I now return to Patel’s fabulous book, Music, Language and the Brain, where he relates research into the expressive timing of good musical performers. I posted about this some time back but a review is in order. Theoretically all eighth notes in the same time signature should be the same length, but in reality they vary a good deal with an average length of 652 milliseconds +/- 250 msecs in one study, so that eighth notes range from 400 msecs to 900 msecs. The important aspect here is that the variation is not random but purposeful, intentionally done as a way to convey the style and emotional tone of the performer in playing the piece. When music is electronically manipulated and note length is varied, listeners can tell the difference, and if the music is machine generated with all the notes standardized to some length, e.g., all eighth notes are 652 msecs, that music lacks vitality and is clearly machine made, i.e., mechanical and not musical, and listeners reject it. Consider the musician, say a pianist, as they play a piece expressively and to do so must intuitively vary note length by such very small increments, say a fifth of a second or less. Quite a feat of motor control, and now I come to a greater consideration: how does that expressive feeling that guides motoric movements come about? Oh, my, let me list, in no particular order, what might be the biological components:
–the self, whatever that is that gives rise to artistic touch or vision or voice. This is hypothesized by Damasio to be a very complex group of brain functions from the brainstem to neocortex.
–social intelligence or that understanding which enables one self to communicate subtle emotions with another self or which contributes to well received aesthetic expression. This coalesces in the right hemisphere, we know, around the temporal-parietal junction.
–musicality in general is seen as a right hemisphere function but professional musicians rely on the left side for some important functions. Perhaps this shift in laterality comes as a musician learns to sight read (certainly left sided) and grows more automatic and facile with the movements needed to produce music.
–and now I bring in the dorsal-ventral loops composed of the long fiber networks of the cortex. I will say simply now before explicating the idea more in the following paragraphs that the dorsal loop, e.g., the arcuate fasciculus, facilitates the regular repetition or accurate mirroring of a heard or known passage, while the ventral loop, e.g., the uncinate fasciculus, facilitates the rendering of meaning and novelty from what has been mirrored. (Please see my post on 9/27/15 to better understand my use of ‘mirroring’).
I have been studying an article by Michel Rijmtjes. Corneilius Weiler, Tobias Bormann, and Mariacristina Musso in Frontiers of Evolutionary Neuroscience from 3 July 2012 entitled “The dual loop model: its relation to language and other modalities”. The dual loop is the dorsal and ventral loops mentioned just above. They focus on the left side because they are working on understanding language, so my extrapolation to the right side is just that, mine. Also, their work, like most of our neuroscience examining particular human abilities, focuses on reception, mostly because one can study the brain’s response to a specific input. Studying expression is more difficult because how we motivate, generate and enact behavioral impulses, especially those with aesthetic attributes, is currently lost in the neurological depths from whence expressive behaviors emerge. Aesthetic ones are the most problematic in this regard, because creative processes are the most distant and dissociated from the reception of input stimuli and a highly original and creative symbolic expression from an individual self. So with that in mind . . . .
These authors review many studies and hypotheses about how human language can be so different from other animal communications, i.e., a lot here to digest. The two loops are actually structures I have discussed before but did not know at the time they were part of a more comprehensive model. Both of these loops connect back (input/receptive) and front (output/expressive). The first of these is called the dorsal (sort of over the top of the brain) loop, exemplified by our old friend the arcuate fasciculus (remember it enables our ability to repeat words, so it is an important part of the mirror system) that connects Wernicke’s area of the auditory cortex in the temporal lobe with Broca’s area in the motor cortex of the frontal lobe. (See my post, Arcuate fasciculus, mirror neurons, and memes from 4/24/14). In my thinking the arcuate fasciculus organizes surface structure, the mapping of sound to motor patterns thereby enabling meanings to be understood and expressed. Here is its pictorial representation.
The second loop is called the ventral (sort of running along the sides of the brain) loop, exemplified here by the uncinate fasciculus that runs from the temporal lobe to the frontal lobe. It does not originate solely in Wernicke’s area nor does it end solely in Broca’s area but rather from areas cradling both of the dorsal junctures. Here is its pictorial representation.
The ventral loop is less concerned with organizing surface structure for mirroring and more with organizing deep structure, that poorly understood function whereby linguistic meaning is derived from thinking, so that we can understand and express not just words and sentences but the conceptual workings underlying them. The dual loop hypothesis focuses on how these two systems interact in the special ways required for human language.
Oh so complicated and much more can and will be said at some later time about this neurolinguistic hypothesis, but I want to swing from the left side to the right side, from language to the social intelligence captured by our musicality. (and this post is getting longer than usual already). The dorsal and ventral loops are also on the right side; we know less about them for a variety of reasons both experimental and conceptual. In my most popular post of all time cited above, that continues to gather hits to this day, I discussed the arcuate fasciculus (AF) on the right side, citing new research that confirmed it existed there (for a long time it was thought to be only on the left) and also that it seemed to help to mirror social communication. I speculated that maybe gifted mimics, such as Jim Carey,Tina Fey or Rich Little, had a stronger AF system that enabled them to mirror another’s emotional expressions, so that they can sound like and mimic facial expressions of some public figure, say President Nixon, Sarah Palin or some other public figure.
Now we can develop the dual loop hypothesis for the right side. Rijmtjes and his colleagues report that experienced musicians have a larger AF than the rest of us, most probably because they have practiced playing and mentally rehearsing musical pieces. The AF here would seem to play an analogous role from the left on the right side as it helps to mirror a piece for performance, either from hearing it before or even sight reading it, so the right sided AF would help to map the sounds and motor patterns for their playing. This is the dorsal loop’s primary function.
What of the ventral loop on the right side? If it organizes thought and semantic meaning for language on the left, what might it do on the right? Ah, what is the artistic import of any musical piece or any artistic production for that matter? (see post 11/4/15 Musical brain and artistic import) It is not standardized through convention the way words are; artistic import, to echo Susanne Langer’s writings here once more, is not from a discursive, linear symbolic form but a presentational, non-linear symbolic form. It is a symbol for a particular experience of felt life, and that is one of the beautiful complexities of our minds.
Returning to where I started, how does a musician play with exquisite feeling some piece from musical notation? How does a pianist play with vital variations of note length, tempo and loudness to give a coherent and musical rendering of the piece? Part of the answer lies in the dual loop hypothesis, wherein the dorsal AF supports the mirroring of the piece (connection between sounds and motoric production) while the ventral supports the variation of the individual performance in a (hopefully) aesthetically pleasing way. It does so by engaging the systems listed earlier, the self, the emotional responsiveness and social intelligence of the performer along with their sense of musicality (likewise the composer though that is even more complicated).
I have gone a long way to connect to the beginning and I want to close with yet another line of thinking I read about recently in the Origin of Music. A very unusual man by the name of Manfred Clynes developed, among his many efforts that included coining the term ‘cyborg’, the science of sentics. This focuses on how emotions are communicated through patterns of touch, their tempo, strength, etc. As an example, Clynes had Americans communicate how they were feeling different emotions through touch and then tried these out on Australian aborigines, who were able to decode the emotions so presented. Clynes also translated this notion to the touch of a musician as he or she plays their instrument and the piece being performed. Clynes used this knowledge to program a computer to play music with a human feel and listeners could not pick out the machine version. Clynes is clearly a genius; in addition to being an engineer and neuroscientist, he was also a concert pianist who played for and with Einstein, what used to be called a polymath. More later. Now I think it is time to turn on the old ipod and listen to a vital aesthetic form contained therein.