Oscillatory activity in neocortical networks during tactile discrimination near the limit of spatial acuity

• Type of Material: Article
• Authors: Bhim M Adhikari, Georgia State University; Krishnankutty Sathian, Emory University; Charles Epstein, Emory University; Bidhan Lamichhane, Georgia State University; Mukesh Dhamala, Georgia State University
• Language: English
• Date: 2014-05-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2014 The Authors.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.neuroimage.2014.01.007
• Title of Journal or Parent Work: NeuroImage
• ISSN: 1053-8119
• Volume: 91
• Start Page: 300
• End Page: 310
• Grant/Funding Information: MD was supported by an NSF CAREER Award (BCS 0955037); and KS by NIH grants R01EY12440 and K24EY17332; and by the Veterans Administration.; This work was supported by the Atlanta VAMC Rehabilitation R&D Center of Excellence.
• Keywords: Brain rhythms; GAMMA-BAND ACTIVITY; EVENT-RELATED POTENTIALS; GRANGER CAUSALITY; LATERAL OCCIPITAL COMPLEX; Perceptual decision-making; DECISION-MAKING; Oscillations; Touch; Life Sciences & Biomedicine; EEG; MAGNETIC-FIELDS; Somatosensory; Granger causality; Neuroimaging; Connectivity; Radiology, Nuclear Medicine & Medical Imaging; SOMATOSENSORY CORTICAL NETWORK; HUMAN PREFRONTAL CORTEX; ATTENTIONAL MODULATION; ERP; Neurosciences; MEDIAN NERVE-STIMULATION; Neurosciences & Neurology; Science & Technology
• Research Categories: Biology, Neuroscience; Health Sciences, Rehabilitation and Therapy

Abstract

Oscillatory interactions within functionally specialized but distributed brain regions are believed to be central to perceptual and cognitive functions. Here, using human scalp electroencephalography (EEG) recordings combined with source reconstruction techniques, we study how oscillatory activity functionally organizes different neocortical regions during a tactile discrimination task near the limit of spatial acuity. While undergoing EEG recordings, blindfolded participants felt a linear three-dot array presented electromechanically, under computer control, and reported whether the central dot was offset to the left or right. The average brain response differed significantly for trials with correct and incorrect perceptual responses in the timeframe approximately between 130 and 175. ms. During trials with correct responses, source-level peak activity appeared in the left primary somatosensory cortex (SI) at around 45. ms, in the right lateral occipital complex (LOC) at 130. ms, in the right posterior intraparietal sulcus (pIPS) at 160. ms, and finally in the left dorsolateral prefrontal cortex (dlPFC) at 175. ms. Spectral interdependency analysis of activity in these nodes showed two distinct distributed networks, a dominantly feedforward network in the beta band (12-30. Hz) that included all four nodes and a recurrent network in the gamma band (30-100. Hz) that linked SI, pIPS and dlPFC. Measures of network activity in both bands were correlated with the accuracy of task performance. These findings suggest that beta and gamma band oscillatory networks coordinate activity between neocortical regions mediating sensory and cognitive processing to arrive at tactile perceptual decisions.