No Central Executive? Decision Formation Through Multi-Area Population Dynamics

Perceptual decision-making is the process by which sensory evidence is combined with prior knowledge and transformed into possible movement plans according to a rule or policy. Classic studies suggested that perceptual decisions emerge from a feedforward hierarchy of brain areas with distinct functions and fairly homogeneous neural representations. However, more recent findings argue that decisions emerge from distributed, recurrent computations across many brain areas (a "heterarchy") with complex, heterogeneous representations. How can we make sense of these findings in a way that preserves the computational elegance of the conventional view? In this review, we describe how a new generation of studies is leveraging high-density electrophysiology, incisive task designs, causal manipulations (e.g., optogenetics) and statistical approaches for probing inter-area communication, and theoretical methods that connect population dynamics with representational geometry to build a modern framework for understanding perceptual decisions.