thalamus Flashcards
situated at the rostral end of the brain- stem and functions as an important relay and integrative station for information passing to all areas of the cerebral cortex, the basal ganglia, the hypothalamus, and the brainstem
thalamus
narrow and rounded and forms the posterior boundary of the interventricular foramen
anterior end of the thalamus
expanded to form the pulvinar, which overhangs the superior colliculus
posterior end
continuous with the tegmentum of the midbrain
inferior surface
forms part of the lateral wall of the third ventricle and is usually connected to the opposite thalamus by a band of gray matter, the interthalamic connection
medial surface of the thalamus
thalamus is covered on its superior surface by a thin layer of white matter, called the ___, and on its lateral surface by another layer, the ___
stratum zonale; external medullary lamina
- gray matter of the thalamus is divided by a vertical sheet of white matter, the ___, into medial and lateral halves
- consists of nerve fibers that pass from one thalamic nucleus to another
internal medullary lamina
lies between the limbs of the Y
anterior part
lie on the sides of the stem of the Y
medial and lateral parts
- anterior part of the thalamus contains the ___
- receive the mammillothalamic tract from the mammillary nuclei
- receive reciprocal connections with the cingulate gyrus and hypothalamus
anterior thalamic nuclei
function of the ___ limbic system and is concerned with emotional tone and the mechanisms of recent memory.
anterior thalamic nuclei
- medial part of the thalamus contains the large ___
- two-way connections with the whole prefrontal cortex of the frontal lobe of the cerebral hemisphere
- interconnected with all other groups of thalamic nuclei
dorsomedial nucleus
integration of a large variety of sensory information, including somatic, visceral, and olfactory information, and the relation of this information to oneβs emotional feelings and subjective states
medial part of the thalamus
- lateral dorsal nucleus, the lateral posterior nucleus, and the pulvinar
- have interconnections with other thalamic nuclei and with the parietal lobe, cingulate gyrus, and occipital and temporal lobes.
dorsal tier
- connected to the reticular formation, the substantia nigra, the corpus striatum, and the premotor cortex
- influences the activities of the motor cortex
Ventral anterior nucleus
- major input from the cerebellum and a minor input from the red nucleus
- main projections pass to the motor and premotor regions of the cerebral cortex
- influences motor activity
Ventral lateral nucleus
nucleus is subdivided into the ventral posteromedial nucleus and the ventral posterolateral nucleus
Ventral posterior nucleus
receives the ascending trigeminal and gustatory pathways
ventral posteromedial nucleus
receives the important ascending sensory tracts, the medial and spinal lemnisci
ventral posterolateral nucleus
thalamocortical projections from these important nuclei pass through the posterior limb of the internal capsule and corona radiata to the primary somatic sensory areas of the cerebral cortex in the postcentral gyrus
Ventral posterior nucleus
- small collections of nerve cells within the internal medullary lamina
- receive afferent fibers from the reticular formation as well as fibers from the spinothalamic and trigeminothalamic tracts
- influence the levels of consciousness and alertness in an individual
intralaminar nuclei
- consist of groups of nerve cells adjacent to the third ventricle and in the interthalamic connection
- receive afferent fibers from the reticular formation
- precise functions are unknown
midline nuclei
- thin layer of nerve cells sandwiched between the external medullary lamina and the posterior limb of the internal capsule
- concerned with a mechanism by which the cerebral cortex regulates thalamic activity
reticular nucleus
forms part of the auditory pathway and is a swelling on the posterior surface of the thalamus beneath the pulvinar
medial geniculate body