Veterinary Neurology Flashcards
(35 cards)
what is decussation?
nerve fibres cross the midline of the brain or spinal cord to the opposite side (right cortex controls left and vice versa)
what is a reflex?
automatic, unconscious reflex - it is mediated by subcortical structures
e.g. spinal cord and brainstem
what is a response?
conscious and involves cortical integration
requires forebrain processing
what are examples of a reflex?
pupillary light reflex
patella reflex
flexor withdraw reflex
panniculus reflex
what are examples of a response?
menace response
conscious proprioception
response to pain
what is the RAS?
reticular activating system
- this is a network of neurons found in the gray matter of the brainstem
functions of RAS?
arousal - maintains consciousness (sends signals to cortex)
wakefulness - regulates sleep wake cycles
attention - filters sensory input allowing focus
location of RAS?
medulla oblongata through pons to midbrain
connects to thalamus and then to cortex
abnormal behaviour - neurological? unless…
unless attributed to specific experience
para refers to?
back legs - pelvic limbs
head tilts can be due to?
peripheral vestibular disease
or central vestibular disease
When looking at Gait, what are you looking out for?
inability to negotiate obstacles, titubation, intention tremor and difficulty prehending food (neuronal ceroid lipofuscinosis) - issue w/ cerebellum
loss of balance and jumping ability (inflammatory spinal disease)
circling - important neurological sign of what?
forebrain disease or vestivular syndrom
what is vestibular ataxia?
dysfunction of the reflex pathways of the vestibular system that maintain eye, head and body position
what is ataxia?
lack of coordination of muscle movements
what is cerebellar ataxia?
failure to integrate multimodal neural information to ensure movements are smooth and adjusted in a timely fashion
what is proprioceptive ataxia?
loss of the proprioceptors (muscle spindles, ligament, joint receptors)
vestibular ataxia?
lean to one side
WHEN CIRCLING
struggle to turn on ‘good side’
immediately falls down on ‘bad side’
how does the parasympathetic nervous system control the pupil size?
constricts the pupil (miosis)
controls accommodation (focus adjustment) via the ciliary muscles
how does the sympathetic nervous system control the pupil size?
dilates the pupil (mydriasis)
innervated eyelids to give alert and wide-eyed expression especially in response to stress of excitement
what is horner syndrome?
loss of sympathetic nerve supply to eye
what does horner syndrome look like?
(opposite of what they eye would look like if scared)
pupil constricted
3rd eyelid protrusion
sunken eye
eye more closed
dilated conjunctival blood vessels - looks redder
what is a comitant (non paralytic) strabismus?
misalignment all gaze directions
congenital/development imbalance extraocular muscle tone / length
what is an incomitant strabismus?
misalignment varies in direction of gaze
due to specific muscles/nerve dysfunction
paralytic: CN III, IV, VI
Vestibular / VIII
Restrictive - mechanical restriction
