On Feedback

One of the most fascinating questions in neuroscience, is how "high-level" cognitive properties of mind like attention feed back on and affect our biology. For example, it is known that video-game players have better visual acuity than non-video game players¹. Another example of this phenomenon can be found in the result (described below) from Lee et. al., published in the Journal of Neuroscience².


from reference 2

The authors of this study found differences in the responses of the auditory brainstems of musicians as compared to non-musicians. Specifically, these two groups (musicians and non-musicians) were presented with pairs of consonant and dissonant tones; it was found that musicians showed larger response magnitudes to certain components of consonant tones than did non-musicians (see figure, above).

The hypothesized reason for this difference is that a musician's heightened attention to consonant tones (and their makeup or properties) leads to changes in his or her neurobiology, such that the neurons of the auditory brainstem eventually respond more strongly to certain aspects of these auditory signals. This is especially fascinating because the area of the brain that was measured was not the cortex (usually associated with consciousness and "high-level" cognitive activity), but the brainstem (the area of the brain that is evolutionarily much older; bearing greater resemblance to animal brains ).

How the conscious act of focusing on one aspect of a stimulus can lead to an enhancement of the responses of brain-regions devoted to their representation is an open question, and one with wide-ranging implications. Further research will be required to understand its basis.

References:
1. Green CS, Bavelier D. (2007) Action-video-game experience alters the spatial resolution of vision. Psychol Sci. 18(1):88-94. PMID: 17362383
2. Lee KM, Skoe E, Kraus N, Ashley R. (2009) Selective subcortical enhancement of musical intervals in musicians.
J Neurosci. 29(18):5832-40. PMID: 19420250