A Neurological basis for tonal space

I recently thought of a rough hypothesis for the neurological basis of tonal music: the application of place cells and grid cells to the navigation of tonal space. A lack of relevant hits on the hypothesis' key phrases using Google suggests that it has not previously been proposed.

To simplify egregiously, place cells, found in the hippocampus, remember a "place" in the spatial environment, while grid cells, found in the entorhinal cortex, form a hexagonal grid, and remember the relationships among objects in the spatial environment.

From an evolutionary perspective, having good spatial memory confers a considerable survival advantage on an individual, so it's no surprise that humans have neurological hardware that is optimized for this purpose. Such optimized hardware is often borrowed for related task. I hypothesize that the mind borrows this spatial-memory hardware to process musical information, thereby enabling music to be processed as "movement through tonal space."

Tonal space can also be represented as hexagonal grid, for example as a isomorphic keyboard, of which a subset of notes form a hexagonal tonnetz. If such a tonnetz is tied to specific pitches, then it maps to a pitch space.

However, only one fixed pitch is necessary to map a interval-based tonal space to a pitch space. Consider, for example, the hexagonal isomorphic note-layouts (keyboards) described in the spreadsheet JIMS_Note.xls. These all describe intervals, not pitches. To describe pitches, the origin note [0, 0] needs to be associated with a specific reference frequency (e.g., 440Hz).

With a grid cell describing an isomorphic interval-layout, any given interval, sequence of intervals (melody), or stack of intervals (chord) could be described/recognized by a specific pattern of points on that grid. If any one such point were associated with a specific frequency via a place cell, then the same interval-pattern could be described/recognized by the same grid cells, despite its transposition by octave, key, or tuning.

I have no evidence whatsoever for this hypothesis, nor any counter-evidence. I only thought of it earlier this week.

Many studies have shown that musical training stimulates the development of those parts of the brain dedicated to spatial-temporal processing. The grid & place cell system may be the mechanism by which this stimulation is effected.

But, what do I know? ;-)