Week 3

Question 1

Cochlear canal containing organ of corti

Answer 1

Endolymph containing scala media (High K+ concentration)

Question 2

K+ mediated action potential?

Answer 2

Inner hair cells from organ of corti

Influx of K+ from endolymph during stereocillia displacement

Question 3

First auditory nucleus with biaural input

Answer 3

Superior olivary nucleus (think MSO, LSO); binaural input via trapezoid bodies

Question 4

Organization, functional sig, location of primary auditory cortex

Answer 4

Heschel’s gyrus (insula)
Core, belt, parabelt
Tonotopic organization only in core

Question 5

Superior olivary nucleus (location and functional significance)

Answer 5

Located in brainstem (pons level)

Computes interaural level or time differences (ILD, ITD)

Question 6

Olfaction primary cortex location

Answer 6

Piriform cortex, uncus (medial anterior brain)

Question 7

Cyclic nucleotide gated channel (CNG)

Answer 7

Found in OSN (olfactory) neurons; Responds to cAMP levels by opening Na/Ca channel –> depolarization

Question 8

What type of receptor are the odarant receptor on olfactory sensory neurons (OSN)

Answer 8

GPCR - G(olf)

Acitvate adenylyl cyclase

Question 9

Olfactory cells that project to primary olfactory cortex

Answer 9

Mitral/tuft cells project from glomeruli to piriform cortex (uncus)

Question 10

Gustatory relay to the cortex

Answer 10

Solitary nucleus (VII, IX, X input) gives off axons to VPM of thalamus –> cortex

Question 11

Two systems with “labeled line code”

Answer 11

• Auditory system: cochlea basilar membrane hair cell location correlates with frequency
• Taste: location in taste bud distinguishes type of tastant

Question 12

Insula contains primary sensory cortex for which two sensory modalities

Answer 12

Auditory (via Heschel’s gyrus)

Taste as well

Question 13

TRPM5 channel

Answer 13

Ion channel important downstream target of GPCR for sweet, umami, and bitter taste modalities

Question 14

Type of movements mediated by superior colliculus

Answer 14

Rapid (reflexive) saccades

Question 15

Type of movements mediated by frontal eye fields

Answer 15

Voluntary eye saccades

Question 16

Vestibular organs detecting linear acceleration

Answer 16

Utricle & sacculus

Question 17

Direction of nystagmus in left angular rotation of semicircular canals

Answer 17

Left nystagmus

Question 18

Normal gain of vestibulo-ocular reflex (VOR)

Answer 18

G= -1

Question 19

cGMP role in a sensory system

Answer 19

-Visual system, light transduction in cones/rods

-

Question 20

Explain horizontal cells in retina

Answer 20

• Found in outerplexiform layer
• Connects same type of bipolar cells (OFF or ON) near each other
• Antagonistic actions (when stimulus is the same light/dark in adjacent area)

Question 21

First place of action potential in visual transduction

Answer 21

• At level of ganglion cell

- Rods/cones don’t communicate with bipolar cells via action potentials (per se)

Question 22

Primary sensory cortex for following modalities: Taste, smell, auditory, vestibular (cerebellar region)

Answer 22

Taste - Insula (Gustatory cortex)
Smell - Piriform cortex (uncus)
Auditory - Insula (Heschel’s gyrus)
Vestibular - Floculus

Question 23

Suprachiasmatic nucleus (SCN)

Answer 23

Found in thalamus, receives input from optic tracts, mediates circadian rhythms

Question 24

Degree of binocular overlap in 180 degree field of vision

Answer 24

Middle 120 degrees

Question 25

Explanation for Kaniza triangle illusion via visual system anatomy

Answer 25

Lateral excitatory connections in cortical layers II/III of V1. Connections are excitatory and between cells with same orientation selectivity

Question 26

V2 area where M-cell pathway projects

Answer 26

Thick stripes

Question 27

Akinotopsia lesion site

Answer 27

MT

Question 28

Achromatopsia lesion site

Answer 28

V4

Question 29

Color constancy problem

Answer 29

Maintaining sense of color of an object regardless of quality/composition of ambient light; V4 adjusts for different lighting effects

