Lecture 1 - Biological methods Flashcards
1
Q
Biological Psychology
A
- the study of the relationship between psychological events and processes, and physical events in the brain
- aims to understand: how the brain creates the mind & uncover processes through their reflection in distinct brain processes
2
Q
methods in biological psychology
A
- aim to study the relationship between psychological events and processes any physical events in the brain
- map to structures and processes in the brain
- need to match method to the hypothesis being tested, ethical/practical considerations
3
Q
spatio-temporal scales
A
- relevant sizes:
> whole brain: 26cm
> topographic map: 5mm
> cortical-column: 250um
> cortical layer 50um
> neuron: 10um
> dendrite: 1um
> synapse: 100um - approx 86billion neurons in brain
- relevant times:
- neural refractory period (recovery) after neuron has fired: 2ms
- signal time eye to brain 20-100ms
- for LTP would look at time cells make structural changes in relation to experiences
4
Q
lesions:
A
- changes in psych function accompanying brain damage may reveal something about the function of the damaged tissue
- can look at changes in functions and behaviours as a result to suggest localisations
5
Q
lesions: phineas gage
A
- tamping iron incident to L frontal lobe & reports of personality damage
- conscious immediately after but barely conscious 10 days later then recovered.
- no motor or speech impairments, memory intact
- lack of inhibition, planning all linked to pfc
6
Q
lesions: Tan
A
- Broca observed patient with L frontal brain damage
- damage was localised which became speech production centre (broca’s area)
- broca’s aphasia = limited speech, loss of grammatical structure
7
Q
lesions: Wernicke area
A
- comprehension of language
- damage = can produce speech with recognisable patterns and normal syntax but meaningless with senseless words & impaired ability to read & write
- stroke most common cause
8
Q
lesions: The logic of experimental lesion method
A
- is brain region X important for task A
- logic based on locationalist perspective
- beware: ignoring adaptive and parallel brain processes can lead to false conclusions
- case studies show importance of lesions in understanding functions of regions
9
Q
lesions: HM
A
- surgery for epilepsy removing medial temporal lobes including hippocampus
- severe anterograde amnesia = no new memories but intact childhood memories
- normal implicit learning
- established memory is a distinct cerebral function separable from perceptual and cognitive abilities
10
Q
lesions: Karl lashley
A
- in search of the engram - idea that memory/learning could be localised to specific areas
- principle of mass action: learning occurred everywhere & larger the lesion the larger the deficit
- harder the task the more brain required
- mass action is the null hypothesis that modern behavioural neuroscience is trying to disprove
11
Q
inference problems with single dissociations
A
- need both tasks to be equally sensitive
- single dissociation may result from general effects of trauma
12
Q
lesions: example double dissociation
A
- task A: water maze
- task B: contextual fear conditioning
- Lesion X: dorsal hipp
- lesion Y: ventral hipp
- controls: sham lesions
- results:
> dorsal lesions impaired spatial but not contextual fear learning
> ventral lesions impaired contextual but not spatial learning - shows the involvement of the hipp in contextual fear conditioning is not due to a requirement for spatial learning
13
Q
lesions: destruction vs deactivation
A
- lesions destroy tissue permanently localised to a region
- they are irreversible and invasive
- reversibility allows animals to act as their own controls but can raise design issues
14
Q
temporary manipulation: chemical
A
- drugs can be delivered in small quantities into precisely located brain areas to deactivate them
- uses muscimol a potent GABA agonist that rapidly & reversibly suppresses activity in region
15
Q
temporary manipulation: DREADDS
A
- chemical method. designer receptors exclusively activated by designer drugs
- not as invasive
- engineered receptors that can be activated or deactivated by a certain drug
- allows changes over a sustained and short period of time
16
Q
temporary manipulation: TMS
A
- electrical pulse in coil induces sudden change in magnetic field in the area below it
- temporarily interferes with brain activity (for 100th of a second)
- good temporal resolution
- can have reasonable (<1cm) spatial resolution in conjunction with 3D MRI registration systems
- no known side effects in humans
17
Q
Neuroimaging: MRI
A
- manipulates behaviour of hydrogen ions to yield radio signals
- aligns proton water molecules in the body
- radio-frequency pulses applied to manipulate protons
- can then create an image of the body
18
Q
Neuroimaging: structural mri
A
- uses the fact that different types of tissue produce different radio signals
- used to characterise differences and changes in structure
- Maguire et al 2000
> hipp volume cor with time spent as a taxi driver
> positively in the posterior neg in the anterior
> posterior hipp stores a spatial rep of the environment and can expand to accommodate elaboration of this representation
19
Q
Neuroimaging: fMRI
A
- the resonant frequency can be tuned to detect blood oxygen levels. BOLD = blood oxygen level dependent signal
- a change in signal indicates a metabolically active brain region
- spatial resolution - ‘voxels’
- balance resolution (detail) with area covered and acquisition time
- resolution can vary typically 3mm
- temporal resolution relatively poor - seconds
- magnetic fields make behavioural testing difficult
- no computers displays, keyboards, loudspeakers or electrical response voxes in the machine room
- the confined tube limits what the subject can see and can make them claustophobic
20
Q
Neuroimaging: Imaging Analysis
A
- Analysis involves comparing signal strengths in different behavioural conditions
- whole brain analysis involves tests on every voxel measured
- tricky because there are so many ways of correcting for multiple tests
- region of interest studies only test a few voxels in a particular brain region
- need care picking the region
21
Q
Neuroimaging: criticisms of fMRI
A
- new phrenology
- overemphasises localisation of function - may be common mechanisms underlying
- correlation not causation
- many inc uncorrected statistical tests
- many use different measures of baseline
22
Q
what can functional neuroimaging tell the experimental psychologist
A
- Henson (2005)
- function to structure inference
> if dif activity is detected under different tasks then the tasks are functionally dissociable - structure to function inference
> if the same pattern of activity is detected under two task conditions then the tasks require common function - inferences rely on assumption that there is localisation of function within the brain
- importance of controlling false positives
- require careful behavioural designs and statistical analysis
23
Q
EEG
A
- electrodes on scalp record electroencephalograms
- EEG reuslt of changes of electric fields generated by summing ISPS or ESPS in thousands or millions of cells
- by using multiple electrodes spatial localisation of signals is possible
- good temporal resolution
- weak signals and need to be arranged over many trials to stand out from noise
- spatial resolution poor
- methods aimed at revealing deep sources for scalp activity are complex and controversial
24
Q
single cell recording - electrophysiology
A
- implant small electrode which hangs over a couple of cells and picks up activity of these cells firing
- limited no. but good spatial and temporal resolution
- place cells example
- histology confirms recording sites
- high spatial and temporal resolution but small no. cells
- high channel electrophysiology
- depends on method used.
