Functional Neuroanatomy

Question 1

Which levels of the SC have a lateral horn?

Answer 1

Thoracic and S2-4

Question 2

Where is spinothalamic / anterolateral tract found in the brain stem?

Answer 2

Found laterally in brain stem, close to medial lemniscus in midbrain.

Question 3

Pathway for fine touch, vibration, and position from face

Answer 3

Synapses in ipsi trigeminal ganglion, crosses, and ascends in trigeminothalamic tract, which starts medial and then gets more lateral by the time it reaches the thalamus.

Question 4

Pathway for pain, temp, and gross touch form face

Answer 4

Enters pons via trigeminal nerve but descends down into medulla or upper cervical SC and synapses in spinal trigeminal nucleus. Synapses, crosses, and ascends in trigeminothalamic tract

Question 5

Pathway for viscerosensation

Answer 5

Viscerosensation ascends in viscerosensory tracts to solitary nucleus, synapses and projects bilaterally via solitariothalamic tracts, ultimately projecting to insula

Question 6

Paraesthesia vs Dysesthesia

Answer 6

• Paraesthesia – dysfunction of peripheral somatosensory axon causing spontaneous or evoked positive somatosensory sxs that are not unpleasant / painful.
• Dysesthesias are unpleasant / painful

Question 7

Allodynia

Answer 7

Perception of pain to stimuli that are not normally noxious

Question 8

Cell pathway for vision

Answer 8

Photoreceptors synapse on retinal bipolar cells, which synapse on retinal ganglion cells, whose axons travel to the thalamus

Question 9

Pathway from frontal eye field

Answer 9

• Frontal eye field → contralateral pontine horitzontal gaze center (aka pontine paramedian reticular formation / PPRF) → abducens nucleus → left lateral rectus.
• Pontine horizontal gaze center also projects to oculomotor nucleus on other side via medial longitudinal fasciculus

Question 10

Where are vertical gaze and convergence centers found?

Answer 10

Vertical gaze center found in upper brainstem and is composed of nuclei near oculumotor nucleus. Projects to oculomotor and trochlear nuclei to cause conjugate vertical gaze. This area is also responsible for convergence.

Question 11

• Tropia
• Phoria
• Exotropia
• Esotropia
• Hypertropia
• Hypotropia
• Skew

Answer 11

• Tropia = fixed dysconjugacy
• Phoria = intermittent dysconjugacy
• Exotropia = deviation of an eye laterally
• Esotropia = deviation of an eye medially
• Hypertropia = deviation of an eye superiorly
• Hypotropia = deviation of an eye inferiorly
• Skew = vertical dysconjugacy

Question 12

Pupillary light reflex

Answer 12

Visual info for conscious info goes to lateral geniculate nucleus in thalamus. Unconcious info goes to bilateral pretectal nuclei, each of which receives light info from both eyes. Pretectal nuclei then project short distance to Edinger Westphal nucleus, which contains preganglionic parasympathetic neurons. These axons travel w/ ipsi occulomotor nerve to synapse on ciliary ganglion, which contains postganglionic parasympathetic neurons, which project to iris to innervate iris sphincter muscle (smooth muscle).

Question 13

Term for pupils that aren’t the same size

Answer 13

anisocoria

Question 14

Pupillary dark reflex

Answer 14

Info sent to hypothalamus. Sympathetic tract from hypothalamus down to T1 to synapse on lateral horn (preganglionic). Second neuron runs up sympathetic chain and ascends back to superior cervical ganglion. 3rd neuron (postganglionic) hitches a ride on arteries (carotid, etc), then finally reaches the pupil to innervate the iris dilator muscle.
Whole pathway is ipsilateral.

Question 15

Corneal (blink) reflex

Answer 15

Mechanoreceptors trigger ipsi trigeminal nerve to brainstem. Efferent response involves bilateral facial nerves causing strong eye closure

Question 16

Sound transmission to cochlea

Answer 16

Malleus, incus, stapes vibrate oval window. Endolymph vibrates the basilar membrane.

Question 17

Which nerve innervates tensor tympani? Stapedius?

Answer 17

Tensor tympani innervated by CN V. Stapedius innervated by CN VII.

Question 18

Pathway from cochlea to cortex

Answer 18

• Auditory nerve synapses in ipsi cochlear nucleus. Ascends bilaterally in lateral lemniscus to inferior colliculus in midbrain, which projects to thalamus.
• Auditory radiation = tract from thalamus to primary auditory cortex on superior temporal lobe.

Question 19

Which part of vestibular system uses otoliths?

Answer 19

Vestibule. Senses linear acceleration and gravity.

