Evolutionary motor biases and cognition in children with and without autism

Abstract

Evolution has endowed vertebrates with a divided brain that allows for processing of critical survival behaviours in parallel. Most humans possess a standard functional brain organisation for these ancient sensory-motor behaviours, favouring the right hemisphere for fight-or-flight processes and the left hemisphere for performing structured motor sequences. However, a significant minority of the population possess an organisational phenotype that represents crowding of function in one hemisphere, or a reversal of the standard functional organisation. Using behavioural biases as a proxy for brain organisation, results indicate that reversed brain organisation phenotype increases in populations with autism and is associated with weaker cognitive abilities. Moreover, this study revealed that left-handedness, alone, is not associated with decreased cognitive ability or autism. Rather, left-handedness acts as a marker for decreased cognitive performance when paired with the reversed brain phenotype. The results contribute to comparative research suggesting that modern human abilities are supported by evolutionarily old, lateralised sensory-motor processes. Systematic, longitudinal investigations, capturing genetic measures and brain correlates, are essential to reveal how cognition emerges from these foundational processes. Importantly, strength and direction of biases can act as early markers of brain organisation and cognitive development, leading to promising, novel practices for diagnoses and interventions.

Asymmetry in the Central Nervous System: A Clinical Neuroscience Perspective

“…Investigating the link between functional hemispheric asymmetries and mother-infant positioning during interactions has a long tradition in human laterality research (Bourne and Todd, 2004) and is still popular today (Packheiser et al, 2019(Packheiser et al, , 2020Malatesta et al, 2020b). Importantly, a relation between maternal cradling asymmetries and typical and atypical development has been suggested by several studies (Forrester et al, 2019(Forrester et al, , 2020Malatesta et al, 2020a,c). Regarding ASD, an absence of cradling bias has been reported for children with ASD compared to intellectually disabled and typically developing children (Pileggi et al, 2015).…”

The Precision of the Human Hand: Variability in Pinch Strength and Manual Dexterity

“…Pegboard tests are designed to examine fine motor dexterity and gross movements of the hands, fingers, and fingertips [50]. The pegboard test we used was modified from [51], including a 10 × 10 holes pegboard and a bowl of multi-colored pegs centrally placed behind the pegboard, as shown in Figure 3. The pegboard was colored in green, red, and blue and the bowl included the same-colored pegs, as well as white and yellow distracter pegs.…”

Human Lateralization, Maternal Effects and Neurodevelopmental Disorders

“…Similarly, the negative association between atypical (right) cradling and the quality of the mother-infant relationship seems to be confirmed by the fact that stress and negative affective states reduce the leftward asymmetry (Bogren, 1984 ; Weatherill et al, 2004 ; Suter et al, 2007 , 2011 ; Reissland et al, 2009 ; Scola et al, 2013 ; Boulinguez-Ambroise et al, 2020 ; Pileggi et al, 2020 ). Furthermore, a link between this population-level bias and the later development of a typical cognitive and socio-emotional functioning has been suggested by recent findings associating developmental disorders—such as autism spectrum disorder (ASD)—and atypical patterns of lateralization in cradling (Jones, 2014 ; Pileggi et al, 2015 ; Forrester et al, 2019 , 2020 ; Herdien et al, 2020 ; Malatesta et al, 2020a , d ). This link is also highlighted by evidence unveiling that ASD constitutes a group of neurodevelopmental disorders that, besides entailing chronic and severe impairment in socio-communicative and empathic relationships, are also characterized by an early hypolateralization of brain functions (e.g., Escalante-Mead et al, 2003 ; Stroganova et al, 2007 ), including a reduced left bias for faces (Ashwin et al, 2005 ; Dundas et al, 2012 ).…”