Ways Of Studying The Brain Flashcards
What are FMRI’s?
-Brain activity requires oxygenated blood
-Areas more active require more oxygenated blood
-To meet this need blood flow is directed to that area known as haemodynamic response
-FMRI’s detect this change in blood flow and produce 3D images of the brain which map the areas in response to the task.
What did FMRI’s result in the discovery of?
-As a result it is possible to draw links between certain mental processes/activities and increased activity in the brain areas, and therefore make inferences that these areas may be responsible for these tasks.
What are the strengths of FMRI’s ?
-Non invasive and does not expose the brain to potentially harmful radiation
-Other forms of scanning techniques may do this tho
-making it more ethical
-Provides high quality spacial resolution images
-meaning it can provide highly detailed information(to the mm) about the brain area involved whilst being engaged in a specific task
-So, can offer highly objective pictures of brain localisation of specific functions
What are the limitations of FMRI’s?
-Not a direct measure of neural activity in particular brain areas
-As, an FMRI measures changes of blood flow in the brain
-so, not a truly accurate measure of mental activity in these brain areas.
-Poor temporal resolution images
-Refers to the fact that their is approximately a 5 second lag between the neuron firing and the FMRI image being produced
-Meaning you cannot identify the area active at the same point the specific task is being completed
What are EEG’s?
-Measures electrical activity in the brain
-procedure involves electrons being fixed to the scalp using a cap
-Cap detects small electrical charges resulting from the activity of brain cells and record brain wave patterns
-Can detect irregular patterns of activity which may indicate an underlying neurological abnormality such as epilepsy, Alzheimer’s or sleep disorders.
What are the strengths of ERP’s?
-More useful application of the raw EEG data
-Provide a continuous measure of processing in response to a particular stimulus meaning it is more possible to determine how processing is affected by a specific event
-Making it more possible to identify general areas linked to any cognitive dysfunction
-High temporal resolution in contrast to FMRI’s
-Can identify neural response to an event as it occurs
-This is because it used EEG data which can record electrical changes just one millisecond after it occurs.
What are the limitations of ERP’s?
-To establish pure data all other background distractions and extraneous stimuli must be eradicated via the statistical averaging technique
-Therefore require a large number of trials to gain meaningful data
-This issues places limitations on the type of questions/range of uses to which ERP’s can realisitically be applied
-Only electrical activity occurring in the cerebral cortex can be recorded, whereas brain waves in deeper regions cannot be assessed using this method
-Again limits use of this method of brain investigation.
What are the strengths of EEGs
-Provides a recording of the brains activity in real time rather than a still image of the passive brain
-Means researcher can accurately measure a particular task or activity with the brain activity associated with it
-high temporal solution as can accurately detect neuronal activity only one millisecond after the neuron has fired
-provides almost instantaneous feedback on neuronal activity at the point at which it occurs
-Useful in clinical diagnosis
-records electrical brain activity to make possible brain comparisons with measures of typical electrical brain activity to identify if any irregularities exist in the individual being assessed
-useful method for detecting abnormal neural activity associated with conditions such as epilepsy
What are the limitations of EEGs?
-Represent the firing of millions of neurons so they have a low quality spatial resolution and are unable to locate specific regions relating to the electrical activity
-SO still possible to connect the specific brain activity being recorded to the specific activity/task being completed
-Therefore, limiting the amount of information which can be obtained from this method of investigating the brain.
What are ERPs?
-Reflect electrical brain activity related to a particular stimulus or event
-Rather than a singular presentation of the stimulus/task like EEGs the stimulus/ task is completed on many occasions and then responses are averaged together using a mathematical technique called statistical averaging
-So any neural activity that is not related to the specific stimulus will be cancelled out, revealing the specific neural activity related to the specific stimulus
What are post mortem examinations?
-Used to understand the underlying neurobiology of a particular behaviour
-Involves a deep analysis of the actual brain after death
-Indiivduals with a rare disorder or unusual brain deficits are likely to be subject to this
-Brain is rigorously assessed to identify areas of damage/irregular structure
-In order to help determine regions linked to the condition from which they suffered
e.g Brocas work with patient Tan -speech production
What are the strengths of post mortem exams?
-Allow for a more detailed examination of anatomical and neurochemical aspects of the brain that wouldn’t be possible with other forms of studying the brain(EEGs and ERPs)
-Key psychological knowledge has be obtained such as the key processes and areas of the brain linked to psychological behaviours such as language and memory.
-Post mortems have played a central role in understanding the orgins of certain conditions
-From post mortem exams , researchers have discovered structural abnormalities of the brain and found evidence of changes in neurotransmitters both which are associated with the disorder
-Can help to stimulate and direct further research/hypotheses in the condition
What are the limitations of post mortem exams?
-Difficult to draw conclusions about whether the structural abnormality was the reason for the cogntive dysfunction
-This is because people die in a variety of circumstances and at a varying stages of decease,and these other factors can influence the post-morten brain.
-So difficult to determine whether damage to the brain areas was linked to the cogntive deficits or a result of some other trauma or decay and it is not possible to follow up on anything that arises from the post-mortem t validate a possible relationship between brain abnormalities and cognitive functioning.
-Ethical concerns
-Difficult to gain informed consent from individuals with rare conditions that result in cognitive impairments
-May unwittingly become a research subject which was in fact against their wishes.
