5 Representation: Binding and Schizophrenia Flashcards
What is Area V4 involved in?
Colour Perception
Predator detection in Dichromates vs Trichromat’s
Trichromatic are a lot better at detecting predators
What is area V5 involved in?
Detection of motion
Neuropsychological evidence for a motor perception module
Bilateral lesions of V5
Colour and form perception intact
Akinetopsia: colour and form perception intact, however movement happens in steps.
What is the value of motion detection?
- Captures attention
- Segments foreground from background
- Helps compute the distance to various objects in the scene
- Helps in computing 3D shapes of an object.
- Allows estimation of the direction in which you are heading
- Allows recognition and prediction of actions
What is looming?
Looming: occurs when you are moving towards a object and it takes up more of your visual field. Looming helps judge the distance between you and the vehicle ahead of you.
It expands when you get closer, however it is not linear.
Why does object perception require processing in parallel pathways?
Because we need to process motion, colour, shape, orientation, texture.
What is a binding problem?
How does the brain put different areas in the brain that are required for certain processing together?
Why is temporal binding a potential solution?
- Distributed neural responses are tied together by the coordinated timing of their firing patterns
- This synchrony is often associated with repeated, oscillatory activity.
- Cells firing in synchrony form “cell assemblies” that collectively represent a given object at a moment in time
- Thus shared timing tags specific cells ads sharing the same “message” and links the features of an object together.
What is schizophrenia?
A disorder characterised by abnormalities in perception, cognition and emotion.
Positive schizophrenia symptoms.
Hallucinations, dellusions
Negative schizophrenia symptoms.
Lack of motivation, apathy
Cognitive symptoms of schizophrenia
Disorganised thinking, memory, word salad
Risks of schizophrenia
- Genetics
- Complications during pregnancy or at birth
- Season of birth (spring) - the flue?
- Socioeconomic factors
- Drug use in teens and young adult hood
The brain in schizophrenia
- Enlarged ventricles
- Reduction in size of several regions including the frontal cortex and medial temporal lobes
- reduction of activity in the frontal cortex and medial temporal lobes
- Excessive subcortical dopaminergic activity with increased DA release synthesis and storage
- Decrease activity in GABAergic inhibitory systems
- Decrease activity at the Nmda subtype of glutamate receptors
What does the reduced gamma band energy in response ti Mooney faces in Schizophrenia tell us?
It takes us some time to resolve what the image is. So in the control group, there is a burst of activity in the brain. However, in schizophrenics, there is reduced activity. This suggests there is a reduced ability to use these cells.
Change in physiology seems to be linked with symptoms.
What is TMS?
transcranial magnetic stimulation (TMS)
The electromagnet painlessly delivers a magnetic pulse that stimulates nerve cells in the region of your brain involved in mood control and depression. It’s thought to activate regions of the brain that have decreased activity in depression
EEG difference in schizophrenia?
There are significant changes in EEG coherence and synchrony in schizophrenia
EEG effects are observed mainly in primary and secondary auditory cortex although involvement of brainstem and frontal structures.
What hippocampal receptor availability is reduced in schizophrenia?
GABA receptor
