Effects of brain damage and brain stimulation Flashcards
1
Q
What is the issue of causality?
A
- brain imaging makes it possible to examine the brain substrates of psychological processes
- neuroimaging techniques suffer from one serious limitation: that some brain activity is associated with a task/hypothetical psychological process
- it means the activity doesn’t necessarily cause the observed behaviour/hypothesised psychological process
2
Q
What are non-essential activations?
A
- some brain regions may be involved in learning of any new task but not required once the task has been learned
- some brain areas are recruited as ‘back-up’ in case processing requires extra resources/effort
3
Q
The effects of what in humans can be examined?
A
- neurosurgery
- stroke
- brain trauma/tumours
- neurodegeneration
- infection
4
Q
What is neuropsychology?
A
- area that examines effects of brain damage on abilities and behaviour
- if damage to particular region/structure is systematically associated with certain cognitive impairment, that region is necessary for the cognitive process to function
- therefore must be part of the anatomical substrate for the given cognitive process
5
Q
What types of problems can occur when the brain is damaged?
A
- fatigue
- epilepsy
- concentration troubles
- paralysis
- disinhibition
- language problems
- apraxia
- executive, attentional, and emotional regulation problems
- low insight
- personality change
6
Q
What is the Broca’s area and how is it linked to speech?
A
- left inferior frontal lobe
- lesions to the area result in language impairments, as seen in Tan who could only say that word
- Wernicke’s aphasia: ability to comprehend meaning of words is highly impaired, often use sentences but with wrong words/non-existent words
7
Q
What is the contusion and frontal lobe disorder?
A
- brain damage as a consequence of a blow to the head
- several axonal damage, frontal cell damage, swelling and bleeding
- symptoms include: disorientation, memory loss, disinhibition, problems with emotional regulation, planning problems/goal directed behaviour, highly distractible
8
Q
What is temporal lobe amnesia and who is HM?
A
- to treat his severe epilepsy had bilateral, medial temporal lobe resection
- had profpund anterograde amnesia (no episodic memories)
- also had retrograde amnesia (recalled childhood but not time before surgery)
- working memory was relatively normal, procedural and lexical memory were close to normal
9
Q
What is hemispatial neglect?
A
- inattention to parts of the visual field so they can see everything but no attend to it
- neglect symptoms: only attending to things on the right, move in opposite direction if coming from neglected side, problems reading, ignoring objects in environment, problems navigating space and using certain limbs, no insight
- lateralization to left side suggests attention is inherently biased to the right and function bringing it left is impaired
- other possibility is that internal representation wen wrong or motor system in certain directions is impaired
10
Q
What are dissociations?
A
- neuropsychological data can be used to test theories about the architecture of psychological processes even without knowing the exact location of the damage
- whether things are processed differently
11
Q
How do single case studies differ from group studies?
A
- group-level analysis reduces contribution of irrelevant factors and emphasises effect of manipulation
- not always possible to do groups though in neuropsychology
12
Q
What are the strengths and limitations of neuropsychology?
A
- enables causal inference (which electrophysiology and neuroimaging doesn’t)
- main drawback is that lesions resulting from trauma/neurological degeneration is rarely anatomically selective (affect multiple)
- damage is always associated with general cognitive,emotional and personality changes which is difficult to separate from damage to specific region
13
Q
What is the neurophysiology of TMS?
A
-large current briefly discharged into coil of wire on subjects head, current makes rapidly changing magnetic field that passes into brain and sends random signals
14
Q
What effects do TMS have on performance and what can be inferred from them?
A
- TMS pulse typically induces brief chaotic increase in neural activity often followed by more sustained reduction in excitability
- inevitably results in disorganisation of neural activity (usually impaired performance)
- effect is similar to that of neurological lesion but mild, reversible and safe
15
Q
What’s a suitable control condition for TMS?
A
- need to control for somatosensory and auditory effects of TMS
- no TMS isn’t enough as a control because some of the effect of TMS is due to the noise and sensation it elicits
- sham TMS (noise but no stimulation) doesn’t control for somatosensory component (the sensation on the scalp, muscle twitches, discomfort)
- control site (over area that’s unlikely to be involved in task)
- sometimes difficult to ensure that control site has equivalent somatosensory and auditory effects to test site
