Dendritic Integration of Sensory Evidence in Perceptual Decision-Making

Summary Perceptual decisions require the accumulation of sensory information to a response criterion. Most accounts of how the brain performs this process of temporal integration have focused on evolving patterns of spiking activity. We report that subthreshold changes in membrane voltage can represent accumulating evidence before a choice. αβ core Kenyon cells (αβc KCs) in the mushroom bodies of fruit flies integrate odor-evoked synaptic inputs to action potential threshold at timescales matching the speed of olfactory discrimination. The forkhead box P transcription factor (FoxP) sets neuronal integration and behavioral decision times by controlling the abundance of the voltage-gated potassium channel Shal (KV4) in αβc KC dendrites. αβc KCs thus tailor, through a particular constellation of biophysical properties, the generic process of synaptic integration to the demands of sequential sampling.
Graphical Abstract
Highlights • Synaptic integration can implement a process of bounded evidence accumulation • FoxP acts in αβc Kenyon cells (KCs) to repress the voltage-gated potassium channel Shal • Shal regulates the ability of αβc KCs to summate synaptic inputs over time • Altering Shal currents in αβc KCs changes spike latencies and decision times
How is information integrated to allow perceptual decision-making? FoxP-expressing neurons in fruit flies accumulate sensory evidence as subthreshold voltage changes. The first spike signals that a decision.