Investigating the Role of Subcortical Visual Pathways for 'Blindsight' and Gist Perception in Parkinson's Disease Using Multimodal Neuroimaging and Computational Neuroscience

Parkinson's disease (PD) is primarily known as a movement disorder, but emerging evidence suggests that it might also significantly impact visual processing, specifically 'blindsight' and gist perception (Diederich et al., 2014;Uchiyama st al., 2012). Gist perception is critical since it gives us the ability to rapidly orient ourselves in a complex environment. Gist perception involves a series of processes that rapidly and non-selectively extracts global structure and statistical regularities from our visual environment (Evans& Tresiman, 2005; Wolfe,Vo, Evans & Greene, 2010).

Preliminary findings indicate early degradation of the subcortical visual pathways, like the SC (superior colliculus) and Pulvinar may be responsible for these impairments. Interestingly, when scenes or objects are chiefly defined by S-cone inputs to the koniocellular pathway (which also bypass the SC), gist perception also appears to be compromised. This project proposes a fusion of computational neuroscience techniques with multimodal neuroimaging methods to comprehensively investigate these associations.

We will examine the hypothesis that selective damage to subcortical visual pathways is responsible for the loss of gist perception in PD. This PhD will focus on two approaches:

1. We will test gist perception in normal controls using a variety of chromatic stimuli that can selectively target or bypass the superior colliculus. We will measure subjects’ gist perception for these stimuli using psychophysics and we will also use functional neuroimaging (fMRI) to measure cortical and sub-cortical activations driven by these stimuli.
2. We will test gist perception in subjects with Parkinson’s disease to measure the full extent of the visual impairment and the degree to which this affects their everyday function. Using systematic psychophysical and neuroimaging measurements at different times in the progression of the disease starting with initial mild cognitive impairment stage, initial diagnosis and subsequent progression we will track the progression of behavioral and neuronal changes in gist perception.

Significance:

This project will not only expand our understanding of Parkinson's disease beyond the motor symptoms but also shed light on the intricate visual processing mechanisms that are often overlooked. By identifying the specific neural pathways and mechanisms involved, we can provide more targeted therapeutic strategies for PD patients.

The York Biomedical Research Institute at the University of York is committed to recruiting extraordinary future scientists regardless of age, ethnicity, gender, gender identity, disability, sexual orientation, religion/belief, marital status, pregnancy and maternity, or career pathway to date. We understand that commitment and excellence can be shown in many ways and have built our recruitment process to reflect this. We welcome applicants from all backgrounds, particularly those underrepresented in science, who have curiosity, creativity and a drive to learn new skills.