Brain + Behavior 2009 -- Week 1

Front 1

What causes holoprosencephaly?

Back 1

Loss of SHH signaling

Front 2

Which part of notocord secretes Sonic Hedgehog? What signaling molecule is secreted by the opposite part?

Back 2

Floor plate secretes SHH: roof secretes BMPs

Front 3

What causes smooth brain (no gyri)?

Back 3

Called lissencephaly; Caused by abnormal migration of neurons

Front 4

What protein monitors the stability of microtubules?

Back 4

Tau

Front 5

What are the types of glia in the CNS?

Back 5

Astrocytes, oligodendrocytes, microglia

Front 6

What is the glia cell type that mylinates in the CNS?

Back 6

Oligodendrocytes

Front 7

Difference in mylination between CNS and PNS?

Back 7

In CNS, one oligodendrocyte can mylinate many axons; in PNS one schwann cell myelinates one segment of one axon

Front 8

What is wallerian degeneration?

Back 8

Degeneration of parts of neuron separated from cell body

Front 9

What is the major CNS excitatory neurotransmitter?

Back 9

Glutamate

Front 10

What is the major CNS inhibitory neurotransmitter?

Back 10

GABA

Front 11

Excitatory receptors use ligand gated ion channels selective for what type of ions?

Back 11

Cations

Front 12

Inhibitory receptors use ligand gated ion channels selective for what type of ions?

Back 12

Anions

Front 13

What part of neurotransmitter biology is altered in fragile X mental retardation?

Back 13

Metabotropic glutamate receptor function

Front 14

Difference between AMPA and NMDA receptors?

Back 14

(Note that both are glutamate receptors)
AMPA receptors are primary mediator of fast excitation; NMDA currents are slower and more sustained and receptor function can be modulated (critical for synaptic plasticity)

Front 15

Purpose of acetylcholine as neurotransmitter?

Back 15

Major excitatory transmitter at NMJ and autonomic ganglia; also minor excitatory transmitter in CNS

Front 16

Biggest medical impact mediated through Acetylcholine receptors?

Back 16

Tobacco addiction (nicotine is an agonist at AChRs)

Front 17

Disease caused by antibody-mediated autoimmune response to muscle AChRs?

Back 17

Myasthenia Gravis

Front 18

Major neurologic disease category associated with mutations in GABA receptor subunits?

Back 18

Epilepsy

Front 19

What is axoplasmic transport TOWARD the cell body called?

Back 19

Retrograde

Front 20

Which types of axoplasmic transport are microtubule associated?

Back 20

Fast anterograde and retrograde

Front 21

What is special about design of NMJ?

Back 21

Designed so a single EPP causes a muscle fiber action potential (NOT true in CNS)

Front 22

How do you affect specificity of a ligand gated ion channel?

Back 22

Change combination of subunits

Front 23

How does topiramate (anticonvulsant) work?

Back 23

Inhibits AMPA receptors (glutamate receptors)

Front 24

Nicotine is an agonist to what?

Back 24

Acetylcholine receptors

Front 25

What type of receptors are found around the nervous system as well as in heart, smooth muscle, and exocrine glands?

Back 25

muscarinic acetylcholine receptors

Front 26

What is the difference between ionotropic and metabotropic acetylcholine receptors?

Back 26

Ionotropic respond better to nicotine than muscarine and are ligand-gated ion channels; metabotropic receptors respond better to muscarine and are GPCRs

Front 27

Atropine, a drug used to dilate pupils, is an antagonist to what?

Back 27

Acetylcholine receptors

Front 28

What does glutamic acid decarboxylase do?

Back 28

Makes GABA from glutamate

Front 29

How are muscular nerve fibers classified?

Back 29

Fiber diameter (roman numerals)

Front 30

How are cutaneous nerves classified?

Back 30

Conduction velocity (ABCs)

Front 31

Where do the UMNs for conscious movement cross the midline?

