Often called ‘Where Pathway’, the dorsal visual pathway is involved in the processing of spatial position and related motion control like saccade and reaching. Notably, the dorsal visual pathway starts from area v1, passes through areas v2 and v3, and then projects to the middle temporal area (area v5) and inferior parietal lobule 3. Visual-processing abnormality resulting from AD has attracted much attention in recent years. Experimental results reported that the visual function of AD patients was selectively lost, including losses of color discrimination, stereoacuity, contrast sensitivity and backward masking, which were all caused by the lesion of primary and association visual cortices in AD patients 2. Specifically, research on the visual cortex in AD showed that the spatial contrast sensitivity of the primary visual cortex in AD patients was significantly lower than that in elder adults with normal health 1. Follow-up clinical works found that AD would also impair language, executive and visual functions. In the early clinical stage, memories and powers of concentration would be affected first. Similar content being viewed by othersĪlzheimer’s disease (AD) is the most common neurodegenerative disease in elderly people. Hopefully, the results of this study could provide theoretical guidance for understanding the dynamical mechanism of AD. decrease in descending projections from area v2 to v1 and v5 to v2 and ascending projection from area v2 to v5. The results demonstrate that the coherence between these interconnected cortical areas showed an obvious decline with the gradual decrease of long synaptic projections, i.e. Then, the loss of long synaptic projections on coherence among different visual cortex areas was explored by means of power spectral analysis and coherence function. Next, the pathological condition of loss of long synaptic projections in AD was simulated by reducing the parameters of long synaptic projections in the model. The three interconnected cortical areas were connected by ascending and descending projections. Firstly, according to the hierarchical organization of the cerebral cortex and the information flows of the dorsal visual pathway, a more physiologically plausible neural mass model including cortical areas v1, v2, and v5 was established in the dorsal visual pathway. This work aimed to investigate the effect of AD on coherence in the dorsal visual pathway by the technique of neurocomputation. Decreased coherence in electroencephalogram (EEG) has been reported in Alzheimer’s disease (AD) experimentally, which could be considered as a typical electrophysiological characteristic in AD.

Global phase coherence matlab