https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2021.784026/full
The grey matter of the cerebellum primarily houses several types of neurons crucial for processing and coordinating motor signals. However, grey matter plays the most significant part in allowing humans to function normally daily.[1] Grey matter makes up the outer most layer of the brain. The grey matter gets its grey tone from a high concentration of neuronal cell bodies.
SUMMARY OF FINDINGS:
1) Rhythm/timing is left cerebellum dominant while pitch/frequency/melody is right cerebellum dominant.
2) Early music training shows decreased volume in the white matter of the cerebellum and increased neurons as gray matter - this continues through all of life with music training. This shows more sophisticated efficient use and even is demonstrated in twins, one with early music training, one with no music training. Music is proven to achieve strong activation of the cerebellum for coordination of emotion and movement and cognition. This leads to better filtering skills of the cerebellum as metaplasticity of the brain.
3) Rhythmic musical activities are proven to heal various conditions like strokes, Parkinsons, dementia and ASD. ASD is show to have a larger cerebellum and thus less sophisticated use of the cerebellum.
4) Perfect Pitch is left brain dominant with musicians showing stronger left brain processing than just nonmusicians listening to basic melodies as right brain dominance. The cerebrum and cerebellum cross coordinate so early trained musicians have a larger corpus callosum that integrates the left and right brains.
5) right hand movements on an instrument for pitch perception then also exhibit stronger beta brain wave suppression and greater training of Mu waves as alpha brain waves for sensorimotor processing. A basic timing rhythm is "preattention" - meaning even babies have it and thus the left hand keeps a simple regular beat as left-brain cerebellum activation. Thus not only is there an increased corpus callosum for brain integration but there is an increased focus on sensorimotor processing as alpha brain dominance for deep relaxation. This alpha brain wave deep relaxation dominance is maintained with listening to discrete words also.
left cerebellum has reciprocal projections with
the right cortex, which is classically associated with
certain spatial cognitive and music processes.
If the motor system
contributes to offline processing of sequential or rhythmic
sounds at the level of discrete sounds, then one could predict
beta desynchronization or mu synchronization in response to
heard sounds without movement.
Suppressing activity in the right cerebellum by inhibitory 1 Hz TMS worsened participants’ ability to discriminate pitch but not timbre.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11102367/
Cantonese-speaking amusic subjects exhibit abnormal brain activities in a widely distributed neural network during the processing of lexical tone and musical stimuli. While control subjects exhibit significant activation in the right superior temporal gyrus and in the cerebellum regardless of the lexical tone and music conditions, no activation was found in the amusic subjects in these regions including the cerebellum. This likely reflects a dysfunctional neural mechanism of relative pitch processing in the amusic subjects. No significant group difference was found in the right inferior frontal gyrus. These findings imply that the neural deficits in tonal language speakers might differ from those in non-tonal language speakers.
the cerebellum is involved in pitch (but probably not in timbre) processing in a clinically relevant way.
cerebellar gray and white matter volumes were measured. Early-trained musicians had reduced volume in bilateral cerebellar white matter and right lobules IV, V, and VI, compared to late-trained musicians. Strikingly, better timing performance, greater musical experience, and an earlier age of start of musical training were associated with smaller cerebellar volumes. Better timing performance was specifically associated with smaller volumes of right lobule VI. Collectively, these findings support the sensitivity of the cerebellum to the age of initiation of musical training and suggest that lobule VI plays a role in timing. The smaller cerebellar volumes associated with musical training and timing performance might reflect a more efficiently implemented low-level timing and sensorimotor process.
musical training induces morphological changes in the cerebellum independently from the type of musical performance.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11102367/
The Cerebellum in Musicology: a Narrative Review
The discrimination thresholds for the Beat Finding Interval Test (quarter note beat) were positively associated with gray matter volume variation in cerebellum lobule IX in the left hemisphere and [12]. The results demonstrate the importance of the cerebellum in beat interval discrimination skills suggesting that cerebellar gray matter and overall cerebellar integrity are important for rhythm discrimination abilities.
The major activation for music identification was found in the left anterior cerebellum.
