Neural circuits and pharmaco-physiology fundamental to neocortical dynamics in the macaque monkey

Neurons in the brain continuously undergo rhythmic oscillations in neuronal excitability. Interconnected neuronal groups synchronize their excitability oscillations, and they do so at different frequencies depending on behavioural state and task demands. Because excitability state determines whether neurons respond to sensory inputs, these grouped oscillations are critical to brain operations. Under high attentive conditions with sparse stimulation, neuronal groups synchronize activities at higher frequencies compared to awake quiescent states. However, many important environmental stimuli are themselves organized in rhythmic streams (e.g., the sounds of people and other animals walking and vocalizing), and in these cases, the input rhythm of the attended stream seems to dictate the frequency at which brain oscillatory rhythms entrain. Such cases have received little attention to date. Similarly the contribution of the brain’s neurotransmitter systems to attentional control of oscillatory entrainment is largely unknown. I aim to: 1) study rhythmic sensory processing in the auditory system of the monkey, and 2) describe how neurotransmitters contribute to attentional control of oscillatory entrainment, and thus to adaptive sensory processing and perception. Monkeys will be trained to alternate attention between concurrent rhythmic streams of stimuli, modelled after naturalistic events streams. Multielectrode laminar arrays will be used to record from numerous brain areas simultaneously to examine how specific neurotransmitter manipulations affect attention-related entrainment within localized neuronal ensembles, as well as between ensembles in different areas