A slice of π : An exploratory neuroimaging study of digit encoding and retrieval in a superior memorist

Abstract

Subject PI demonstrated superior memory using a variant of a Method of Loci (MOL) technique to recite the first digits of the mathematical constant π to more than 216 decimal places. We report preliminary behavioral, functional magnetic resonance imaging (fMRI), and brain volumetric data from PI. fMRI data collected while PI recited the first 540 digits of π (i.e., during retrieval) revealed increased activity in medial frontal gyrus and dorsolateral prefrontal cortex. Encoding of a novel string of 100 random digits activated motor association areas, midline frontal regions, and visual association areas. Volumetric analyses indicated an increased volume of the right subgenual cingulate, a brain region implicated in emotion, mentalizing, and autonomic arousal. Wechsler Abbreviated Scale of Intelligence (WASI) testing indicated that PI is of average intelligence, and performance on mirror tracing, rotor pursuit, and the Silverman and Eals Location Memory Task revealed normal procedural and implicit memory. PI’s performance on the Wechsler Memory Scale (WMS-III) revealed average general memory abilities (50th percentile), but superior working memory abilities (99th percentile). Surprisingly, PI’s visual memory (WMS-III) for neutral faces and common events was remarkably poor (3rd percentile). PI’s self-report indicates that imagining affective situations and high emotional content is critical for successful recall. We speculate that PI’s reduced memory for neutral/non-emotional faces and common events, and the observed increase in volume of the right subgenual cingulate, may be related to extensive practice with memorizing highly emotional material.

Physical Loci

“…Many of the studies, often conducted with students, typically were designed for remembering lists of 20, 40 or 50 words [11,12,17]. Some people have been known to achieve amazing performance, such as remembering thousands of digits in memory contests [22,28].…”

Motor imagery and higher-level cognition: four hurdles before research can sprint forward

“…(see Yates 1966, for an in-depth discussion of the origin of the method of loci). Furthermore, the method of loci has been shown to be a particularly effective memory strategy and has been found to be employed by the world's best mnemonists (Maguire et al 2003)-and does not necessarily rely on visual memory (Raz et al 2009). Interestingly, unlike other memory strategies that often involve a visual imagery component, the method of loci also invokes motor imagery (e.g., walking through the imagined environment).…”

Learning System-assigned Passwords (up to 56 Bits) in a Single Registration Session with the Methods of Cognitive Psychology

“…Research results have revealed that memory champions do not necessarily have extraordinary brains; rather they use their normal spatial abilities to great effect [40], [34]. This makes us think that regular users can also take advantage of these abilities, if they have guidance to facilitate quick adoption of the method of loci via our training interfaces.…”