This article will uncover the advantages as well as the disadvantages of methods and techniques that cognitive neuroscientists use to study various brains. Few of the frequently asked questions would be answered at the end of the article.
What kind of techniques Can Cognitive Neuroscientists Use to Study the Brain?
There are several brain imaging tools that are available to cognitive neuroscientists. Here are some of the techniques:
positron emission tomography (PET), near-infrared spectroscopy (NIRS), functional magnetic resonance imaging (fMRI), magnetoencephalogram (MEG), electroencephalography (EEG), and transcranial magnetic stimulation (TMS)
Electroencephalography (EEG)
EEG was discovered about a century ago, electrodes are placed on the scalp of the patient’s brain to measure several electrical activities of the brain. The way that EEG is collected is from about tends to hundreds of electrodes placed on different locations of the brain. About 64- 256 electrodes are used in EEG systems in recent cognitive neuroscience studies.
In this method, scalp EEG represents the aggregates of post-synaptic currents of millions of neurons. There are two types of brain activities that are reflected through the recorded EEG signals:
The spontaneous EEG is one that has been used in a clinical setting for a long time and is usually used to evaluate seizure disorders and reflects neuronal responses that occur in the absence of behavioural. This kind of process is yet to be used in cognitive neuroscience research. (Williamson, Kaufman, Lu, Wang, & Karron, 1997).
This method and its manifestations occur unprovoked, i.e., in the absence of any identifiable stimulus. Recent studies are focused on examining how the background brain activities as measured by spontaneous EEG affect current cognitive activities (Ergenoglu et al., 2004; Romei et al., 2008).
Event-related potentials (ERPs) are associated with specific thoughts or stimuli. The amplitudes of ERPs tend to range from low, less than a microvolt to several microvolts, compared to tens of microvolts for spontaneous EEG.
Functional magnetic resonance imaging (fMRI)
One of the most recent forms of neuroimaging technique was discovered in the 1990s. This has relatively become the most used and dominant technique due to its lack of radiation exposure, wide availability and low invasiveness. Several neural activities in the brain lead to metabolic activities such as the oxygen supply to the local vasculature and increased blood flow to the brain.
There are several techniques that are used to detect several changes in metabolic activities that including fMRI, blood-oxygen-level-dependent (BOLD) fMRI, and perfusion fMRI.
The fMRI is an indicator of neural activity that detects the amount of blood flow in each brain region. The images are taken in the form of cross-sectional “slices” that are obtained as the magnetic field is passed across the brain. These images in the form of slices are taken at a rapid rate and are imposed on images of the brain structure. These show how brain activities change over time.
The advantage of fMRI is that it is non-invasive. The images collected via the scanner can reveal which parts of the brain are associated with which type of other tasks, this was found while studying the participant’s behaviour (e.g., while they were playing a game with another person).
The procedure beings when the research participant simply enters the machine and the scans begin. There are several advantages of the fRMIs, in recent days, is now the most commonly used method of learning about brain structure hence, many university and hospital settings, have accommodated this.
Transcranial magnetic stimulation (TMS)
Another approach to better understands the brain and which has been more frequently implemented to understand brain function is the Transcranial magnetic stimulation (TMS) procedure. In this procedure, magnetic pulses are applied to the brain of a living person.
The goal of this procedure is to safely and temporarily deactivate small regions of the brain. In this study, the participant is first scanned in an fMRI machine to determine the exact location of the brain area to be tested.
In this method, the participant is provided with electrical stimulation before working on a cognitive task, after which the effects of these stimulations on the participant’s performance are assessed.
If that particular ability of the brain performs well after the stimulation, it can be then concluded that this area of the brain is significant in order to carry out those tasks. The brain region is less active when the TMS pulses are applied to that region of the brain. This kind of deactivation influences the responses of the research participants.
Another advantage of the TMS process is that it allows the researchers to draw various conclusions about the brain structures of several thoughts, feelings, and behaviours of people. TMS is used as a treatment for a variety of psychological conditions, including migraine, Parkinson’s disease, and major depressive disorder.
Near-infrared spectroscopy (NIRS)
Near-infrared spectroscopy (NIRS) is a non-invasive technology that continuously monitors regional tissue oxygenation. It was originally used to assess the oxygen saturation of the brain. However, over a period of time, it has been used in the evaluation of oxygenation of tissues other than the brain.
Magnetoencephalography (MEG)
Magnetoencephalography (MEG) is a non-invasive medical test. This test maps the function of the brain and identifies the location and the source of epileptic seizures. This test measures the magnetic fields that are produced by the brain’s electrical currents. It is also used to map the various other functions of the brain such as the centre of the sensory, motor, language and memory activities.
Positron Emission Tomography (PET)
A positron emission tomography (PET) scan is a type of imaging test that can help understand and reveal the biochemical function of your tissues and organs, as well as the metabolic activities of the brain. This test uses
a radioactive drug (tracer) and also shows both normal and abnormal metabolic activity.
This type of test also detects the abnormal metabolism of the tracer in diseases before the disease is more prominent in other tests such as computerized tomography (CT) and magnetic resonance imaging (MRI).
Computed Tomography (CT)
This is a computerised x-ray imaging procedure in which a narrow beam of x-rays is aimed at a patient and quickly rotated around the body. This produces signals that are then further processed by the machine’s computer to generate cross-sectional images, or “slices.”
These are called tomographic images and give the clinician better and more detailed information than conventional x-rays. To form a three-dimensional (3D) image of the patient, these slices are collected by the machine’s computer, they are digitally “stacked” together to form a three-dimensional (3D) image of the patient. This allows the physician to identify potential tumours as well as other abnormalities at an early stage.
Conclusion
This article answered “What techniques can cognitive neuroscientists use to study the brain?” in detail. It also highlights the advantages and disadvantages of each of these methods. It will also answer some frequently asked questions about the same in the end.
Frequently Asked Questions: What Techniques Can Cognitive Neuroscientists Use to Study the Brain?
What is neuroimaging used for?
Current neuroimaging techniques reveal the interconnections as well as the integrity of the brain structures. They are also used to understand chemistry, physiology, and electrical and metabolic activity.
Why are neuroimaging techniques important?
These are important in order to understand the psychology within and to allow in-depth study of certain areas of the brain and their function. This method also allows to identify the differences in the brain as well as understand several mental health conditions and brain disorders.
What’s the difference between fMRI and MRI?
The fMRI looks at the function of the brain, whereas the MRI allows the physicians to examine the patient’s organs, tissue, or bones.
References
Kalbe, E., Schlegel, M., Sack, A. T., Nowak, D. A., Dafotakis, M., Bangard, C., & Kessler, J. (2010). Dissociating cognitive from affective theory of mind: A TMS study. Cortex: A Journal Devoted to the Study of the Nervous System and Behavior, 46(6), 769–780.
Williamson SJ, Kaufman L, Lu ZL, Wang JZ, Karron D. Study of human occipital alpha rhythm: The alphon hypothesis and alpha suppression. Int J Psychophysiol. 1997;26(1-3):63–76.
