Response of Brain’s Temporal Lobe Cells to Music
Tehran (ISNA) – Imaging studies of the cerebral cortex find greater activation in the auditory regions of the right temporal lobe when subjects are focusing on aspects of harmony.
According to ISNA, until the advent of modern imaging techniques, scientists gleaned insights about the brain’s inner musical workings mainly by studying patients–including famous composers–who had experienced brain deficits as a result of injury, stroke or other ailments.
Studies of rhythm have concluded that one hemisphere is more involved, although they disagree on which hemisphere.
In an interview with ISNA, Bijan Norouz, physicist and musician who is the CEO of one of the active startups in the field of science and astronomy, mentioned the studying on brain’s inner musical workings on patients who had experienced brain deficits as a result of injury and curing them. He added as a result, the supposition of independent processing appears to be true, although more recent work has yielded a more nuanced understanding, relating to two of the features that music and language share: both are a means of communication, and each has a syntax, a set of rules that govern the proper combination of elements (notes and words, respectively).
According to Bijan Norouz of the Institute Future and Emerging Music Technologies – FEMT in Tehran, imaging findings suggest that a region in the frontal lobe enables proper construction of the syntax of both music and language, whereas other parts of the brain handle related aspects of language and music processing.
He confirmed that the imaging studies have also given us a fairly fine-grained picture of the brain’s responses to music. These results make the most sense when placed in the context of how the ear conveys sounds in general to the brain. Like other sensory systems, the one for hearing is arranged hierarchically, consisting of a string of neural processing stations from the ear to the highest level, the auditory cortex.
As he mentioned, the processing of sounds, such as musical tones, begins with the inner ear (cochlea), which sorts complex sounds produced by, say, a violin, into their constituent elementary frequencies. The cochlea then transmits this information along separately tuned fibers of the auditory nerve as trains of neural discharges. Eventually these trains reach the auditory cortex in the temporal lobe.
The CEO of the Startup group added, “Different cells in the auditory system of the brain respond best to certain frequencies; neighboring cells have overlapping tuning curves so that there are no gaps. Indeed, because neighboring cells are tuned to similar frequencies, the auditory cortex forms a frequency map across its surface”.
As he confirmed, “The response to music per se, though, is more complicated. Music consists of a sequence of tones, and perception of it depends on grasping the relations between sounds. Many areas of the brain are involved in processing the various components of music. Consider tone, which encompasses both the frequencies and loudness of a sound”.
He mentioned, “At one time, investigators suspected that cells tuned to a specific frequency always responded the same way when that frequency was detected. He added: Most research has focused on melody, but rhythm (the relative lengths and spacing of notes), harmony (the relation of two or more simultaneous tones) and timbre (the characteristic difference in sound between two instruments playing the same tone) are also of interest. Studies of rhythm have concluded that one hemisphere is more involved, although they disagree on which hemisphere”.
Norouz added, “The problem is that different tasks and even different rhythmic stimuli can demand different processing capacities. For example, the left temporal lobe seems to process briefer stimuli than the right temporal lobe and so would be more involved when the listener is trying to discern rhythm while hearing briefer musical sounds”.
“The situation is clearer for harmony. Imaging studies of the cerebral cortex find greater activation in the auditory regions of the right temporal lobe when subjects are focusing on aspects of harmony. Timbre also has been assigned a right temporal lobe preference,” he went on to say.
He confirmed, “OUR studies on contour, however, made us suspect that cell tuning might be altered during learning so that certain cells become extra sensitive to sounds that attract attention and are stored in memory”.