Thalamus and Internal Capsule Flashcards
What are the parts of the diencephalon (and function)?
o Epithalmus: Pineal and habenular nuclei
o Subthalamus: Involved with accessory structures of basal ganglia
o Hypothalamus: Involved with the pituitary gland
o Thalamus: Major relay center for all sensory pathways except smell
The Thalamic Nuclei are composed of what 2 types of neurons?
- Projection (75%)
- Interneurons (25%) - utilize GABA for inhibition
Thalamic nuclei are based according to their input and output: what are they?
Relay nuclei: receive specific input fibers and project to appropriate areas of the cortical areas
Association nuclei: receive input from the cerebral cortex and distribute to the association cortex
Input of Thalamic nuclei can further be subdivided into two types which are:
Specific: Those that convey information to the thalamic nuclei and parcel out information to the cortex
Regulatory: Those that integrate information and “decide” where it should be sent (if it is sent at all)
What are the 10 Nuceli of the Thalamus?
- Anterior Nucleus
- Dorsomedial
- Lateral Dorsal
- Ventral Anterior
- Ventral Lateral
- Ventral Posterior Lateral
- Ventral Posterior Medial
- Pulvinar
- Medial Genticulate
- Lateral Genticulate
What is the blood supply to the Thalamus? A lesion to this area can result in what?
- Posterior Cerebral Artery and Posterior Communicating A.
- Global Deficits including: Contralateral sensation loss, ataxia and Thalamic pain (cannot be treated with painkillers)
Name the function, input and output of the Anterior Nucleus
Principle relay for the limbic system (memory and emotion)
Input: mammillary bodies of the hypothalamus and the hippocampus
Output: cingulate gyrus and frontal cortex
Name the function, input and output of the Dorsomedial Nucleus
Association nucleus (memory, affect, and foresight)
Input: basal ganglia, olfactory cortex, amygdala, and prefrontal cortex
Output: Prefrontal cortex
Name the function, input and output of the Lateral Dorsal Nucleus
Relay nucleus (pain circuit)
Input: hippocampus
Output: cingulate gyrus
Name the function, input and output of the Ventral Anterior nucleus
Motor relay (motor coordination)
Input: Basal ganglia and cerebellum
Output: Pre-motor cortex
Name the function, input and output of the Ventral Lateral nucleus
Motor relay (motor coordination)
Input: Basal ganglia and cerebellum
Output: Primary motor cortex
Name the function, input and output of the Ventral Posterior Lateral nucleus
Somatosensory relay for body sensation (conscious fine touch, proprioception, pain, and temperature)
Input: Medial lemniscal tract and spinothalamic tract
Output: Somatosensory cortex
Name the function, input and output of the Ventral Posterior Medial nucleus
Somatosensory relay for the head sensation (conscious fine touch, proprioception, pain, and temperature)
Input: Medial lemniscal tract and spinothalamic tract
Output: Somatosensory cortex
Name the function, input and output of the Pulvinar nucleus
Association nucleus (integration of association areas: attention)
Input: parietal, occipital, and temporal association cortex loops
Output: parietal, occipital, and temporal association cortex loops
*Reptile nucleus
Name the function, input and output of the Medial Genticulate Nucleus
Relay nucleus (hearing)
Input: inferior colliculus
Output: Auditory cortex
Name the function, input and output of the Lateral Genticulate nucleus
Relay nucleus (vision)
Input: Optic tract and superior colliculus
Output: Visual cortex
The epithalamus contains what 2 structures?
Pineal Gland - melatonin (sleep-wake cycle)
Habenular nuclei - eating behaviors
The subthalamus contains what 3 structures?
Red nucleus: cerebellar connections
Subthalamic nucleus: basal ganglia connections
Zona incerta: rostral extent of reticular formation
The hypothalamus has 10 different nuclei. We are concentrating on 3. Which ones are responsible for: the master clock, Oxytocin & ADH release, and Limbic circuit, respectively?
- Suprachiasmatic nuclei
- Supraoptic/ paraventricular nuclei
- Mammillary nuclei
What are the 5 major limbs of the Internal Capsule?
1. Anterior Limb 2 .Posterior Limb 3. Genu 4. Retrolenticular Limb 5. Sublenticular Limb
What is the blood supply to the Internal Capsule?
- Lateral Straite (anterior, posterior limb and genu)
- Anterior Choroidal (Retrolenticular and Sublenticular)
Hemmorhage to the Lateral Striate can result in what deficits? Anterior Choroidal?
- Lateral Straite: Spastic paralysis and hemianesthesia
- Anterior Choroidal: Visual and minor auditory deficits (minor because of bilateral auditory pathway)
