Extensive long-term verbal memory training is associated with brain plasticity.
Uttam Kumar et al. (2021) · Scientific reports
This cross-sectional study with 50 male participants explored whether decades of intensive oral memorization can leave a lasting signature on brain structure. It compared 25 Hindu Vedic pandits -- priests and scholars trained from childhood to recite over 20,000 Sanskrit mantras and verses from memory -- against 25 closely matched non-pandit controls. Vedic recitation follows a strict oral tradition (shruti-parampara): hymns are learned entirely by ear, using several formal recitation methods that reorder and repeat words to lock in exact pronunciation and sequence. The study asked which brain regions differ after such training -- regions governing memory, breath control, and precise speech articulation. Fifty right-handed men aged 21-28 took part: 25 pandits who began Vedic schooling around age ten and had logged nearly 17,750 hours of recitation training, and 25 controls matched for age, Sanskrit fluency, and general intelligence. All participants completed a 3-Tesla structural MRI brain scan, analyzed for grey- and white-matter volume, cortical thickness, and the folding pattern (gyrification) of the brain's surface. Memory was measured with the PGI-Memory Scale, a tool standardized for Indian populations covering immediate recall, attention, and retention. Pandits recalled significantly more information immediately after learning it than controls (a score of 11.2 versus 8.7, a large and statistically reliable gap), and this recall advantage tracked closely with the volume of grey matter in the thalamus (more volume, better recall). Brain scans showed pandits had more grey matter in the midbrain, pons, thalamus, and right frontal and pallidum regions -- areas tied to auditory processing, breath regulation, and sustained attention. They also had more white matter near the hippocampus and in frontal and temporal regions supporting memory consolidation, a thicker cortex in areas linked to emotional processing (temporal pole) and memory retrieval (caudate), and more surface folding in regions that coordinate speech articulation (insula, supplementary motor area). The longer a pandit had spent teaching Vedic recitation after training, the more grey matter he had in the angular gyrus, a region tied to retrieving well-learned verbal material. The authors interpret these differences as reflecting the specific mental and physical demands of Vedic training -- precise auditory memory, controlled breathing, and articulate speech -- rather than a single, generic meditation effect. Because the study compared existing groups at one point in time rather than tracking pandits before and after training, it cannot rule out that people with certain brain traits were more likely to complete Vedic schooling in the first place. The sample was small, male-only, and drawn from one religious and linguistic community, limiting how broadly the findings apply.