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Flashcards in Brainstem Tracts Flaschards Upper Deck (46)
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1

What is the Crus Cerebri aka Cerebral Peduncle?

The crus cerebri (cerebral peduncle) is the major bundle of nerve fibers leaving the cerebral cortex enroute to the brain stem (corticobulbar) or spinal cord (corticospinal).

2

What is the Corpus Collosum?

The corpus callosum is the very large bundle of nerve fibers that connect the left and right cerebral hemispheres.

3

What are Optic Radiations?

The optic radiations are nerve fibers arising from the lateral geniculate nucleus and projecting to the visual cortex.

4

What is the Optic Tract?

The optic tract contains nerve fibers from retinal ganglion cells that convey visual information from the contralateral visual world. It terminates in the lateral geniculate nucleus of the thalamus.

5

What are the Cerebellothalamic Fibers?

Cerebellothalamic fibers, for the most part, are axons arising in the dentate nucleus and projecting to the ventral lateral nucleus of the thalamus. Damage would produce severe incoordination of the contralateral side of the body.

6

What is the Fornix?

The fornix is a pathway connecting the hippocampi with the septal nuclei and the hypothalamus (particularly mamillary bodies).

7

What is the Quadrigeminal Cistern?

The Quadrigeminal cistern is a large collection of cerebrospinal fluid immediately dorsal to the tectum of the midbrain.

8

What is the Posterior Commissure?

The posterior commissure connects one side of the pretectal region to the other. Is part of the system which permits the pupillary light responses to be bilateral (consensual).

9

What is the Habenulo-Interpeduncular Tract?

The habenulo-interpeduncular tract tract arises from the habenular nuclei and terminates in the interpeduncular nucleus of the midbrain. It is part of a pathway that connects the forebrain with the brain stem.

10

What is the Lateral Geniculate?

The lateral geniculate is a nucleus located at the posterior inferior aspect of the thalamus (metathalamus) that receives visual input from the contralateral part of the visual world and projects to the primary visual cortex. Damage would produce a contralateral homonomous hemianospia.

11

What is the Pretectal Nuclei?

The pretectal nuclei consist of a group of nuclei in the rostral midbrain that are involved in visual reflexes, notably, the pupillary light reflex.

12

What is the Internal Capsule?

The internal capsule separates the thalamus from the lenticular nuclei posteriorly and the caudate from the putamen anteriorly. It contains the vast majority of nerve fibers leaving the cerebral cortex on their way to brain stem (corticobulbar) or spinal cord (corticospinal). The internal capsule also contains nerve fibers reciprocally connecting the cerebral cortex to the thalamus.

13

What is the Pulvinar of the Thalamus?

The pulvinar of the thalamus is a portion of the thalamus that is interconnected mostly with the parietal and visual association cortices and plays a role in attention. It also is involved in visual tracking of interesting or novel stimuli.

14

What is the Caudate Nucleus?

The caudate nucleus major component of the basal ganglia. It receives input from the cerebral cortex and substantia nigra. Most of its output is to the globus pallidus. It is heavily involved in motor control. It has a head, a body and a tail that follows the sweep of the lateral ventricle.

15

What is the Stria Terminalis (near Caudate)?

The stria terminalis is a pathway that runs in the floor of the lateral ventricle, directly between the bulge for the caudate nucleus and the thalamus, is a connection between the amygdala of the temporal lobe and the septal nuclei and hypothalamus. Often, the thalmiostriate veins can be seen attached to this tract.

16

What is the External Medullary Lamina?

The external medullary lamina is a capsule of nerve fibers lateral to the thalamus, which contains nerve fibers entering and leaving the thalamus.

17

What is the Putamen?

The putamen is a major component of the basal ganglia that is adjacent to the globus pallidus. Along with the caudate nucleus it makes up the corpus striatum. The putamen and globus pallidus together make up the lenticular nucleus It receives input from the cerebral cortex and substantia nigra. Most of its output is to the globus pallidus. It is heavily involved in motor control.

