To study the brain in psychology, we need tools that accurately represent the complex organ and provide data scientists and medical personnel can analyse. These data must reflect the brain activity and functions and show precisely where the activity occurs in the brain.
Modern technology has made significant advances in studying the brain in relation to behaviour, allowing more profound, less invasive insights into how the mind works. However, the history of how the brain was studied before this time is still critical and was essential to the discovery of language centres before these new experimental techniques became available. So we will cover both the older ways of studying the brain in psychology and the modern methods of studying the brain.
- We are going to delve into the different ways of studying the brain in psychology.
- First, we will establish the different techniques used to study the brain, particularly in relation to behaviour.
- We will highlight modern ways of studying the brain, as well as older ways of studying the brain.
- Finally, we will then briefly provide a way of studying the brain evaluation.
Fig. 1: There are multiple ways of studying the brain.
Ways of Studying the Brain in Psychology
There are a variety of methods available for studying the brain in psychology. Before delving into these methods, however, here are some important terms to remember:
Spatial resolution is the degree of accuracy that a technique achieves when examining brain activity. It is the accuracy with which the exact areas of brain structures and activity are identified.
Temporal resolution is the degree of accuracy in determining brain activity over time that the technique provides. It relates to when the activity virtually occurred and how accurately the technique can record this information.
The main ways of studying the brain consist of:
- Post mortem examinations
- Functional Magnetic Resonance Imaging (fMRI)
- Electroencephalograms (EEGs) and Event-related Potentials (ERPs)
That's not to say these are the only methods of studying the brain. Other techniques exist, such as computerised tomography scans (CT scans) and positron emission tomography scans (PET scans), however, our focus will be on the aforementioned three methods for this explanation.
Methods of Studying the Brain in Psychology
As we mentioned briefly above, the three main techniques of studying the brain we are going to focus on are post-mortem examinations, functional magnetic resonance imaging (fMRI), electroencephalograms (EEGs) and event-related Potentials (ERPs). Each has its own preferred method of analysing the brain and its components. Let's explore them further.
Post-mortem Examinations of the Brain
Post-mortems were the first official technique for examining the brain. It is now usually performed by pathologists who examine the body and brain after death.In a post-mortem, the brain is treated with a chemical fixative to make it resistant to handling and cutting. This way we can analyse the different sections. Usually, autopsies are good for finding damaged areas of the brain and assigning the injured area to a function, depending on how the patient behaved or suffered while alive.
Broca's area, located in the left hemisphere, is a good example of where a post-mortem examination could identify a functional area in the brain after a patient had suffered from speech problems while alive.
Fig. 2: Post-mortem examinations look at the brain after death.
Functional Magnetic Resonance Imaging (fMRI): Modern Ways of Studying the Brain
Functional Magnetic Resonance Imaging (fMRI) detects the change of blood flow in the brain using a magnetic field and is one of the modern ways of studying the brain. This technique can also be used on the brain in relation to behaviour. It does this by detecting the change and flow of oxygenated and deoxygenated haemoglobin during neural activity.
Active brain areas consume more blood (they need more oxygen and glucose to perform activities) and fMRI machines can measure this (the BOLD signal, Blood-Oxygenation-Level-Dependent). fMRI scans provide 3D images of the brain, producing a neuroimage of the brain with areas of activity highlighted. It is a great diagnostic tool as a result.
Abnormalities can be detected using fMRI scans, such as showing a damaged area in the brain.
Fig. 3: An fMRI scan shows areas of activity during tasks, such as a memory task.
Electroencephalograms (EEGs)
Electroencephalograms (EEGs) are a type of brain-studying technique where electrodes (up to 34) are placed on the head/scalp with conductive gel. These electrodes detect patterns of activation and electrical activity in the whole brain, made by the many neurones within your brain firing together. These patterns are represented as brain waves:
The amplitude is the brain wave's size and intensity, and the frequency is the distance between each wave, showing the speed of activation. We can infer consciousness and brain activity by analysing brain waves.
EEGs are often used in sleep studies, as they can detect the changes in brain waves that indicate different stages of sleep.
If a person is suffering from a sleep disorder, an EEG can help identify where problems are occurring, detecting abnormal brain waves.
They can also be used in other disorders, highlighting their diagnostic properties.
Fig. 4: Brainwave EEG data over the course of ten seconds.
Event-Related Potentials (ERPs)
Event-related potentials (ERPs) are very similar to EEGs because they also use electrodes and record the tiny electrical changes in the neurons of the brain. The difference is that researchers present participants with a stimulus many times, and each wave response is added to a pool of data. This creates a smooth activation curve of the collected data, called statistical averaging.
