Research Methods In Biopsychology

Biopsychological research methods represent a great advance in the study of the brain. Thanks to these methods, we can better understand the functioning of our most mysterious organ. But what are these methods?

Authors such as Dewsbury (1991) define biopsychology as “ the scientific study of the biology of behavior ”. We also talk about psychobiology. However, other authors prefer the term biopsychology because “ it indicates a biological approach to the study of psychology rather than a psychological approach to the study of biology ” .

Thanks to scientific progress, research methods in biopsychology have undergone a major revolution in recent years. How many old researchers thought they would come and watch the brain work live? There are many research methods in biopsychology. However, we will focus here on those who study what happens in the brain under certain conditions.

Methods of stimulation and visualization of the human brain

Observing and recording brain activity in vivo is an important step obtained thanks to the various techniques developed during the 20th century. Techniques which have undoubtedly constituted a breakthrough in the knowledge of our most unknown organ.

X-ray contrast

This technique involves injecting an x-ray absorbing substance into one part of the body, which allows you to observe a contrast between it and the tissues around it.

Cerebral angiography is an X-ray contrast technique. A dull radio-dye is introduced into a cerebral artery. The goal will be to observe the cerebral circulatory system while taking an x-ray. This technique is useful for locating vascular lesions and brain tumors.

Computed tomography (CT)

The structure of the brain can be visualized with CT. During the test, the patient lies down in the center of a large cylinder. An x-ray tube and a receiver (placed diametrically opposed) take a large number of photographs separately. This occurs when the transmitter and receiver rotate around the subject’s head.

The information gathered from the photographs is gathered on a computer. This unification allows exploration through a horizontal plane of the brain. Normally, you can do this exploration through eight or nine horizontal sections of the brain (cuts). Once all the explorations are combined, we obtain a three-dimensional representation of the brain.

Nuclear Magnetic Resonance (NMR)

NMR makes it possible to produce high-resolution images thanks to the different waves that the hydrogen atoms emit when they are activated by radiofrequency waves in a magnetic field. This technique provides high spatial resolution and produces three-dimensional images.

Positron Emission Tomography (PET)

PET provides images of brain activity rather than the structure itself. To obtain these images, radioactive 2-deoxyglucose (2-DG) is injected into the subject’s carotid artery. Active neurons take up 2-DG quickly, and since they do not metabolize it, 2-DG builds up until it is gradually broken down. In this way, we observe which neurons are active at a given time during different activities.

Functional Magnetic Resonance Imaging (fMRI)

The fMRI provides images of the increased supply of oxygen in the blood to regions of the brain. It is therefore a very effective technique for measuring brain activity. It has 4 additional advantages over PET. Indeed, she:

Does not require injection
Provides both functional and structural information
?? Offers better spatial resolution
Can provide three-dimensional images of the entire brain

Magnetoencephalography

It measures changes in magnetic fields that occur on the surface of the scalp. These changes are produced by variations in the patterns that underlie neuronal activity .

Transcranial Magnetic Stimulation (TMS)

Walsh and Rothwell (2000) underline that TMS “ consists of a technique allowing to modify the activity of an area of the cortex by creating a magnetic field ”. This technique makes it possible to temporarily “turn off” a part of the brain while evaluating the effects of this failure on behavior and cognition.

Harmful methods

Harmful methods are those that destroy an area of the brain to check its effect on behavior.

?? Suction Injury: This method is usually used to cause an injury in an area of cortical tissue visible to the naked eye. The tissue is extracted using a fine-tipped glass pipette.
?? Radiofrequency injuries : These are small subcortical injuries. For this, an electrode is used which channels a high frequency current through the tissue to be destroyed. The size and shape of the lesion depends on three factors:
- Duration
- Current intensity
- Electrode tip configuration
- Scalpel cuts : these consist of cutting the area of the brain that you want to destroy
- Cold blocking: this technique is reversible. Instead of destroying the structure, it is cooled to keep it above the freezing point. Neurons stop sending signals, which blocks the functioning of the cooled brain region. In this way, it is possible to observe which changes in behavior cause the intervention areas. Once the temperature returns to normal, normal brain functions are restored.

Electrical stimulation

Another method of research in biopsychology is electrical stimulation. A structure of the nervous system is electrically stimulated to obtain data on its functioning. Usually a bipolar electrode is used.

This stimulation triggers neurons and modifies their behavior. Usually, it often causes the opposite effect of injury. If, for example, a person drastically decreases their sleep hours due to an injury, the stimulation may appear to be disproportionate sleeping behavior.

Harmful methods with electrophysiological recording

?? Intracellular recording of a unit: this technique consists of the introduction of a microelectrode inside a neuron. Provides a record of gradual fluctuations in the membrane potential of the same.
?? Extracellular recording of a unit: a microelectrode is placed in the extracellular fluid surrounding the neuron through which the neuron shots are collected. However, it does not collect information about the potency of the membrane.

?? Recording of multiple units: in this case, the tip of the electrode is larger than that of a microelectrode, so that it picks up signals from several neurons at the same time. The detected action potentials are directed to a circuit which integrates and adds them.
?? Invasive EEG recording: in this case, electrodes are implanted. When searching for cortical EEG signal registers, stainless steel cranial electrodes are used. For subcortical signals, cable electrodes implanted by stereotaxic surgery are generally used.

Research methods in biopsychology: a long way to go

You have just discovered all the most representative research methods in biopsychology. However, there are also other research methods in biopsychology that study other areas of the body. Among them we can find: measurement of muscle tension, recording of eye movements, skin conductivity or cardiovascular activity.

Undoubtedly, the advances in research methods in biopsychology in recent years have been spectacular, but not for this reason. That is, in a few years, new techniques may emerge, which we cannot even imagine at the moment. All of this will contribute to the advancement of neuroscience which, in turn, will help improve the quality of life for many people affected by one type of neural disorder.