Olfactory neural connections associated with cognition in Parkinson’s disease progression

Abstract

To study the neural connections between orbitofrontal cortex (OFC) and olfactory cortex and analyze their consistency ranging from control group to Parkinson’s Disease (PD) affected groups of different stages of progression. The OFC plays an important role in drawing perceptions from sensory stimuli. The visual aspect of the same has been greatly explored, but olfactory aspect still remains a matter of curiosity. A study done on this topic states that the OFC plays a major role in olfactory perception, and the right OFC is relatively more dominant. A disruption of neural connections of the OFC has been known to cause disturbances in cognitive, behavioral and emotional functions. Therefore, a disruption of neural connections of this region with the olfactory cortex could potentially alter normal processing of stimuli causing changes in one’s response to them. This would give rise to an olfaction associated cognitive dysfunction, which is often reported to precede motor symptoms seen in PD. Fiber tractography performed using Diffusion Tensor Imaging in 4 groups of 40 datasets each, obtained from different individuals. These groups include a control group and three PD affected groups from different stages of severity. The difference noted in fibres of control group and PD affected group is statistically significant with a p-value of 0.00001, the average number of fibres noted in a normal was 56 while that in a PD affected person was 16. The difference noted in fibres among different stages of progression was also significant with a p-value of 0.00001 (figure 1–4).