MRI scans
show that memorizing ancient mantras increases the size of brain regions
associated with cognitive function
- By James Hartzell on January 2, 2018
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A hundred dhoti-clad young men sat cross-legged on
the floor in facing rows, chatting amongst themselves. At a sign from their
teacher the hall went quiet. Then they began the recitation. Without pause or
error, entirely from memory, one side of the room intoned one line of the text,
then the other side of the room answered with the next line. Bass and baritone
voices filled the hall with sonorous prosody, every word distinctly heard,
their right arms moving together to mark pitch and accent. The effect was
hypnotic, ancient sound reverberating through the room, saturating brain and
body. After 20 minutes they halted, in unison. It was just a demonstration. The
full recitation of one of India´s most ancient Sanskrit texts, the Shukla Yajurveda, takes six hours.
I spent many
years studying and translating Sanskrit, and became fascinated by its apparent
impact on mind and memory. In India's ancient learning methods textual
memorization is standard: traditional scholars, or pandits, master many
different types of Sanskrit poetry and prose texts; and the tradition holds
that exactly memorizing and reciting the ancient words and phrases, known as
mantras, enhances both memory and thinking.
I had also
noticed that the more Sanskrit I studied and translated, the better my verbal
memory seemed to become. Fellow students and teachers often remarked on my
ability to exactly repeat lecturers’ own sentences when asking them questions
in class. Other translators of Sanskrit told me of similar cognitive shifts. So
I was curious: was there actually a language-specific “Sanskrit effect” as
claimed by the tradition?
When I entered the cognitive neuroscience doctoral
program at the University of Trento (Italy) in 2011, I had the opportunity to
start investigating this question. India's Vedic Sanskrit pandits train for
years to orally memorize and exactly recite 3,000-year old oral texts ranging
from 40,000 to over 100,000 words. We wanted to find out how such intense
verbal memory training affects the physical structure of their brains.
Through the India-Trento Partnership for Advanced
Research (ITPAR), we recruited professional Vedic pandits from several
government-sponsored schools in the Delhi region; then we used structural
magnetic resonance imaging (MRI) at India’s National Brain Research Center to
scan the brains of pandits and controls matched for age, gender, handedness,
eye-dominance and multilingualism.
What we
discovered from the structural MRI scanning was
remarkable. Numerous regions in the brains of the pandits were dramatically
larger than those of controls, with over 10 percent more grey matter across
both cerebral hemispheres, and substantial increases in cortical thickness.
Although the exact cellular underpinnings of gray matter and cortical thickness
measures are still under investigation, increases in these metrics consistently
correlate with enhanced cognitive function.
Most
interestingly for verbal memory was that the pandits' right hippocampus—a
region of the brain that plays a vital role in both short and long-term
memory—had more gray matter than controls across nearly 75 percent of this
subcortical structure. Our brains have two hippocampi, one on the left and one
on the right, and without them we cannot record any new information. Many
memory functions are shared by the two hippocampi. The right is, however, more
specialized for patterns, whether sound, spatial or visual, so the large gray
matter increases we found in the pandits’ right hippocampus made sense:
accurate recitation requires highly precise sound pattern encoding and
reproduction. The pandits also showed substantially thickening of right
temporal cortex regions that are associated with speech prosody and voice
identity.
Our study was
a first foray into imaging the brains of professionally trained Sanskrit
pandits in India. Although this initial research, focused on intergroup
comparison of brain structure, could not directly address the Sanskrit effect
question (that requires detailed functional studies with cross-language
memorization comparisons, for which we are currently seeking funding), we found
something specific about intensive verbal memory training.
Does the
pandits’ substantial increase in the gray matter of critical verbal memory
organs mean they are less prone to devastating memory pathologies such as
Alzheimer's? We don't know yet, though anecdotal reports from India's Ayurvedic
doctors suggest this may be the case. If so, this raises the possibility that
verbal memory “exercising ‘or training might help elderly people at risk of
mild cognitive impairment retard or, even more radically, prevent its onset.
If so, the
training might need to be exact. One day I was filming four senior pandit
teachers demonstrating the different recitation speeds. Partway into one
session all four suddenly stopped. “What’s wrong? ‘ I asked. “One of us made a
slight error," came the response. "I don’t mind," I said.
"Yes, but we do," and they restarted the entire recitation from the
beginning.
Author's note: Senior personnel
responsible for this project were not involved in the conception or writing of
the blog text; it was not presented to them for approval; any opinions or
conclusions expressed in the blog are Dr. Hartzell's alone.
This post was written by a graduate of the online
course Share
Your Science: Blogging for Magazines, Newspapers and More, offered by Scientific
American and the Alan Alda Center for Communicating Science at Stony Brook
University, with sponsorship from the Kavli Foundation.
The views
expressed are those of the author(s) and are not necessarily those of
Scientific American.
ABOUT THE AUTHOR(S)
James
Hartzell
James Hartzell is a postdoctoral researcher at the
Basque Center on Cognition, Brain and Language, in Spain; a Guest Researcher at
the Center for Mind/Brain Sciences at University of Trento, in Italy, and a
Consultant for the Center for Buddhist Studies at Columbia University, in New
York.
SOURCE:
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MIND & BRAIN
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January 10,
2018
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