Biological 1: Methods for studying the brain Flashcards
(46 cards)
What is biological psychology?
The study of the relationship between psychological events and processes, and physical events in the brain
What is the aim of biopsych methods?
To study the relationship between psychological events and processes and physical events in the brain.
What might be issues with matching methods to hypotheses?
- Causal or correlative?
- Species psychologically applicable? (rodents) (Invasive?)
- Spatio-temporal resolution physically applicable?
What is important to consider when choosing spatial and temporal scales with which to measure the brain?
Size scale - Is the hypothesis about individual neurons or cerebral hemispheres?
Time scale - Is the hypothesis about individual action potentials or long-lasting changes in synapses?
Approximately how many neurons do we have, and are these all the same size?
86 billion
No, neuron size varies a lot
How long is the neural refractory period? (hyperpolarisation in action potential)
2ms
How long is the signal time from eye to brain?
20-100ms
What new brain imaging techniques have developed since 1988?
Microstimulation
Optogenetics
Field potentials
Calcium imaging
Electron microscopy
fMRI imaging
TMS
How do lesions give us information about the brain?
- Changes in psychological function accompanying brain damage may reveal something about the function of the damaged tissue
- Accidental injury in humans, intentional damage in animals
e.g. Phineas Gage - prefrontal cortex function for inhibition, planning and personality
What were confounding variables to Phineas Gage’s change in behaviour?
Trauma
Facial damage - people treated him differently
How did patient Tan enable the localisation of speech production?
Suffered left frontal brain damage following a stroke (post mortem showed this) - could only say ‘Tan’
- No other deficits e.g. hand gestures and tone
Broca observed that many patients with speech production problems shared left hemisphere brain damage in common.
‘Broca Aphasia’
Limited speech, loss of grammatical structure.
Less severe cases - lose conjugations like ‘and but’
What do Broca’s and Wernicke’s areas do? Are these the only regions involved in language?
Broca’s - speech production
Wernicke’s - language comprehension
No - now we know many other regions are involved
HM had surgery for epilepsy, removing large parts of the medial temporal lobes including the hippocampus. What happened to his memory?
Could remember previous episodic memories
No ability to store or retrieve new memories
Normal implicit learning
Could learn a new task (procedural) but could not remember getting better
What is an issue with the logic of the experimental lesion method?
Logic is based on a locationalist perspective
Ignoring adaptive and parallel brain processes can lead to false conclusions - other areas other than lesioned area may be involved
What was Lashley’s principle of mass action?
- Lashley concluded that learning occurred everywhere in the brain.
- The larger the lesion the larger the learning deficit.
- The harder the task the more brain required, therefore as task difficulty increases the effectiveness of a lesion increases.
Mass action is the null hypothesis that modern behavioural neuroscience is trying to disprove
What is a single dissociation design?
Lesion group completes Task A and Task B
Control group completes Task A and Task B
Lesion group can do B but not A
Control can do A and B
Lesioned area must help with abilities needed to perform Task A
What is an issue with single dissociation designs?
Single dissociation may result from general effects of trauma, not specific effect of lesion
What is a double dissociation design?
Tasks A and B performed by:
Lesion Group X
Lesion Group Y
Controls
Perfect double dissociation:
Lesion Group X can do A but not B
Lesion Group Y can do B but not A
Controls can do both
Shows functions of lesioned areas, and shows that difference is not due to confounds of trauma
What is the double dissociation for fear and spatial learning in the hippocampus?
Dorsal lesion group:
Cannot do spatial
Can do contextual fear
Dorsal hippocampus = spatial navigation
Ventral lesion group:
Can do spatial
Cannot do contextual fear
Ventral hippocampus = fear conditioning
Controls can do both
Can tell that part of hip for fear conditioning is not affected by part of hip for spatial learning - these areas have independent functions
What is one thing to be careful of in double dissociations?
Order effects
Counterbalance two halves of each group
Can rats with a dorsal hippocampus lesion navigate in a Morris water maze?
No
Dorsal hippocampus involved in spatial navigation
Can rats with a dorsal hippocampus lesion learn to associate a tone with a footshock?
Yes
Rats with a ventral hippocampus lesion cannot
Ventral hippocampus involved in associative conditioning
Reversible methods of lesions can be used on animals so that they can act as their own controls. What is an issue with this?
Can raise design issues - do they get better at task over time?
Counterbalancing should help with this
How is reversible deactivation done in animal brains?
Chemical methods
Drugs can be delivered in minute quantities into precisely located brain areas to deactivate specific regions temporarily.
(Cannula)
