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116 Cards in this Set
- Front
- Back
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What is the landmark we can use to figure out all the structures in the diencephalon?
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They are all the structures surrounding the 3rd ventricle. (3rd ventricle is the cavity of the diencephalon)
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What are the structures in the diencephalon? What is the biggest one?
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Thalamus- biggest
hypothalamus epithalamus basal ganglia (subthalamus) optic "nerves" |
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What is in between the thalami?
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the 3rd ventricle!
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What are the 3 structures that make up the epithalamus?
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1. Pineal body/gland
2. 2 habenular nuclei |
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Draw the epithlalmus in relation to the 3rd ventricle and the thalami.
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What is the commissure that connects the two habencular nuclei called?
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habencular commissure
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Show the interthalamic adhesion
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Where is this adhesion?
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Right in the middle of each thalami and it makes a hole in the 3rd ventricle so it is not a complete box
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What does the anterior and posterior commissure connect? Are they part of the diencephalon?
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anterior- the temporal lobes (telencephalon)
posterior- pretectal nuclei (mesencephalon) |
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What happens when you walk anteriorly in the 3rd ventricle past the thalami?
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You pass the midbrain, but start walking on additional grey matter that is the hypothalamus whih also starts to surround you on the left and right.
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Draw how the 3rd ventricle sits in the hypothalamus. Add in the thalamic adhesion too.
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How heavy is the hypothalamus?
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only 4 grams (very small!)
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How is the hypothalamus related to the thalamus? What separates them?
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it starts exactly where the anterior part of the thalamus ends. This junction is called the hypothalamic sulcus or sulcus of monro.
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Where is the foramen of monro in relation to the thalami?
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It starts right after the sulcus where the thalami end
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Where does the 3rd ventricle end in relation to the thalamus?
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exactly where the posterior part of the thalamus ends
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Where does the 3rd ventricle end in relation to the hypothalamus?
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till the very end of it anteriorly
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Draw all of the swellings around the structures surrounding the third ventricle. (include the ones in the thalami
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Which genticulate body of the thalamus is more posterior? Why/
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The medial because the lateral is at the widest part so as you go in, you go posterior.
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Show the optic chiasm. (how the optic nerve connects with the brain)
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What structure marks the beginning of the optic chiasm?
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The hypothalamus
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Where do the optic nerves terminate in the brain?
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in the lateral genticulate nuclei
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How can I use my midbrain knowledge to remember what nuclei the optic nerve terminates on?
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Inferior colliculi goes to MGB for all hearing
Superior colliculi goes to LGB for all visual processing!!! |
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Where along the hypothalamus do the optic nerves run?
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near the bottom of it.
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Since the optic nerves are so close to the hypothalamus, are they part of the diencephalon?
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YES
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Will MS affect the eyes? Why?
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Yes because the optic nerve is actually a tract myelinated by oligodendrocytes
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Are the posterior and anterior pituitary glands part of the diencephalon?
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The PP is, but the AP is not.
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Why is the AP not part of the diencephlon?
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It is actually derived from different tissue. It come from Rathke's pouch which is an invagination of the epithelium of the nasopharynx.
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Can you draw the nasopharynx in relation to the pituitary gland and the migration of rathke's pouch?
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NOW WE GET INTO THE THALAMUS LECTURE
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WOOT!
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What is another name for the thalamus?
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dorsal thalamus
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What part of the diencephalon is directly underneath the thalami?
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SUBthalami (basal ganglia)
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Essentially, what is the thalamus?
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A collection of nuclei
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What divides the thalamus into 3 sections?
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The medullary lamina (shaped like a peace sign)
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Essentially what are the medullary lamina?
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myelinated axons
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I have already gone through the thalamus in the sensory lectures. Just pull the picture of the different nuclei from there.
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What are the axons in the medullary thalamic lamina connecting?
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Alll the nuclei within the thalamus
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What is the stratum zonale?
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A sheet of white matter covering the top of the thalamus
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What is the external medullary lamina?
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A sheet of white matter lining the side of the thalamus
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Is the thalamic adhesion made of white or grey matter?
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grey
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Are the genticulate bodies lateral or posteriolateral to the thalami?
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posterolateral
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Draw the three types of white matter in/around the thalamus and label them. Also note the position of the genticulate nuclei and the thalamic adhesion.
