4. Thalamocortex Flashcards
(38 cards)
What is the THALAMOCORTEX
Thalamus + cerebral cortex, with their bidirectional connections
Where is the THALAMUS located?
- Dorsral to the ventral portion of the 3rd ventricle
- Medial to internal capsule
Main function of the THALAMUS
- RELAY station for sensory and motor signals. Integration and Processing of info before projecting to the cerebral cortex
- Makes up most of the DIENCEPHALON (thalamus, epithalamus, subthalamus, hypothalamus, metathalamus)
What are the two MEDULLARY LAMINAE of the thalamus (slide 5)
Layers of white matter dividing the thalamic nuclei
- EXTERNAL medullary lamina
- Separates the thalamus from internal capsule
- Contains projection fibres - INTERNAL medullary lamina
Separates thalamus in its groups of nuclei:
- Lateral vs medial thalamic nuclei
- Rostral vs caudal thalamic nuclei
- Interlaminar (midline) thalamic groups
Nucleus of the ROSTRAL thalamic group
- Rostral thalamic nucleus (limbic system)
Nucleus of the MEDIAL thalamic group
- Medial dorsal nucleus
Nuclei of the LATERAL thalamic group (dorsal, ventral and ventral caudal divisions)
DORSAL Tier
* Dorsolateral nucleus
* Caudolateral nucleus
* Pulvinar nucleus
VENTRAL tier
* Ventral rostral nucleus (extrapyramidal)
* Ventral lateral nucleus (cerebellum)
VENTRAL CAUDAL group
* Ventral caudal medial nucleus (cranial nerves)
* Ventral caudal lateral nucleus (spinal nerves)
Nucleus of the CAUDAL thalamic group
- Medial geniculate nucleus (auditory, vestibular)
- Lateral geniculate nucleus (vision)
Nucleus of the MIDLINE (intralaminar) thalamic group
- Central medial nucleus
- Paraventricular nucleus
What is the thalamic RETICULAR nucleus
- Borders the internal capsule (laterally) and external medullary lamina (medially)
- Receives ARAS sensory afferents
- Projects to thalamic association areas
What are the 3 projection systems of the thalamus
- Direct cortical projection system
- Diffuse cortical projection system
- Thalamic reticular formation
Memorize table slide 17
Good luck
Location of FRONTAL lobe
- Rostral to cruciate sulcus
Location of TEMPORAL lobe
- Ventrolateral aspect of cerebrum (includes sylvian gyrus)
Location of PARIETAL lobe
- Caudal to cruciate sulcus
- Dorsal to sylvian gyrus
Location of OCCIPITAL lobe
- Caudal third of cerebrum
Name the 5 primary cortical areas
- Somesthetic
- Motor
- Olfactory
- Auditory
- Visual
What is the role of association areas
- Integrate info from primary sensory areas
- Allows perception of complex stimuli
- Associative memory
- Learning
Areas of the PRIMARY somesthetic cortex (SI) are activated by stimuli from ____ side of the body
Contralateral, except rostral face (teeth, palate, lip)
Areas of the SECONDARY somesthetic cortex (SII) are activated by stimuli from ____ side of the body
BOTH sides of the body
Understand somatotopic organization of the body parts for SI and SII
Slides 23-24
Which primary sensory area does not involve cortical projections via the thalamus?
Primary olfactory area (piriform lobe).
Receives direct projections from the lateral olfactory tracts
Describe menace response pathway (slide 34)
- Retina
- Optic nerve
- Optic chiasm
- Optic tract
- LGN
- Optic radiations
- Visual cortex
- Association fibers (internal capsule)
- Motor cortex
- Projection fibers (internal capsuel)
- Crus cerebri (mes)
- Longitudinal fibers (pons)
- Pontine nucleus (pons)
- Transverse fibers and middle cerebellar peduncle
- Cerebellar cortex
- Cerebellar efferents
- Facial nuclei (bilat)
- Orbicularis-oculi
PRIMARY MOTOR CORTEX
- Location
- Postcruciate ± precruciate gyri
- Rostral suprasylvian gyrus