Current ResearchersNeeraj Kumar
Vinsea AV SIngh Representative PublicationsSpatiotemporal mapping of the neural markers of prediction error processing across multisensory and unisensory modalities (preprint)
Effective networks mediate right hemispheric dominance of human 40 Hz auditory steady-state response (Neuropsychologia, 2023) Organization of directed functional connectivity among nodes of ventral attention network reveals the common network mechanisms underlying the saliency processing across distant spatial and spatio-temporal scales (Neuroimage, 2021) Psychophysical data to study the brain network mechanisms involved in reorienting attention to salient events during goal-directed visual discrimination and search task (Data in Brief, 2021) Biophysical mechanisms governing large-scale brain network dynamics underlying individual-specific variability of perception. (European Journal of Neuroscience, 2020) Large-scale Functional Integration, Rather than Functional Dissociation along Dorsal and Ventral Streams, Underlies Visual Perception and Action. (Journal of Cognitive Neuroscience, 2020) Empirical Mode Decomposition Algorithms for Classification of Single-Channel EEG Manifesting McGurk Effect. (Intelligent Human Computer Interaction. IHCI 2019. Lecture Notes in Computer Science, vol 11886. Springer, Cham) Chronometry on Spike-LFP Responses Reveals the Functional Neural Circuitry of Early Auditory Cortex Underlying Sound Processing and Discrimination. (eNeuro, 2018) Segregation and integration of cortical information processing underlying cross-modal perception (Multisensory research, 2018) Large scale functional brain networks underlying temporal integration of audio-visual speech perception: An EEG study (Frontiers in Psychology , 2016) |
Sensory Processing involves effective registration and reliable interpretation of sensory input in the environment. How the brain receives, organizes and responds to sensory input in order to behave in a meaningful and consistent manner intrigues researchers.
(A) Neurophysiology of Speech Perception Multisensory signals seamlessly enrich our knowledge of the world. Multisensory processing involves participation of individual sensory streams, for example, vision, audition to facilitate perception of environmental stimuli. An experimental realization of the underlying complexity is captured by the "McGurk-effect" - incongruent auditory and visual vocalization stimuli eliciting perception of illusory speech sounds (Demo : http://www.youtube.com/watch?v=aFPtc8BVdJk). The aim of our lab is to characterize the dynamics of the whole brain network for understanding the neurophysiology of multisensory speech perception. As per the recent observation there is a broadband enhancement in the global coherence at theta, alpha, beta and gamma bands aids multisensory perception for asynchronous AV stimuli, as the brain engages more energy for multisensory integration(Figure 1). We also aim to study the inter-individual and inter-trial variability in perception among the participants subjected to McGurk illusion. Our lab has proposed a dynamical model consisting of three coupled Kuramoto oscillators, coupled via electric coupling and time-delay (Figure 2). (B) Neurobiology of Attention
How the brain processes information to execute a visual search over a static image is entirely different from the sensory and cognitive processing deployed in executing a task involving tracking of a dynamic stimulus? As the reorientation of attention towards unexpected salient changes around us is critical for survival, our lab aims to investigate the effect of saliency across different task conditions. Our recent work suggests that the EEG signal power at alpha band showed near identical rise in amplitude during salient conditions for a visual search and a dynamic motion tracking task. The results suggested a more general role of alpha oscillations which is dependent on the task context (saliency) but not on the task complexity or goals. We are employing phase amplitude coupling algorithms to explore the associated regions of high/low coupling during the visual task conditions of with and without saliency. (C) Neurobiology of Auditory Processing Several studies have shown asymmetric distribution of large-scale structural and functional brain networks involved in healthy auditory processing. One way to characterize the functional organisation of auditory processing is to access auditory steady-state responses (ASSRs), robust cyclic responses in the auditory networks entrained to the amplitude modulated tones. Our lab aims to identify the functional organisation of the brain that entails during 40 Hz ASSR employing EEG recordings followed by coherence, Granger causality and source analysis. We are also employing computational models (Kuramoto oscillators) to study the underlying dynamics of oscillatory mechanisms that lead to the generation of a steady-state response in a large-scale brain network. |