Hand Preference for Tool‐Use in Capuchin Monkeys (Cebus apella) Is Associated With Asymmetry of the Primary Motor Cortex

Abstract

Skilled motor actions are associated with handedness and neuroanatomical specializations in humans. Recent reports have documented similar neuroanatomical asymmetries and their relationship to hand preference in some nonhuman primate species, including chimpanzees and capuchin monkeys. We investigated whether capuchins displayed significant hand preferences for a tool use task and whether such preferences were associated with motor-processing regions of the brain. Handedness data on a dipping tool-use task and high-resolution 3T MRI scans were collected from 15 monkeys. Capuchins displayed a significant group-level left-hand preference for this type of tool use, and handedness was associated with asymmetry of the primary motor cortex. Left-hand preferent individuals displayed a deeper central sulcus in the right hemisphere. Our results suggest that capuchins show an underlying right-hemisphere bias for skilled movement.

Hand Preference during Tool Use in Wild Bearded Capuchins

“…The high degree of lateralization in capuchins has been highlighted in a series of studies in captive groups tested with bimanual tasks and in tool use [Westergaard and Suomi, 1996a, b;Spinozzi et al, 1998;Lilak and Phillips, 2007;Meunier and Vauclair, 2007], which could indicate asymmetries in the motor cortex [Fagot and Vauclair, 1991;Phillips and Thompson, 2013]. Tool use, particularly nut cracking, has been associated with strong individual laterality and also population-level right-handedness in communities of wild chimpanzees [Boesch, 1991;Lonsdorf and Hopkins, 2005;Humle and Matsuzawa, 2009; but see Marchant and McGrew, 2013] and in captive groups of capuchin monkeys the use of tools to pound/crack is right-handed [Westergaard and Suomi, 1996b].…”

“…Given the association between tool use, finer motor control and the leading role of the left hemisphere for highly demanding processes [Fagot and Vauclair, 1991;Hammond, 2002;IturriaMedina et al, 2011], right-handedness could be expected. Although there are some studies that show a left-hand bias during tool use in non-human primates [Westergaard, 1991;McGrew and Marchant, 1992;Anderson, 1996;Bogart et al, 2012;Phillips and Thompson, 2013], they focused on tool use involving probing, which probably requires more tactile input. The left-hand preference could reflect asymmetry favouring the right cerebral hemisphere for its haptic sensory inputting [Cochet and Byrne, 2013;Phillips and Thompson, 2013].…”

“…Although there are some studies that show a left-hand bias during tool use in non-human primates [Westergaard, 1991;McGrew and Marchant, 1992;Anderson, 1996;Bogart et al, 2012;Phillips and Thompson, 2013], they focused on tool use involving probing, which probably requires more tactile input. The left-hand preference could reflect asymmetry favouring the right cerebral hemisphere for its haptic sensory inputting [Cochet and Byrne, 2013;Phillips and Thompson, 2013]. Lonsdorf and Hopkins [2005] found that termite fishing in wild chimpanzees is left-handed at population level, while nut cracking elicits right-handedness, and they suggest that differential cognitive, sensory and motor demands of these tool activities might be responsible for the directional biases in hand use.…”

Capuchin monkeys use only proto-tools to crack jatobá hard-shelled fruits in an urban environment

“…Several studies have reported the relation between tool-use and the capuchin monkey handedness and cognitive skills (Spinozzi et al, 2004;Phillips and Thompson, 2013).…”

Morfologia radicular da dentição permanente de Sapajus apella: morfometria, anatomia macroscópica, ultraestrutura e propriedades físicas

“…A literatura relata alguns estudos sobre a morfologia desta espécie em algumas regiões do sistema nervoso central (Guerreiro-Diniz et al 2012, Phillips & Thompson 2013, do sistema circulatório (Rosa et al 2012) e de algumas estruturas ósseas (Byron 2009). Além disso, existem pesquisas sobre o aparelho estomatognático desta espécie que buscam associar a sua arquitetura morfológica com os seus hábitos comportamentais e sua dieta (Tylor & Vinnyard 2009, Muchlinski et al 2011.…”