Individual Differences in the Expression of a “General” Learning Ability in Mice

Abstract

Human performance on diverse tests of intellect are impacted by a "general" regulatory factor that accounts for up to 50% of the variance between individuals on intelligence tests. Neurobiological determinants of general cognitive abilities are essentially unknown, owing in part to the paucity of animal research wherein neurobiological analyses are possible. We report a methodology with which we have assessed individual differences in the general learning abilities of laboratory mice. Abilities of mice on tests of associative fear conditioning, operant avoidance, path integration, discrimination, and spatial navigation were assessed. Tasks were designed so that each made unique sensory, motor, motivational, and information processing demands on the animals. A sample of 56 genetically diverse outbred mice (CD-1) was used to assess individuals' acquisition on each task. Indicative of a common source of variance, positive correlations were found between individuals' performance on all tasks. When tested on multiple test batteries, the overall performance ranks of individuals were found to be highly reliable and were "normally" distributed. Factor analysis of learning performance variables determined that a single factor accounted for 38% of the total variance across animals. Animals' levels of native activity and body weights accounted for little of the variability in learning, although animals' propensity for exploration loaded strongly (and was positively correlated) with learning abilities. These results indicate that diverse learning abilities of laboratory mice are influenced by a common source of variance and, moreover, that the general learning abilities of individual mice can be specified relative to a sample of peers.

Explaining brain size variation: from social to cultural brain

“…They are particularly well documented in rodents, which also provide some insight into the evolutionary continuity of the mechanism. For instance, like in humans, g-factors extracted in rodent studies covary with efficacy in selective attention and working memory capacity [86,87]. the fact that species living in simple social systems, such as orangutans, aye-ayes or bears [20] have large brains.…”

Age-related declines in general cognitive abilities of Balb/C mice are associated with disparities in working memory, body weight, and general activity

“…To quantify individual differences in learning among mice, a variant of the procedures previously reported was used (Matzel et al 2003(Matzel et al , 2006Kolata et al 2005Kolata et al , 2007Kolata et al , 2008). All animals were tested in a series of six independent learning tasks (Lashley III Maze, passive avoidance, spatial water maze, odor discrimination, and fear conditioning) that place unique sensory, motor, motivational, and information processing demands on the animals.…”

Acute cognitive impairment after lateral fluid percussion brain injury recovers by 1 month: Evaluation by conditioned fear response

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