User:Vbraddick/sandbox

Draft of Posterior Cortical Atrophy page edits: I am working on this project with a partner for our Introduction to Neuroscience course, and we are both undergraduate students at Middlebury College.

Symptoms

The main symptom resulting from PCA is a decrease in visuospatial and visuoperceptual capabilities . Because the posterior region of the brain is home to the Occipital lobe, which is responsible for visual processing, visual functions are impaired in PCA patients. The atrophy is progressive; early symptoms include difficulty reading, blurred vision, light sensitivity, issues with depth perception, and trouble navigating through space . Additional symptoms include Apraxia, a disorder of movement planning, Alexia, an impaired ability to read, and Visual agnosia, an object recognition disorder. Damage to the ventral, or “what” stream, of the visual system, located in the temporal lobe, leads to the symptoms related to general vision and object recognition deficits; damage to the dorsal, or “where/how” stream, located in the parietal lobe, leads to PCA symptoms related to impaired movements in response to visual stimuli, such as navigation and Apraxia .

As Neurodegeneration spreads, more severe symptoms emerge, including the inability to recognize familiar people and objects, trouble navigating familiar places, and sometimes visual hallucinations . In addition, patients may experience difficulty making guiding movements towards objects, and may experience a decline in literacy skills including reading, writing, and spelling . Furthermore, if neural death spreads into other anterior cortical regions, symptoms similar to Alzheimer’s disease, such as memory loss, may result . Because the Parietal lobe contains the primary motor cortex, as PCA progresses patients may experience jerky movements and even seizures . PCA patients with significant Atrophy in one hemisphere of the brain may experience Hemispatial neglect, the inability to see stimuli on one half of the visual field . Anxiety and Depression (mood) are also common in PCA patients .

Connection to Alzheimer's Disease

Studies have shown that PCA may be a variant of Alzheimer’s disease (AD), with an emphasis on visual deficits . Although in primarily different, but sometimes overlapping, brain regions, both involve progressive neural degeneration, as shown by the loss of neurons and synapses, and the presence of neurofibrillary tangles and senile plaques in affected brain regions; this eventually leads to Dementia in both diseases . PCA patients have more cortical damage and Gray matter (cell body) loss in posterior regions, especially in the occipital, parietal, and temporal lobes, whereas Alzheimer’s patients typically experience more damage in the Prefrontal cortex and Hippocampus . PCA tends to impair Working memory and antereograde memory, while leaving Episodic memory intact, whereas AD patients typically have damaged episodic memory, suggesting some differences still lie in the primary areas of cortical damage .

Over time, however, atrophy in PCA patients may spread to regions commonly damaged in AD patients, leading to common AD symptoms such as deficits in memory, language, learning, and cognition . Although PCA has an earlier onset, many PCA patients have also been diagnosed with Alzheimer’s, suggesting that the degeneration has simply migrated anteriorly to other cortical brain regions .

PCA may also be correlated with the diseases of Lewy body, Creutzfeldt–Jakob disease, Bálint's syndrome, and Gerstmann syndrome . In addition, PCA may in part result from mutations in the presenilin 1 gene (PSENI1) .

This is my sandbox. Below are coding reminders for me.

Posterior Cortical Atrophy

Posterior Cortical Atrophy

PCA

• PCA is related to Alzheimer's Disease
  • Research shows that these two diseases are similar

1. PCA
   1. Atrophy
2. Alzheimer's
   1. Cortical

External Link Sample: Middlebury College Website

Internal (WIKI) Link Sample: Middlebury College Posterior cortical atrophy