Thalamus and Hypothalamus 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
Diencephalon consists of
Thalamus, subthalamic nucleus–parkinsons- deep brain stimulation, hypothalamus
Thalamus in relation to the lateral ventricle
ventral and inferior
Thalamus function
key relay centre to cortical sensory areas
-enhances and restricts signals
Only sensory function thalamus isn’t involved in
Olfactory
Describe the somatosensory pathway
touch and proprioception- cell bodies are located in dorsal root ganglia
primary sensory neuron from skin to dorsal column nuclei -gracilis nucleus/ cuneate nucleus
secondary neuron from dorsal column nuclei to thalamus - secondary neuron where crossing over occurs
Thalamus:- posterior lateral nucleus of thalamus –> processes touch and proprioception
tertiary nueorn from thalamus to primary somatosensory cortex
Where is primary sensory cortex located
post central gyrus
- behind central sulcus of parietal lobe
Apart from discrete nuclei you also have
intralaminar nuclei
Intralaminar nuclei project to
various medial temporal lobe structure
medial temporal lobe structures and function of these structures
Amygdala: fear, anxiety, emotions
Hippocampus: memory
Basal ganglia: movement– parkinsons- shaky hands
Neurons in intralaminar nuclei are mostyle
Glutamatergic neurons – excitatory
conditions apart from parkinsons associated with the intralaminar nuclei
PSP– progressive supra nuclear palsy
–> problems with walking and balance
Reticular nucleus found
outer covering of thalamus
Majority of reticular nucleus type
GABAergic–> inhibitory
Reticular nucleus function and how
internal regulation of thalamus
- connect with local NOT distal thalamic nuclei (local circ)
- Receive inputs from collaterals of their axons form thalamic nuclei
Reticular formation– what and function
set of interconnected pathways in the brainstem
Send ascending projections to forebrain nuclei (to intralaminar retiular nuclei), Ascending Reticular Activating System – ARAS
Involved in consciousness and arousal
-increased activity of ARAS= increased wakefulness.
Hypothalamus directly connected to
p.g – neuroendocrine functions
Hypothalamus in relation to 3rd ventricle
are the walls and floor of the 3rd ventricle
Hypothalamus is divided by
What is the hypothalamus
divided by the 3rd ventricle
Collection of individual nuclei with distinct functions
Connection to other nuclei by hypothalamus
ipsilateral
Which nucleus in hypothalamus can send projections to endocrine and ANS systems ?
paraventricular nucleus (has MAGNOCELLULAR and PARVOCELLULAR neurons) - involved in feeding behaviour slide 27
function of hypothalamus
4 Fs of life
Fighting, fleeing, feeding, fucking
Structure below hypothalamus
Pituitary gland
what structure located above optic chiasm
supraoptic nuclei
Paraventricular system also involved in
feeding– GABAergic stim of LH neuron in PV nucleus results in feeding
Hyothalamus-feeding– Expression of GLP-1r in hypothalamus – inhibit eating
Which nucleus is involved in the circadian rhythm?
Suprachiasmatic nucleus- above optic chiasm. it is part of the hypothalamus
Hypothalamus
- Regulate ANS: Direct connections with autonomic nervous system, neurons from paraventricular nucleus of hypothalamus can go all the way down to the spinal cord to synapse with a preganglionic neuron that then leaves the spinal cord IMPORTANTTTTT
2.Connection with endocrine system
3. Control of behaviour ie 4 F’s of life
Fighting
Fleeing
Feeding
Fucking
3 autonomic control examples
kidneys, vasculatur heart
How does suprachiasmatic nucleus control circadian rhythm
and other function
connected to pineal gland–> release of melatonin
autonomic outflow through connections to paraventricular nucleus.
3 characterstics of parkinsons
tremor, akinesia, sleep disturbances
