Functional mapping of the somatosensory cortex using noninvasive fMRI and touch in awake dogs

Abstract

Dogs are increasingly used as a model for neuroscience due to their ability to undergo functional MRI fully awake and unrestrained, after extensive behavioral training. Still, we know rather little about dogs’ basic functional neuroanatomy, including how basic perceptual and motor functions are localized in their brains. This is a major shortcoming in interpreting activations obtained in dog fMRI. The aim of this preregistered study was to localize areas associated with somatosensory processing. To this end, we touched N = 22 dogs undergoing fMRI scanning on their left and right flanks using a wooden rod. We identified activation in anatomically defined primary and secondary somatosensory areas (SI and SII), lateralized to the contralateral hemisphere depending on the side of touch, and importantly also activation beyond SI and SII, in the cingulate cortex, right cerebellum and vermis, and the sylvian gyri. These activations may partly relate to motor control (cerebellum, cingulate), but also potentially to higher-order cognitive processing of somatosensory stimuli (rostral sylvian gyri), and the affective aspects of the stimulation (cingulate). We also found evidence for individual side biases in a vast majority of dogs in our sample, pointing at functional lateralization of somatosensory processing. These findings not only provide further evidence that fMRI is suited to localize neuro-cognitive processing in dogs, but also expand our understanding of in vivo touch processing in mammals, beyond classically defined primary and secondary somatosensory cortices.

Comparative neuroimaging of the carnivoran brain: Neocortical sulcal anatomy

“…While knowledge of the sensory regions in carnivoran brains is still limited, the best-understood brain of the species in our sample was the domestic cat (second row, right), followed by the domestic dog (top row, left), African wild dog (top row, second from right), and the raccoon, coati, and red panda (fourth row). Based on prior electrophysiological, histological and neuroimaging research (e.g., Boch et al, 2021; Chengetanai et al, 2020a, 2020b; Douglas Jameson et al, 1968; Guran et al, 2024; Hardin et al, 1968; Kosmal, 2000; Stolzberg et al, 2017; Tunturi, 1944; Welker and Campos, 1963), we indicate approximate locations of unimodal sensory cortices on a lateral view of the brains of these species. Darker shades indicate primary sensory cortices, including the primary visual (V1, yellow), auditory (A1, pink), motor (M1) and somatosensory (S1) cortex.…”