Neuro 6: Thalamus and hypothalamus Flashcards
List the 3 parts of the diencephalon
Thalamus, hypothalamus and subthalamus
What intersects the thalamus
3rd ventricle
Locate the thalamus
Ventral to the lateral ventricle
Which 2 thalamic neurons associated with the resticular activating system
RETICULAR nucleus (all around the outside of the thalamus)… does not project to cortex, provides negative feedback to the thalamus
and
INTRALAMINAR… projects to all other areas of cortex including medial temporal lobe structures (amygdala, hippocampus and basal ganglia)
State the function of the thalamus
Key relay centre to cortical sensory areas
Involved in almost all sensory systems (not olfactory)
Enhance or restricts signals
Which sense does not travel through the thalamus
Olfactory
The thalamus only enhances signals t/f
F it can restrict too
Which thalamic nucleus is responsible for transmitting fine touch
Ventral posterior lateral nucleus
What are intalaminar nuclei
Give the functions of the areas it projects to
Thalamic nucleus: Project to MEDIAL temporal lobe structures like amygdala, hippocampus and basal ganglia
Amygdala= fear, emotions, anxiety
Hippocampus= memory and learning
Basal ganglia= movement
What type of neurons exist in the intralaminar neuclei
Glutamaterigic
Loss of intralaminar nucleus neurons asociated with parkinsons and supranuclear palsy (=rare brain disorder causing problems with walking and balance)
What nucleus forms the outer covering of the thalamus +
what type of neurons here
Reticular nucleus (thalamic)- doesn’t connect with distal regions, but instead all other thalamic nuclei
GABAergic (compared to glutamatergic in intralaminar)
Function of reticular nucleus
Mostly inhibitory on thalamic nuclei
Where do reticular nuclei receive inputs from
receives sensory information from thalamic neurons via COLLATERALS of their axons
Modulates thalamic activity -ve feedback depending on this input
Where is the reticular formation found and what is it involved in
Area of grey matter in brainstem, set of interconnected pathways
Send ascending projections to forebrain nuclei via ascending reticular activating system (ARAS)
Conscioussness and arousal. Degree of wakefullness dependent on ARAS (increased activity of ARAS –> increased wakefullness)
Intralaminar and reticular nuclei receive input from ARAS
What is ascending reticular activating system
Consciousness and arousal- degrees of wakefullness proportional to activity of ARAS Intralaminar and reticular nucleus receive input from the ARAS