Question 20

Pathway from vestibular nucleus to cortex

Answer 20

Vestibular nucleus –> lateral lemniscus –> thalamus –> insula
Vestibular nuclei also connect to cerebellum to control movements as well as to brainstem to control eye movements

Question 21

Smell pathway

Answer 21

Olfactory nerve is actually a bunch of little “nervelets”. Connects to olfactory bulb, which is CNS. Bulb axons make up olfactory tract, which projects bilaterally to primary olfactory cortex on medial temporal lobe near hippocampus. Only sense that does not go through the thalamus before going to cortex

Question 22

Which CN’s carry taste info?

Answer 22

CN VII, IX, and X

Question 23

Where do vagus and glossopharyngeal nerves synapse?

Answer 23

Ambiguus nucleus

Question 24

• Palsy
• Hemiparesis / plegia
• Paraparesis / plegia
• Diparesis / plegia
• Monoparesis / plegia

Answer 24

• Palsy – another term for weakness that does not distinguish b/w paresis and plegia
• Hemiparesis / plegia – unilateral weakness / paralysis
• Paraparesis / plegia – bilateral leg weakness / paralysis
• Diparesis / plegia – weakness of all 4 limbs that is worse in legs
• Monoparesis / plegia – weakness / paralysis of one limb

Question 25

What is normal reflex? | What is 4/4 reflex?

Answer 25

Normal reflex is 2/4. 4 = increased reflux + reflex spread or clonus.

Question 26

Strength 0-5

Answer 26

``` 0 = no muscle contraction 1 = contraction without movement 2 = movement but inability to overcome gravity 3 = antigravity strength but no resistance to the examiner 4 = some resistance to the examiner but not full strength 5 = full strength. ```

Question 27

LMN signs

Answer 27

hyporeflexia, hypotonia, atrophy, fasciculations

Question 28

UMN signs

Answer 28

hyperreflexia, spasticity, extensor plantar response

Question 29

Arm UMN damage

Answer 29

Distal muscles are weaker, extensor / supinator muscles are weaker. Pronator drift, slow fine finger movements

Question 30

Leg UMN damage

Answer 30

Distal muscles are weaker than proximal muscles, flexors are weaker than extensors, and dorsiflexion is weaker than plantarflexion. Hemiparetic gait.

Question 31

Reflexive limb withdrawal

Answer 31

Complex motor reflex that occurs when a noxious stimulus to a limb activates LMN’s at multiple spinal levels causing movement of multiple joints leading to withdrawal of limb. UMN dysfunction may cause increased reflexive limb withdrawal to noxious or nonnoxious stimuli

Question 32

Paratonia

Answer 32

Type of hypertonia in which pxs are unable to relax muscles voluntarily. Gets worse the harder they try, and gets better w/ distraction. Seen in pxs w/ damage to frontal association cortex

Question 33

Anterior corticospinal tract

Answer 33

Minority of axons that do not decussate at pyramidal decussation descend in ipsi anterior column of SC and control movement of torso / neck

Question 34

Corticobulbar tract

Answer 34

UMN’s going from motor cortex to brain stem. Most get bilateral innervation, except for lower face, which only gets CONTRA innervation. Lips innervated by the facial nerve for speaking. Unilateral dysfunction of nerves to lower face cause dysarthria (abnormal enunciation) and dysphagia

Question 35

Where does each cerebellar peduncle attach?

Answer 35

Inferior cerebellar peduncle connects to medulla. Middle connects to pons. Superior connects to midbrain

Question 36

Pathway for correcting info from lateral cerebellum

Answer 36

Correcting info from lateral cerebellum is sent to dentate nucleus. Dentatothalamic tract crosses in the upper brainstem prior to synapsing in contra thalamus.

Question 37

Dysmetria

Answer 37

limb misses target

Question 38

Intention tremor

Answer 38

When limb approaches target. Due to damage in lateral cerebellum.

Question 39

* Dyskinesia * Chorea * Athetosis * Myoclonus * Ballism

Answer 39

* Dyskinesia – abnormal movements / postures w/o weakness. * Chorea – involuntary, fast, irregular, mostly distal limb movements that may resemble dancing * Athetosis – involuntary, slow, writhing, mostly distal limb movements that may resemble movement of snakes * Myoclonus – involuntary, small, fast movements (jerks), usually of the torso and proximal limbs, simultaneously * Ballism – involuntary, fast, large proximal limb movements

Question 40

Dystonia

Answer 40

* Involuntary sustained contraction of one or more muscles causing abnormal movement posture * Muscles may hypertrophy * Dystonic tremor may occur which is produced w/ movements that lengthen the effected muscles

Question 41

Prosody

Answer 41

Emotional content of speech / inflection

Question 42

Where is ascending arousal system found?

Answer 42

Ascending arousal system scattered throughout reticular formation in brainstem. Also in thalamus and cortex.

Question 43

Prosopagnosia

Answer 43

inability to visually recognize familiar faces

Question 44

Anosognosia

Answer 44

inability to perceive neurological deficit such as weakness or sensory loss. Often occurs w/ lesions of right association sensory cortex