Practical (from checklist)

List the 6 nuclei of the Papez circuit

hippocampus, mammillary body, anterior nucleus of thalamus, cingulate gyrus, parahippocampal gyrus

List the 5 connections of the Papez circuit

perforant pathway (EC → hippocampus)

fornix (hippocampus → mammillary bodies)

mammillothalamic tract (mammillary bodies → ant nuc of thalamus)

internal capsule (ant nuc of thalamus → cingulate gyrus)

cingulum (cingulate gyrus → parahippocampal gyrus)

papez circuit (start at hippocampus)

hippocampus → fornix → mammillary body → mammillothalamic tract → ant nucleus of thal → internal capsule → cingulate gyrus → cingulum → parahippocampal gyrus → entorhinal cortex → perforant path → back to hippocampus

what is highlighted in green?

hippocampus

what structures make up the interlocking C shapes of the hippocampal formation?

CA1-3 (hippocampus) and the dentate gyrus

afferents and efferents of the hippocampus are

bundled together in the same paths

list the sections of the hippocampal formation from outermost to innermost (ending with dentate)

parahippocampal (on posterior edge) and entorhinal cortex (anterior), subiculum, CA1-CA3, dentate gyrus

what are the inputs to the hippocampus?

subiculum → hippocampus

EC → subiculum → hippocampus

Amygdala → EC → hippocampus

what are the outputs of the hippocampus?

hippocampus → subiculum → cortex

hippocampus → cortex → subcortical areas

what are the inputs to the mammillary bodies?

hippocampus

what are the outputs of the mammillary bodies?

anterior nucleus of the thalamus

what are the inputs of the cingulate gyrus?

anterior nuc of thalamus, visual cortex

what are the outputs of the cingulate gyrus?

parahippocampal gyrus

what are the inputs of the parahippocampal gyrus?

cingulate gyrus

what are the outputs of the parahippocampal gyrus?

entorhinal cortex

what are the inputs to the amygdala?

thalamus

what are the outputs of the amygdala?

cerebral cortex, hypothalamus

what are the inputs of the septal nuclei?

hippocampus

what are the outputs of the septal nuclei?

hypothalamus

what is shown?

septal nuclei

cingulate gyrus

A

anterior nucleus of thalamus

B

fornix

C

dentate gyrus

E

entorhinal cortex

F

hippocampus

G

amygdala

H

mammillary body

K

nucleus accumbens

L

septal area

M

accumbens

A

medial forebrain bundle

B

ventral tegmental ares

C

nucleus accumbens (recall: where caudate and putamen meet)

what is the function of the limbic system?

fight/flight

feeling (especially fear)

forgetting/memory

sexual function

what is the function of the hippocampus?

spatial memory, learning

amygdala function

anger and fear

involved in reward, pleasure, and addiction, located where the caudate and putamen meet

nucleus accumbens

cingulate gyrus function

emotion processing, learning and emotional memory

attention flexibility (shifting attention, switching from ideas)

empathy

septal nuclei function

serve as relay of hippocampus to hypothalamus, septal rage, emotional memory

loss of episodic memory, but not semantic memory. patient cannot recall personal details. patient likely has an injury to

the hippocampus

Wernicke-Korsakoff syndrome: lesion, characteristics

caused by thiamine/B2 deficiency, resulting in damage to mammillary bodies. common in alcoholics (due to poor nutrition, not the alcohol itself).

characteristics: confabulation, delusions, hallucinations, disorientation. due to relation to alcoholism, patients may also present with cerebellar degeneration (ataxic gait and dysmetria).

Kleine-Levin syndrome: lesion, characteristics

hypothalamic injury, most often found in adolescent males

cycling periods of hyperphagia, hypersomnolence, sexual aggression, general aggression. think of hypothalamus/pituitary

Kluver-Bucy syndrome: lesion, characteristics

Amygdala injury

memory deficits, flat affect, oral fixation, hypersexuality. hard time recognizing fear

Limbic encephalitis: lesion, characteristics

not one specific lesion, limbic-area issues that may arise from lung carcinoma.

short term memory impairment, quick changes in mood (emotional lability), agitation, sexual disinhibition).

