Neural mechanisms of self-tickle cancellation in humans

Objective

In perception, neural responses are never identical, even to the same sensory stimuli. This variability is particularly evident in the somatosensory domain: why does the same tactile input feel ticklish when applied by others but not by ourselves? The phenomenon of self-tickle cancellation has intrigued philosophers, biologists, and psychologists for centuries. Motor control theories propose that self-generated movements elicit top-down predictions in the cerebellum that suppress bottom-up tactile input in the somatosensory cortex. However, how these top-down and bottom-up signals interact in the somatosensory cortex – and particularly across its different layers – to cancel self-tickle is unclear. NeuroSelfTickle aims to unravel these complexities with advanced electroencephalography, psychophysical modelling and laminar magnetoencephalography. The project seeks to identify neural markers of tickle sensation, map layer-specific cortical activity in top-down and bottom-up signal integration, and apply these insights to understand the neurocognitive mechanisms of self-tickle cancellation. This interdisciplinary approach combines well-established motor control theories with cutting-edge neuroimaging techniques and state-of-the-art haptic robotics, allowing for highly controlled yet naturalistic self-touch stimulation. The findings are expected to provide fundamental insights into how self-generated predictions influence neural computations and enhance our understanding of brain disorders where self-tickle cancellation fails, such as schizophrenia and autism. NeuroSelfTickle will create a synergy between the applicant's expertise in somatosensory neural oscillations and excitability fluctuations, and the host lab's pioneering research on tickle perception and self-tickle cancellation. The Donders Institute, along with Dr. Kilteni's lab, will provide the necessary theoretical knowledge in sensorimotor control, as well as technical expertise and support in neuroimaging.