Brain regions arrange the same signals differently during monkey choices
Motion and reward signals appeared in two brain regions during a monkey experiment, but their arrangement differed. Electrical stimulation then shifted choices in distinct ways. This single peer-reviewed animal study used a task with juice rewards and eye movements, linking population-level neural organization with behavior within that specific experimental setting.
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Electrical stimulation changed choices in different ways
Small electrical interventions shifted motion judgments differently in two brain regions of monkeys. In the visual motion area, choices moved along a more continuous distribution. In prefrontal cortex, one of two directions tended to dominate instead. This single peer-reviewed animal experiment connected these behavioral differences with how groups of neurons organized motion and reward signals, rather than simply whether either region contained information about them.[1]
Eye movements revealed the balance between motion and reward
Two adult male rhesus monkeys indicated the direction of moving dots by looking toward a ring. Its colors marked differences in the juice reward associated with possible choices. Across 27 sessions, the animals made 41,106 choices. Simultaneous recordings compared the middle temporal area, a visual motion region abbreviated MT, with dorsolateral prefrontal cortex, involved in decision processing. Motion and reward were represented more separately in the former and more jointly in the latter.[1]
Network models guided the intervention hypotheses
Two-module recurrent neural networks generated qualitative expectations about stimulation; they were not exact reconstructions of the biological circuit. Prefrontal stimulation depended on the rewarded direction, while the corresponding dependence was absent in MT. The experiment's two-animal sample and particular reward task define its scope. Other tasks can produce different arrangements in the visual region, so the observed division of roles concerns these experimental conditions rather than fixed categories for every brain area.[1]
