Thalamus and internal capsule (Chapter 16) Flashcards
(32 cards)
Name the four regions of the diencephalon:
The diencephalon consists of the: Epithalamus Dorsal thalamus Subthalamus Hypothalamus
What structures are included in the epithalamus?
Pineal gland and habenula.
What structures are included in the dorsal thalamus?
Thalamic nuclei.
What structures are included in the subthalamus?
Red nucleus and substantial nigra. (Also contains zone incerta and sub thalamic nucleus).
What structures are included in the hypothalamus?
Mammillary bodies and infundibular stalk.
How is the pineal gland light-regulated?
Contains photoreceptors and receives inputs from retinal cells via the hypothalamus and spinal cord.
What is the function of the pineal gland?
Regulates circadian rhythms (+ seasonal sexual cycles in other mammals), secretes melatonin.
Where is the habenula located?
2 structures (habenular nuclei) anterior to the pineal.
Inputs and outputs of the habenula?
Inputs: globus pallidus, limbic structures.
Outputs: to midbrain/brainstem reticular formation.
What is the function of the habenula?
General regulation of emotion-related arousal via the brainstem, may be involved in assigning reward value to stimuli.
What type of tracts traverse the subthalamus?
Somatosensory pathways (mostly), also tracts to/from basal ganglia.
The subthalamus represents an extension of the __________.
Midbrain tegmentum .
What is the general role of the thalamus?
Regulating and directing behavior (arousal & attention), “relay station”, also sensory gating mechanisms (?)
What are the three main regions or groups of the dorsal thalamus and how are they defined?
Anterior, medial, and lateral divisions, defined by the internal medullary lamina.
What is the internal medullary lamina?
A thin, curved sheet of myelinated fibers that splits and encloses groups of nuclei.
Where is the dorsomedial nucleus found?
The DM nucleus is found in the medial division.
Where is the anterior nucleus found?
The anterior nucleus is found in the anterior division. It borders on the intraventricular foramen.
Where is the pulvinar found?
The pulvinar is posterior.
The ______________ wraps all around the dorsal thalamus.
The external sheet of the reticular nucleus wraps all around the dorsal thalamus.
Describe the two categories of inputs to the thalamus.
Specific inputs: From periphery. Thalamic nucleus passes on information accurately.
Regulatory inputs: From cortex, other thalamic nuclei, reticular nucleus. Contribute to decisions about the form in which information leaves the thalamus.
Name the three types of thalamic nuclei:
Relay nuclei, association nuclei, intralaminar/midline nuclei.
What is the function of relay nuclei?
The role of relay nuclei is to deliver information from particular functional areas to appropriate cortical areas (i.e., from and to specific areas).
What is the function of association nuclei?
Association nuclei relay/modulate information between cortical regions.
Dorsomedial nucleus: PFC, olfactory, limbic –> PFC.
Pulvinar: Parietal-occipital-temporal association cortex.
Lateral-posterior nucleus: Parietal lobe-parietal lobe.
What is the function of the intralaminar and midline nuclei?
Not well understood, but seem to have special role in the function of limbic and motor circuits (limbic system and basal ganglia).
