| Project Detail |
Perception, attention, and working memory (WM) are strongly intertwined cognitive constructs. The central premise of the current state-of-the-art is that these cognitive constructs can be understood from the perspective of their brain correlates, i.e. cortical “representation”. For example, evidence from human and non-human primate electrophysiology suggests that visual gamma oscillations (40-100 Hz) link object constituents into a coherent percept (“Gestalt”) through internal cortical circuit mechanisms. Participants attention directed towards an object or spatial location attenuates the power of occipital alpha oscillations (8-14Hz). The increase of item quantity temporarily stored in WM is associated with a power increase of posterior alpha oscillations. The validity of this premise that brain rhythms underpin cognition has far-reaching consequences for scientific funding, theoretical thinking, and model development. Current experimental practice, such as invasive and non-invasive brain stimulation, neurofeedback, brain-computer interface, and large-scale clinical trials utilizing electrophysiology, depends upon its validity. The present research proposal challenges this premise. The ongoing scientific discourse disagrees on what alpha and gamma activity actually “represent”. There is an inconsistency in that, increase in WM load has been associated with both an increase and decrease in alpha power. Similarly, the variability of gamma oscillations depends largely on stimulus properties rather than internal cortical circuit mechanisms. Supported by preliminary data, I propose a new framework that potentially resolves this inconsistency. The overarching hypothesis is that alpha and gamma oscillations are primarily associated with oculomotor action. This association is endogenous, hence present during awake rest as well as during cognitive tasks conditions. A new framework of Oculo-Cortical-Coherence (OCC) is developed that aims to explain the contradictory findings on alpha power modulations with attention and WM and gamma oscillations with varying stimulus properties (e.g. spatial frequency and contrast). Utilizing widely used tasks, consistently linked to alpha and gamma oscillations, this project aims to provide evidence that: a) oculomotor action is continuously monitored by the brain reflected in OCC present during task and rest, b) the direction of gaze differs across commonly utilized WM tasks (i.e. Sternberg, N-back and spatial WM) and it is this gaze pattern that predicts alpha power variation, and c) gamma power modulation during perception depends on miniature fixational eye movements (FEM) and manifests through OCC. Based on general principles that vision is defined through eye movements and bodily movement is controlled by the central nervous system, the proposed research aims to explain why power modulations of alpha oscillations are observed in nearly every cognitive construct studied to date. I propose that cognitive operations entail coordinated eye movements and eye movement control depends on cortical alpha oscillations. Affirmative support of the proposed framework would have a significant impact on the scientific community investigating cognitive constructs with EEG by setting up a new complementary direction of combined EEG and eye-tracking analysis and interpretation of the results. The proposed research is expected to contribute to the emergent shift of the current neuroscientific paradigm from the traditional passive, stimulus-induced, representational view towards an active observer-dependent framework where cognition emerges through oculomotor action. |