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Draw the reticular nuclei in relation to the thalami.
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Pull the picture of the thalamus, internal/extermal capsule and the lentiform nucleus.
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Label the lateral and medial part of the lentiform nucleus.
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NOW WE TALK ABOUT THE CAUDATE NUCLEUS
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PROOOSH
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What two things have I compared the caudate nucleus to?
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A rat tasting the outer part of a cheese (putamen)
A ear conforming headphone with the putamen as the speaker part and the thalamus as the ear |
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What is the little bulb at the tip of the rat's tail? grey or white matter?
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amygdala- grey matter
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What happens if you pull the rat's tail?
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it gets really angry (also responsible for sexual arousal)
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Holy ****, the same area that controls anger controls sex in our brain. Can we just take a moment to ponder that?
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WOAAAAHHHH!
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Show a picture of the amygdala in relation to the caudate nucleus
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What is the part of the internal capsule where it bends from the anterior to posterior limb called?
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The genu (knee) of the interior capsule
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Is the headphone analogy oriented correctly in terms of front and back? Why?
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Yes, the head of the rat tasting the cheese is anterior.
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NOW WE TALK ABOUT THE LATERAL VENTRICLE
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OK!
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Show a pic of the lateral ventricles compared to the 3rd ventricle
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Where are the frontal horns compared to the 3rd ventricle?
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extending directly in front starting at the foramen of mondo
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Where are the bodies of the lateral ventricles compared to the 3rd ventricle? to the thalamus?
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lateral to the 3rd ventricle and on top of the thalamus
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Is it directly on top of the thalamus?
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No, it is on top of the caudate nucleus which is directly on top of it.
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What kind of spatial mnemonic can you use to envision the lateral ventricles that adds onto the earphones one?
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Think about elf ears on top of the earphones that are tilted so the point is horizontal.
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Do the frontal horns line up with the bottom lateral/posterior horns?
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No, the lower horns are spread out wider.
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What is the intimate relationship of the caudate nucleus with the lateral ventricle then? (give picture)
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If you are a little person walking into the temporal horn of the lateral ventricle, what would it look like? Label the drawing.
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Explain what just happened.
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The temporal horn follows the tail of the caudate nucleus and terminates where the amygdala is. The tail of the caudate nucleus is directly on top and on the bottom sits the fornix/hippocampus.
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When the 3rd ventricle enters the hypothalamus, does it tilt up or down?
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down
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What animal does the fornix look like? Show a picture.
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A seahorse! The body of the seahorse is the hippocampus.
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Describe the course of the fornix.
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It lines the outside of the lateral ventricle from the bottom of the temporal horn by beginning at the hippocampus to the top of the body just before the hypothalmus begins.
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Draw the fornix by itself and label what part is white/grey matter.
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Explain what just happened.
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The grey matter of the fornix is the hippocampus (I couldn't understand him earlier!) at it's bottom end at the temporal lobe. The rest is white matter looping around to the hypothalamus.
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Is the caudate nucleus grey or white matter? What tiny part of it is different?
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Grey matter, but it gives off one tiny string of white matter called the striae terminalis.
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Draw the course of the striae terminalis.
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Describe what just happened.
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A string of white matter comes off the amygdala and follows the outside of the caudate nucleus and terminates of the hypothalamus.
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What particular part of the hypothalamus does the fornix terminate?
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At the mamillary body!
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Draw a frontal view of all the structures we talked about. In particular, show show how everything stacks on top of the thalamus.
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In order of closest to furthest away, what is on top of the thalamus?
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1. Stratum zonale (lamina white matter)
2. Striatum terminalis (thin white matter tail) 3. Head of caudate nucleus 4. Lateral ventricle 5. Fornix |
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NOW WE TALK ABOUT THE NUCLEI OF THE THALAMUS AND THEIR FUNCTIONS.
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SO GREAT!
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What is the function of the anterior nucleus?
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to regulate mood according to recent memories
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What can I infer about my own tendency to think that I have been feeling a particular way my whole life and freak out?
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I must have a very active anterior thalamic nucleus
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What mental illness is prone to underactivation of the anterior thalamic nuclei and it's pathway?
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depression
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So which two things should the anterior thalamic nucleus be connected to?
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the center for recent memory and the center for mood
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What system are both these two things contained in?
