The Diencephalon

1. Thalamus:

A) What is the Thalamus?

A relay station that sits above the brain stem and is the "gateway" to the cerebral cortex. It relays sensory information (except smell), information regarding perception of pain, temperature, and touch, imparts sense of pleasantness and noxiousness, and maintains cortical arousal, attention & sleep/wake cycle.

B) Thalamic Problems 

• Dejerine-Roussy Syndrome (a.k.a, Thalamic pain syndrome) can result in hemiparesis/hemiplegia, dysesthesia  (pain), and slight ataxia. However, cognition, speech and language are intact.
• Thalamic Aphasia results in a fluent verbal output with semantic paraphasias, mild auditory comprehension issues, and mild to normal repeating skills.

2. Hypothalamus

A) What is the Hypothalamus?

A regulator of the autonomic nervous system, metabolism, water balance, sleep/wake mechanism, body temperature, food intake and secondary sex characteristics. The pituitary gland is in the hypothalamus.

B) Pituitary Problems

• Cushing's Disease is an endocrine (hormone) disorder caused by a tumor on the pituitary. It results in high levels of cortisol. Symptoms include moon facies, emotional disturbances, osteoporosis, hypertension, buffalo hump, obesity, amenorrhea (loss of menstruation), muscle weakness, and abdominal stripes. 
• Acromegaly is caused by a pituitary tumor and means extreme largeness. It results in the pituitary producing too much human growth hormone. Symptoms include large stature, large nose and jaw, large hands, hypertension, and peripheral neuropathy 

3. Epithalamus

A) What is the Epithalamus?

Connects the limbic system to the forebrain and other parts of the brain.It  includes the Pineal Gland, Habenula, and Stria Medularis. It controls the sleep/wake cycle and olfactory reflexes.

4. Subthalamus

A) What is the Subthalamus?

Lies below the thalamus and connects the basal ganglia to the motor cortex, thus is more related to the basal ganglia than thalamus. Damage can result in hemiballism.