Lecture 7 - Schizophrenia II Flashcards
What is bottom up and top down processing and how is it linked to schizophrenia?
Bottom up = new sensory information coming in from the outside world.
Top down = all information that is learned interacting with new information to influence how we view it.
Normally these 2 processes link up but patients with schizophrenia struggle to link the information together.
How can we test working memory, what does the task depend on and how is this linked to schizophrenia?
Match to sample task tests spatial WNM where subjects must remember the location of an object and determine if it matches the original sample.
Task dependent on sustained firing of PFC pyramidal cells, fast spiking interneurons also being active in the delay phase.
Schizophrenic patients show these cells aren’t working properly.
What is the disconnection hypothesis?
Basal ganglis, auditor complex, parietal lobe, occipital lobe, hippocampus, limbic system and frontal cortex all involved in schizophrenia.
Imaging studies have shown decreased functional connectivity between these regions.
In the hollow mask illusion there is decreased connectivity between parietal and occipital lobes in schizophrenics.
Describe brain oscillations in schizophrenic patients.
Sensory evoked beta/gamma activity is decreased and spontaneous beta/gamma activity in the background is increased.
Gamma waves are present much later and fewer because PV neurons and pyramidal cells are impaired.
Hallucinations associated with an increase in gamma sensory areas, increases in long range synchrony and abnormal plasticity.