Statistical averaging allows ERPs to remove background noise that has nothing to do with the stimulus, so researchers can say with greater certainty that activation is due to the stimulus and not just background noise. The waves have peaks and troughs that represent cognitive processes in the brain and are called event-related potentials.
ERPs are great for use in memory studies.
Fig. 5: An EEG measures brain activity using electrodes.
Techniques Used to Study the Brain in Relation to Behaviour
All of the techniques we have discussed thus far are techniques we can use to study the brain in relation to behaviour. We can infer function, and therefore behaviour, through analysing the brain structures, activity, and any abnormalities associated with a decline in function with these techniques.
For instance, Broca's and Wernicke's areas associated with language function in the brain were initially identified through post-mortems, as dysfunction in language abilities whilst the patients were alive were associated with lesions in these areas found when they had died.
fMRI scans show us functional areas without being invasive.
We can see how if someone were to flex their fingers, an fMRI will show areas of activity in the brain associated with this movement.
EEGs and ERPs can indicate behavioural responses to exposure to a stimulus, and also indicate how behavioural changes can be detected in those with certain disorders.
EEGs can be used to detect abnormal brain waves in patients with schizophrenia. Arora et al. (2021) investigated auditory hallucinations and changes in frequency bands of resting EEG data in hallucinating patients, non-hallucinating patients, and controls.
To give a few examples of how EEGs revealed information on schizophrenia, they found that:
- Delta and theta waves were largely unaffected by auditory hallucinations.
- They differed between schizophrenic patients and controls however, highlighting EEG differences exist.
- Alpha activity was affected by auditory hallucinations.
Amongst other EEG data results.
Ways of Studying the Brain Evaluation
Each method has its own strengths and weaknesses. To give a brief summary of each concerning their resolution:
- Post-mortem examinations have a high spatial resolution, but cannot prove that the damaged/examined areas are definitely responsible for specific functions. Unfortunately, they can only be performed after death, and infer function rather than causally relate it to brain area.
- fMRI usually has a highly detailed spatial resolution but poor temporal resolution. They are quite expensive to run, but are non-invasive.
- EEGs have a great temporal resolution but poor spatial resolution.
- ERPs have a high temporal resolution, but like EEGs, poor spatial resolution.
| Method | Technique description | Advantages | Disadvantages |
| Post-mortem examinations | Fixation and examination of dead brain tissues. | High spatial resolution | Cannot prove the functions of brain regions (inference only) |
| fMRI | Detection of the change in blood flow in the brain using a magnetic field. | High spatial resolutionNon-invasive | Poor temporal resolutionExpensive |
| EEG | Detection of electric activity in the brain using electrodes placed on the scalp. | Good temporal resolution | Poor spatial resolution |
| ERP | Detection of electric activity in the brain using electrodes placed on the scalp on repeated occasions to average the findings. | High temporal resolution | Poor spatial resolution |
Table 1. Summary table of the ways of studying the brain.Ways of studying the brain - Key takeaways
- There are many different ways to study the brain, most notably post-mortem examinations, fMRI, EEG, and ERP.
- Spatial resolution is the degree of accuracy a technique achieves in examining brain activity. Temporal resolution is the degree of accuracy in determining activity in the brain over time that the technique provides.
- Post-mortem examinations occur after death and assign a function to damaged areas by analysing the patient's behaviour before death.
- In fMRIs, magnetic fields are used to detect changes in blood flow in the brain in response to activity, which creates a neuroimage of the brain with the areas highlighted.
- EEGs and ERPs measure brain waves by attaching electrodes to the scalp to measure activity. EEGs measure activity in the whole brain. In ERPs, the stimulus is given repeatedly to participants.
References
- Fig. 2: Post mortem by Internet Archive Book Images, No restrictions, via Wikimedia Commons
- Fig. 4: Brain waves by Laurens R. Krol, CC0, via Wikimedia Commons
- Fig. 3: fMRI scan by John Graner, Neuroimaging Department, National Intrepid Center of Excellence, Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA, Public domain, via Wikimedia Commons
- Fig. 5: EEG by Baburov, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
- Arora M, Knott VJ, Labelle A, Fisher DJ. Alterations of Resting EEG in Hallucinating and Nonhallucinating Schizophrenia Patients. Clinical EEG and Neuroscience. 2021;52(3):159-167. doi:10.1177/1550059420965385
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