Functional Activity of the Retina and Visual Evoked Cortical Potentials in Simulation the Factors of Space Flight in Conditions of Four Month Isolation in a Hermetic Object with Artificial Habitat

Background. The artificial environment of confined space causes a decrease in the functional reserve of the central nervous system and can affect human health and the success of space missions. In solving this problem, the urgent task is to study adaptation mechanisms that adapt the functioning of the visual sensory system to the conditions of the extreme environment. Purpose to obtain new objective data on the alterations in the functional activity of the visual system during prolonged stay of a person in extreme environmental conditions. Methods. Before and after a 4-month isolation experiment simulating a flight to the moon, an electrophysiological study was conducted of six practically healthy crew members with registration of a set of electroretinograms (ERG) and pattern-reversal visual evoked cortical potentials (VEP) according to the ISCEV standards. In dynamics, corrected monocular visual acuity (MVA) was assessed on board. Results. After the end of the experiment, on average for the group, there were no statistically significant changes in the MVA and functional activity of the retina and visual cortex compared with the initial data. However, individual changes on the part of the flicker ERG and reduction of VEP to small patterns stimulating the parvocellular channel of the visual system were revealed in three testers. These changes were associated with higher visually intense work and physical activity of these crew members, and with an individual reaction to sleep deprivation of pilots with increased responsibility. Conclusion. Four-month isolation with imitation of a space mission did not cause significant changes in the functional activity of the retina and visual pathways in healthy crew members. Individual differences of VEP-responses of the parvocellular visual system were revealed, which can reflect a high level of psychophysiological adaptation and stress resistance in physically active crew members.

Multi-Voiced Music Bypasses Attentional Limitations in the Brain

Attentional limits make it difficult to comprehend concurrent speech streams. However, multiple musical streams are processed comparatively easily. Coherence may be a key difference between music and stimuli like speech, which does not rely on the integration of multiple streams for comprehension. The musical organization between melodies in a composition may provide a cognitive scaffold to overcome attentional limitations when perceiving multiple lines of music concurrently. We investigated how listeners attend to multi–voiced music, examining biological indices associated with processing structured versus unstructured music. We predicted that musical structure provides coherence across distinct musical lines, allowing listeners to attend to simultaneous melodies, and that a lack of organization causes simultaneous melodies to be heard as separate streams. Musician participants attended to melodies in a Coherent music condition featuring flute duets and a Jumbled condition where those duets were manipulated to eliminate coherence between the parts. Auditory–evoked cortical potentials were collected to a tone probe. Analysis focused on the N100 response which is primarily generated within the auditory cortex and is larger for attended versus ignored stimuli. Results suggest that participants did not attend to one line over the other when listening to Coherent music, instead perceptually integrating the streams. Yet, for the Jumbled music, effects indicate that participants attended to one line while ignoring the other, abandoning their integration. Our findings lend support for the theory that musical organization aids attention when perceiving multi–voiced music.