Chapter 12 - Thalamus Flashcards
Functions as an important relay and integrative station for information passing to all areas of the cerebral cortex, basal nuclei, hypothalamus, & brainstem
Thalamus
Thalamus positon
as an egg-shaped gray matter; sits on both sides of the third ventricle (#2)
The diencephalon consists of the dorsal (1) and the ventral (2)
(1) thalamus
(2) hypothalamus
The right and left thalamus is connected by the
interthalamic connection
white matter thin layer covering the superior part of the thalamus
stratum zonale
White matter covering the lateral surface of the thalamus
external medullary lamina
Vertical sheet of white matter that divides the gray matter of the thalamus into medial and lateral halves;
what is its function?
internal medullary lamina
Function as nerve fibers that pass signals between multiple thalamic nucleus
Nuclei present at the anterior part of the thalamus
anterior thalamic nuclei
Function of the anterior thalamic nuclei
Receives signals from the mammillothalamic tract, cingulate gyrus, and hypothalamus
Mostly associated with the limbic system, emotional tone, and mechanisms of memory
Nuclei present at the medial part of the thalamus
(1) a large dorsomedial nucleus
(2) several smaller nuclei
Function of the dorsomedial nucleus of the thalamus
Has connections with the prefrontal cortex, frontal lobe of the cerebral hemisphere, hypothalamus
Integrates sensory information (visceral, somatic, olfactory) and relates it to emotional feeling and subjective stress
Nuclei present at the lateral part of the thalamus (Dorsal tier) & (Ventral tier)
(Dorsal Tier)
* lateral dorsal nucleus
* lateral posterior nucleus
* pulvinar
(Ventral Tier)
* ventral anterior nucleus
* ventral lateral nucleus
* ventral posterior nucleus (ventral posteromedial nucleus and ventral posterolateral nucleus)
Has connections to the reticular formation, the substantia nigra, the corpus striatum, and premotor cortex as well as to thalamic nuclei
Influence motor cortex
Ventral anterior nucleus
Major input from the cerebellum and minor input from the red nucleus
Influences motor activity
Ventral lateral nucleus
Receives ascending trigeminal and gustatory pathways
Ventral posteromedial nucleus
Receives the important ascending sensory tracts - the medial and spinal lemnisci
Ventral posterolateral nucleus
Afferent Neural Loop:
Mammillothalamic tract, cingulate gyrus, hypothalamus
Efferent Neural Loop:
Cingulate gyrus, hypothalamus
Function:
Limbic system - emotional tone and mechanism of recent memory
Anterior (thalamic nucleus)
Afferent Neural Loop:
prefrontal cortex, hypothalamus, other thalamic nuclei
Efferent Neural Loop:
prefrontal cortex, hypothalamus, other thalamic nuclei
Function:
Integration of somatic, visceral, and olfactory sensory to relate to emotional feelings and subjective stress states
dorsomedial (thalamic nucleus)
Afferent Neural Loop:
Cerebral cortex, other thalamic nuclei
Efferent Neural Loop:
Cerebral cortex, other…
Function:
Unknown
Lateral dorsal, lateral posterior, pulvinar
Afferent Neural Loop:
Reticular formation, substantia nigra, corpus striatum, premotor cortex, other…
Efferent Neural Loop:
Reticular formation, substantia nigra, corpus striatum, premotor cortex, other thalamic nuclei
Function:
Influences activity of motor cortex
Ventral anterior
Afferent Neural Loop & Efferent Neural Loop:
as in ventral anterior nucleus but also major input from cerebellum and minor from red nucleus
Function:
Influences motor activity of the motor cortex
Ventral lateral
Afferent Neural Loop:
trigeminal lemniscus, gustatory fibers
Efferent Neural Loop:
Primary somatic sensory (areas 3, 1, and 2) cortex
Function:
Relays common sensations to consciousness
Ventral posteromedial (VPM)
Afferent Neural Loop:
Medial and spinal lemnisci
Efferent Neural Loop:
Primary somatic sensory (areas 3, 1, and 2) cortex
Function:
Relays common sensations to consciousness
Ventral posterolateral (VPL)
Afferent Neural Loop:
Reticular formation, spinothalamic and trigeminothalamic tracts
Efferent Neural Loop:
Cerebral cortex via other thalamic nuclei, corpus striatum
Function:
Influences levels of consciousness and alertness
Intralaminar
Afferent Neural Loop:
Reticular formation
Efferent Neural Loop:
Unknown
Function:
Unknown
Midline
Afferent Neural Loop:
Cerebral cortex, reticular formation
Efferent Neural Loop:
Other thalamic nuclei
Function:
Cerebral cortex regulates thalamus
Reticular
Afferent Neural Loop:
Inferior colliculus, lateral lemniscus from both ears but predominantly the contralateral ear
Efferent Neural Loop:
Auditory radiation to superior temporal gyrus
Function:
Hearing
Medial geniculate body
Afferent Neural Loop:
Optic tract
Efferent Neural Loop:
Optic radiation to visual cortex of occipital lobe
Function:
Visual information from opposite field of vision
Lateral geniculate body
(True/False)
The Thalamus is made up of complicated collections of nerve cells that are centrally placed in the brain and are interconnected
True
(True/False)
All sensory information converges on the thalamus and presumably is integrated through the interconnections between thalamus nuclei
False
Vast amount of different types are integrated in the thalamus except for olfactory (smell) information which is first integrated at a lower level with taste and other sensations and is relayed to the thalamus from the amygdaloid complex and hippocampus through the mammillothalamic tract
Nuclei associated with the personality of the individual
Dorsomedial nucleus
Thalamic Nuclei: Its Connections and Functions
Memorize
Main Connections of the Thalamus
Memorize