Monozygotic twins who were highly discordant for piano practice showed that the musically active twin had greater cortical thickness in the auditory-motor network of the left hemisphere and more developed white matter microstructure in relevant tracts in both hemispheres and the corpus callosum. Furthermore, the volume of gray matter in the left cerebellar region (comprising lobules I–IV + V) was larger in the playing group. This finding supports the hypothesis that a significant portion of the differences in brain anatomy between experts and non-experts depends on causal effects of training.
After 8 weeks of group drumming instruction, the cerebellum significantly changed its gray (volume increase of left VIIIa, relative decrease of VIIIb and vermis Crus I volume) and white matter microstructure in the inferior cerebellar peduncle.
One study revealed that moving to music compared with self-paced movement resulted in a significantly increased activation in the left cerebellum VI.
. When hearing music and music imagery were contrasted directly, movements in the music condition showed significantly more activity in left hemisphere cerebellum VII and right hemisphere and vermis of cerebellum IX, while music imagery condition revealed more significant activity in pre-SMA. These results suggest that cueing movement with actual or imagined music impacts upon engagement of motor network regions during movement.
https://www.sciencedirect.com/science/article/pii/S0531556523002759
Rhythmic musical activities may strengthen connectivity between brain networks associated with aging-related deficits in timing and executive functions
motor response to musical rhythm is inherent in the human perception and experience of rhythm. Therefore, physical engagement with musical rhythm may assist in extending functional connectivity between not only motor areas of the brain, but also coordination centers (e.g., cerebellum).
https://journals.lww.com/annalsofian/fulltext/2024/27050/reduced_cerebellar_white_matter_volume_in.30.aspx
Music therapy has been found to be beneficial in several neurologic and neuropsychiatric conditions like dementia, stroke, Parkinsons’s disease, and autism spectrum disorder (ASD).[3] Herholz et al. (2012) reported that the benefits of musical training are highly dependent on the age at which the training began.[4] The cerebellum has often been reported to be involved in music perception, singing, pitch discrimination, and plasticity related to musical training.[5] Lifelong engagement in musical activities maintains cerebellar volumes even in old age, which extends its benefits to cognitive functioning.[6] On the contrary, early training (before 7 years of age) and musical expertise have been associated with decreased cerebellar volumes.[7] These learnings directed us to explore the differences in cerebellar volumes between musicians and non-musicians.
These findings are suggestive of a reduced activation due to expertise,
which has been noticed in the cortical regions of musicians and dancers
in previous studies.[11,12]
This could be attributed to the concept of metaplasticity that allows
more sophisticated processing of musical notes and filters out
irrelevant sensory inputs, thereby utilizing lesser brain volumes.[5,7]
Metaplasticity refers to the long-term neural changes that occur due to
repeated exposure to an activity over a significant amount of time and
often acts as a scaffold for further development.[13]
It is important to appreciate the morphologic changes induced by music in specific brain regions like the cerebellum. It is interesting to note that cerebellar size is larger in neuropsychiatric disorders like ASD, where music therapy has found a niche in recent years.
We observed a significant increase of CBFV in the right hemisphere in non-musicians during harmony perception but not during rhythm perception; this effect was more pronounced in females. Language perception was lateralized to the left hemisphere in all subject groups.
https://academic.oup.com/brain/article-abstract/122/1/75/330299
The time taken to reach the peak of CBFV was significantly longer in non-musicians when compared with musicians during rhythm and harmony perception. Pulse rates were significantly decreased in non-musicians during harmony perception, probably due to a specific relaxation effect in this subgroup.
neuropsychological investigations on dichotic
listening which showed a left hemisphere dominance for
language perception and a right hemisphere dominance for
melody perception (Kimura, 1961; 1964)
Stefan Evers, Jörn Dannert, Daniel Rödding, Günther Rötter, E.-Bernd Ringelstein, The cerebral haemodynamics of music perception: A transcranial Doppler sonography study, Brain, Volume 122, Issue 1, January 1999, Pages 75–85
The hypothesis of a left
hemisphere dominance in musicians recently has even been
supported by morphological studies with MRI showing a
stronger leftward planum temporale in musicians with
absolute pitch ability (Schlaug et al., 1995). https://bmcneurosci.biomedcentral.com/articles/10.1186/s12868-015-0200-4
Wow Perfect Pitch is a left-brain dominant skill!!
