*Article* **Event-Related Coherence in Visual Cortex and Brain Noise: An MEG Study**

**Parth Chholak 1,\*,†, Semen A. Kurkin 2,†, Alexander E. Hramov <sup>2</sup> and Alexander N. Pisarchik 1,2**


**Abstract:** The analysis of neurophysiological data using the two most widely used open-source MATLAB toolboxes, FieldTrip and Brainstorm, validates our hypothesis about the correlation between event-related coherence in the visual cortex and neuronal noise. The analyzed data were obtained from magnetoencephalography (MEG) experiments based on visual perception of flickering stimuli, in which fifteen subjects effectively participated. Before coherence and brain noise calculations, MEG data were first transformed from recorded channel data to brain source waveforms by solving the inverse problem. The inverse solution was obtained for a 2D cortical shape in Brainstorm and a 3D volume in FieldTrip. We found that stronger brain entrainment to the visual stimuli concurred with higher brain noise in both studies.

**Keywords:** MEG; FieldTrip; Brainstorm; source reconstruction; flickering; cognitive neuroscience; visual perception
