Size isn't everything: A study of brain volume, intelligence and auditory evoked potentials

Egan, Vincent; Chiswick, Ann; Santosh, Celestine; Naidu, K.; Rimmington, J E; Best, J. J. K.

doi:10.1016/0191-8869(94)90283-6

Cited by 62 publications

(42 citation statements)

References 21 publications

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“…In addressing our study's second major question, we found that the target P3 latency (a measure of information processing speed) was shorter for cognitively high performing adults than cognitively average performing adults, a result consistent with the findings of several previous investigations (Egan et al, 1994;O'Donnell et al, 1992;Polich et al, 1983;Walhovd and Fjell, 2002). As predicted, the largest difference between the cognitively high and average groups was observed for old subjects.…”

Section: Discussionsupporting

confidence: 91%

“…This result suggests that for younger adults, cognitively high performing subjects may be able to process novelty more efficiently, thus appropriating fewer resources than cognitively average performing subjects (Haier et al, 1988;McGarry-Roberts et al, 1992). Consistent with this notion are studies that have shown that young subjects with greater intellectual capacity generate smaller target P3 amplitudes (Egan et al, 1994;McGarry-Roberts et al, 1992); however, this has not been an invariant finding (e.g., Jausovec and Jausovec, 2000). The literature on 'cognitive reserve' (Katzman, 1993;Satz, 1993;Stern, 2002) also is informative.…”

Section: Discussionmentioning

confidence: 92%

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Compensatory neural activity distinguishes different patterns of normal cognitive aging

et al. 2008

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Most cognitive neuroscientific research exploring the nature of age-associated compensatory mechanisms has compared old adults (high vs. average performers) to young adults (not split by performance), leaving ambiguous whether findings are truly age-related or reflect differences between high and average performers throughout the lifespan. Here, we examined differences in neural activity (as measured by ERPs) that were generated by high vs. average performing old, middle-age, and young adults while processing novel and target events to investigate the following three questions: 1) Are differences between cognitively high and average performing subjects in the allocation of processing resources (as indexed by P3 amplitude) specific to old subjects, or found throughout the adult lifespan? 2) Are differences between cognitively high and average performing subjects in speed of processing (as indexed by target P3 latency) of similar magnitude throughout the adult lifespan? 3) Where along the information processing stream does the compensatory neural activity attributed to cognitively high performing old subjects begin to take place? Our results suggest that high performing old adults successfully manage the task by a compensatory neural mechanism associated with the modulation of controlled processing and the allocation of more resources, whereas high performing younger subjects execute the task more efficiently with fewer resources. Differences between cognitively high and average performers in processing speed increase with age. Middle-age seems to be a critical stage in which substantial differences in neural activity between high and average performers emerge. These findings provide strong evidence for different patterns of agerelated changes in the processing of salient environmental stimuli, with cognitive status serving as a key mediating variable.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 92%

Compensatory neural activity distinguishes different patterns of normal cognitive aging

et al. 2008

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“…Moreover, the study purposefully did not include cognitively low performers (i.e., those scoring in the bottom third on neuropsychological tests) to exclude old adults who may be exhibiting signs of mild cognitive impairment or early dementia. Consistent with our findings, prior studies have suggested that individuals with better concentration spans exhibit shorter target P3 latencies ( Walhovd & Fjell, 2002;Egan et al, 1994;O'Donnell et al, 1992;Polich, Howard, & Starr, 1983). However, most of these investigations either did not include old subjects (Egan et al, 1994) or studied relatively few older than 60 years (O'Donnell et al, 1992;Polich et al, 1983) and made no direct comparisons within the subset of older adults.…”

Section: Discussionsupporting

confidence: 79%

“…Studies have found differences in P3 amplitude between cognitively normal and demented elders, with the latter usually having smaller P3 amplitudes (Olichney & Hillert, 2004). In young subjects, reports have varied regarding whether the target P3 amplitude increases ( Jausovec & Jausovec, 2000) or decreases (Egan et al, 1994) as a function of higher intellectual capacity. Walhovd and Fjell (2002) found a correlation between target P3 amplitude and performance on digit span, matrix reasoning, and block design, which did not remain significant after controlling for age.…”

mentioning

confidence: 99%

Increased Responsiveness to Novelty is Associated with Successful Cognitive Aging

Daffner

Ryan

Williams

et al. 2006

Journal of Cognitive Neuroscience

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Abstract& The animal literature suggests that exposure to more complex, novel environments promotes neurogenesis and cognitive performance in older animals. Studies in humans indicate that participation in intellectually stimulating activities may serve as a buffer against mental decline and help to sustain cognitive abilities. Here, we show that across old adults, increased responsiveness to novel events (as measured by viewing duration and the size of the P3 event-related potential) is strongly linked to better performance on neuropsychological tests, especially those involving attention/executive functions. Cognitively high performing old adults generate a larger P3 response to visual stimuli than cognitively average performing adults. These results suggest that cognitively high performing adults successfully manage the task by appropriating more resources and that the increased size of their P3 component represents a beneficial compensatory mechanism rather than less efficient processing. &

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“…MRI provides a more accurate measure of the size of the brain, as head size includes both brain volume and thickness of the skull. Several studies have correlated MRI-brain volumes with measures of intelligence, and, on average, brain volume as measured with MRI and IQ correlate around 0.40 (e.g., Andreasen et al, 1993;Egan et al, 1994;Raz et al, 1993;Storfer, 1999;Wickett et al, 2000;Willerman et al, 1992).…”

mentioning

confidence: 99%

Genetic Correlations Between Brain Volumes and the WAIS-III Dimensions of Verbal Comprehension, Working Memory, Perceptual Organization, and Processing Speed

Posthuma¹,

et al. 2003

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We recently showed that the correlation of gray and white matter volume with full scale IQ and the Working Memory dimension are completely mediated by common genetic factors . Here we examine whether the other WAIS III dimensions (Verbal Comprehension, Perceptual Organization, Processing Speed) are also related to gray and white matter volume, and whether any of the dimensions are related to cerebellar volume. Two overlapping samples provided 135 subjects from 60 extended twin families for whom both MRI scans and WAIS III data were available. All three brain volumes are related to Working Memory capacity (r = 0.27). This phenotypic correlation is completely due to a common underlying genetic factor. Processing Speed was genetically related to white matter volume (r g = 0.39). Perceptual Organization was both genetically (r g = 0.39) and environmentally (r e = -0.71) related to cerebellar volume. Verbal Comprehension was not related to any of the three brain volumes. It is concluded that brain volumes are genetically related to intelligence which suggests that genes that influence brain volume may also be important for intelligence. It is also noted however, that the direction of causation (i.e., do genes influence brain volume which in turn influences intelligence, or alternatively, do genes influence intelligence which in turn influences brain volume), or the presence or absence of pleiotropy has not been resolved yet.

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Size isn't everything: A study of brain volume, intelligence and auditory evoked potentials

Cited by 62 publications

References 21 publications

Compensatory neural activity distinguishes different patterns of normal cognitive aging

Compensatory neural activity distinguishes different patterns of normal cognitive aging

Increased Responsiveness to Novelty is Associated with Successful Cognitive Aging

Genetic Correlations Between Brain Volumes and the WAIS-III Dimensions of Verbal Comprehension, Working Memory, Perceptual Organization, and Processing Speed

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