others have evidenced that beat processing is in
fact preattentive [73], since it runs in sleeping newborns
[74]....This suggests that detection of a beat is preattentive when
highly beat inducing stimuli are used. Importantly, they did
not find any effect of musical expertise, suggesting that beat
processing in metrically simple rhythms with clear accents
does not need attention or musical expertise.
https://onlinelibrary.wiley.com/doi/epdf/10.1155/2015/638202
If the motor system is routinely recruited for musical or
auditory processing, what might it contribute as part of a
distributed auditory network? Or to put it another way,
what aspects of musical experience might be explained by a
distributed audiomotor system which are not explained by an
auditory system without motor contributions?
https://onlinelibrary.wiley.com/doi/epdf/10.1155/2015/638202
If mu enhancement reflects increased difficulty of auditory
sequencing, then listening to complex rhythmic patterns
may elicit greater enhancement of mu rhythms than simple
rhythmic patterns.
We additionally report a novel inclusion of musically
experienced subjects with the piano learning ear training
task. At the individual subject level, previous music expe-
rience was not associated with any other measure, except
the length of time it took to complete the first day of ear
training. At the group level, previous musical training was
associated with lower levels of mu and beta suppression
over the left sensorimotor cortex. For instrumentalists who
have experience associating right hand movements with pitch
perception in music performance, this may represent a more
efficient use of cortical resources. The right sensorimotor
cortex, contralateral to piano trained hand, exhibited greater
beta suppression in musically experienced subjects. This
might be explained in part by previous reports indicating a
preferential role of the right hemisphere in relative pitch pro-
cessing [46]. Musical training may be represented in this case
by increased recruitment of right hemisphere sensorimotor
networks during pitch processing, resulting in increased
suppression.
Mu waves are alpha brain waves for motor processing.
Taken in light of previous findings, enhanced mu and
suppressed beta might indicate greater cortical demands in
response to sounds associated with a motor action.
https://onlinelibrary.wiley.com/doi/epdf/10.1155/2015/638202
If the motor system
contributes to offline processing of sequential or rhythmic
sounds at the level of discrete sounds, then one could predict
beta desynchronization or mu synchronization in response to
heard sounds without movement.
left cortical
hemispheric processing is more specialized for high
frequency information (e.g., phonological segmental
information) and right hemispheric processing is
more specialized for relatively low frequency infor-
mation (e.g., prosody, musical melodies).
These counterbalanced
tendencies in lateralization of speech and song in
the cerebellum are consistent with corresponding
findings about specializations in left and right
cerebral cortex (see Brown et al. 2006 (28)).
the right cerebellum,
which has reciprocal projections with the left
cerebral cortex, is thought to be involved with
certain specialized language functions (6), whereas
the left cerebellum has reciprocal projections with
the right cortex, which is classically associated with
certain spatial cognitive and music processes. For
example, children who had their right cerebellar
hemisphere removed as a result of a tumor showed
auditory and language processing deficits, whereas
those who had their left cerebellar hemisphere
removed showed spatial and visual sequential
memory deficits (49).
Music stimulates the vagus nerve, which in turn
stimulates the ANS system via VNS and relaxes the body,
it means music activates the PNS and have prominent roll
in relaxation because of decrease heart rate, blood
pressure, respiration rate, increase motility and relaxation
of sphincters, Increase insulin and digestive enzymes (it
can solve some gut problems), contraction of kidneys
muscles, contraction of bladder muscles (more activation of
kidneys and bladder) and relaxation of internal sphincter
that aids to urination[14], [16], [25], [22], [27].
https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2021.784026/full
Neural Advantages of Older Musicians Involve the Cerebellum: Implications for Healthy Aging Through Lifelong Musical Instrument Training
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