The neurophysiology of decision-making as a window on cognition

Nervous systems extract sensory information from the environment to guide behavior. The underlying neural mechanisms have been studied extensively, in part by identifying neurons with responses linked deterministically to sensory and motor events. Higher nervous systems are also capable of widespread cognitive abilities, includin interpretation, decision-making, valuation, intention, language, and learning. The mechanisms underlying these abilities is less clear, in part because they seem beyond the scope of the machine-like behavior of sensory and motor neurons. This chapter examines this conundrum: How do properties of neurons and neural circuits give rise not just to reflexive sensory and motor abilities, but to cognition, as well? We suggest that an answer can be found in circuits that link sensory input to motor output. Here, transformations of sensory and motor signals reflect the kinds of nuance and flexibility that are hallmarks of cognition.