Cerebrum - Epi, Hypo, Thalamus

What makes up the diencephalon?

thalamus, hypothalamus, epithalamus

Where is the hypothalamus in relation to the thalamus?

Rostral + caudal (anterior + inferior)

What parts of the diencephalon are the lateral walls of the 3rd ventricle?

Epithalamus

Thalamus

Hypothalamus

What is the roof of the third ventricle?

fornix

What is the lateral wall of the third ventricle at the posterior limb of the internal capsule?

Thalamus

What is the medullary lamina?

Y-shaped line that splits the thalamus into 3 nuclei (anterior, medial, lateral)

What is the massa intermedia?

Connection between R + L medial nuclei of the thalamus

What nuclei of the thalamus form the lateral wall of the 3rd ventricle?

Anterior + middle: medial nuclei of thalamus

Posterior: lateral nuclei (pulvinar) of thalamus

Where does the anterior nuclei of the thalamus get input from? How?

Hippocampus + hypothalamus via mamillothalamic tract

Pathway of information going to anterior nuclei of thalamus

Hippocampus —> fornix —> maxillary nuclei of hypothalamus —> mamillothalamic tract —> anterior nuclei

Where does the anterior nuclei of the thalamus give info to? How?

Hippocampus via Cingulum

What is the cingulum? What is it continuous with?

Projection bundle inside cingulate Gyrus

Continuous with parahippocampal gyrus

Where is the cingulate gyrus located?

above corpus callosum

What does the medial nuclei of the thalamus connect to?

Prefrontal cortex

Lateral subnuceli of medial nuclei of thalamus function

Helps control eye movements and attention to visual stimuli, plays role in emotional tone

Where does the Lateral subnuceli of medial nuclei of thalamus get input from?

Superior colliculus

Olfactory cortex

Ventral palladium

Where does the Lateral subnuceli of medial nuclei of thalamus give info to?

Frontal eye fields

Prefrontal cortex

medial subnuclei of medial nuclei of thalamus function

Tie emotion to gut (autonomic regulation)

Where does the medial subnuclei of medial nuclei of thalamus give info to?

Limbic cortex (insular cortex, orbital frontal cortex)

Lateral nuclei of the thalamus consist of what

Specific relay nuclei (LGN, MGN, VPL, VPM)

Association nuclei (pulvinar)

VPL of thalamus

somatosensory

VPM of thalamus

Trigeminal fibers run here

Where does the pulvinar receive info from ?

Superior colliculus

Where does the pulvinar give info?

Secondary visual areas (posterior parietal cortex)

Pulvinar function

Contributes to visual perception + eye movements

Modulates attention to visual stimuli

What is the Subthalamic sulcus

Dividing line between thalamus + hypothalamus

What is the median eminence?

Connects posterior pituitary to main hypothalamus

What is the infudibular recess?

Part of 3rd ventricle that dips down @ median eminence

What is the optic recess?

Part of the 3rd ventricle that is formed due to optic chiasm

Infundibualr recess vs optic recess location

Optic recess is anterior to infundibular recess

Where is the optic chiasm located?

Below the hypothalamus + anterior to posterior pituitary

If you cut through the optic chiasm what is the space above it? What is the structure/wall of that space?

Space: 3rd ventricle

Wall: hypothalamus

What nuclei of the hypothalamus make the hormones of the posterior pituitary?

Supraoptic

Paraventricular

Where is the supraoptic nuclei located?

In hypothalamus Above chiasm

Where is the paraventricular nucleus located?

In hypothalamus Closest to 3rd ventricle

What forms the mammillary body?

Mammillary nucleus

What does the Epithalamus contain?

pineal gland

Posterior commissure

What does the posterior commissure do? What is the test for this

Allow fibers associated with the pupil to cross midline

test: shine light in one eye, both pupils should constrict

Where is the posterior commissure located?

Anterior/rostral to midbrain

Caudal + rostral to pineal gland

Where is the pineal gland located?

Cranial to midbrain

Posterior + cranial to posterior commissure

If the pineal gland is swollen, what will it push on?

Midbrain

What does the pineal gland do?

circadian rhythm + photosensitivity

Produces melatonin

What projects to the pineal gland? What does it do?

ipRGCs

Suppress melatonin releases

What are ipRGCs?

intrinsically photosensitive retinal ganglion cells

What are the only non myelinated cells of the retina?

IpRGCs

What kind of receptive field do ipRGCs have?

Large

Why can a TBI lead to sleep problems?

Damage the ipRGCs, causing their activity to be turned up

When do ipRGCs peak?

In blue light