Disorders of decision-making behavior such as attention-deficit and hyperactivity disorder (ADHD) and obsessive-compulsive disorder are thought to result in part from abnormalities in the function of prefrontal """"""""executive"""""""" circuitry. Yet few laboratories have recorded simultaneously from task-related sensory, prefrontal and motor areas to determine the millisecond-scale interactions among them as rats or monkeys perform choice-making tasks. Our long-term goal is to understand normal information flow through cortical and subcortical circuits involved in decision-making, ultimately to shed light on executive disorders, by using rodent """"""""decision-making"""""""" behavioral tasks; multisite, multielectrode recordings; and dopaminergic manipulations. The proposed studies will track information flow at the multi-single unit and local field potential levels across multiple components of rats' sensory, """"""""executive,"""""""" and motor circuitry as they perform a task in which, after a short delay, they have to press a lever (GO trials) or not (NO-GO trials) depending on which of two olfactory cues they have just sniffed. Preliminary data from our laboratory suggests that upon sniffing the GO odor but not the NO-GO odor, (1) a brief broadband (1-90 Hz) signal is sent from the primary motor cortex (M1) to the posterior piriform cortex; (2) this signal is followed by resonant though transient (>100 ms) 40-90 Hz oscillations in both areas; and (3) the firing rate of a large subpopulation of cells in olfactory and motor areas is strongly and transiently (< 100 ms) inhibited just prior to activation of motor areas as the paw is moved. In the proposed experiments, using a task with more precisely timed odorant delivery and evacuation, we will study information flow through the output layers of M1, the posterior piriform cortex, and the prelimbic and orbitofrontal cortices during odor recognition and execution of the operant response. These studies will provide evidence on the """"""""communication protocol"""""""" used across sensory, prefrontal and motor brain areas that leads to action when a reward-associated cue has been detected. Relevance to public health: These experiments will shed light on how a complex cognitive process -- evaluating external stimuli and choosing a behavioral response from among many possibilities -- occurs in a simplified, rodent model of executive function. Knowledge of how these neural processes normally occur will aid in remediating their dysfunction in multiple psychiatric disorders. ? ?
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| Hermer-Vazquez, Linda (2008) Tracing 'driver'versus 'modulator'information flow throughout large-scale, task-related neural circuitry. J Comb Optim 15:242-256 |
| Hermer-Vazquez, Raymond; Hermer-Vazquez, Linda; Srinivasan, Sridhar et al. (2007) Beta- and gamma-frequency coupling between olfactory and motor brain regions prior to skilled, olfactory-driven reaching. Exp Brain Res 180:217-35 |
| Hermer-Vazquez, Linda; Hermer-Vazquez, Raymond; Chapin, John K (2007) The reach-to-grasp-food task for rats: a rare case of modularity in animal behavior? Behav Brain Res 177:322-8 |
