Entropy-driven visual choice in Parkinson's disease

Area of Science:

• Neuroscience
• Ophthalmology
• Movement Disorders

Background:

• Parkinson's Disease (PD) is known to affect visual search and navigation, primarily attributed to top-down cognitive processes.
• Understanding the role of bottom-up visual mechanisms in PD is crucial for a comprehensive view of visual dysfunction.

Purpose of the Study:

• To investigate the independent influence of bottom-up visual mechanisms on visual exploration and perceptual decision-making in Parkinson's Disease.
• To utilize synthetic, low-semantic value visual stimuli to minimize top-down biases.

Main Methods:

• Recorded binocular eye movements at 1000 Hz using the Eyelink 1000 Plus system.
• Presented participants with pairs of grayscale images of varying entropy, requiring a choice while recording gaze patterns.
• Extracted data including saccade latency, choice latency, and image entropy at first saccade and choice for both PD subjects and Healthy Controls (HCs).

Main Results:

• PD subjects exhibited an age-related tendency to choose high-entropy images and direct their first saccade towards them, unlike HCs.
• A direct correlation was found between the latency of choice and PD disease severity.
• Increased preference for and fixation on high-entropy images correlated with age in PD patients compared to HCs, suggesting progressive basal ganglia dysfunction.

Conclusions:

• The intrinsic entropic value of visual scenes significantly influences visual exploration and choice in PD.
• Bottom-up visual and motor control mechanisms appear linked to bradykinesia in Parkinson's Disease.
• Progressive dysfunction in basal ganglia mechanisms controlling visual attention and motor targeting of high-entropic images is indicated in aging PD patients.