NS67-68: Hypothalamus and Limbic System

What are the four parts of the diencepthalon?

EpithalamusDorsal ThalamusVentral ThalamusHypothalamus

What are the boundaries of the hypothalamus?

Rostral: lamina terminalis, anterior commissureDorsal: hypothalamic sulcusVentral: optic chiasm and base of brainCaudal: posterior to mammillary bodies

What are the four hypothalamic regions?

Pre-Optic AreaAnterior Supraoptic AreaMiddle Tuberal RegionPosterior Mammillary Region

What are the 3 zones medial to lateral in the hypothalamic regions?

Periventricular continuous with PAGMedial mostly nucleiLateral lateral hypothalamic nucleus, traversed by the medial forebrain bundle (MFB)

What structures does the anterior (supraoptic) region house?

1. Periventricular2. supraoptic nucleiparaventricular nucleisuprachiasmatic nucleianterior nuclei3. Lateral Hypothalamus

What structures does the middle (tuberal) region of the hypothalamus house?

1. Periventricular2. arcuate nucleiventromedial nucleidorsomedial nuclei3. Lateral hypothalamus

What structures does the Posterior (mammillary) region house?

1. Periventricular2. mammillary bodiesposterior nuclei3. Lateral hypothalamus + MFB

What structures does the Preoptic Region house?

1. Medial preoptic nucleus2. Lateral preoptic nucleus MFB

What is the function of the preoptic nuclei?

Male sexual behavior

What is the function of the periventricular areas of the anterior/middle/posterior regions of the hypothalamus?

feeding behaviors

What is the purpose of the suprachiasmatic nuclei of the anterior region of the hypothalamus?

necessary for diurnal cycles (retinal axons terminate here)

What is the purpose of the supraoptic and paraventricular nuclei?

to project to the posterior pituatary andcan make ADH and oxitosinALSO paraventricular contributes to the Central Sympathetic Tract

What does the anterior nucleus do?

thermoregulation

What does MFB stand for?

medial forebrain bundle = activating behaviors such as feeding, sexual, etc

What does the lateral hypothalamus of the anterior and middle regions of the hypothalamus do?

activate the limbic system

What does the arcuate nucleus of the middle tuberal region do?

projects to the anterior pituitary gland via a venus plexus (no direct connection)

What does the ventromedial part of the middle tuberal region of the hypothalamus do?

feeding, rage, female sexual behavior

What does the dorsal medial nucleus of the middle region of the hypothalamus do?

regulates ingestive behavior

What does the posterior nucleus of the posterior region of the hypothalamus do?

contributes to the central sympathetic tract

Which parts of the hypothalamus project to the central sympathetic tract?

Paraventricular region of the Anterior Region of the HypothalamusPosterior nucleus of the Posterior Region of the Hypothalamus

What two nuclei feed information to the anterior and posterior pituitary glands respectively?

Arcutate nucleus of the middle region of the HypothalamusSupraoptic and Paraventricular of the anterior region of the Hypothalamus

The MFB (Median Forebrain Bundle) carries many fibers through the hypothalamus and even contributes with reciprocal connections. What two structures outside of the hypothalamus does the MFB connect?

BrainstemSeptum/Amagdala/Telencephalon

To which part of the hypothalamus do fornix fibers contribute?

Mammillary Bodies

What are three parts of the amygdala?

Cortical Medial AmygdalaCentral AmygdalaBasal Lateral Amygdala

What fibers feed into the suprachiasmatic nucleus?

Retinal fibers

Some of the Paraventricular nuclei and most of the Supraoptic nuclei make up the input to the posterior pituitary. What do these cells produce and how does it reach the posterior pituitary?

ADH (anti-duretic hormone) and OxytocinThis reaches the posterior pituitary via axonal transport and releasing of the chemicals into the capillary bedsThis then migrates to kidney, uterus, and breasts

What does the arcuate nucleus contain?

many clusters of cells that make different factors that are directed for the anterior pituitarythese factors include hypothalamic releasing hormones and release-inhibiting hormones an example of a release-inhibiting hormone used in class was dopamine which inhibits pro-lactin release

What are the 7 hypothalamic regulatory hormones released by the arcuate nucleus?

