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

MRI Unit in the Department of Psychiatry, Columbia University College of Physicians & Surgeons and the New York State Psychiatric Institute, New York, NY, USA.
Neurocase (Impact Factor: 1.12). 08/2009; 15(5):361-72. DOI: 10.1080/13554790902776896
Source: PubMed


Subject PI demonstrated superior memory using a variant of a Method of Loci (MOL) technique to recite the first digits of the mathematical constant pi to more than 2(16) 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 pi (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.

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Available from: Gerianne Alexander, Oct 04, 2015
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    • "Selfgenerated loci have been shown to be more effective than ones supplied by others (Moè & De Beni 2005). One memorist used a variant of the method of loci to memorize π to 65,536 digits (Raz et al. 2009). "
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    ABSTRACT: This article argues that rapid eye movement (REM) dreaming is elaborative encoding for episodic memories. Elaborative encoding in REM can, at least partially, be understood through ancient art of memory (AAOM) principles: visualization, bizarre association, organization, narration, embodiment, and location. These principles render recent memories more distinctive through novel and meaningful association with emotionally salient, remote memories. The AAOM optimizes memory performance, suggesting that its principles may predict aspects of how episodic memory is configured in the brain. Integration and segregation are fundamental organizing principles in the cerebral cortex. Episodic memory networks interconnect profusely within the cortex, creating omnidirectional "landmark" junctions. Memories may be integrated at junctions but segregated along connecting network paths that meet at junctions. Episodic junctions may be instantiated during non-rapid eye movement (NREM) sleep after hippocampal associational function during REM dreams. Hippocampal association involves relating, binding, and integrating episodic memories into a mnemonic compositional whole. This often bizarre, composite image has not been present to the senses; it is not "real" because it hyperassociates several memories. During REM sleep, on the phenomenological level, this composite image is experienced as a dream scene. A dream scene may be instantiated as omnidirectional neocortical junction and retained by the hippocampus as an index. On episodic memory retrieval, an external stimulus (or an internal representation) is matched by the hippocampus against its indices. One or more indices then reference the relevant neocortical junctions from which episodic memories can be retrieved. Episodic junctions reach a processing (rather than conscious) level during normal wake to enable retrieval. If this hypothesis is correct, the stuff of dreams is the stuff of memory.
    Behavioral and Brain Sciences 12/2013; 36(6):589-607. DOI:10.1017/S0140525X12003135 · 20.77 Impact Factor
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    • "Selfgenerated loci have been shown to be more effective than ones supplied by others (Moè & De Beni 2005). One memorist used a variant of the method of loci to memorize π to 65,536 digits (Raz et al. 2009). "
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    ABSTRACT: I argued that rapid eye movement (REM) dreaming is elaborative emotional encoding for episodic memories, sharing many features with the ancient art of memory (AAOM). In this framework, during non–rapid eye movement (NREM), dream scenes enable junctions between episodic networks in the cortex and are retained by the hippocampus as indices for retrieval. The commentaries, which varied in tone from patent enthusiasm to edgy scepticism, fall into seven natural groups: debate over the contribution of the illustrative dream and disputes over the nature of dreaming (discussed in sect. R1); how the framework extends to creativity, psychopathology, and sleep disturbances (sect. R2); the compatibility of the REM dream encoding function with emotional de-potentiation (sect. R3); scepticism over similarities between REM dreaming and the AAOM (sect. R4); the function of NREM dreams in the sleep cycle (sect. R5); the fit of the junction hypothesis with current knowledge of cortical networks (sect. R6); and whether the hypothesis is falsifiable (including methodological challenges and evidence against the hypothesis) (sect. R7). Although the groups in sections R1–R6 appear quite disparate, I argue they all follow from the associative nature of dreaming.
    Behavioral and Brain Sciences 12/2013; 36(06):634-659. DOI:10.1017/S0140525X1300160X · 20.77 Impact Factor
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    • "Self-generated loci have been shown to be more effective than ones supplied by others (Moè & De Beni 2005). One memorist used a variant of the method of loci to memorize π to 65,536 digits (Raz et al. 2009). Along with the evidence (presented in the last section) that the AAOM is the basis of all effective memory techniques (and that memory " champions " employ these techniques rather than being born with exceptional memories), this section has reviewed experimental work in psychology that confirms the mnemonic properties of the AAOM. "
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    ABSTRACT: Brain activation patterns and mental, electrophysiological, and neurobiological features of rapid eye movement (REM) sleep suggest more functions than only elaborative encoding. Hence, the periodic occurrence of REM sleep episodes and dreaming may be regarded as a recurrent adaptive interference, which incorporates recent memories into a broader vital context comprising emotions, basic needs and individual genetic traits.
    Behavioral and Brain Sciences 12/2013; 36(6):621-2. DOI:10.1017/S0140525X13001362 · 20.77 Impact Factor
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