Abulia: lesion, characteristics

frontal lobe lesion. personality changes, apathy, lack of initiation of action. patient may not eat when hungry, move when in pain, speak much/at all, use the restroom on own.

which structures arise from the fibrous tunic?

cornea and sclera

which structures arise from the vascular tunic?

the iris, pupil, ciliary body, choroid, and lens

which structures arise from the neural tunic?

the retina

the sclera is an extension of ___

dura

in the iris, the circular fibers ___ and the radial fibers ___

circular constrict, radial dilate

superior rectus muscle

A

conjunctiva

E

cornea

H

inferior rectus muscle

O

optic nerve

P

pupil

Q

Lens

R

Iris

S

CN III innervates which eye muscles?

medial rectus, superior rectus, inferior rectus, inferior oblique

CN IV innervates which eye muscle?

superior oblique (for intorsion)

CN VI innervates which eye muscle?

lateral rectus (for abduction)

circular fibers are innervated by ___ neurons, while radial fibers are innervated by ___ neurons

circular - parasympathetic

radial - sympathetic

red

optic nerve

green

short ciliary nerve

purple

long ciliary nerve

vitreous body is the gel within the ___ chamber

anterior

rods contain ___ and cones contain ___. which is more numerous?

rhodopsins, iodopsins, rods.

what do horizontal cells do?

modify responses of bipolar cells

what do amacrine cells do?

modify resp

which cell in the retina can generate action potentials?

ganglion cells

what are the three layers of the LGN? describe each.

parvocellular - 4 dorsal layers, small cells, small receptive fields

magnocellular - 2 ventral layers, large cells, large receptive fields

koniocellular - between each layer

on a fundus exam, the dark area is the ___. the light spot is the ___.

macula, optic disk (blind spot)

at the center of the macula is the

fovea

what is in orange?

parvocellular layers

what is in green?

magnocellular layers

what is in pink?

koniocellular layers

give the main functions for each section of the visual cortex.

V1 - primary visual cortex, perceives object

V2/V3 - fills in gaps, perceives complex form

V4 - perceives complex form

V5 - motion perception

describe the visual streams

dorsal stream (where) - dorsolateral parietotemporal

ventral stream (what) - inferior occipitotemporal cortex

lesion to the optic nerve results in

unilateral field loss

lesion to the optic chiasm results in

bitemporal hemianopia

lesion to the optic tract results in

homonymous hemianopia

lesion to optic radiation results in

quadrantanopia (myers loop - superior quadrantanopia, parietal loop - inferior)

meyer’s loop

D

what is B

calcarine sulcus

what is F?

lateral geniculate nucleus of thalamus

what diagnosis

papilledema

papilledema is characterized by

a bulging optic disk. can see a large dark ring around the optic nerve on fundus. no visual field deficit except enlarged blind spot.

inflammation of the optic nerve, presents with a blind spot. eye pain common.

optic neuritis

visual spells (can be transient) are a sign of

ophthalmic artery occlusion

A 28-year-old former gymnast noticed difficulty seeing fine lines with her left eye. The symptoms progressed over the next day, and she had difficulty reading newspaper headlines. Pain in the left orbit was minor at first but worsened and increased with eye movement.

Vision was 20/200 in the left eye and 20/30 in the right eye. There was a central scotoma (blind spot), and red was less intense in the left eye.

optic neuritis

A 66-year-old woman presents to her primary care physician with a 3-week history of visual spells

During each spell she had sudden onset of cloudy darkening of vision in her left eye. Each spell lasted a few minutes and abated suddenly

During one spell she covered the left eye and noted normal vision in the right eye

ophthalmic artery occlusion

A 25 yo woman became ‘sluggish’ and easily fell asleep. She had gained 17 pounds in the last three months, and on exam her face looked ‘like a mask’ – her jaw was large and her eyebrow ridges prominent.

She had trouble seeing to the left in the left eye, and to the right in her right eye

pituitary tumor pressing on chiasm, leading to bitemporal hemianopia

prosopagnosia

face blindness, lesion to fusiform gyrus

what color is the superior temporal gyrus?

purple

what color is the middle temporal gyrus?

green

what color is the inferior temporal gyrus?

red

what color is the occipitotemporal (fusiform) gyrus?

blue

what color is the lingual gyrus?

orange

where is the superior temporal sulcus?

between the superior and middle temporal gyri