An enormous amount of information constantly reaches our senses, both from the environment and our own organism, and each person has their own subjective experience of what they perceive. This subjective experience is what we refer to when we study perceptual consciousness. This type of process has been extensively studied in psychology and neuroscience, with special interest in which brain regions are involved and how they function.
A study by researchers from different CIMCYC groups explored how brain stimulation (specifically, transcranial magnetic stimulation or TMS) in frontal regions of the brain can affect conscious perception processes. This technique generates magnetic pulses that, in a completely safe way for the participants (as long as previous neurological history and/or substance use, among other variables, is controlled), momentarily interferes with the functioning of a brain area, thus allowing to observe its role in the cognitive processes to be studied.
In addition, it was studied how the cerebral white matter is related to the effect of this stimulation. This white matter is a set of fibers that function as the brain's communication pathways, transmitting information between the different regions they connect.
These fibers can have different integrity, even among healthy people, and this gives a measure of how information flows through them. An advantage of this research over previous studies is that the sample of participants was much larger, which allowed for variability, and there were people with higher and lower integrity of the white matter studied. The results showed that if this connection is robust (i.e., if these fibers transmit information more “efficiently”), people are less sensitive to TMS modulation, and vice versa. Specifically, the fibers involved were those that connect frontal regions (such as those stimulated) with more posterior regions of the brain, as well as those that connect both cerebral hemispheres (the corpus callosum).
These findings allow us to better understand which brain areas are involved in these conscious perception processes and the role of the white matter. Furthermore, in the future, it could help to understand how brain damage and lesions in these fibers are related to visual perceptual deficits.
Researchers: Cristina Narganes-Pineda, Mar Martín Signes, Elisa Martín-Arévalo, Pablo Rodríguez-San Esteban, Alfonso Caracuel, Jose Luis Mata y Ana Chica.
Reference
Contact:
Pablo Rodríguez-San Esteban (prodriguez@ugr.es)
Mar Martín Signes (msignes@ugr.es)