Human Brain

Q: Why do we need to know about the brain when we learn about psychology?

A: By learning the brain, we can examine how people think, remember, and learn. It also provides insight into the brain part that causes someone to behave in a certain way. For example, if someone is forgetful, it doesn’t necessarily mean that that person has bad memory, it could be due to the damage at the hippocampus -- a region that is in charge of memory.

So how much do you know about your brain🧠🤔? Today we would like to start off with the basics by learning the brain parts and their functions!

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The Human Brain

The human brain controls almost every aspect of ourselves from physiological responses to cognitive abilities. It can also be known as encephalon which literally means “in the head”.

There are 3 main parts (forebrain, midbrain, and hindbrain). Each main part has its own division too:

Three main parts of the human brain

Overview of brain parts 

Forebrain

Forebrain is the largest part of the brain.

It is divided into two sections: telencephalon (also known as cerebrum) and diencephalon.

About telencephalon

It is inclusive of three parts: Cerebral Cortex, Basal Ganglia, and Limbic System

1. Cerebral Cortex

The cerebral cortex is the outer layer of the cerebrum. It is also the largest part of the cerebrum compared to the other parts. It could be divided into 4 major lobes:

• Frontal Lobe: in charge of motor, cognition, and speech
• Parietal Lobe: responsible for somatosensory (perception through 5 senses)
• Occipital Lobe: manage our visual system
• Temporal Lobe: mainly in charge of the hearing, cognition, emotion, and memory

2. Basal Ganglia

It is inclusive of the striatum (combination of caudate nucleus and putamen) and the globus pallidus. The striatum will collect related information and send it to the globus pallidus.

The basal ganglia are mainly in charge of movement control, motor learning (action learning), and sensitivity to rewards.

3. Limbic System

The limbic system is made up of several parts:

• limbic cortex: make sure you avoid negative stimuli
• amygdala: learn fear (learn what is scary or not)

• hippocampus: transfer and consolidate short-term memory into long-term memory, spatial navigation

• fornix: regulate episodic memory

• mammillary bodies: in charge of recollective memory

About Diencephalon

It consists of the thalamus and hypothalamus:

1. Thalamus

It is the largest portion of the diencephalon, in the middle of cerebral hemispheres. It has two lobes in total – one lobe in each hemisphere, separated by grey matter.

The thalamus includes 3 nuclei:

• Lateral geniculate nucleus: responsible for visual information

• Medial geniculate nucleus: in charge of audio information

• Ventrolateral nucleus: in charge of motor information.

When the thalamus receives sensory information, the related nucleus would process the info and project that information to the related cortex respectively.

2. Hypothalamus

It is connected to the pituitary gland, which is in charge of the production and secretion of hormones. The hypothalamus controls the endocrine system and the autonomic nervous system (ANS). Its main function is to maintain the body’s internal balance (homeostasis).

In the endocrine system, which controls the release of hormones secreted by neurosecretory cells throughout the body, the hypothalamus would control what kind of hormones should be released. It helps to stimulate or inhibit some of your body’s key processes such as your heart rate and blood pressure, appetite, and body weight, etc in the ANS through the secretion of specific hormones.

Midbrain

The midbrain is the smallest part and it is located at the center of the brain. It does not have any subdivision. It only consists of two structures – Tectum and Tegmentum.

Tectum

It is made up of inferior colliculi which are in charge of hearing, while superior colliculi are in charge of vision.

Tegmentum

It includes:

• Reticular formation – controls breathing, heart rate, and blood pressure

• Periaqueductal grey matter – allows you to feel pain, and reduce pain

• Red nucleus – in charge of movement control

• Substantia nigra – in charge of movement too. If this part fails to function, it will cause Parkinson’s disease.

Hindbrain

It is situated at the lower part of the brain and has two subdivisions: metencephalon and myelencephalon.

Metencephalon

This division consists of the pons and cerebellum.

1. Pons

The pons is responsible for sending information from the cortex to the cerebellum. It also controls (a) our sleep and arousal (alert/awake) state as well as (b) respiratory rate.

2. Cerebellum

The cerebellum is covered by the cerebellar cortex. Its main function is to coordinate our movements. If our cerebellum is damaged, it would affect our standing, walking, performance of coordinated movements. We will have poor movement coordination or exaggerated movement.

Myelencephalon

It mainly has medulla oblongata in this division. The medulla oblongata is responsible for:

• Regulating cardiovascular system – keeps our heart pumping

• Skeletal muscle tonus – the ability of your muscles to hold your body

• Regulate respiration – converting glucose into energy

• Vital reflexes – sneezing, coughing, etc

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Reference/Resources:

1. Psychology and Neuroscience 101 (wordpress.com)