Lesson 9 – Studying the Brain Flashcards
How many ways are there to study the brain?
4
What are the ways in which the brain can be studied?
1) Post mortem examinations
2) fMRI (functional magnetic 🧲 resonance imaging)
3) EEG (Electroencephalogram)
4) Event related potentials
What are post mortem examinations?
Psychologists may study person who displays interesting 🏃♂️ while they are alive
- when person dies psychologists look for abnormalities in 🧠- help explain 🏃♂️
- Post-mortem studies found link between 🧠 abnormalities and psychiatric disorders e.g. evidence of reduced glial cells in frontal lobe of patients with depression
What are the evaluation points of post mortem examinations?
👍- allow for ⬆️ detailed examination of anatomical and neurochemical aspects of 🧠 than would be possible with other methods of studying 🧠
- enabled researchers to examine deeper regions e.g. hippocampus and hypothalamus
👎- Studies using post-mortems may lack validity due to small sample size (special permission needs to be granted)- ✖️ everyone agrees
ALSO because people die in variety of circumstances and at varying stages of disease- length of time between death and the post-mortem and drug treatments all affect 🧠 … findings unique to individual
What is fMRI?
Functional Magnetic Resonance Imaging (fMRI)- uses 🧲 fields and 📻 waves to monitor 🩸 flow in 🧠
- measures change in energy released by haemoglobin- reflects activity of 🧠 (oxygen consumption) to give moving picture of 🧠
- activity in regions of interest can be compared to base line (previous research etc)
What are the evaluation points of fMRI?
👍- fMRI captures dynamic 🧠 activity as opposed to an MRI/post-mortem examination- ONLY show physiology of 🧠
👎- interpretation of fMRI complex and affected by temporal ⏰ resolution (resolution of measurement with respect to ⏰), biased interpretation and by base line task used
👎- fMRI research expensive … small sample sizes- negatively impacts validity of research
What is an EEG?
An electroencephalogram (EEG)- measures GENERAL ⚡️ activity in 🧠usually linked to states such as 💤 and arousal
- electrodes placed on scalp and detect neuronal activity directly below where placed
- differing numbers of electrodes used depending on focus of research
- When ⚡️ signals from different electrodes graphed over ⏰ resulting representation is called an EEG pattern
- EEG patterns of patients with epilepsy show spikes of ⚡️ activity
- EEG patterns of those with 🧠 injury show a slowing of ⚡️ activity
What are the evaluation points of an EEG?
👍- useful in clinical diagnosis- can record neural activity associated with epilepsy so that doctors can confirm person experiencing seizures
👍- cheaper than fMRI … can be used ⬆️ widely in research
👎- poor spatial resolution (refers to smallest feature measurement can detect)
What are event related potentials?
Electrodes placed on scalp and detect neuronal activity (directly below where they are placed) in response to SPECIFIC stimulus introduced by researcher
- Event-related potentials difficult to pick out from all the other ⚡️ activity being generated within 🧠
- To establish a specific response to a target stimulus requires many presentations of this stimulus and the responses are then averaged together
- Any extraneous neural activity not related to specific stimulus ✖️ occur consistently whereas activity linked to stimulus will
- ERP waves generated in 1st 100 milliseconds after stimulus presented are termed sensory ERPs as reflect initial response to physical characteristics of stimulus
- ERPs generated after 1st 100 milliseconds reflect manner in which subject evaluates stimulus- termed cognitive ERPs (demonstrate info processing)
What are the evaluation points of event related potentials?
👍- can measure processing of stimulus even in absence of behavioural response … possible to measure ‘covertly’ the processing of a stimulus
👎- only sufficiently 💪 voltage changes generated across scalp are recordable- important ⚡️ activity occurring deeper in 🧠 ✖️ recorded
