Rhythmic Fluctuations in Evidence Accumulation during Decision Making in the Human Brain

Abstract

Categorical choices are preceded by the accumulation of sensory evidence in favor of one action or another. Current models describe evidence accumulation as a continuous process occurring at a constant rate, but this view is inconsistent with accounts of a psychological refractory period during sequential information processing. During multisample perceptual categorization, we found that the neural encoding of momentary evidence in human electrical brain signals and its subsequent impact on choice fluctuated rhythmically according to the phase of ongoing parietal delta oscillations (1-3 Hz). By contrast, lateralized beta-band power (10-30 Hz) overlying human motor cortex encoded the integrated evidence as a response preparation signal. These findings draw a clear distinction between central and motor stages of perceptual decision making, with successive samples of sensory evidence competing to pass through a serial processing bottleneck before being mapped onto action.

Visual Causality Judgments Correlate with the Phase of Alpha Oscillations

“…Individual alpha frequency bands (8-12 Hz) were extracted using third-order Butterworth filters, and the phase and power of these narrow-band signals were extracted using the Hilbert transform. To explore whether alpha phase was correlated with causality judgments, we measured the correlation between alpha phase and CT using an approach similar to the methods used in previous studies, detailed below (Cravo, Rohenkohl, Wyart, & Nobre, 2013;Wyart, de Gardelle, Scholl, & Summerfield, 2012).…”

Cortical delta activity reflects reward prediction error and related behavioral adjustments, but at different times

“…Lateral parietal neurons are commonly implicated in evidence accumulation (Sugrue et al, 2005;Gold and Shadlen, 2007), and parietal delta oscillations modulate rhythmic gain of information accumulation with phase-specific dynamics (Lakatos et al, 2008;Schroeder and Lakatos, 2009;Wyart et al, 2012;Cheadle et al, 2014). Indeed, the current findings suggest that delta phase links integrative parietal activities with motor cortex disinhibition to motivate rulebased action selection (Fig.…”

Do humans make good decisions?

“…for indicating whether the orientations were on average closer to the cardinal or diagonal axes. In this task, DU is orthogonal to the perceptual input [50]. B.…”