Project:

„Theta-Gama-Coupling“ as predictor of working memory performance

Mentor (Advisor):

RNDr. Eugen Kvašňák, Ph.D.

Department:

Department of medical biophysics and informatics

Contact information:

26710 2304

Project Narrative:

The prefrontal cortex (PFC) provides the structural basis for numerous higher cognitive functions. The functional architecture of cognition is profoundly rhythmic and it serves as a conductor to orchestrate task-relevant large-scale networks which contain phase resetting, cross-frequency coupling, entrainment and recruitment of task-relevant regions into coherent functional networks. The PFC is also implicated in several executive processes associated with various stages of memory formation and retrieval, particularly working memory. Working memory functioning is supported by local neuronal circuits within the prefrontal cortex and re-entrant circuits connecting the prefrontal cortex to more posterior cortices. These circuits result in neuronal oscillations which are driven by repetitive and synchronized firing of groups of neurons. These oscillations display distinctive changes in response to cognitive, motor and sensory inputs. A fundamental feature of oscillatory activity is neuronal coherence. Cross-frequency coupling between the phase of theta (4–8 Hz) and amplitude of gamma (30–80 Hz (theta-gamma coupling, TGC) underlies working memory processes. TGC codes the ordering of items of information during working memory time intervals, i.e., the manipulation component of working memory. Gamma oscillations represent these individual items of information, while theta oscillations represent the time interval during which the items are held in memory. Recent findings suggest that theta-gamma coupling is the most significant predictor in working memory performance (N-back task). In this project, the volunteers will complete the N-back working memory task while an EEG recording and fronto-parietal transcranial electrical stimulation with theta (frontal) and gamma (parietal) will be applied. Both the enhancement and the inhibition effects of transcranial alternating current stimulation in both theta and gamma bands on TGC will be analysed, while better or worse TGC will be reflected in behavioural task results (reaction time, score, etc.) and EEG-based features (synchrony, coherence, frequency content, power spectrum, etc.). . The experimental team will provide assistance with the technical side of the experiment.

Requirements for student applicants:

Completed university education in general medicine, or, psychology or natural sciences or biological signal processing.