Poster Session: Chromatic and luminance contrast adaptation measured using pupillometry and SSVEP

Area of Science:

• Neuroscience
• Visual Perception
• Physiological Optics

Background:

• Contrast adaptation typically reduces visual sensitivity.
• This effect is known to be chromatically tuned.
• Previous fMRI data indicated S-cone adaptation may increase post-stimulus BOLD signal.

Purpose of the Study:

• To investigate physiological correlates of chromatic and luminance contrast adaptation.
• To determine if pupil diameter and V1 activity reflect adaptation.
• To test if adaptation effects are chromatically tuned.

Main Methods:

• Steady-state visually evoked potentials (SSVEPs) from V1 and pupillometry were recorded.
• Participants underwent adaptation to chromatic (L+M or S-cone isolating) or luminance stimuli.
• Stimuli were contrast-reversing disks presented during pre-adaptation, adaptation, and probe periods.

Main Results:

• Both pupil diameter and V1 SSVEP responses increased after adaptation.
• Pupil dilation was greater for L+M adaptation with L+M probes compared to S probes.
• V1 adaptation effects were observed but lacked chromatic tuning, unlike pupil responses.

Conclusions:

• Contrast adaptation may not solely reduce sensitivity, as evidenced by increased pupil and V1 activity.
• Pupillometry is sensitive to chromatic tuning during adaptation.
• V1 adaptation appears independent of stimulus chromaticity in this paradigm.