Major Depressive Disorder – Neurobiology and Aetiology

To understand psychiatric disorders, it is important to have a working understanding of the normal structure and function of the nervous system.

To understand psychiatric disorders, it is important to have a working understanding of the normal structure and function of the nervous system. The central nervous system (CNS; brain, spinal cord) and peripheral nervous system (PNS) are made up of neurones and glial cell…

The neurone constitutes the functional unit of the nervous system; there are over 100 billion neurones in the brain.^{[Purves, Augustine, & Fitzpatrick et al., 2008; Martin 2003]} Each neurone has the ability to interact with and influence many other cells, which creates a s…

The brain is divided into four anatomical regions: the diencephalon, brainstem, cerebrum, and cerebellum, as described on the slide.^{[Kandel, Schwartz & Jessell, 2000; Tortora & Derrickson, 2009]}

References:
Kandel ER, Schwartz JH, Jessell TM (eds). Principles of Neural Sc…

The cerebral cortex is the main functional unit of the cerebrum. The three main functional areas of the cerebral cortex are:^{[Tortora & Derrickson, 2009; Price & Wilson, 2003]}

• motor areas that control voluntary movement (primary, secondary, and association motor areas)
• se…

The brain can be thought of as comprising five ‘lobes’ – the four lobes of the cerebral cortex and a fifth lobe, the insula, deep within the brain, as shown on the slide.^{[Martin 2003; Tortora & Derrickson, 2009; Price & Wilson, 2003]} The lobes of the cerebral cortex are n…

Information moves through the nervous system via two integrated forms of communication – electrical neurotransmission and chemical neurotransmission, as shown on the slide.^{[Kandel, Schwartz & Jessell, 2000]}

An action potential is generated at the origin of the axon follow…

Neurones do not physically touch one another; two neurones are separated by a gap, known as a synaptic cleft.^{[Kandel, Schwartz & Jessell, 2000]} Because neurones do not touch, and an action potential cannot ‘jump’ across a synaptic cleft, the signal must be converted to a …

The idea that neurotransmission occurs at synapses and is mediated by chemicals was, at first, a contentious issue.^{[Purves, Augustine & Fitzpatrick et al., 2008]} It was in the first half of the 1900s that experiments proved chemical neurotransmission occurred.^{[Purves, Aug…}