Back 31

In pyramidal decussation in lower medulla

Front 32

What type of muscles are innervated by the reticulospinal tract?

Back 32

extensor muscles (for postural support)

Front 33

What muscles are innervated by the medial vestibulospinal tract?

Back 33

Neck and upper limb muscles; used to respond to vestibular stimuli

Front 34

Spastic paralysis is a sign of what?

Back 34

UMN lesion

Front 35

Where are the cell body of the three neurons making up in the dorsal column/medial lemniscus system?

Back 35

(1) dorsal root ganglion; (2) nucleus gracilis and cuneatus in medulla; (3) in VPL of the thalamus

Front 36

What sends inputs to the VPL nucleus in the thalamus? Where does it project?

Back 36

Spinal thalamic tract and Medial lemniscus system; projects to postcentral gyrus

Front 37

What sends inputs to the VPM nucleus in the thalamus? Where does it project?

Back 37

trigeminothalamic tract; projects to postcentral gyrus

Front 38

What system carries proprioceptive signals from body?

Back 38

Dorsal column/medial lemniscus

Front 39

Where does fasciculus cuneatus start?

Back 39

T5 and up

Front 40

Where do axons in the dorsal column/medial lemniscus cross the midline?

Back 40

In medulla where the nucleus gracilis and cuneatus are located and the medial lemniscus forms

Front 41

If a patient sways or fall down while standing with eyes closed (but is fine with open eyes), what is this called and what does it signal?

Back 41

Positive Romberg sign; means patient has lost proprioreceptive capabilities, has sensory ataxia; likely has lesion of dorsal column/medial lemniscus system

Front 42

What system carries pain and temperature?

Back 42

Anterolateral system

Front 43

Better name (more inclusive) for spinothalamic tract?

Back 43

Anterolateral system

Front 44

What is Lissauer's tract?

Back 44

Ascending primary neurons of anterolateral system (1-2 spinal segments) before they synapse in dorsal horn

Front 45

Where do axons in the anterolateral system cross the midline?

Back 45

in ventral commissure of spinal cord, 1-2 segments above where primary neurons entered spinal cord

Front 46

Purpose of spinoreticular tract?

Back 46

Projects pain information to brainstem reticular formation and from there to limbic system to process emotional content and remember the painful stimulus

Front 47

Purpose of spinocerebellar system?

Back 47

Transmitts unconscious ipsilateral proprioception to cerebellum

Front 48

What sensory tracts project to the ipsilateral side of the brain?

Back 48

Spinocerebellar

Front 49

Where do axons of the spinocerebellar system synapse?

Back 49

In Clarke's nucleus or in the external cuneate nucleus in the caudal medulla

Front 50

What sensory tract crosses the midline twice?

Back 50

Ventral spinocerebellar tract

Front 51

What division of the nervous system do the decending hypothalamic axons contribute to?

Back 51

Sympathetic preganglionic neurons

Front 52

What happens if you lesion decending hypothalamic neurons in the brainstem?

Back 52

Horner's syndrome on ipsilateral side
* pupillary constriction (miosis)
*drooping eyelid (ptosis)
*no sweating (anhydrosis)

Front 53

What causes an uninhibited or infantile bladder?

Back 53

Lesions to cortical areas above pons

Front 54

What causes a spastic bladder?

Back 54

Spinal cord lesion above sacral levels that lesions preganglionic parasympathetic fibers

Front 55

What happens in ALS?

Back 55

Progressive loss of motor neurons and axons

Front 56

What is difference between Becker and Duchenne muscular dystrophy?

Back 56

In Becker's, a deletion in th dystrophin gene leaves the reading frame intact and some protein is produced; In Duchenne, the reading frame is disrupted and no protein is produced

Front 57

Most common muscle disease in adults?

Back 57

Myotonic dystrophy; involves repeat in DMPK gene on chromosome 19

Front 58

What is first affected with a central cord lesion?

Back 58

Bilateral crossings of spinothalamic tracts (anterolateral system) AT THAT LEVEL