Chapter 1: clinical neuropsychology - a histrorical sketch Flashcards
Phrenology (Gall)
Doctrine of the skull. Alle psychological functions are innate and located somewhere on the outside of the brain (cortex). When a part of the brain is bigger, it’s more developed and reflects a psychological function. He saw loss of functions due to brain damage as proof for his theory.
Luria
Luria thought that all brain areas are involved in 3 core functions (units) that ineract with each other:
1. Subcortical brain areas: arousal and attention.
2. Posterior brain areas: processing information from the senses.
3. Anterior brain area: for planning and organising actions.
Information in each unit is processed in 3 hierarchically organised zones (primary, secondary, tertiary).
The left hemisphere is important for linguistic tasks and the right hemisphere for non-linguistic tasks.
Geschwind
Made an assumption that functional centers exist in the brain and those centers are interconnected. A disruption of these connections leads to specific deficits: dissociations. He used dissociation and double dissociation for his studies.
Dissociation
A patient with a lesion in region X had impaired performance on task A, but not task B.
Dissociation occurs when a lesion or damage to a particular brain region affects one cognitive function but not another. This suggests that the affected function is localised in the damaged area, while the unaffected function is likely localised elsewhere.
If a patient has damage to brain region A and as a result, they can no longer perform task X but can still perform task Y, this is a dissociation. For instance, if someone has damage to Broca’s area and they struggle with speech production (task X) but can still understand speech (task Y), this indicates a dissociation between speech production and speech comprehension.
Double dissociation
Double dissociation involves two patients with different lesions that affect two different cognitive functions in an opposite manner. This provides stronger evidence that the two functions are processed by distinct and independent brain regions.
Example: Imagine Patient 1 has damage to Broca’s area and thus has trouble with speech production (impaired task X) but can still understand speech (unimpaired task Y). Patient 2, on the other hand, has damage to Wernicke’s area and struggles with speech comprehension (impaired task Y) but can still produce speech (unimpaired task X). This pattern of results shows a double dissociation because it clearly indicates that speech production and speech comprehension are managed by different neural mechanisms located in different brain regions.
Hemispheric specialisation
Sperry researched split brain surgery and found that the right hemisphere was better than the left hemisphere at certain functions. This was the end of the left-hemisphere dominance.
Visual agnosia
A disorder of recognising objects. Someone is unable to recognise object, but can see and draw them.
Apperceptive agnosia
Deficit in de apperception stage. Inability to combine individual features into the concept as a whole. Inability to recognize objects.
Associative agnosia
People who are able to copy and draw the object, but are unable to say what they drew. They can see the house, but can’t say what a house is for.
CT scan
Computed tomography. It can detect lesions in brain tissue.
MRI
Magnetic Resonance Imaging. Looks at blood flow to certain brain area’s.
EEG (plakkers op hoofd)
Electroencephalography. Links electrical activity to the perception of a particular stimulus characteristic.
Conduction aphasia
When someone is able to speak and understand, but unable to repeat spoken words.
