6. Thalamus and Hypoothalamus Flashcards
Where is the thalamus found within the brain?
It is right in the middle the brain just under the posterior half of the corpus callosum
What separates the two halves of the thalamus?
3rd ventricle
Some people have a bridge connecting the two halves
(Its called vestigeal structure)
Describe the connections of the thalamus with the forebrain.
Each half of the thalamus has ipsilateral connections with the forebrain
3 components of diencephalon
Thalamus, subthalamus and hypothalamus
What is the main function of the thalamus?
[[[It is a relay centre between the cerebral cortex and the rest of the CNS, to cortical sensory areas]]]
Enhances and restricts signals
Connection is reciprocal
Integration and modification of information as it goes through thalamus
nucleus for every functional system in NS but not for olfaction
What is the only function that is not represented within the thalamus?
olfaction
Describe how thalamic nuclei are named.
They are named based on their location within the thalamus
What is the classification of thalamic nuclei based on and what are the four different classes?
The classification is based on the connections of the thalamic nuclei with the cortex
SPECIFIC – connected to primary cortical areas
ASSOCIATION – connected to association cortex
INTRALAMINAR – connected to ALL cortical areas
RETICULAR – not connected to the cortex
Describe somatosensory pathway
Vibration/propioception/light touch TO dorsal root ganglion TO posterior dorsal columns TO primary sensory neuron TO gracile nucleus seen in medulla and sensory decussation (cuneate nucleus maybe) TO thalamus VPLN via secondary sensory neurone TO primary somatosensory cortex via tertiary neuron.
Which nuclei connect with the motor cortex (primary, premotor and supplementary)?
Ventral lateral
Ventral anterior
Which nuclei relay sensory information from different parts of the body?
Head – Ventral posteromedial
Below the neck – Ventral posterolateral
Which nucleus is connected to the primary visual cortex?
Lateral geniculate nucleus
Which nucleus is connected to the primary auditory cortex?
Medial geniculate nucleus
The association cortex can be divided into three areas based on thalamic function. What are these three areas?
Prefrontal Cortex
Parieto-tempero-occipital Cortex
Cingulate Cortex
What do the anterior, lateral dorsal and dorsomedial nuclei connect with?
Prefrontal and Cingulate Cortex