Beta oscillations reflect supramodal information during perceptual judgment

Abstract

Previous work on perceptual decision making in the sensorimotor system has shown population dynamics in the beta band, corresponding to the encoding of stimulus properties and the final decision outcome. Here, we asked how oscillatory dynamics in the medial premotor cortex (MPC) contribute to supramodal perceptual decision making. We recorded local field potentials (LFPs) and spikes in two monkeys trained to perform a tactile-acoustic frequency discrimination task, including both unimodal and crossmodal conditions. We studied the role of oscillatory activity as a function of stimulus properties (frequency and sensory modality), as well as decision outcome. We found that beta-band power correlated with relevant stimulus properties: there was a significant modulation by stimulus frequency during the working-memory (WM) retention interval, as well as modulation by stimulus modality-the latter was observed only in the case of a purely unimodal task, where modality information was relevant to prepare for the upcoming second stimulus. Furthermore, we found a significant modulation of beta power during the comparison and decision period, which was predictive of decision outcome. Finally, beta-band spike-field coherence (SFC) matched these LFP observations. In conclusion, we demonstrate that beta power in MPC is reflective of stimulus features in a supramodal, context-dependent manner, and additionally reflects the decision outcome. We propose that these beta modulations are a signature of the recruitment of functional neuronal ensembles, which encode task-relevant information.

An Intrinsic Role of Beta Oscillations in Memory for Time Estimation

“…pitch, numerosity, size), or they may be specific to time judgments. Yet, we note here that our results need not apply only to time; indeed, recent work has begun to show that beta oscillations are evoked during a variety of perceptual decision making tasks 69 – 71 . One possibility, then, is that beta oscillations serve to index a remembered standard not just for time, but for a variety of perceptual phenomena 72 .…”

Emergence of β and γ networks following multisensory training

“…Very recently, β oscillations have been proposed to be markers of internal content ( Spitzer and Haegens, 2017 ) and supramodal processing ( Haegens et al., 2017 ): following learning, rhythms such as β oscillations may regulate the feedback processing of sensory analysis ( Brincat and Miller, 2016 ) based on abstract categorical representations. These internal network dynamics were observed in prefrontal cortices, and operated in the α / β bands ( Brincat and Miller, 2016 ).…”

“…Third, as the AV group improved most, we also expected a strong top-down drive in the POST compared to the PRE for this group. As current research assigns an important role to beta ( β ) activity in the shaping of top-down predictions and decisional values ( Engel and Fries, 2010 ; Siegel et al., 2011 ; Spitzer and Haegens, 2017 ; Haegens et al., 2017 ; Bressler and Richter, 2015 ), beta networks were expected to be a major differential driver between the three groups.…”

Reciprocal Interactions Between Audition and Touch in Flutter Frequency Perception

“…Recent studies have identified neural populations in traditionally-defined sensory cortices that respond to flutter signals experienced in both modalities 22 ; however, the weak relationship between perception and the crossmodal activity in these areas implies that multimodal encoding and perceptual judgments are supported by neurons residing in regions outside of the sensory cortices 22 . These population may instead be found in frontal regions like pre-supplementary motor area 23 and medial premotor cortex 35 where individual neurons represent auditory and tactile flutter analogously. While neurons in frontal regions have been shown to support unimodal comparisons between pairs of tactile signals or auditory signals and crossmodal comparisons between tactile and auditory signals, the role of these neurons in representing combinations of co-occurring auditory and tactile signals remains to be tested.…”