Is there collaboration specific neurophysiological activation during collaborative task activity? An analysis of brain responses using electroencephalography and hyperscanning.

Collaboration between two individuals is thought to be associated with the synchrony of two different brain activities. Indeed, prefrontal cortical activation and alpha frequency band modulation has been widely reported, but little is known about interbrain synchrony (IBS) changes occurring during social interaction such as collaboration or competition. In this study, we assess the dynamic of IBS variation in order to provide novel insights into the frequency band modulation underlying collaboration. To address this question, we used electroencephalography (EEG) to simultaneously record the brain activity of two individuals playing a computer-based game facing four different conditions: collaboration, competition, single participation, and passive observation. The computer-based game consisted of a fast button response task. Using data recorded in sensor space, we calculated an IBS value for each frequency band using both wavelet coherence transform and phase-locking value and performed single-subject analysis to compare each condition. We found significant IBS in frontal electrodes only present during collaboration associated with alpha frequency band modulation. In addition, we observed significant IBS in the theta frequency band for both collaboration and competition conditions, along with a significant single-subject cortical activity. Competition is distinguishable through single-subject activity in several regions and frequency bands of the brain. Performance is correlated with single-subject frontal activation during collaboration in the alpha and beta frequency band.

Changes in eye movement parameters in the presence of an artificial central scotoma.

BACKGROUND: Central vision loss, such as in the case of age-related macular degeneration (AMD), has a a major negative impact on patients' quality of life. However, some patients have shown spontaneous adaptive strategies development, mostly relying on their peripheral vision. OBJECTIVE: This study assesses eye movement and eccentric visual function adaptive behaviors of a healthy population in the presence of simulated central vision loss. We wished to determine how central vision loss affects eye movements, specifically the foveal-target alignment. METHODS: Fifteen healthy participants (7 females, M = 21.69, SD = 2.13) discriminated the orientation of a Gabor relative to the vertical located at 12 deg of eccentricity to the right of fixation, in the presence of a gaze-contingent artificial central scotoma either visible or invisible. The artificial central scotoma was 4° diameter in order to simulate an earlier stage of degenerative disease while still impairing foveal vision. The target's orientation varied between 10° counter-clockwise and 10° clockwise. Each participant performed four blocks of 75 trials each per day over 10 days, the first day being a baseline without scotoma. RESULTS: We found changes in the endpoints of the 1st saccade over the practice days. The most common pattern was a gradual upward shift. We also observed a significant increase in discrimination performance over the 9 days of practice. We did not find any difference linked to the scotoma types. CONCLUSIONS: These findings suggest that the presence of an artificial central scotoma combined with a challenging discrimination task induces both changes in saccade planning mechanisms, resulting in a new eccentric-target alignment, and improvements in eccentric visual functions. This demonstrates the potential of this research paradigm to understand and potentially improve visual function in patients with central vision loss.