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What is the purpose of the neurological exam
What are the functions of the:
-Supplementary motor area
-Primary Motor Cortex
- 1) Supp: programming complex series of movements
- 2) Premotor: Integration of visual and somatosensory cues
- 3) Primary motor cortex: execution; force and direction of movement
What do unimodal association areas do?
- Single modality of sensation
- - complex aspects of sensation
- - compensating for missing information (think of the Kaniza triangle example)
What are the the shaded areas
- Blue (somatosensory)
- Horizontal (primary)
- bricks (premotor)
- Checkerboard (supplementary)
What happens in multimodal association areas?
- multiple modalities of sensation
- Integration of:
- - sensory information across modalities
- - sensory with limbic information (brain more active when looking at face)
Name the three areas of the limbic system and what they do.
- responsible for:
- -assigning emotion to sensory imput
- -attending to relevant or interesting stimulii
What are some examples of dominant and non-dominant hemisphere cooperation?
Dominant: language; skilled motor (praxis); sense of direction (follow a sense of written directions)
Nondominant: prosody (emotion conveyed by voice); spatial attention; sense of direction (via spatial orientation)
What are some hemispherical specializations?
Dominant: handedness; language; complex motor tasks (for both R and L limbs)
Non-dominant: complex visual spatial skills; emotional sig to events and language; spatial attention to both sides; music perception
What are 5 functions of the thalamus?
- Process/relay sensory info to the cortex
- Modulate motor-specific cerebral functions
- Control level of cortical activity (arousal, etc.)
- Modulate emotional/motivational responses
- complex visual/language functions
What are the 2 motor and 2 somatosensory thalamic nuclei?
- - ventral anterior
- - ventral lateral
- - Ventral posteromedial (cranial nerves)
- - ventral posterolateral (spinal nerves) (think of Lateral for Limbs and body)
What are the 6 sections of the neurological exam?
- 1) Mental Status
- 2) Cranial Nerves
- 3) Motor Exam
- 4) Reflexes
- 5) Coordination and gait
- 6) Sensory Exam
Motor control is primarily contralateral except:
- axial muscles
- facial motor nucleus (forehead is bilateral)
- complex motor using both limbs
What is apraxia?
Impaired ability to carry out some complex movement (like combing your hair)
When would you have strong or weak commissural linkages?
- -control vertebral or abdominal muscles
- -i.e. muscles routinely used bilaterally
- -controlling limb muscles
- -routinely used independently
What are the three main functions of the somatosensory system
- Conscious perception (cortical)
- Modulation of movement (cerebellar)
- Arousal and Alertness (brainstem and thalamus)
What information do the anterolateral and dorsal column pathways carry
DC: 2 point discrimination; proprioception light touch; vibration
Anterolateral: nociception and pain
How would one test cortical somatosensory function?
- 1) conscious perception: localization and 2 point discrimination (tests primary somatosensory)2) Identification of: objects by palpation (sterogenesis); writing on skin (complex tactile)
- - These test unimodal and MM association
What is monocular vision loss?
Losing sight from one eye (or optic nerve). Contained to one eye.
What is Bitemporal hemianopia?
Injury to the optic chiasm. Lose the lateral portion of visual field (medial part of retina) in BOTH eyes. Therefore only binocular vision remains.
What is contralateral homonymous hemianopia?
Caused by a lesion in the optic tract (after decusation) or any point after. Same visual field deficit in BOTH eyes. Contralateral visual field defect.
What is the clinical significance of Meyer's loop?
The thalamocortical pathway has two loops one for the superior (Meyer's) and inferior quadrants. Meyers loop is long and goes around the inferior horn of the lateral pathway. Therefor more susceptible to damage
What is contralateral superior quadrantanopia?
The same upper quadrant is blocked in both visual fields because of a lesion in Meyer's loop.
What are the possible outcomes of the Weber test? (putting fork against forehead)
- Normal: equal sound on both sides
- Sensorineural loss: louder tone on normal side
- conductive hearing loss: louder tone on affected side (less environmental noise?)
Role of cerebellum in motor control
- •!planning purposeful actions
- •!preparing motor areas of cortex for action
- •!correcting errors in output (real or impending)
- •!postural adjustments
- •!skilled movements (new & previously learned)
all work to modulate the motor system
What are apraxia and ataxia?
Apraxia is not being able to comb your hair (cortical problem)
Ataxia is being able to comb your hair, but you are bad at it (cerebellar problem)
What are the three functional areas of the cerebellum?
- 1) FN lobe and vermis
- -FN lobe: vestibulo ocular reflex (tracking object with eyes only)
- -vermis: coordination of trunk and proximal limb miscles; balance
- 2) intermediate hemisphere: coordinate distal limb movement; modulate ongoing movement
- 3) lateral hemisphere: motor planning
What are the three layers of the cerebellum
What are the types of afferents in the cerebellum?
- 1) Climbing fibres: (climb from medulla)
- -go to purkinje cells
- -arise from medulla
- -arise from inferior peduncle
- 2) Mossy fibres:
- -stimulate purkinje via granule cells
- -enter mainly by middle and inferior peduncles
What are the three sources of mossy fibre afferents?
