Exam 2: Lecture 13 Forebrain Flashcards
parts of the diencephalon (4)
Epithalamus: pineal gland
Thalamus: many important functions
Subthalamus: involved with basal ganglia
Hypothalamus: many functions ⇒ autonomic regulation
what does the hypothalamus do for functions? (5)
autonomic regulation for:
- Temperature regulation
- Feeding and drinking
- Circadian rhythms
- Aggression and flight
- Sexual activity
–> release hormones into the blood that act on the pituitary gland which dumps stuff into the bloodstream to cause hormonal signals (vasopressin, oxytocin, etc.)
pituitary stalk
where the pituitary gland is attached to the hypothalamus
What can be seen in the images of the thalamus? (5)
- reticular nucleus
- 3rd ventricle
- inter thalamic adhesion
- corpus callous
- internal capsule
thalamic reticular nucleus
the thalamus is surrounded by a thin outer shell of neurons and relays many things
the thalamus relays everything but what?
smell
internal medullary lamina
sheets of axons running through the middle of the thalamus
- These separate different thalamic nuclei (groups of neurons)
- divides the thalamus into 3 regions
intralaminar nuclei
clusters of neurons in the axons of the internal medullary lamina
3 types of nuclei in the thalamus
- specific nuclei
- association nuclei
- nonspecific nuclei
specific nuclei
(tract specific) relay specific sensory or motor information to specific regions of cortex ⇒ visual thalamus projects to visual cortex
- Associated with somatosensory or motoneurons in the cerebral cortex
- Relay the information from one point to another
Functions of association nuclei
relay information from association thalamus to association cortex ⇒ respond to more than one type of sensory stimulus
- Neurons in the pulvinar nucleus of the thalamus may respond to both visual and auditory stimuli
- Association nuclei project their axons to association cortex in the posterior parietal lobe
nonspecific nuclei
have diffuse (all over) projections to cortex ⇒ respond to 1+ sensory stimuli
- Thalamic neurons in these regions may also respond to more than one stimulus
- They project widely throughout the cerebral cortex not just to association cortex and include the intralaminar nuclei
inter thalamic adhesion
where the two thalamus halves touch, nothing goes on here
what surrounds the outside of the thalamus
reticular nucleus
what runs like a band through the middle (white band)
Internal medullary lamina
what does the medial geniculate nucleus do?
relay hearing from the thalamus
what does the lateral geniculate nucleus do?
relay vision from the thalamus
what does the anterior and ventral lateral nucleus do?
relay motor from the thalamus
what does the ventral posterior medial nuclei do?
touch and pain
- also relays head and face information from the thalamus
what does the ventral posterior lateral nuclei do?
relay information from the thalamus to the rest of the body
relay nuclei
send axons to the cerebral cortex
- projections are ipsilateral (same side)
where do the visual, motor, and associated thalamus go?
go to the visual, motor, and associated cortex
what are the association thalamus regions?
medial dorsal nucleus and pulvinar nucleus
medial dorsal nucleus
prefrontal association cortex
pulvinar nucleus
parietal-occipital temporal association cortex
what are the nonspecific nuclei of the thalamus
reticular nucleus and intralaminar nuclei
what is the nucleus and output related to the hypothalamus and hippocampus?
anterior nucleus and cingulate cortex (limbic)
what is the nucleus and output related to the cerebellum?
ventral lateral nucleus and motor cortex
what is the nucleus and output related to the retina?
lateral geniculate nucleus and visual cortex
what is the nucleus and output related to the somatosensory and visceral sensory?
ventral posterior nucleus (lateral and medial) and somatosensory cortex and visceral cortex
what is the nucleus and output related to the inferior colliculus?
medial geniculate nucleus and auditory cortex
what is the nucleus and output related to the cortex and other areas?
other nuclei and association cortex
what does the thalamus do?
the flow of information from the thalamus to cortex is gated by inputs from the cortex and the brain stem reticular activating system via the reticular nucleus of the thalamus
- inhibits neuron output
what is the result of gating thalamic output?
sleep and concentration
internal capsule
superhighway of axons entering and exiting the cortex relaying information ascending from the thalamus and descending from the cortex
what axons keep descending from the thalamus?
corticospinal tract and cortical neurons for fine motor control
what is the telencephalon made up of? (3)
neocortex, limbic and olfactory cortex, and the basal ganglia
what structures are in the cerebral cortex?
the allocortex (3-5 cell layers that includes the hippocampus) and the neocortex which is 6 cell layers
how does the wiring of the neocortex work? (4)
- Thalamus projects to layer IV
- Layer IV projects to II and III which interconnect with other cortical areas (info from thalamus)
- Layer V projects to brainstem and spinal cord ⇒ fine motor movements
- Layer VI projects back to thalamus ⇒ input from cerebral cortex back to the thalamus as well
what are the primary cortical regions (2)
primary sensory cortex and primary motor cortex
primary sensory cortex
cortex that is innervated by specific thalamic relay nuclei for the same sense ⇒ first stop in cerebral cortex from thalamus which can get processed further
- includes vision and somatosensation
primary motor cortex
cortex that innervates spinal cord or brainstem and controls motoneurons
what input goes in to the association and what goes out?
in: visual, somatosensory, auditory cortexes
out: speech, writing, functional correlation, sensory motor coordination
cerebral commissures
A region of cortex on one side of the brian communicates with the same region on the other side
- discrete bundle of axons that cross the midline
what are the 2 cerebral cortex commissures?
- corpus callous
- anterior commissure for olfactory system and related information (all vertebrates)
what happens when there are lesions of the corpus callosum
epilepsy via uncontrolled contraction and possibly full body seizure
- CC can be cut but then you have “2 minds”
what is part of the limbic and olfactory cortical areas? (3)
- hippocampus
- amygdala
- fornix
hippocampus location
in the temporal lobe inside the parahippocampal gyrus
amygdala
in the anterior temporal lobe, just rostral to the hippocampus
- Involved in conditioned fear responses
fornix
from the hippocampus to mammillary bodies of the hypothalamus
- tract of the limbic system
basal ganglia
group of nuclei in the midbrain, diencephalon, and basal region of the telencephalon with roles in the motor system and motivation
- includes drug use
major nuclei of the basal ganglia (4)
- striatum (telencephalon)
- globus pallidus (telencephalon)
- sub thalamic nucleus (diencephalon)
- substantia nigra (midbrain)
striatum (3 nuclei)
Caudate nucleus
Putamen
Nucleus accumbens
globules pallidus
part of the basal ganglia
sub thalamic nucleus
part of the diencephalon positioned ventral to the thalamus and dorsolateral to the mammillary bodies
- motor control and movement
