lecture 2- approaches and methods Flashcards
nikolaas tinbergen (1907-1988)
- nobel prize (1973) in medicine or physiology
- with karl von frisch and Konrad lorenz
ethologist:
- the organisation and elicitation/causes of individual and social patterns of behaviour in animals
what are Tinbergens 4 questions?
-functional mechanism: why are they doing it
-physiological mechanism: what causes it to happen?
-ontogenetic mechanism: how does this behaviour develop?
-evolutionary mechanism: why did the behaviour originally develop?
single cell recording
-insertion if micro-electrodes into brain to record changes in individual cells
- invasive technique
- temporal resolution: wide ranging (ms to hours)
- spatial resolution: limited (one cell)
electroencephalography (EEG)
- measurements of electrical brain activity at scalp surface
- repeated stimulus exposure in studies to identify the response to specific stimulus
- key uses: studies of language
- non-invasive
- temporal resolution: excellent
- spatial resolution: poor
Magneto-encephalography (MEG)
- measures the magnetic fields produced by brain activity at the skull
- non invasive
- temporal resolution: excellent-ms level
- spatial resolution: reduced disortion compared to EEG; magnetic fields are not distorted by the skull
positron emission tomography (PET)
- detects regions of activity by tracking emission from radioactive substances
- invasive (injection)
- temporal resolution: low: records activity over +60sec
- spatial resolution: reasonable: locates activity within 3-4mm
functional magnetic resonance imaging (fMRI)
- detects functionally induced changes in blood oxygenation in the brain
- an indirect measure: only looks at blood flow, not neural activity
- non invasive
- temporal resolution: poor: tracks over several seconds; indirect measure of activity
- spatial resolution: excellent
a new phrenology
- neuroimaging has sometimes been referred to as ‘the new phrenology’
- region ‘lights up’ -> responsible for the function
- imaging doesnt indicate a casual link
- strong evidence: methodological convergence (cross-referencing findings across methods)
trans-cranial magnetic stimulation (TMS)
- simulates ‘temporary lesions’- magnetic pulse of current used to temporarily inhibit processing in an area
- examine whether inhibiting a region interferes with a particular task
- temporal resolution: poor, the length of the influence of TMS is not known precisely
- spatial resolution: limited; the spatial area affected by TMS is fairly large
lesion studies
- observing patients following damage
- what tasks are patients unable/able to perform?
- spatial: poor- lesions are typically wide spread making it difficult to determine where the boundaries are
- temporal: allows assessment of long term damage, but patients may develop coping strategies which make it difficult to determine the exact effect of the lesion
the use of animals in research, what are a few reasons why animals are used for research
- to understand the basic processes underlying animal behaviour
- to understand the basic processes underlying human behaviour, which is often similar to the processes underlying animal behaviour
- hope to find methods to treat or prevent Alzheimers, AIDS, strokes
pros of studying non-humans
- develop drugs and treatment (HIV and cancer drugs, vaccines, antibiotics)
- improve human health
- ensure safety for drugs
- alternative methods for testing do not stimulate humans that well
cons for studing non-humans
- animals are killed or kept in captivity
- some substances used may never be used for anything useful
- it is very expensive
- animals and humans are never directly comparable
in favour of animal experiments:
-experimenting on animals is acceptable if (and only if)
- suffering is minimized in all experiments
- humans benefits are gained which could not be obtained by using other methods
against animal experiments:
- experimenting on animals is always unacceptable because:
- it causes suffering to animals
- the benefits to human beings are not proven
