Biopsychology

Definition of Biopsychology

Biology and psychology are already vast fields of study. When these two studies come together as biopsychology, what does that mean?

Our functions as humans rely on several parts moving in tandem for proper function and efficiency. Biopsychology helps us understand how biology and psychology work together to create the well-working machine of our bodies and psyche.

Biopsychology History

Biology is not a new study, nor is psychology, but biopsychology is considered to be a relatively new field of study in history, all things considered. So, where does the field of biopsychology begin?

Franz Gall, in the earlier 1800s, introduced his theory of phrenology. Gall theorised that the bumps on our skulls could reveal an individual's mental abilities, processes, and character traits. Franz's theory became so popular that Britain once had 29 phrenological societies. These societies would travel to North America, reading the bumps on people's heads as a psychological reading.

However, there were sceptics of Gall's theories that a mere lump of the skull could be so forthcoming with such personal and unique information.

Biopsychological Model

While the field of biopsychology seems vast, there are three specific focuses -- biological, psychological, and social. The biopsychological model encompasses these aspects of biopsychology.

The Biological (bio-) – is associated with the relationship between disease and bodily health.

The Psychological (-psycho-) – are the aspects of emotional and mental wellness that relate to behaviour.

The Social (-social) – these are our social interactions within our family or community.

Fig. 2: The biopsychosocial model explores various aspects of psychology, bringing them together¹.

Biopsychology Tests

The functions within us that affect our psychology need to be researched. So what biopsychology tests can be performed for better understanding? Three major tests are utilised to advance biopsychological studies -- fMRI, EEG, and ERP.

fMRI

Functional magnetic resonance imaging (fMRI) is a brain-scanning technique that measures blood flow in the brain as a person performs a task. But how does this test work? An fMRI detects the changes in our blood oxygenation and flow when there is neural activity (when a brain is more active, it consumes more oxygen).

EEG

Electroencephalogram (EEG) measures electrical currents on the surface of the head to reflect real-time changes in the whole brain. EEG can measure general brain consciousness changes, such as when we sleep or meditate or detect epilepsy, called a spontaneous EEG. It can also measure small brain waves called event-related potentials (or ERP) created by the reaction to specific stimuli, such as when a person hears a tone.

ERP

The Event-Related Potentials (ERP) test uses equipment similar to an EEG. An ERP test also uses electrodes attached to the scalp to record information. But there is a significant difference in the information that is being recorded. How so? The stimulus that is presented to the individual is a picture or sound, and the researcher will look for activity in the brain related to the presentation of the stimulus, inferring the specific change is because of the stimulus.

Examples of Biopsychology

Several areas of function fall under the umbrella of the biopsychological field -- the nervous system, endocrine system, fight or fight response, localisation of the brain, and the structures and functions of the sensory and motor system.

Nervous System

The nervous system is a network of nerves and control centres that run through your entire body parallel to your other body systems, such as the cardiovascular or respiratory system. Its main function is to pass on information via its specialised cells, the neurones, which, when grouped, are called nerves. Nerves connect all the parts of the body the way that roads connect villages and cities.

Our brains supply conscious awareness and are involved in our psychological processes.

The nervous system is divided into the peripheral nervous system (PNS) and the central nervous system (CNS).

• The central nervous system includes the brain and spinal cord. It's here that all information is filtered, integrated with memories, and all conscious and unconscious movement is controlled. The control system is separated from the rest of the body by the blood-brain barrier, which keeps toxins from getting into the central nervous system from the blood.
• The peripheral nervous system connects the central nervous system to the senses and the muscles, enabling the body to perceive the outside world and react to it. If the central nervous system is like a motorway into and out of the brain, the peripheral nervous system would be similar to the rural roads. The peripheral nervous system is again subdivided into the somatic (voluntary) nervous system and the autonomic (involuntary) nervous system.

Endocrine System

The endocrine system controls the release of hormones and helps regulate our emotions. Unlike the fast-processing nervous system, the endocrine system moves more slowly. As the information processor of emotions and hormonal growth, the endocrine takes a slower approach, but the effects are still as impactful.

How does the endocrine system make these slow yet large impacts? The pituitary glands! Let's take a look at how this process works.

• The endocrine system has glands and fat tissues that secrete the chemical messenger, hormones.
• Hormones travel in the bloodstream and affect other tissues (including the brain). What happens when hormones make the journey in the bloodstream? When hormones affect the brain, they can influence focus on aggression, food, or sex.

Again, these endocrine messages move slowly like a letter in the postal service, while a message from the nervous system moves like a text message. But endocrine messages last longer than the messages sent by the zippy neural pathway.

Fight or Flight Response

Another example of biopsychology is our innate ability to react to an event considered frightening or stressful. These reactions are known as our fight-or-flight responses. How do we tap into this deep instinct?

When we perceive a threat, the sympathetic nervous system activates and triggers a stress response that will prepare our body to fight or flee through biological responses (increased heart rate, increased blood pressure, dilated pupils, energy release for use).

Localisation of Brain Function

Brain (neural) imaging advances have shown that different brain parts have different functions. Different areas in the brain are in charge of various functions,m such as motor function, sensory perception and speech. These are located in four major subdivisions of the brain, called lobes:

• Frontal lobe: This part of the brain is responsible for planning, conscious decisions and voluntary movement.
• Parietal lobe: This part of the brain is responsible for integrating sensory information and memory.
• Temporal lobe: This part of the brain is responsible for processing sound, speech and language.
• Occipital lobe: This part of the brain is connected to the processing of vision.

Researchers have also pinpointed unilateral areas of the brain responsible for very specific aspects of functions.

Plasticity of the Brain

Plasticity refers to how the brain adapts and changes both in structure and function throughout our lifetimes. The brain changes during development and in response to its environment, through instances of disease or trauma.

Structure and Function of Sensory and Motor Neurones

If you look at brain tissue with a microscope, you'd see it's mostly made up of neurones and glial cells.

• Glial cells provide the structure of the network of the central nervous system and provide neurones with nutrients.

• Neurones are cells specialised in transmitting and receiving information. Accordingly, they have parts that other cells don't have: dendrites and an axon.

There are many variations of neurones, which can either be categorised according to how many dendrites or axons they have (the structural classification of neurons) or according to what function they have in the body (the functional classification of neurons).

On the cellular level, you can also look at where two neurons connect. This is called a synapse. A synapse includes the output from the cell transmitting the electrochemical impulse and the location of the cell receiving the electrochemical impulse. The neurone sending the impulse is called the presynaptic neurone, and the cell receiving is called the postsynaptic cell. Between the two cells, there's a little space called the synaptic cleft that's filled with interstitium.

Neurochemicals (neurotransmitters) are released into the synaptic cleft to transmit electrical impulses or action potentials to the next cell. Depending on the neurochemical released, the chemicals interact with the postsynaptic cell membrane can make it more likely for the postsynaptic neurone to fire (this is called excitatory) or less likely for the next neurone to fire (this is called inhibitory).

Fig. 3: Neurones are specialised cells.

Biological Rhythms

Biological rhythms concern circadian, infradian and ultradian rhythms and the difference between these

each of these rhythms.

• Circadian rhythms occur once every 24 hours, for instance, in the sleep-wake cycle.
• Infradian rhythms last longer than 24 hours, for instance, the menstruation cycle.
• Ultradian rhythms occur more than once every 24 hours, such as the sleep cycle (the different stages and rapid eye movement sleep).

Biological rhythms also concern endogenous pacemakers (internal factors) and exogenous zeitgebers (external factors).