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The limbic system and the hippocampus
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So what kind of association should the anterior thalamic nucleus have with the limbic system? What is the whole circuit called?
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a very close one. the Papex circuit
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Draw the papez circuit.
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What just happened?
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hippocampus --> fornix -->mamillary body --> mamillary thalamic tract (very strong) --> anterior thalamic nucleus --> cingulate gyrus
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Show a nice pic of the papez circuit
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There are some diseases that disrupt the anterior and medial thalamus. What is this called and what is it caused by?
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Severe thiamine deficiency (Korsakoff's syndrome)
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What B vitamin is thiamine?
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B1
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What is another name for Korsakoff syndrome that is telling of it's symptoms?
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amnesic-confabulatory syndrome
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Since the mamillary body is so important to the papez pathway, what should be the sx of Korsakoff's syndrome/Thiamine deficiency?
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Loss of SHORT TERM memory
Confabulating memories to fill in gaps Apathy |
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If you had to sum up the role of the anterior thalami, what would it be?
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To adjust your mood according to things that have happened recently
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What happens to short term memory that highly activates the Papez circuit because it is emotionally loaded?
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It gets assimilated into long term memory.
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What implication does this have for studying?
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One way to retain information better is to make the studying of it exciting! You won't remember boring lectures.
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NOW WE DISCUSS THE MEDIAL THALAMUS!
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LET'S GET ******* EXCITED!
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In a nutshell, what does the medial nucleus of the thalamus do?
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It adjusts your behavior and thoughts (psychological and physical state) according to your mood.
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What part of the cerebrum is involved in thinking and behavior?
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prefrontal cortex
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What sensory input has to pass through the thalamus?
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Everything except for olfaction
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Show a picture of the connections of the medial thalamus.
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What connections does the medial thalamus have with the rest of the thalami?
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It gets fibers sent to it from all the other nuclei to update it on all the sensations that are passing through.
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What kind of connection does the medial thalamic nuclei have with the lentiform nucleus?
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A connection with the globus pallidus
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What does this connection with the basal ganglia explain?
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Why you have hunched posture and a sad face when you are feeling down.
And why you get in a better mood with exercise. |
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What else does the medial thalamus get input from?
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The hypothalamus
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So you get some bad news. What does the anterior vs medial thalamic nuclei do about it?
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anterior thamalus- helps you to react emotionally and remember it and also transfers this info to the medial thalamus
medial thalamus- helps you to think it over and mope around about it |
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So whta can you say about which parts of the thalamus are concerned with the limbic system?
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The anterior and medial thalamus are strongly connected to emotion
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NOW WE TALK ABOUT THE INTRALAMINARY NUCLEI
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WOOT
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Essentially what do the intralminar nuclei do?
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Take sensory and motor information and use that for cerebral arousal
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Draw a picture of the connections from below to the intralaminar nuclei
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Why do we get slow and tired when we are awake for too long?
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Our reticular formation is running out of NT's.
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Why would we wake up NATURALLY in the morning?
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Our reticular formation has replenished it's NT's and is working to wake up the brain.
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is it easy to fall asleep you have just stubbed your toe? Why?
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No because thi has activated your reticular formation
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What will tumors or infarctions to the reticular- intralaminar thalamus pathway do?
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Put you in a coma
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Does the intralaminar nuclei also have connections elsewhere?
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Yes, it gets info from the rest of the thalamus as well
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If you are asleep and all of a sudden a really hot guy calls and asks to meet you, you are very awake suddenly. What pathway led to this?
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The medial and anterior thalami receive this very exciting and emotional information and sent signals to the intralaminar nuclei to wake up the whole cortex.
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When would you ever go in and purposely damage the intralaminar nuclei?
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if a pt had terminal cancer and was in a lot of pain
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Which is the biggest intralaminar nuclei? Where is it?
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The centromedial nuclei in the very center.
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What connections does the centrolaminar nuclei have?
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it is connected to the motor cortex and the basal ganglia.
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What does this serve to do?
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If you are moving or thinking about moving, you are activating the intralminar nuclei and becoming more awake?
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Why can't I go to sleep when I have very emotional thoughts, but go right to sleep when I do something boring?
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Since the emotional thalami (medial and anterior) stimulate the intralaminar nuclei, any kind of strong emotion will keep my brain activated.
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