Adaptation aftereffects and the coding of tactile distance
Mon-H9-Talk 3-3603
Presented by: Elena Azañón
Adaptation aftereffects can reveal how different dimensions of stimuli are selectively processed by populations of neurons. In a series of behavioral experiments, we harnessed these aftereffects to gain insights into the representation of tactile distance. Pairs of pointed tactile stimuli separated by particular distances were applied either on the hand, or on the fingers. We subsequently tested the magnitude and gradient of adaptation aftereffects across adjacent skin regions to the adapted one. In addition, we conducted electrophysiological recordings to assess the impact of adaptation to a particular distance following prior adaptation to either a large or small distance. Our findings indicate that the distance between two distinct tactile events on the skin is susceptible to adaptation. Additionally, the transfer of adaptation aftereffects showed a very specific pattern, extending to adjacent areas of the hand and finger but not across fingers, palm and dorsum, or finger and hand. Notably, early electrophysiological differences emerged in response to a given distance, when preceding adapting stimuli were either large or small. These results support the notion that the computation of distance in touch begins at early stages of somatosensory processing. Furthermore, the distinctive pattern of aftereffects across adjacent areas could potentially provide a psychophysical insight into the organization and overlap of tactile receptive fields, particularly concerning anatomical and functional boundaries between different body parts.
Keywords: tactile distance, adaptation aftereffects, receptive fields, electrophysiology