 Fri Jun 21 14:17:41 2024, Oscar Ferrante, University of Birmingham, o.ferrante@bham.ac.uk, 12/31/25, Gating by inhibition: do alpha oscillations modulate early visual or content-specific representations in the brain?, ASP, , , , No, IN PROGRESS, ,
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 Mon Jun 24 09:18:15 2024, Oscar Ferrante, University of Birmingham, o.ferrante@bham.ac.uk, 12/31/25, Gating by inhibition: do alpha oscillations modulate early visual or content-specific representations in the brain?, ASP, , Ole Jensen, Ling Liu, Huan Luo, Liad Mudrik, MEG, No, IN PROGRESS, ,
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Oscillatory brain activity in the alpha band (8-12 Hz) has been associated with inhibitory control [1,2,3], in the sense that alpha oscillations suppress neuronal firing in a rhythmic manner [4]. Consequently, the magnitude and phase of the pre-stimulus alpha oscillations have also been related to conscious perception [5]. It is debated whether alpha oscillations modulate neuronal firing in early sensory regions or rather reflect gating-of-information in downstream regions [6]. We will answer this question using MEG data (and secondarily ECoG data, in collaboration with the team) from Experiment 1 by examining how the phase and magnitude of pre- and post-stimulus alpha oscillations modulate early visual as well as content-specific activity. Specifically, we will use a generalized eigenvalue decomposition (GED) method [7] to identify the single trials time-course reflecting distributed activity responsive to specific stimulus categories (faces and objects). We will then test whether the single-trial activity of this category-selective source is modulated by the phase and magnitude of the alpha activity. We will compare the phasic role of alpha oscillations on activity in early visual regions, as well as on category specific activity generated in the ventral stream. This project aims at extending the current knowledge about the functional role of the alpha rhythm in human cognition and how its inhibitory control is implemented from a mechanistic point of view.
References:
1. Foxe, J. J., & Snyder, A. C. (2011). The role of alpha-band brain oscillations as a sensory suppression mechanism during selective attention. Frontiers in psychology, 2, 154.
2. Klimesch, W., Sauseng, P., & Hanslmayr, S. (2007). EEG alpha oscillations: the inhibition–timing hypothesis. Brain research reviews, 53(1), 63-88.
3. Jensen, O., & Mazaheri, A. (2010). Shaping functional architecture by oscillatory alpha activity: gating by inhibition. Frontiers in human neuroscience, 4, 186.
4. Mazaheri, A., & Jensen, O. (2010). Rhythmic pulsing: linking ongoing brain activity with evoked responses. Frontiers in human neuroscience, 4, 177.
5. Krasich K, Simmons C, O'Neill K, Giattino CM, De Brigard F, Sinnott-Armstrong W, Mudrik L, Woldorff MG. (2022) Prestimulus oscillatory brain activity interacts with evoked recurrent processing to facilitate conscious visual perception. Sci Rep. 12(1):22126. doi: 10.1038/s41598-022-25720-2.
6. Zhigalov, A., & Jensen, O. (2020). Alpha oscillations do not implement gain control in early visual cortex but rather gating in parieto‐occipital regions. Human Brain Mapping, 41(18), 5176-5186.
7. Cohen, M. X. (2022). A tutorial on generalized eigendecomposition for denoising, contrast enhancement, and dimension reduction in multichannel electrophysiology. Neuroimage, 247, 118809. |