Tuesday, 21 July 2015

Memorise and recite Veda: how the brain is modified

A research on Pandit vedici conducted by CIMeC and the National Brain Research Centre (India), published on NeuroImage magazine

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A new research in Pandit vedici, conducted by a group of researchers of the Center for Mind/Brain Sciences (CIMeC) of the University of Trento, in collaboration with the National Brain Research Centre (India), within the ITPAR (India-Trento Program for Advanced Research) framework, confirms that an intense and continuative exercise of the verbal memory modifies in an extensive and significative manner the volume and the organisation of the brain, also in areas not directly engaged in the memory process.

Before the introduction of writing, the oral memorisation was the main method to pass on knowledge of a cultural group.

In India, the practice of oral memorisation and recitation of the Veda (ancient Sanskrit texts) has a history 3.000 years long and it is still practised by the Pandit vedici.

The boys studying to become Pandit attend dedicated schools and follow appropriate courses for about 10 years, at the end of which are able to recite a number of texts, for a total of 40 thousand words.

In the experiment, where data has been collected in India, the researchers have used neuroimmages to examine the cortical thickness and density of the grey matter in a group of Pandit and in a control group.

The results demonstrate an increase of thickness and volume of the cerebral cortex  in Pandits, not only in regions connected to memory but also in areas linked to language comprehension and visual information processing.

«To understand how the human brain is able to sustain the oral transmission of detailed knowledge for thousand of years is one of the main motivations of this experiment» says Uri Hasson, associate professor at CIMeC of the University of Trento; the research has been developed in his laboratory. «It is common knowledge the training of different cognitive skills is associated to changes of the brain structure. We expected that in our case these neuroplasicity phenomenons involved foremost the memorisation regions. The changes we observed are considerably more extended of what we initially anticipated».

James Hartzell is the first author of this article. After attaining a doctorate in Sanskrit and Tibetan at Columbia University, it is currently a doctoral student at CIMeC.

The research in which he is committed answers his wish to create a bridge between the traditions of a millenary culture and the forefront research in cognitive sciences.
Hartzell explains: «the language and linguistics of Sanskrit are fundamental for the system of ancient indian knowledge, as mathematics are fundamental to modern science. The tradition of the Vedica reciting, not only safeguards the text contents, but also guarantees the “effects” of the mantra (of the words and phrases), through the precision of the reciting. Our experiment shows how memorising and reciting Yajurveda at the professional level have a considerable effect on the cerebral structure».

The experiment included 42 participants: 21 Pandits and 21 participants from the control group, comparable to Pandits for age and cultural level. The images of the brain have been acquired by functional magnetic resonance imaging and different converging methods have been used to evaluate differences among the two groups: cortex thickness, grey matter density, characteristics of cerebral circumvolutions in the critical areas, and structural indexes of the white matter. In Pandits, analysis have substantiated the volume of the rearward part of the hippocampus was larger and the front part was reduced compared to the one of the control group. The fact an equivalent observation has been previously done in people with a strong habit to manage themselves in space (like London taxi drivers), it suggests expert space memory and verbal memory share a neurobiological base. In Pandits have been substantiated also a higher density of the grey matter and an increase of cortical thickness in the lateral areas of the temporal lobes involved in the comprehension and in the production of language, in the prefrontal ventromedial cortex, and in the lateral occipital cortex. These results demonstrate that practising verbal memory induce modification on a large scale in the cerebral organisation. 

Also other researchers are involved; from the University of Trento (Ben Davis, Gabriele Miceli, David Melcher e Jorge Jovicich) and from the National Brain Research Center in India (Tanmay Nath e Nandini Chatterjee Singh).

The article is available online on the NeuroImage magazine website.