18

What is the Globus Pallidus?

The globus pallidus is a major component of the basal ganglia. It has two parts (lateral & medial or external & internal). It recieves input from the caudate and putamen (striatum). The lateral part projects to the subthalamic nucleus, the medial to the thalamic VA and VL.

19

What is the Ansa Lenticularis?

Thee ansa lenticularis consists of nerve fibers coursing ventral to the internal capsule, connecting the globus pallidus to the VA/VL of the thalamus.

20

What is the Ventral Posteriomedial Nucleus of the Thalamus?

The ventral posteromedial nucleus of thalamus is the major termination of sensory fibers from the head (via ventral and dorsal trigeminothalamic tracts). It relays this information to the head area of the primary sensory cortex (postcentral gyrus).

21

What is the Ventral Posteriolateral Nucleus of the Thalamus?

The ventral posterolateral nucleus of thalamus is the major termination of sensory fibers in the spinothalamic tract and the dorsal columns/medial lemniscus system (contralateral somatic sensation). This thalamic nucleus relays this information to the primary sensory cortex (postcentral gyrus).

22

What is the Ventral PosterioMEDIAL Nucleus of the Thalamus?

What is the Ventral PosterioLATERAL Nucleus of the Thalamus?

The ventral posteromedial nucleus of thalamus is the major termination of sensory fibers from the head (via ventral and dorsal trigeminothalamic tracts). It relays this information to the head area of the primary sensory cortex (postcentral gyrus).

The ventral posterolateral nucleus of thalamus is the major termination of sensory fibers in the spinothalamic tract and the dorsal columns/medial lemniscus system (contralateral somatic sensation). This thalamic nucleus relays this information to the primary sensory cortex (postcentral gyrus).

23

What is the Hypothalamus?

The hypothalamus is the principal area of integration of behavioral, autonomic and endocrine response to emotional stimuli. It is also involved in feeding, sexual function, and various aspects of homeostasis.

24

What are the Mamillary Bodies?

The mamillary bodies appear as ventral appendages of the posterior hypothalamus. They receive input from the hippocampus (via the fornix) and from other parts of the hypothalamus. They are a route for hypothalamic influence over rostral brainstem (mamillotegmental tract) and receives input from the fornix and makes output to the anterior nuclear group of the thalamus.

25

What is the Zona Incerta?

The zona incerta is an area of the rostral reticular formation that is between the lenticular fasciculus and the thalamic fasciculus (pathways bring basal gangliar and cerebellar inputs to the thalamus, respectively).

26

What is the Thalamic Fasciculus?

The thalamic fasciculus is comprised of the nerve fibers (mostly coming from the globus pallidus of the basal ganglia and from the dentate nuclei of the cerebellum that are going to terminate in the VA/VL of the thalamus.

27

What is the Centromedian Thalamic Nucleus?

The centromedian thalamic nucleus is the largest of the intralaminar thalamic nuclei. It is different than other thalamic nuclei since it has reciprocal connection with the basal ganglia and probably plays a role mainly in motor control.

28

What is the Internal Medullary Lamina?

The internal medullary lamina is comprised of nerve fibers passing through the thalamus. They assume a "Y" shape when observed from the dorsal aspect of the thalamus, dividing the thalamus into a medial, a lateral and an anterior nuclear group.

29

What is the Habenular Nucleus?

The habenular nuclei protrude into the third ventricle. They are at the posterior aspect of the stria medullaris thalami and provide a relay for information from the forebrain to the brain stem interpeduncular nuclei.

30

What is the Dorsomedial (Mediodorsal) Thalamic Nucleus?

The dorsomedial (mediodorsal) thalamic nucleus is part of the thalamus that connects to limbic (primitive) areas of the cerebral cortex. It appears to have some role in attention and in memory.