Sanskrit is an ancient Indo-Aryan language which is deep and rich. The Sanskrit Vedas are late bronze/early iron-age oral texts that passed down for over 3000 years in an unbroken tradition in India. They form the core of ancient Sanskrit knowledge system that once developed extensive oral literature and later written literature too in a wide range of traditional subjects. They are still taught in India’s Sanskrit institutions using traditional oral memorization and recitation methods. The verbal memorization and presentation were very important from ancient times. Now the question is, why was this kind of oral learning was of much importance? Yes, something interesting has been spotted!
The intensive oral memory is associated with structural features of hippocampal and lateral temporal regions implicated in language processing. Recently, research was carried out by a team of scientists from the University of Trento, Italy along with the National Brain Research Centre, India showing significant difference among the brain of pandits.
The Study process
The study was done with 42 volunteers, of which 21 were professionally qualified Sanskrit pandits(aged around 22 years) who have been trained full time for 7years (over 10,000 hours)in their childhood reciting the Yajurveda. These pandits were recruited from Vedic pandit schools in Delhi. They chose 21 controls, who matched for age, gender, handedness, eye dominance and multilingualism. The researchers used MRI at India’s National Brain Research Centre to scan the brains of professionally trained Sanskrit pandits and conducted a structural analysis of the following, relative to the matched controls :
Grey matter (GM)density – Grey matter is a major component of the central nervous system. It includes regions of the brain involved in muscle control and sensory perception such as seeing, decision making and self-control.
Cortical Thickness (CT) – Cortex is the outer layer of the cerebrum composed of grey matter and play an important role in consciousness. Cortical thickness analysis allows relating cognitive abilities, effects of ageing and effects of diseases to structural changes in the brain.
Local Gyrification index (LGI)– Metric that quantifies the amount of cortex buried within the sulcal folds as compared with the amount of cortex on the outer visible cortex.
White matter (WM) structure – White matter is the tissue through which messages pass between different areas of grey matter within the central nervous system.
Voxel- Based Morphometry (VBM) – It is the technique which attempts to judge brain volume purely by brain scans.
Fractional Anisotropy ( FA) – It provides a simple and robust means to assess the anisotropic diffusion occurring within a region.
Analysis
The team analysed the brain regions of the 21 pandits and 21 control volunteers and found some remarkable differences between the two.
Evaluation of covariates:- The VBM, CT, LGI and FA analysis included whole-brain analysis for the pandit group examining correlations of two covariates. These included the starting age of recitation training and Overall Practice Hours since Completion of Training (OPHCT). OPHCT was included since all pandits completed the common training. There was considerable variance in their subsequent practice routine, and it has been shown that even short term cognitive and motor practice impacts neuroplasticity. Age and whole-brain volume are also known to correlate with changes in Grey matter (GM), and hence age and volume were included as additional covariates in all analysis.
Voxel-based morphometry: whole-brain analysis:- The whole-brain VBM analysis revealed extensive GM differences in cortical, cerebellar and subcortical regions. In cortical regions, the pandits demonstrated greater GM than controls in large portions of both left and right hemispheres. Differences were found bilaterally in both auditory and visual-stream regions. Greater pandit GM was also found in large bilateral’s of anterior cingulate and ventromedial prefrontal cortices. In the cerebellum, pandits showed greater GM than controls in multiple bilateral structures.
In the subcortical regions, more heterogeneous result patterns showing greater GM than controls in a small cluster of the posteromedial right hippocampus, whereas they showed less GM than controls in a large cluster encompassing the more anterior portions of the hippocampus bilaterally and bilateral regions of the amygdala, caudate, nucleus accumbens, putamen and thalamus. A whole-brain analysis was conducted within the pandit group to test whether Grey matter density correlated with start age or with OPHTC, both with age and total brain volume as covariates. But no significant correlations were found.
Hippocampus- focussed analysis:- The hippocampal- optimized VBM procedure indicated a large portion of the posterior – middle right hippocampus where pandits had greater GM than controls. The volume of this region formed between 73 and 98% of the hippocampal mask. At larger smoothing kernels, a cluster in the left posterior hippocampus where pandits had greater Grey matter than controls. When tested whether hippocampal GM density or shape correlated with pandits start age or OPHTC, both adjusted for age and total brain volume as covariates, no significant correlation was found.
Cortical thickness analysis:- Several brain regions differed in CT between the pandit and the control group, and in all cases, the pandit group was associated with greater CT. The whole-brain analysis was conducted to test, within the pandit group, whether CT correlated with start age or OPHTC, adjusted for age as a covariate, no significant correlation was found.
Differences in the local gyrification:- Two areas showed differences in local gyrification between the two groups. There were found in the inferior and middle occipital gyri on the left and middle occipital gyrus on the right. In both cases, these cortical regions showed reduced notification for the pandit group. Within the pandit group, for correction of the LGI with the start age or OPHTC variables adjusted for age as a covariate. There was no significant correlation.
Differences in fractional anisotropy:- Two adjacent clusters showed greater FA in pandits compared to controls. No area showed the reverse pattern. Also, a test was conducted, within the pandit group, whether either FA or skeletonized FA correlated with pandit start age or OPHTC, both adjusted for age as a covariate. There was no significant correlation.
Inference
Considerable differences in the organisation of the brains of professional Vedic Sanskrit Pandits have been found. Specifically, they showed extensive cortical and cerebellar GM increase and subcortical GM decrease. The hippocampal GM decreases followed a differential anterior /posterior pattern that has been linked to expert spatial navigation and to improved memory for verbal materials. Cortical CT increases were extensive and overlapped closely with GM differences in right temporal regions, left medial prefrontal and left fusiform areas. Pandits also showed significantly less gyrification in bilateral occipital regions and significantly larger FA in left inferior frontal WM clusters. These findings are consistent with the possibility that the changes to medial-temporal and medial prefrontal regions, accompanied by changes to lateral temporal regions and cerebellum, reflect the impact of the Pandits extensive verbal practice.
Point to the future
It is expected that these research studies will definitely play a vital role in the treatment of Alzheimer’s disease and a lot of memory problems that nowadays people hit at old age or even early.
Exercising our brains by doing memory training may induce short term structural change in the ageing brain. The researchers could not conclude only reciting Sanskrit mantras alone gives a tremendous effect, but the intensive verbal memory training will definitely help.
References: ELSEVIER
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