Biospych - Ways Of Studying The Brain Flashcards
What is spatial resolution?
Level of accuracy in identifying the exact location of a brain structure or brain activity in space.
What is temporal resolution?
Level of accuracy in identifying the exact location of a brain activity in time.
What is a post-mortem dissection?
Brains are precisely cut after treatment to give a firmer texture. Unusual brains are dissected such as brains that suffered trauma, or from individuals with mental illnesses. These brains are compared with Neurotypical brains.
What are the positives of post-mortem dissections?
- It has high spatial resolution, allowing the study of microscopic brain structures down to the neural level.
- post-mortem techniques have been significant in the historical development of psychologies understanding of brain functioning such as the discovery of language centres.
What is a negative of post-mortem dissections?
As post-mortem is not conducted on the living brain, unusual behaviour in life and damage found is correlational.
How does an FMRI scan work?
MRI detect blood flow in the brain. As more active areas of the brain need more blood (containing oxygenated haemoglobin with distinct magnetic properties) these active areas can be compared to low activation areas with a lower blood supply and displayed on an FMRI image.
What are the advantages of fMRI?
– It creates a very good spatial resolution of approximately 1 mm. Precisely identifying active brain regions and patterns of activation overtime while participants complete experimental conditions.
– It is non-invasive and safe technique for experiments compared to options that use radiation like PET scanners.
What is the disadvantage of fMRI scans?
- Poor temporal resolution as one image is taken every few seconds and delay in blood flow after activity. Many brain processes are too fast to study.
- FMRI machines are expensive to build an operate. Also as the participant needs to be still experiments with body movement are not possible.
What is an EEG scan?
The EEG device is a collection of between 22 to 34 electrodes that are attached to a cap, and fitted carefully to the scalp with conductive gel.
The read out from each electrode is the sum total of activation of the brain cortex under the electrode. This is displayed as a series of lines showing distinct patterns called brainwaves. Amplitude shows brain wave intensity frequency and the speed of activation.
What are the advantages of EEG’s?
– Historically important in understanding brain activity in areas such as sleep research and medical diagnosis.
– Cheaper than alternatives and able to be used in experiments in which the participant moves.
– Very good temporal accuracy measuring brain activation with a resolution measured in milliseconds.
What are the disadvantages of EEG’s?
– Poor spatial activity as pattern is some of a large number of neurons in the cortex under the electrode. Also cannot detect activity within the brain.
What is an ERP brain scan?
ERP uses the same technique and equipment as EEG but presents a stimulus many times creating a smooth curve of activation by combining the data in a process called statistical averaging. This removes background electrical noise unrelated to the stimulus.
The wave forms peak and dip to show exactly when cognitive processes in the brain happen after the stimulus is presented.
What are the advantages of ERP?
– ERP allows researchers to isolate and study how individuals cognitive processes take place in the brain, while EEG’s record general brain activity.
– They have very good temple resolution with a millisecond sampling rate.
What are the disadvantages of ERP’s?
– Very poor spatial resolution.
– Some processes cannot be studied by ERP as they cannot be presented a large number of times with the same response.