- 1) vestibular system (balance) -> vermis and FN
- 2) Spinal cord (mostly proprioception) -> vermis and intermediate hemisphere
- 3) pons (convey cortical info) -> lateral hemispheres
What are the three deep cerebellar nuclei?
Describe the gate control theory of pain.
nociceptive info come from C and A-delta fibres and synapse with a projection neuron. At the same time, a non-nociceptive (A-beta) fibre comes in (maybe because of local pressure), synapses with an inhibitory interneuron, which inhibits the projection neuron from firing up to the thalamus
Describe peripheral sensitization
The threshold in peripheral nociceptive neurons is decreased, making them more sensitive to stimuli
How is nociception modulated
- 1) Supraspinal influences: brainstem input, cortical control (mood?)
- 2) Neuromodulators (e.g. GABA)
- 3) Spinal Influences: Interneurons; propriospinal tract
- 4) Peripheral influences (input)
What are the brainstem areas modulating pain
- 1) periaqueductal grey
- 2) raphe nuclei
- 3) locus ceruleus
these inhibit or facilitate nociception in the spinal cord using neurotransmitters
what are the cortical areas involved in pain?
normally innocuous stimulii are painful
increased painfulness of a painful stimulus
define neuropathic pain
pain months after tissue injury
What are the 4 parts of the reticular formation?
- 1) raphe nuclei
- 2) Central group
- 3) Lateral Group
- 4) Precerebellar nuclei
describe the location and function of the Raphe nuclei
location: most medial portion, extends through midbrain pons and medulla
Function: Sleep, pain perception
Describe the location and function of the central group.
Location: just lateral to the raphe nuclei and runs along medulla, pons, and midbrain
Function: Consciousness, alertness, somatic motor (medial motor systems and gaze centres (MLF))
Structure and function of the lateral group
Location: lateral to the central group, run over the pons and medulla
- -Respiration and CV
- -Somatic motor (CN's V, VII, XII)
- -Autonomic functions (e.g. how full bladder is)
Function and location of the precerebellar nuclei
location: 1 in central group from medulla to pons; 1 lateral to the lateral group in medulla
function: somatic motor (sends info to the cerebellum for modulation)
Where are the following functions found:
-consciousness and alertness
-resp and CV
-somatic motor (medial motor)
pons and midbrain: sleep, consc and alert, MLF pain
medulla and pons: nociception, resp and CV, somatic motor, autonomic
Describe an epidural and subdural bleed
epidural: between periosteal layer and skull, fast bleed because of high arterial pressure
subdural: between meningeal dural layer and arachnoid layer, slower bleed because of lower venous pressure
List the 4 ventricles and where they are located
- 1/2) L/R lateral ventricles in cerebral hemispheres
- 3) 3rd ventricle (diencephalon)
- 4) 4th ventricle (brainstem)
What are communicating and non-communicating hydrocephalus?
comm: too much CSF being produced and not draining into the blood stream fast enough
non-comm: blockage of CSF in ventricles
Describe a uncal and subflacene herniation
uncal: compression of midbrain (affects arousal, resp, pupillary light reflex, etc.). Uncus is on the temporal lobe just adjacent to the midbrain
subfalcine: under the faux cerebri
Recall the areas where the three major cerebral arteries supply
What pathways are responsible for the following:
1) holding a pen to write
2) knee flexion
3) elevation of ribs for a breath
4) voluntary control of micturation and defecation
5) detecting a burn on the skin of fingertips
6) referred pain of angina pectoris
- 1) lateral CS; DC pathway
- 2) lateral CS
- 3) medial motor pathways
- 4) corticospinal, corticobulbar, reticulospinal tracts
- 5) AL pathway
- 6) AL pathway
Injury to dorsal roots causes what?
- -loss or decrease in somatic and visceral sensation for structures at the spinal segment
- -hyporeflexia for reflex pathways that involve that spinal segment
What symptom does Broca's and Wernike's aphasia have in common
What is anosognosia?
unaware of having any deficits
What is the cortical region responsible for:
• Trouble recalling things she had been told in recent days or weeks
• Losing her keys and her pocketbook
• Often repeated questions that she had asked few minutes before
• Occasionally had difficulty distinguishing the letter “O” from the number zero on the touch-phone
• She gets lost if she is left 4-5 blocks from home
bilateral dysfunction of medial temporal lobe
What are some causes of diploplia (double vision)?
Not being able to focus image on the same part of the retina in both eyes.
Problems with nerves: III, IV, VI
What is nystagmus?
eye twitching (can be cause by a problem with vestibular function, CN VIII
What is saccades?
high speed movement of the eyes
How are eye movements coordinated?
Via the Medial Longitudinal fasciculus and the vertical and horizontal gaze centres in the brainstem
What does the pupillary light reflex test?
CN II (light enters), CN III (pupil constricts), and midbrain circuitry
What does the gag reflex test?
CN's (X and IX) for afferents (stroke phaynx), medullary circuitry, CN X for efferent (lift pharynx, close esophagus)
What is the corneal reflex testing?
stroke cornea (CN V), circuitry in the pons, bilateral blinking (CN VII)
What cranial nerves comprise the parasymp NS
- III - pupil constriction
- VII - salivation
- IX - salivation
- X - cardio