+ -dependent (type B) activities in response to presentation of relevant verbal stimuli evoking selective attention in humans. Concordant changes in the network activity of A and B neurons were observed, in the form of linked activatory-inhibitory patterns of responses and the appearance, at the moment of presentation of an imperative morpheme of the command stimulus, of rapidly occurring intercellular interactions consisting of local synchronization with simultaneously developing rhythmic oscillatory (3-4 Hz) activity. Data are presented on the existence of a direct connection between these neuronal rearrangements and activation of selective attention, providing evidence for the involvement of the thalamic parafascicular complex (CM-Pf) in the mechanisms of selective attention and processing of relevant verbal information during the preparative period of voluntary actions.