14 Hypothalamic, RF, and Limbic Systems - A Flashcards Preview

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What is the thalamic nuclei responsible for?

1. Relay general & special sensory information

2. Receive inputs from cerebellum & basal ganglia

3. Relay to associative & limbic cortical areas


Why is the thalamus important?

it consists of numerous nuclei, most with extensive reciprocal connections with the cerebral cortex


What is the direction of fibers that project from the functional thalamic nuclei?

Majority project to ipsilateral cerebral cortex

- precise, point-to-point projections between thalamic nuclei & defined cortical regions


What are the five (5) thalamic nuclei that make up the lateral nuclear group?

1. Ventral anterior

2. Ventral lateral

3. VPM/VPL [ventral posteromedial nucleus/v. posterolateral]

4. LGN [Lateral geniculate nucleus]

5. MGN [Medial geniculate nucleus]


What does the ventral anterior thalamic nuclei do?

basal ganglia & primary/supplementary motor areas


What does the ventral lateral thalamic nuclei do?

basal ganglia, cerebellum, & primary/supplementary motor areas


What does the VPM/VPL thalamic nuclei do?

spinothalamic tracts & medial lemniscus, trigeminothalamic tracts


What does the LGN thalamic nuclei do?

visual afferents


What does the MGN thalamic nuclei do?

auditory afferents


The reticular nuclei (brainstem) of the reticular activating system are ______. They are located where?

diffuse and ill-defined, and have little apparent internal organization

- located at midbrain, pons, & medullary levels


What does the reticular activating system (RAS) control? It is interconnected with _____ & _____ in the brainstem.

Controls states of consciousness, sleep, REM, heart rate & respiration

1. basal nuclei

2. motor centers


Descending reticulospinal tracts originate _____ & _____ and influence _____ & ______.

Originate from the medullary and pontine RAS.

Influence muscle tone and posture


Raphe nuclei are a series of _____ nuclei that extend throughout the ________.

MIDLINE nuclei

length of the brainstem


What neurotransmitter are Raphe nuclei responsive to?


Most are serotonergic


Where do the ascending projections of Raphe nuclei go to? (6)

1. thalamus

2. hypothalamus

3. striatum

4. amygdala

5. hippocampus

6. widespread regions of cerebral cortex


What are Raphe nuclei believed to be involved in?  

mood & cognitive function & in the neural mechanisms of sleep


What is the hypothalamus and what surrounds it?





small anatomical region of the diencephalon that is separated superiorly from the dorsal thalamus by the hypothalamic sulcus

Rostral = lamina terminalis

Lateral = substantia innominate (rostral) & medial edge of the posterior limb of the internal capsule (caudal)

Medial = inferior portion of 3rd ventricle

Caudal = merges into the midbrain tegmentum & PAG [periaqueductal gray]

[according to Dennis, location is pretty low-yield but still included]


What is the hypothalamus involved in?

control of visceral functions & emotional behavior


What is the preoptic area of the hypothalamus?

transition region that extends rostrally, forms a continuation with basal forebrain


What is the preoptic area of the hypothalamus composed of?

medial and lateral preoptic nuclei

Medial preoptic nucleus contains neurons that make GnRH


What is the periventricular zone of the hypothalamus adjacent to and what does it do?

adjacent to 3rd ventricle

- synthesizes releasing hormones

- projects via hypophyseal portal system to anterior pituitary


What is the medial zone of the hypothalamus and what "regions" does it contain?

cell-rich region composed of many nuclei

Supraoptic (chiasmatic) region

Tuberal region

Mammillary region



What does the Lateral zone of the hypothalamus contain and what does it interconnect?

contains medial forebrain bundle

- interconnects lateral zone w/ the septal nuclei & the brainstem RF (reticular formation)


What else does the Lateral zone of the hypothalamus contain other than the medial forebrain bundle? And what does it do?

Lateral hypothalamic nucleus - which is a large cell group that constitutes the "feeding center"


What are the three (3) regions of the nuclei of the medial zone of the hypothalamus?

1. Supraoptic region

2. Tuberal region

3. Mammillary region


What three (3) nuclei does the supraoptic region of the medial zone of the hypothalamus?

1. Supraoptic/Paraventricular nucleus

2. Suprachiasmatic nucleus

3. Anterior nucleus


What is the supraoptic/paraventricular nucleus of the supraoptic region of the medial zone of the hypothalamus?

contains oxytocin (SO) & ADH (PVN), and transmit these substances to the posterior pituitary


Describe what the anterior & medial nuclear groups & intralaminar groups of the functional thalamic nuclei do and why are they different than the five (5) that make up the lateral nuclear group?

- 'non-specific' nuclei

- largely project to broad limbic & hypothalamic areas

- among these, the lateral dorsal nucleus is part of the limbic system

- instinctive drives, mood, emotional behavior


What is the anterior nucleus of the supraoptic region of the medial zone of the hypothalamus?

participates in a range of visceral/somatic functions, many neurons involved in temperature regulation


What are the three (3) nuclei that make up the tuberal region of the medial zone of the hypothalamus?

1. Ventromedial nucleus

2. Dorsomedial nucleus

3. Arcuate nucleus