Human tactile discrimination of pulse shape is possible without preadaptation

Area of Science:

• Neuroscience
• Sensory Perception
• Biomechanics

Background:

• Texture discrimination may involve analyzing kinematic properties of frictional stick-slip movements.
• Previous studies focused on adapted tactile responses to repetitive stimuli.

Purpose of the Study:

• To investigate if isolated, single tactile pulses can be perceived based on their shape.
• To determine if neuronal "onset-responses" carry information about pulse shape.

Main Methods:

• A two-alternative forced-choice paradigm was used to test human participants' ability to discriminate pulse shapes.
• Participants identified which of three pulsatile skin indentations (0.5s interval) had a deviating shape.

Main Results:

• A majority of participants (18/30) correctly identified isolated pulse shapes (P(correct) > 0.75).
• Performance improved when identical shape changes were preceded by an adaptive series of pulses.
• Participants did not show a preference for specific kinematic parameters during discrimination.

Conclusions:

• Perceptual systems can access the kinematic shape of single, isolated pulsatile skin deflections.
• Sensory adaptation is critical for the quality and specificity of encoding kinematic pulse profiles.