Visual Responsivity in Autism: Measuring Visual Responses in Autistic and Non-Autistic Adults Using Psychophysics,...

Area of Science:

• Neuroscience
• Psychology
• Sensory Processing

Background:

• Autistic individuals often report visual hypersensitivity, but research findings are inconsistent.
• Hypotheses suggest differences in sensory gain or neural hyperexcitability.
• Methodological variability may explain inconsistent findings in autism visual processing research.

Purpose of the Study:

• To investigate group differences in visual processing between autistic and non-autistic adults.
• To compare neural and behavioral responses to flickering visual stimuli using psychophysics, fMRI, and EEG.
• To explore the relationship between neural responses, brain activity, and sensory hypersensitivity in autism.

Main Methods:

• Thirty-one autistic and 27 non-autistic adults passively viewed flickering checkerboards at varying contrasts.
• Blood oxygenation level-dependent (BOLD) signals via fMRI and steady-state visual evoked potentials (SSVEPs) via EEG were recorded.
• Psychophysical measures assessed behavioral thresholds.

Main Results:

• Contrast modulated neural responses, but no group differences were found in BOLD signals or behavioral thresholds.
• Autistic individuals exhibited significantly higher SSVEP amplitudes, indicating greater neural entrainment.
• SSVEP amplitudes correlated with BOLD responses and self-reported visual hypersensitivity.

Conclusions:

• Differences in visual processing between autistic and non-autistic individuals are more apparent in frequency-locked neural responses (SSVEPs).
• Heightened neural entrainment in autistic adults is linked to visual cortical activity and sensory hypersensitivity.
• SSVEPs offer a sensitive measure for understanding visual processing differences in autism.