DIENCEPHALON Flashcards
Components of epithalamus
STRIA MEDULLARIS THALAMI
HABENULAR NUCLEI
PINEAL GLAND
secretions of the pineal gland
serotonin, norepinephrine, and melatonin and contains several hypothalamic peptides including thyrotropin-releasing hormone (TRH), leuteinizing hormone–releasing hormone (LHRH), and somatostatin–release inhibitory factor (SRIF).
he pineal gland usually calcifies after the age of _____
16
The ______ is the largest component of the diencephalon
thalamus
Parts of the thalamus
Anterior Medial Lateral Intralaminar and reticular Midline Posterior
The _______separates the medial from the lateral group of nuclei.
internal medullary lamina
the _______ forms the lateral boundary of the thalamus medial to the internal capsule
external medullary lamina,
connections of anterior thalamus
hypothalamus (mamillary bodies) cerebral cortex (cingulate gyrus) cerebral cortex (subiculum and presubiculum)
functions of anterior thalamic group
concerned with emotional behavior and memory mechanisms.
Discrete damage to the mamillothalamic tract has been associated with deficits of::
in a specific type of memory, episodic long-term memory, with relative sparing of short-term memory and intellectual capacities.
MEDIAL NUCLEAR GROUP`parts
dorsomedial magnocellular division located rostrally,
a dorsolateral parvicellular division located caudally,
and a paralaminar division adjacent to the internal medullary lamina
The dorsomedial nucleus belongs to a neural system concerned :
ith affective behavior, decision making and judgment, memory, and the integration of somatic and visceral activity.
Lateral nuclear group parts
Dorsal Subgroup
Ventral Subgroup
_______is functionally part of the anterior group of thalamic nuclei, with which it collectively forms the limbic thalamus
lateral dorsal nucleus
connections of the pulvinar–lateral posterior complex
caudally with the lateral geniculate body and rostrally with the association areas of the parietal, temporal, and occipital cortices
functions of pulvinar
The pulvinar has a role in selective visual attention.
There is evidence that the pulvinar nucleus plays a role in speech mechanisms.
play a role in pain mechanisms.
Ventral Subgroup
modality-specific thalamic nuclei
VA nucleus receives from
Globus pallidus: Inhibitory
Substantia nigra pars reticulata: Inhibitory
Intralaminar thalamic nuclei.
Premotor and prefrontal cortices: excitatory
the ________ nucleus is a major relay station in the motor pathways from the basal ganglia to the cerebral cortex.
ventral anterior
The ______ part of the ventral anterior nucleus is concerned with control of voluntary eye, head, and neck movements.
The lateral ______part of the nucleus is concerned with control of body and limb movements.
medial (magnocellular)
parvicellular
role of the VL nucleus
motor integration
Inputs of the VL
Deep cerebellar nuclei.
Globus pallidus (internal segment)
Primary motor cortex
It receives the long ascending tracts conveying sensory modalities (including taste) from the contralateral half of the body and face.
VP nucleus
VPM:
VPL:
trigeminal lemniscus and taste fibers
medial lemniscus and spinothalamic tracts
most important intra-laminar functional nuclei in humans
centromedian and parafascicular
Afferent connections on the IL nuclei
Reticular formation of the brain stem: major input Cerebellum: dentatorubrothalamic system Spinothalamic and trigeminal lemniscus Globus pallidus (mainly VA) Cerebral cortex
Efferent projections of IL nuc
Other thalamic nuclei The striatum (caudate and putamen)
Midline Nuclei:
role:
paraventral, central, and reunien nuclei.
emotion, memory, and autonomic function.
Reticular Nuclei’s role
the reticular nucleus plays a role in integrating and gating activities of thalamic nuclei.
parts of metathalamus
MGN: relay thalamic nucleus in the auditory system.
LGN: relay thalamic nucleus in the visual system
The efferent outflow from the medial geniculate nucleus forms the a________
uditory radiation of the internal capsule (sublenticular part) to the primary auditory cortex in the temporal lobe (areas 41 and 42)
POSTERIOR THALAMIC NUCLEAR GROUP
receives inputs from all somatic ascending tracts (medial lemniscus and spinothalamic), as well as from the auditory pathways and possibly the visual pathways.