Question 30

Aperture problem

Answer 30

Difficult to detect movement direction of an object when looking through a single aperture (receptive field); MT integrates fields

Question 31

End point of ventral/what pathway

Answer 31

Inferior temporal cortex

Question 32

End point of dorsal/where pathway

Answer 32

Posterior parietal cortex

Question 33

Most common cause of a bitemporal hemiapnosia

Answer 33

Optic chiasm compression mediated by a pituitary adenoma

Question 34

Localization of alexia w/o agraphia syndrome

Answer 34

Left occipital lobe lesion affecting splenium of corpus callosum

Question 35

Stroke territory causing hemi-achromatopsia

Answer 35

- PCA territory affecting lingual & fusiform gyrus of occipital lobe - Loss of color vision due to damage to V4 (what pathway)

Question 36

Three symptoms of Balint's syndrome

Answer 36

Bilateral parietal lobe damage causing | Simultagnosia, optic ataxia, ocular ataxia

Question 37

Ocular ataxia

Answer 37

Inability to move eyes under visual guidance | *Associated with Balint's

Question 38

Optic ataxia

Answer 38

Inability to reach under visual guidance | *Associated with Balint's

Question 39

Difference between dysmetria and optic ataxia

Answer 39

Optic ataxia patients can't reach their hand to the doctor's target; Dysmetria patients take a circuitous route to the doctor's finger

Question 40

Isolated repetition aphasia and lesion localization

Answer 40

Conduction aphasia | Arcuate fasciculus lesion

Question 41

Apraxia vs. ataxia and associated brain regions

Answer 41

- Apraxia - Motor planning disorder: inability to execute learned purposeful movements (left parietal lobe lesion) - Ataxia - Lack of coordination of movements (cerebellar damage)

Question 42

Testing for apraxia

Answer 42

Ask to pantomime some complex action; inability to plan out and execute a movement (e.g. pretend using a hammer) suggests left parietal lesion mediated apraxia

Question 43

4 Symptoms of Gerstmann's syndrome

Answer 43

- Left parietal lobe damage | - Agraphia, acalculia, finger agnosia (inability to distinguish or name fingers), R/L confusion

Question 44

Somatophrenia

Answer 44

- Patient complains left side limbs don’t belong to them | - Severe neglect from right parietal lesion

Question 45

Capgrass and Fregoli syndrome lesion localizations

Answer 45

``` Perirhinal cortex (input to hippocampus) Capgrass is loss of familiarity, Fregoli is the opposite ```

Question 46

Ribot's law

Answer 46

Graded retrograde memory loss | Suggests role of consolidation

Question 47

Two histological hallmarks of Alzheimer's disease

Answer 47

``` Amyloid plagues (extracellular) Neurofibrillary tangles (intracellular) ```

Question 48

Scopolamine

Answer 48

- Blocks ACh | - Wreaks havoc on Alzheimer's disease patients by inhibiting ACh delivery from basal forebrain

Question 49

Common Alzheimer's treatment

Answer 49

ACh esterase inhibitors --> increases ACh available from basal forebrain diffuse projections

Question 50

pCREB

Answer 50

Important gene for LTP long term effects

Question 51

Schaffer collaterals (location, experimental uses & significance)

Answer 51

Connect CA3 - CA1 in hippocampus | Used to study LTP

Question 52

Physiological mediator of long term potentiation (LTP)

Answer 52

Insertion of AMPA receptors into post-synaptic neuron memebrane (in response to NMDA mediated Ca influx)

Question 53

Two main histological symptoms found in fronto-temporal dementia

Answer 53

Tau protein aggregates | TDP-43 aggregates

Question 54

Clinical disease that can present with hallucinations and RBD (violent flailing during REM sleep; acting out dreams)

Answer 54

Dementia with Lewy Bodies (counterintuitive b/c RBD sounds hyperkinetic and Parkinson's is hypokinetic)