Brain reorganization as a function of walking experience in 12-month-old infants: implications for the development of manual laterality

Abstract

Hand preference in infancy is marked by many developmental shifts in hand use and arm coupling as infants reach for and manipulate objects. Research has linked these early shifts in hand use to the emergence of fundamental postural–locomotor milestones. Specifically, it was found that bimanual reaching declines when infants learn to sit; increases if infants begin to scoot in a sitting posture; declines when infants begin to crawl on hands and knees; and increases again when infants start walking upright. Why such pattern fluctuations during periods of postural–locomotor learning? One proposed hypothesis is that arm use practiced for the specific purpose of controlling posture and achieving locomotion transfers to reaching via brain functional reorganization. There has been scientific support for functional cortical reorganization and change in neural connectivity in response to motor practice in adults and animals, and as a function of crawling experience in human infants. In this research, we examined whether changes in neural connectivity also occurred as infants coupled their arms when learning to walk and whether such coupling mapped onto reaching laterality. Electroencephalogram (EEG) coherence data were collected from 43 12-month-old infants with varied levels of walking experience. EEG was recorded during quiet, attentive baseline. Walking proficiency was laboratory assessed and reaching responses were captured using small toys presented at mid-line while infants were sitting. Results revealed greater EEG coherence at homologous prefrontal/central scalp locations for the novice walkers compared to the prewalkers or more experienced walkers. In addition, reaching laterality was low in prewalkers and early walkers but high in experienced walkers. These results are consistent with the interpretation that arm coupling practiced during early walking transferred to reaching via brain functional reorganization, leading to the observed developmental changes in manual laterality.

Parallel Emergence of True Handedness in the Evolution of Marsupials and Placentals

“…In primates, bipedality has also been shown to be associated with enhanced manual lateralization (e.g., [8,10,37,38]). Bipedalism, along with other factors [3,24], has been suggested as a catalyst for the emergence of robust handedness in humans [8,39]. Our findings on marsupials further emphasize the role of bipedality in the evolution of manual lateralization.…”

Lateralization and cognitive systems

“…With more than 5500 article views and an AM score of more than 50 by the time this editorial was written, this article has gained more online attention than almost any other work published in Frontiers in Cognition. Other authors investigated visual lateralization (Asanowicz et al, 2013 ; Pellicano et al, 2013 ; Helon and Króliczak, 2014 ), asymmetries in emotional processing (Propper and Brunyé, 2013 ; Grimshaw and Carmel, 2014 ), behavioral lateralization (Morton, 2013 ; Corbetta et al, 2014 ), and asymmetries in face (Coronel and Federmeier, 2014 ) and body representation (Hach and Schütz-Bosbach, 2014 ), as well as in word generation (Meyer et al, 2014 ) and word recognition (Izura et al, 2014 ). Finally, some authors also investigated the impact of lateralized processing on executive functioning, the topic which had initially inspired this Research Topic (Marsh et al, 2013 ; Ocklenburg et al, 2013a ; Kéïta et al, 2014 ; Stock and Beste, 2014 ).…”

The Development of Bimanual Coordination Across Toddlerhood

“…Such differentiation is highly task‐dependent, however, and many actions in which the hands act in complementary roles emerge early in the second year (Bruner, ; Kimmerle et al, ; Kimmerle et al, ; Potier et al, ; Ramsay & Weber, ) or even later (Brakke et al, ; Connolly & Dalgleish, ; Fagard & Jacquet, ). Kimmerle et al () have suggested that this shift in infants’ approach to manipulation represents a transition in neural control of the hands, perhaps related to the fluctuations in coordination tendencies that Corbetta et al () observed and related to the onset of walking.…”

“…Corbetta and Thelen () have examined the coordinative tendencies of infant reaching throughout the first year of life and found that the tendencies to use one or both hands fluctuate throughout the year, starting with the earliest reaching actions (see also Fagard & Pezé, ; Goldfield & Michel, ; Ramsay, ). The research on infant bimanual action has also suggested that the fluctuating use of one or two hands during the first year appears to be linked to fluctuations in the strength of neural coupling (Corbetta, Friedman, & Bell, ; Fagard & Pezé, ), often accompanying the emergence of new behaviors in other domains such as reduplicated babbling (Ramsay, ) or walking (Corbetta & Bojczyk, ).…”