Question

For the brain structure/ areas below, provide the following information

1. Location

2. General function

3. Example of when the structure/ area would be active

4. A disease/ disorder that affects the structure/ area, and why physiology dysfunction this would result in

• Prefrontal association area

• Basal ganglia

• Pineal gland

• Medulla oblongata

Answer 1

Prefrontal association area:

• It is located on the the rostral part of cerebral hemisphere in front of the the premotor area and includes areas 9 to 14.
• This area is subdivided into orbital region and dorsolateral region.
• This area is involved in control of visceral functions and emotional behaviour, thus making it a seat of human personality.
• This area becomes active when it receives inputs from various sensory modalities like emotional incidents by visual inputs from prestriate cortex and inferior temporal gyrus and by auditory inputs from superior temporal gyrus.
• Prefrontal lobotomy and frontal lobe syndrome occur when the connection of thalamus with prefrontal lobe is is cut and major areas of prefrontal lobe are disconnected.
• There will be a difficulty in planning, failure to understand the seriousness of others feeling, loss of recent memory with impairment of moral and social sense, loss of attention and ability to concentrate, decreased mental drive and emotional instability.

Basal ganglia:

• Basal ganglia or a group of deep subcortical nuclei located at the base of forebrain.
• This is primarily involved in the control of posture and movement planning and programming of motor activities. Also plays a role in cognitive functions.
• They receive inputs mainly from cortex and project to cortex via thalamus and this area becomes active when there is a change in posture or movement.
• The disorders resulting in basal ganglia dysfunction or Parkinson's disease, huntington's disease, athetosis, ballism and chorea etc.
• The dysfunctions that result in these disorders are akinesia, bradykinesia, decreased associated movements, rigidity, tremors and festinant gait.

Pineal gland:

• ​​​​​​Pineal gland is located on the back of the third ventricle of brain in the epithalamus.
• Pineal gland secretes melatonin which shows a definite diurnal pattern, control skin colour and inhibits gonadal functions.
• Pineal gland secretes melatonin in maximum in night between 11 p.m. to 7 a.m. due to alteration in sympathetic discharge to the gland.
• The disorders that occur due to pineal abnormality are precocious puberty and sexual precocity.
• The dysfunction of the gland results in pubic hair growth, acne, body odour, breast enlargement in men, deepening of voice, short stature and facial hair etc.

Medulla oblongata:

• It is the part of brain stem that is located anterior to cerebellum and it continues as spinal cord.
• It regulate the functions of autonomic nervous system like respiratory and cardiac functions as respiratory and cardiac centres are located in it. It also controls the reflexes like vomiting, coughing, sneezing and swallowing.
• It is activated when there is an alteration in the respiration or cardiac functions like heart rate, cardiac output.
• Disorders of medulla oblongata results in respiratory paralysis, facial paralysis, quadriplegia.
• Dysfunctions that result due to lesions of medulla oblongata are breathing problems, loss of balance, vomiting, swallowing problems, hiccups etc.