NSCI 2101 Exam 2

parts of the diencephalon

• epithalamus

• thalamus

• subthalamus

• hypothalamus

where is the epithalamus?

highlighted in blue

where is the thalamus

highlighted in green

where is the subthalamus?

highlighted in yellow

where is the hypothalamus?

highlighted in red

functions of the hypothalamus (5)

• temp regulation

• feeding and drinking

• circadian rhythms

• aggression and flight

• sexual activity

hypothalamic neurons

release hormones into the blood that act on the pituitary gland

pituitary gland

neuroendocrine function. attached to hypothalamus by pituitary stalk.

what is this structure outlined in pink?

reticular nucleus of thalamus

thalamus

every sensory input (expect smell) is relayed to the thalamus

what is this whole structure?

thalamus.

• myelin=black

• neurons=pink

what are the right two arrows pointing at?

3rd ventricle— separates the 2 halves of the thalamus

what is the left arrow pointing at?

(inter)thalamic adhesion

what is the structure outline in pink?

internal medullary lamina

internal medullary lamina

sheets of myelinated axons that divide thalamic relay nucleus into three regions

specific thalamic nuclei

relay specific sensory/motor info to specific regions of the cortex

• eg visual thalamus projects to visual cortex

association thalamic nuclei

responds to more than one sensory input and relays info from association thalamus to association cortex

• sends axons to rest of cerebral cortex aka associated cortex

non-specific thalamic nuclei

sends axons anywhere, beyond cortex, and responds to more than one sensory input

what do the colored regions represent?

specifc thalamic nuclei

what is the dark green region?

medial geniculate nucleus, relays HEARING input

what is the red region?

ventral lateral nucleus, relays MOTOR input

what is the teal region?

ventral anterior nucleus, relays MOTOR input

what are the dark purple regions?

ventral posterior lateral and ventral posterior medial nuclei, relays TOUCH and PAIN

ventral posterior lateral nucleus

relays touch and pain info from body

ventral posterior medial nucleus

relays touch and pain info from the head and face

relay nuclei

specific and association nuclei. project axons to cortical regions serving the same functions as their respective thalamic regions

• eg visual thalamus → visual cortex

• eg motor thalamus → motor cortex

where does the dorsomedial nucleus project?

prefrontal association cortex

where does the pulvinar nucleus project?

visual and auditory association cortex

where are non-specific nuclei?

reticular nucleus and intralaminar nuclei of thalamus

input from hypothalmus/hippocampus goes to…

anterior nucleus → cingulate (limbic)cortex

input from cerebellum goes to…

ventral lateral nucleus → motor cortex

somatosensory/visceral sensory goes to…

ventral posterior (lateral & medial) → somatosensory cortex and visceral cortex

input from retina goes to…

lateral geniculate nucleus → visual cortex

input from the inferior colliculus goes to…

medial geniculate nucleus → auditory cortex

input from the cortex and other areas goes to…

other nuclei → association cortex

thalamic reticular nucleus

• inhibits output of other thalamic nuclei in the cerebral cortexi

• reduces info flow when it is not needed eg sleep, concentration

internal capsule

carries axons in and out of the cortex

what is this region?

internal capsule

telencephalon

two hemispheres with three interrelated parts

• neocortex (most of cerebral cortex)

• limbic and olfactory cortex

• basal ganglia

neocortex

most of the cerebral cortex, has 6 cell layers

layer IV (4)

layer of the neocortex that the thalamus projects to

• projects to layers II & III

layers II & III

layers of the neocortex that interconnect with other cortical areas

layer V (5)

layer of the neocortex that projects to the brainstem and spinal cord

layer VI (6)

layer of the neocortex that projects back to the thalamus

primary sensory cortex

cortex that is innervated by specific thalamic relay nuclei for the same sense

• eg lateral geniculate nucleus → primary visual cortex

primary motor cortex

cortex that innervates spinal cord or brain stem and controls motorneurons

• eg corticospinal tract

association cortex

involved in the integration of sensory input where decisions have to be made about appropriate responses

cerebral commissures

discrete bundles of axons that cross the midline

• region of cortex on one side of the brain communicates with the same region on the other side

what are the two main commissures of the cerebral cortex?

