The relationship between behavioural and hemispheric sleep laterality in dogs

Most research into human cognition has focused predominantly on right-handed individuals, ignoring the left-handed minority due to assumed differences in their brain lateralization. Although practical limitations make it challenging to recruit an equal number of left- and right-handed human participants, research into animal models may shed light on the assumed, but rarely tested, associations between motoric handedness, side preference and brain lateralisation. In the present study, we used the family dog, often studied as a model for complex human-analogue socio-cognitive skills. In Study 1, N = 19 dogs completed a range of behavioural tests assessing lateralisation followed by a sleep EEG recording. In Study 2, N = 14 dogs, specifically selected based on prior side bias history in other cognitive experiments, were behaviourally tested in two side-preference tasks and assessed in a sleep EEG measurement. Results show that both negative and positive correlations exist between certain behavioural lateralisation parameters and hemispheric asymmetry in sleep EEG spectrum. These partly support the use-dependent recovery function of sleep (negative correlations) as well as suggest fingerprint-like individual-level associations between sleep and waking behaviour. These findings are relevant for future research capitalizing on the dog as a model for human visuo-spatial attentional biases.