GHRH: Growth Hormone Releasing HormoneGHIH: Growth Hormone Inhibiting HormonePRH: Prolactin Releasing HormonePIH (dopamine): Prolactin Inhibiting HormoneCRH: Corticotropin Releasing HormoneTRH: Thyrotropin Releasing HormoneLHRH/FRH: Luteinizing Hormone Releasing Hormone/Follicle-Stimulating Releasing Hormone

GHRHAnterior Pituitary HormoneFunctional Result

increase in Growth Hormonestimulates linear growth in epiphyseal cartilages

GHIHAnterior Pituitary HormoneFunctional Result

reduction in production of growth hormonereduces linear growth in epiphyseal cartilages

PRHAnterior Pituitary HormoneFunctional Result

increase in prolactinstimulates lactogenesis

PIH (dopamine)Anterior Pituitary HormoneFunctional Result

decrease the production of prolactinreduces lactogenesis

CRHAnterior Pituitary HormoneFunctional Result

adrenocorticotropic hormonestimulates adrenal gland to produce corticosteriods and sex hormones

TRHAnterior Pituitary HormoneFunctional Result

Thyroid Stimulating Hormonestimulates thyriod gland to produce thyroxine

LHRH/FRHAnterior Pituitary HormoneFunctional Result

Lutenizing HormoneFollicle-Stimulating Hormonestimulates ovarian follicles and production of estrogen and progesterone

What effect does dopamine have when released from the Arcuate nucleus of the middle region of the hypothalamus and goes to the anterior pituitary?

suppresses the secretion of pro-lactin

What effect does serotonin have on the anterior pituitary?

Increases secretion of prolactin

Patient X comes in and is pyschotic, so you give them a dopamine D2 blocker. What side effects should you be concerned about as a result of drug interactions in the hypothalamus/anterior pituitary if X is a male? What if X is a female?

Male: decrease in libido, impotence, infertility, and in a few rare, but exciting cases, galactorrhoea and gynaecomastia (breast enlargement)Women: galactorrhea, irregular menses, decreased libido, infertility

What four places do the mitral and tufted cells of the olfactory nerve project to?

Corticomedial Amygdalapyriform/olfactory cortexseptumsubstantia innominata/anterior perforated substance

What should we know about the limbic overview circuitry?

Everything is connected to everything!

What is a common target of the Herpes (HSV1 (adults) & HSV2 (children))? What will likely be affected?

Anterior Cingulate Gyrus of the limbic cortexprocessing of emotion and short term memories

What does Hippocampus mean in Greek?

Sea Horse

What are the four main components of the Hippocampus?

Dentate GyrusHippocampusSubiculumParahippocampal Gyrus

What is the function of the Hippocampus?

consolidation of short term memory into long term memoryThe hippocampus is the index of sorts for memory

What is the breakdown on percentages of people and their hippocampi after they reach 60 years old?

30% entorhinal area compromised due to Alzheimers30% subiculum compromised and they have benign senescent forgetfullness40% show healthy aging----hopefully me!

Where do most of the sensory areas feed into in the hippocampus?

Entorhinal cortex

What good is the Papex Circuit?

short term memory (up to 2 minutes)

What structures comprise the Papez Circuit?

Entorhinal cortexDentate gyrus/Amon's HornMammillary BodiesMammillothalamic TractAnterior Thalamic NucleusCingulate GyrusInternal CapsuleFornix

What is the part of the Amygdala that deals mainly with fear?

The central Amygdala

What part of the Amygdala gives correlation between emotion and vision/sounds?

Basolateral Amygdala

If you suffer a lesion in the Amygdala, what will happen to you as far as sex, eating, and mood?

HypersexualEat a lotBe Aggressive

If you suffer a lesion in the septum, what's going to happen to you?

Low levels of limbic activity: no sex, no eating, no motivation/aggression

33-year-old neurology resident with a history of migraine fell backward whileattempting a ski jump, struck his occiput on the snow, and suddenly developed amnesia.He began asking the same questions repeatedly, was unable to retain any newinformation for more than 1 to 2 minutes, and he did not recall any events thathad occurred during the previous approximately 1 year. After about 5 hours memories began to returngradually, with the most remote memories generally returning first.Location??

medial temporal or part of Papez circuit, bilaterally.?

A 40-year-old right-handed woman came to the emergencyroom because of unusual episodes of an indescribable unpleasant odor, nausea,and a panicky, fearful sensation. This lasted for 2 to 3 minutes, after whichshe felt very tired and went back to sleep. During the following week episodesincreased, followed by decreased responsiveness and slow, inappropriate speechlasting 2 to 3 minutes. After each episode she had a bifrontal headacheand tiredness.Location?

Unpleasant odor, nausea, and a panicky,fearful sensation?Amygdala andadjacent cortical areas.Decreased responsiveness and slow,inappropriate speech? Left hemisphere, amygdala andadjacent areas and/or secondary cortical involvement.