• corpus callosum

• anterior commissure (“corpus callosum” of olfactory system)

allocortex

parts of the limbic system and olfactory systems that are not in the neocortex

what is the structure circles in red?

hippocampus

what is the arrow pointing to?

amygdala (responsible for fear responses)

limbic system

regulates emotions and behaviors, processes memories, controls thoughts and motivations

• hippocampus

• amygdala

fornix

tract of the limbic system that travels from hippocampus to mammillary bodies of hypothalamus

what is this arrow pointing to?

fornix

basal ganglia

group of nuclei that plays important roles in motor system and motivation (including drug abuse)

what doe the highlighted regions represent?

nuclei of the basal ganglia

• all located in the midbrain, diencephalon, and basal region of telencephalon

major nuclei of the basal ganglia

• striatum

• globus pallidus

• subthalamic nucleus

• substantial nigra

striatum

in telencephalon. has three subnuclei:

• caudate nucleus

• putamen

• nucleus accumbens

what is the circled region?

caudate nucleus

what is the circled region?

putamen

what is the circled region?

nucleus accumbens

what is the circled region?

internal capsule

what are the arrows pointing to?

globus pallidus

what are the arrows pointing to?

subthalamic nucleus

what are cranial nerves?

nerves that enter and exit the central nervous system through cranial foramen

spinal foramina

intervertebral openings in which spinal nerves exit

how are spinal nerves formed?

via the fusion of one dorsal root and one ventral root

afferents

sensory innervation

• somatic sensory

efferents

motor innervation

• skeletal muscles

cranial nerve I (1): olfactory nerves

responsible for sense of smell, located in the nasal epithelium

• enters through cribiform plate

• continues to cerebral cortex

where does CN I synapse?

olfactory bulbs

what are the blue highlighted regions?

olfactory bulbs

where do neurons in the olfactory bulb go to?

olfactory bulb neurons send their axons through the olfactory tract then to the CEREBRAL CORTEX

cranial nerve II (2): optic nerve

vison, receives input from retina cell axons

• continues to thalamus

cranial nerve III (3): oculomotor nerve

innervates skeletal muscle to open eye and constricts pupil and focus lens

cranial nerves IV (4): trochlear nerve

innervates superior oblique extraocular muscle and is the only cranial nerve to exit from the dorsal surface of the brain

what does the circled structure?

superior oblique muscle, innervated by CN4. moves eye down and out

cranial nerve V (5): trigeminal nerve

innervates muscles of mastication and other sensation from the face and head

3 branches:

• opthalmic

• maxillary

• mandibular

what nerve is shown here?

trigeminal nerve

what branch is circles in blue?

opthalmic branch: receives info from the forehead

what branch is circled in green?

maxillary branch: receives info from cheek and nose

what branch is circled in purple?

mandibular branch: receives info from lower jaw

cranial nerve VI (6): abducens nerve

innervates lateral rectus extraoccular muscle

what is the circled structure?

lateral rectus muscle, innervated by CN6. pulls eye to the side

cranial nerve VII (7): facial nerve

innervates muscles of facial expression, autonomic ganglia responsible for tears, snot, and saliva, and 2/3 of tongue taste receptors

cranial nerve VII (8): vestibulocochlear nerve

responsible for hearing and balance. receives info from hair cells in cochlea

cranial nerve IX (9): glossopharyngeal nerve

innervates one skeletal muscle parotid gland, and receives sensory info from poster 1/3 of tongue

parotid gland

responsible for salvation, innervated by CN9 via autonomic ganglion

cranial nerve X (10): vagus nerve

innervates skeletal muscle, sensation, and senses blood oxygenation and CO2 levels

what skeletal muscle does CN 10 (vagus nerve) innervate?

muscles of throat and larynx for swallowing

what sensations is the vagus nerve responsible for?

taste and general sensation behind the ear and of larynx

what skeletal muscle does CN 9 (glossopharyngeal nerve) innervate?

muscles for elevating pharynx while swallowing

cranial nerve XI (11): spinal accessory nerve

innervates 2 muscles that allowing turning of head and shrugging shoulders

cranial nerve XII (12): hypoglossal nerve

innervates muscles of the tongue that allow for tongue movements

nerves that carry special senses (simplified)

olfactory, optic, vestibulocochlear

nerves that innervate skeletal muscle

oculomotor, trochlear, abducens, spinal accessory, hypoglossal

nerves that innervate muscle and carry general sensation

trigeminal

nerves that are mixed function

facial, glossopharyngeal, vagus

conjuctiva

lines inner surface of the eyelids and outer surface of the sclera

• protects and excretes mucus and tears

• prevents microbes from entering