Domain-specific and domain-general learning factors are expressed in genetically heterogeneous CD-1 mice

Abstract

It has been established that both domain-specific (e.g. spatial) as well as domain-general (general intelligence) factors influence human cognition. However, the separation of these processes has rarely been attempted in studies using laboratory animals. Previously, we have found that the performances of outbred mice across a wide range of learning tasks correlate in such a way that a single factor can explain 30-44% of the variance between animals. This general learning factor is in some ways qualitatively and quantitatively analogous to general intelligence in humans. The complete structure of cognition in mice, however, has not been explored due to the limited sample sizes of our previous analyses. Here we report a combined analysis from 241 CD-1 mice tested in five primary learning tasks, and a subset of mice tested in two additional learning tasks. At least two (possibly three) of the seven learning tasks placed explicit demands on spatial and/or hippocampusdependent processing abilities. Consistent with previous findings, we report a robust general factor influencing learning in mice that accounted for 38% of the variance across tasks. In addition, a domain-specific factor was found to account for performance on that subset of tasks that shared a dependence on hippocampal and/or spatial processing. These results provide further evidence for a general learning/cognitive factor in genetically heterogeneous mice. Furthermore (and similar to human cognitive performance), these results suggest a hierarchical structure to cognitive processes in this genetically heterogeneous species. KeywordsIntelligence; Working Memory; Learning; Cognitive Abilities; Hippocampus; Spatial Learning; Mice For much of the history of animal studies of learning and memory, research has focused primarily on the processes and mechanisms that regulate single domains of learning (e.g., spatial abilities or Pavlovian conditioning). While this tactic has been successful in delineating the neuroanatomical substrates of certain forms of learning (e.g., Christian & Thompson;2003;Eichenbaum, 2000;Phelps & LeDoux, 2005;White & McDonald, 2002) it has left unexplored those aspects of learning that are common across all domains. Conversely, studies of humans have focused extensively on the mechanisms that underlie general influences that impinge on all cognitive abilities (i.e., general intelligence). However, such studies are constrained by certain practical and ethical considerations that do not similarly limit studies of Corresponding Author: Louis D. Matzel, Department of Psychology, Rutgers University, Piscataway, NJ 08854, Email: Matzel@rci.rutgers.edu, Phone: 732/445-5940, Fax: 732/445-2263. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note tha...

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“…Animals exhibited a wide range of variability in performance across tasks, although some individuals consistently performed better or worse than the median performance on all tasks, a result that is consistent with prior work (Matzel et al 2003(Matzel et al , 2006Kolata et al 2008) and indicative of a conserved influence on performance across tasks. To quantify these observations, first a principal component analysis was conducted on the acquisition data, the reversal data, and selective attention data from the subset of mice that contributed data to all of these tasks (ns ¼ 11, 6, and 9, Groups OLD/WM, OLD/C, and YOUNG/C, respectively).…”

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

“…Animals exhibited a wide range of variability in performance across tasks, although some individuals consistently performed better or worse than the median performance on all tasks, a result that is consistent with prior work (Matzel et al 2003(Matzel et al , 2006Kolata et al 2008) and indicative of a conserved influence on performance across tasks. To quantify these observations, first a principal component analysis was conducted on the acquisition performance of the entire sample of 58 animals (including 30 young and 28 old mice, collapsed across males and females) that contributed data to every learning task.…”

“…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.…”

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