Hypothalamus Flashcards
What are the 2 types of drives that the hypothalamus is responsible for?
(give some e.g.’s of each)
- Homeostatic drives (e.g. feeding, thirst, salt, thermoregulation, sleep, sickness)
- Species-survival drives (e.g. sex behavior, parenting, social curiosity, aggression)
What general part of the limbic system is the hypothalamus associated with?
“reward system”
Describe the functional and anatomical boundaries of hypothalamic nuclei.
Vague, nondistinct
What are the 3 main input routes to the hypothalamus?
Where do each come from?
- Fornix (from hippo)
- Stria terminalis (from amygdala)
- Medial forebrain bundle (from amygdala and others)
What are the 3 main monoamine NTs that are important in the hypothalamus?
- 5-HT
- NE
- DA
Most dopaminergic pw’s leaving the SN and VTA travel through the _____________________ on their way to limbic areas and frontal lobe.
Medial forebrain bundle
Before norandrenergic fibers reach the limbic areas, frontal lobe, cingulate gyrus, these fibers pass through the _____________________ and enter the amygdala and thalamus.
Median forebrain bundle
The most widespread monoamine NT in the brain is _____________.
Serotonin
What are 2 places serotonergic cells originate in?
- Dorsal and median raphe nuclei
When traveling to the lateral hypothalamic area, serotonergic axons pass through the __________________.
Median forebrain bundle
Mammillary bodies of the hypothalamus function primarily in what type of memory?
Recollective memory (also spatial memory)
[Recollective memory: recalling info from the past]
*What are the 3 pw’s associated w/the mammillary bodies, and what brain areas do they project to?
- Mammillothalamic tract (thalamus)
- Mammillotegmental tract (midbrain tegmentum)
- Mammillary peduncles (reticular formation)
With what major brain areas does the hypothalamus have bilateral inputs/outputs?
- Cortex
- Midbrain (via dorsal longitudinal fasciculus of Schutz)
- Amygdala (via median forebrain bundle)
In what 3 ways does the hypothalamus communicate w/the amygdala? (give directionality of each)
- Input to hypo via stria terminalis
- Input to hypo via diagonal band of Broca
- Bilateral via media forebrain bundle (olfactory cortex, preoptic area, septal area, accumbens, NTS)
How do the sc and hypothalamus communicate w/each other? (what direction as well)
Hypo –> sc (via hypothalamospinal tract)
How do the eye and hypothalamus communicate w/each other? (what direction as well)
Eye –> hypo (via retino-hypothalamus tract)
How do the thalamus and hypothalamus communicate w/each other? (what direction as well)
Hypo –> thalamus (via mammillothalamic tract; info hits cortex and can come back)
How do the midbrain and hypothalamus communicate w/each other? (what direction as well)
Bidirectionally (via dorsal longitudinal fasciculus of Schutz)
How do the hypothalamus and cortex communicate w/each other? (what direction as well)
Bidirectionally (corticohypothalamic tract)
How do the cortex and hippocampus communicate w/each other? (what direction as well)
Cortex –> hippo (via parahippocampal cortex and cingulate cortex)
* There is bidirectionality in other tracts
How do the hippocampus and hypothalamus communicate w/each other? (what direction as well)
Hippo –> hypo (via fornix)
What system is the Papez circuit associated w/?
Limbic (emotional cognition)
What nucleus in the thalamus is strongly associated w/the limbic system?
Anterior nucleus
*Follow the BASIC path of the Papez circuit, starting at the hippo.
- Hippocampus gives output to mammillary bodies of hypo (via fornix)
- Mammillary bodies give output to ant nuc of thalamus (via mammillothalamic tract)
- Thalamus gives output to cingulate gyrus
- Cingulate gyrus gives output to hippo
How is the amygdala involved in the modern understanding of the Papez circuit?
It receives input from the hippocampus and gives output to the hypothalamus
How is the prefrontal cortex involved in the modern understanding of the Papez circuit?
Receive input from the hypothalamus and communicates w/the association cortex
How is the association cortex involved in the modern understanding of the Papez circuit?
Communicates bidirectionally w/cingulate gyrus and hippocampus.
- Is also communicating w/PFC
The mammillary bodies of the hypo area associated w/emotional _____________. The cingulate gyrus (of limbic system) is associated w/emotional _____________.
- expression
- experiences
Regarding pituitary control, the anterior pituitary has ________ control, the posterior pituitary has ________ control.
- Indirect (2 levels of control from hypo)
- Direct from hypo (1 level of control)
Random: Most physiologic processes are regulated by some form of “____________.”
Servomechanism
Biological rhythms that occur less than 24 hrs are deemed ___________.
What are e.g.’s?
Ultradian
- HR, RR
Biological rhythms that occur ~ 24 hrs are deemed ___________.
What are e.g.’s?
Circadian
- Sleep, corticosterone
Biological rhythms that occur 24 hrs to 1 year are deemed ___________.
What are e.g.’s?
Infradian
- Menstrual cycles
Hypothalamic circadian rhythms require a “clock” or timing device. This function is controlled primarily by the ___________.
SCN
Which of the following fiber bundles contains bidirectional connections between the septal nuclei, lateral hypothalamic nucleus, tuberal nuclei, and brainstem areas such as the periaqueductal gray and the tegmental nuclei?
a. Mammillotegmental tract
b. Mammillothalamic tract
c. Medial forebrain bundle
d. Stria terminalis
e. Stria medullaris thalami
c. Medial forebrain bundle
A 61-year-old woman presents with a complaint of persistently seeing “two of everything.” The examination reveals a dilated left pupil and an inability to look up, down, or medially with that eye. MRI reveals an aneurysm of the basilar bifurcation. During surgery to clip this aneurysm, the small perforating branches of P1 (posterior perforating arteries off the posterior cerebral arteries) are inadvertently occluded by the clip. Which of the following structures would be most adversely affected by this disruption of blood supply?
a. Anterior hypothalamic nucleus
b. Mammillary nuclei
c. Medial preoptic nuclei
d. Paraventricular nucleus
e. Tuberal region nuclei
(B) Mammillary nuclei
The mesolimbic system has cell bodies in the ventral tegmentum that send projections to the ____________________________.
Hypothalamus and other limbic areas
The nigrostriatal system is found in the ____________________________.
Basal ganglia (substantia nigra pars compacta)