Nomenclature of the thalamic system
(1) modality-specific, (2) multimodal associative, and (3) nonspecific and reticular.
modality-specific group of nuclei
they receive direct inputs from long ascending tracts concerned with somatosensory, visual, and auditory information (ventral posterior lateral and medial, lateral geniculate, medial geniculate)
or else process information derived from the basal ganglia (ventral anterior, ventral lateral),
the cerebellum (ventral lateral), or the limbic system (anterior, lateral dorsal);
______receives no direct inputs from long ascending tracts and projects to association cortical areas in the frontal, parietal, and temporal lobes.
multimodal associative
dorsomedial nucleus and the pulvinar–lateral posterior nuclear complex.
characterized by diffuse and widespread indirect cortical projections and by inputs from the brain stem reticular formation
nonspecific and reticular group of nuclei
Another grouping of thalamic nuclei:
(1) motor, (2) sensory, (3) limbic, (4) associative, and (5) nonspecific and reticular.
The motor group:
receives motor inputs from the basal ganglia (ventral anterior, ventral lateral)
or the cerebellum (ventral lateral)
The sensory group
receives inputs from ascending somatosensory (ventral posterior lateral and medial), auditory (medial geniculate), and visual (lateral geniculate) systems
The ______is related to limbic structures (mamillary bodies, hippocampus, cingulate gyrus)
limbic group
Blood supply of the thalamus is derived from four parent vessels:
basilar root of the posterior cerebral, posterior cerebral, posterior communicating, and internal carotid.
supplies the medial thalamic territory.
The basilar root of the posterior cerebral artery, via paramedian branches,
supplies the posterolateral thalamic territory.
posterior cerebral artery, via its geniculothalamic branch
supplies the anterolateral thalamic territory.
posterior communicating artery, via the tuberotha-lamic branch,
supplies the lateral thalamic territory
internal carotid artery, via its anterior choroidal branch,
anterior limb of the internal capsule is supplied by:
striate branches of the anterior and middle cerebral arteries
genu is supplied by
branches of the middle cerebral and internal carotid arteries
provides supply to the caudal portion of the posterior limb.
anterior choroidal artery
All somatic and special senses, except ________ pass through the thalamus before reaching the cerebral cortex
olfaction
It is this type of pain that is believed to terminate in the thalamus,
C-fibers.
In patients with intractable pain, placement of a surgical lesion in the ________may provide relief.
ventral posterior or intralaminar nuclei (centromedian)
This syndrome is usually associated with a marked affective response attributed to the intact dorsomedial nucleus, usually unaffected by the vascular lesion.
Thalamic pain syndrome
connections of the medial thalamus with the prefrontal cortex reflect its role in ____________
affective behavior and executive function
anterior thalamic nuclei with the hypothalamus and cingulate gyrus enable them to play a role in___________
memory, visceral function, and emotional behavior.
Nociceptive information reaches the thalamus via the _________
spinothalamic tracts (lateral and anterior) and the trigeminothalamic pathways
The subthalamus consists of three main structures; _________
these are the subthalamic nucleus, the fields of Forel, and the zona incerta.
the subthalamic nucleus receives a massive GABAergic__________ input from the external segment of globus pallidus and a glutamatergic_________input from the cerebral cortex (areas 4 and 6).
inhibitory
excitatory
The two subthalamic nuclei communicate via the ________
supramamillary commissure.
lesions of the __________is responsible for the involuntary violent hyperkinesia of the contralateral upper and lower extremities known as hemiballismus.
subthalamopallidal pathways or the subthalamic nucleus
fiber bundles containing pallidal and cerebellar efferents to the thalamus.
FIELDS OF FOREL
is the rostral continuation of the mesencephalic reticular formation that extends laterally into the reticular nucleus of the thalamus
ZONA INCERTA
