Brain and Neuropsychology

The brain and neuropsychology are fundamentally tied together. By studying the brain, you are studying neuropsychology. The brain weighs around three pounds and is the control centre, made up of approximately 86 billion neurons. It is what makes you, you.

Neuropsychology studies the brain by observing and relating biological functions to our psychological functioning and behaviour. Observation of the central nervous system and the brain are core aspects of studying neuropsychology.

• First, we will provide a neuropsychology definition, followed by giving neuropsychology examples to illustrate neuropsychology and brain development.
• We will cover brain structure and neuropsychology, specifically the nervous system, which will lead us to the topic of neuron structure and function.
• Finally, we will delve further into the world of neuropsychology, including brain and body neuropsychology, and examine the various scanning techniques in neuropsychology.
• Towards the end, we will discuss the theories of neuropsychology, including Hebb's theory of learning and neuronal growth.
• We will briefly cover the impact of neurological damage.

Figure 1 - The branch of neuropsychology is interested in studying the brain and behaviour from a biological perspective, freepik.com/pch.vector

Neuropsychology Definition

As we established above, we can define neuropsychology as:

Neuropsychology ties biology with psychology and aims to understand human behaviour and issues with cognition through the lens of biology. Cognitive neuroscience, for instance, connects the biological structure of your brain to how your brain functions, and how this impacts behaviour.

Humans, for example, have one of the most extensive cerebral cortex surface areas when compared to animals. The cerebral cortex is where higher cognitive functioning takes place, so having such a large surface area allows us to do more complex actions and have more complex thoughts. It's why we're so smart!

Neuropsychology and Brain Mental Health

Neuropsychological disorders are conditions caused by biological trauma to the brain and include examples such as:

• Alzheimer's disease
• Strokes
• Dementia
• Parkinson's disease

Each disorder is characterised by a biological cause or sign that can be associated heavily with the resulting symptoms. For example, Parkinson's disease is a result of the loss of nerve cells that produce dopamine in the substantia nigra.

Neurological Damage

As we mentioned above, damage to the brain can result in neuropsychological disorders. A stroke is an example of a neuropsychological disorder.

Neurological damage is not limited to loss of motor ability. The brain is what makes you who you are, and how you feel and think can be affected by trauma to the brain.

Scanning techniques such as a computerised tomography scan (CT), a position emission tomography scan (PET), and a functional magnetic resonance imagery scan (fMRI) are all techniques medical, and research professionals can use to identify brain functioning.

Brain Structure and Neuropsychology

The frontal lobe, temporal lobe, parietal lobe, occipital lobe and cerebellum make up the core regions of the brain. Localisation of function suggests certain regions in these lobes are responsible for specific functions.

• The frontal lobe is responsible for voluntary movement and executive functioning (think higher-level cognitive functioning).
• The temporal lobe is responsible for processing emotions and interpreting language (auditory stimulation) and is associated with memory.
• The parietal lobe is responsible for processing information from your senses, known as somatosensory information, which includes touch, pain, temperature.
• The occipital lobe is responsible for understanding visual information, visual perception, and visuospatial awareness.
• The cerebellum is responsible for physical movement involving balance and coordination.

Figure 2 - The brain has four lobes and has localised areas of function, freepik.com¹

Considering their roles and responsibilities, we can state that the brain has localised areas of function they are specialised in carrying out. These areas work alongside other areas of the brain to integrate the information. There are a few particular areas we are more concerned with:

• The motor cortex resides in the frontal lobe and is responsible for controlling your muscles.
• The somatosensory cortex resides in the parietal lobe and helps you feel and experience various sensations.
• The visual cortex resides in the occipital cortex and allows you to perceive your environment.
• The auditory cortex resides in the temporal lobe and enables you to process auditory information.
• Broca's area is involved in speech production and resides in the left frontal lobe, close to the temporal lobe.
• Wernicke's area is involved in speech comprehension and resides in the upper temporal lobe.

The interpretive cortex: Penfield's 1959 Study

Penfield's (1959) study aimed to understand consciousness in the brain using electrical stimulation to see if this could artificially provoke experiences.

Penfield probed the patient's brains using electrical stimulation during surgeries to see if the probes could evoke a memory or sensation in the patient. They found that patients did experience memories and sensations, such as hearing sounds like a piano playing a particular song.

Penfield noted a particular experience in a young boy known as R.W.

Brain and Body Neuropsychology: The Nervous System

The nervous system is separated into the central nervous system (CNS) and the peripheral nervous system. The brain and the spinal cord form the CNS, and the peripheral nervous system connects the CNS to the body, so the CNS can give commands and receive information from the body.

The peripheral nervous system can be further separated into the autonomic and somatic nervous systems.

• The somatic nervous system is responsible for allowing movement by controlling skeletal muscle.

The autonomic nervous system can then be split even further into the sympathetic nervous system and the parasympathetic nervous system.

• The sympathetic nervous system is involved in the fight or flight response, so it prepares your body for action.
• The parasympathetic nervous system is involved in the rest and digest response, so it prepares your body for normal functioning.

Figure 3 - The human nervous system is divided into different systems.

The James-Lange Theory of Emotion

The James-Lange theory posits that emotions happen in response to bodily changes.

Physical changes occur before and subsequently create emotions.

There are issues with this theory, in that an increased heart rate and sweating can be associated with many emotions. An increase in heart rate may be due to excitement rather than due to the individual being scared or anxious.

Neuron Structure and Function

Neurons are the cells of the nervous system and are made up of a cell body, axon, and dendrites in their most basic form. Neurons can differ in structure and function, but all have these three attributes.

They transmit messages to and from the body using neurotransmitters, and this process is known as synaptic transmission. Neurotransmitters are chemical messengers released from one neuron (the presynaptic neuron) into the synaptic cleft, to be received by another neuron (the postsynaptic neuron).

They are then removed from the synaptic cleft through a reuptake process to prevent repeated and unnecessary firing of the receiving neuron. Neurotransmitters can have an excitatory or inhibitory effect.

Neurotransmitters that cause excitation of the receiving neuron make them more likely to fire (create an impulse), whereas those with an inhibitory effect make them less likely to fire.

Figure 4 - Neurons transmit impulses to one another through synaptic transmission, freepik.com²

We are concerned with three types of neurons:

• Sensory neurons detect information from the environment and send it to the brain and CNS
• Relay neurons connect sensory neurons to motor neurons, so they can communicate and transmit impulses and commands to one another
• Motor neurons enact commands from the CNS to effectors, for example, glands and muscles

Hebb's Theory of Learning and Neuronal Growth

Hebb suggested neuronal growth occurs when repeated excitation occurs between neurons, strengthening and developing the connection and embedding the information the person is learning. The synaptic knob grows larger during neuronal growth, according to Hebb.