Gait/Mentation/some random horse reflexes

ataxia

paresis

what are the 2 major gait abnormalities we see with neurological disease?

general proprioceptive

vestibular

cerebellar

what are the 3 major types of ataxia?

afferent neurons

ascending proprioceptive tracts (cord and brainstem, goes to forebrain as well for consciousness)

what do we need for normal proprioception?

cerebellum

brainstem

parietal lobe of the forebrain

where do the ascending proprioceptive tracts go to?

dorsolateral white matter of the spinal cord

where are the ascending tracts found?

PNS (out on the limb) or CNS (brainstem, cord)

where can lesions be for there to be proprioceptive deficits?

-look at cranial nerves

if normal, lesion is in c1-c5 cord

how do you know if the lesions is of the cord or the brainstem in an animal with proprioceptive deficits?

UMNs

LMNs

muscles

what is required for normal motor function?

the brain

where are UMN cell bodies located?

brainstem

where are the majority of the UMN centers located?

ventral and lateral parts of white matter

-deeper than ascending tracts

where are descending tracts located?

no

if they are its mild

if an animal has a forebrain lesion, will they be paretic?

profoundly

if an animal has brainstem lesion, will they be paretic?

brainstem

spinal cord

where can lesions be located that will have an effect on motor function?

-look at cranial nerves, mentation

if normal, lesion is in c1-c5 cord

how do you localize a lesion (brainstem or cord) that is resulting in UMN paresis?

flaccid paresis/paralysis

hyporeflexia to areflexia

hypotonia to atonia

neurogenic atrophy

list the lower motor neuron signs

spastic paresis/paralysis

normoreflexia to hyperreflexia

normotonia to hypertonia

dissuse atrophy

list the upper motor neuron signs

level of awareness, arousal, consciousness

what is mentation

lesions of brain/forebrain

what leads to changes in mentation

alert and responsive (normal)

obtunded (depressed)

stuporous (semi-comatose)

comatose

what are some descriptors that clinicians use to describe mentation?

ARAS (in the brainstem)

where is the starting point for normal mentation?

cortical neurons found in the cerebral cortex of the forebrain

what are the target neurons for the ARAS?

reticular formation

where do all sensory systems "feed into"?

-relay into all cerebral cortex areas

and keeps the cortex "awake"

once the reticular formation neurons are activated, what do they do?

the lesion would reduce the amount of info that the cortical neurons are getting, so there would be a drop in mentation

How would a lesion in the brainstem affect the cortical neurons?

might not see any change in mentation

How would a lesion in the cerebral cortex affect mentation?

if its really big or diffuse (encephalitis)

when would a lesion in the cerebral cortex affect mentation

PLR and oculocephalic

which cranial nerve reflexes are the last to go when there is a lesion?

-tap skin in c1-c3 vertebral area

-should see ears flick forward

- efferent is facial nerve (CN VII)

Upper cervical reflex

-what do you do

-what should be the response

-what is the efferent nerve

- tap skin cranial to the shoulder

- contraction of brachiocephalicus m.

- afferent/efferent c3-c6 spinal nerves

Lower cervical reflex

-what do you do

- what should be the response

- what is the afferent/ efferent nerves

c1-c5 cord

what is the thoracolaryngeal reflex useful in evaluating?

slap test

another name for thoracolaryngeal reflex

-gently slap just caudal to the wither during expiration

- brief adduction of contralateral arytenoid cartilage

-afferent: dorsal branch of thoracic spinal nerve

-efferent: CN X

-How do you preform the thoracolaryngeal reflex

-what should be the response

-afferent

-efferent

-shine really bright light into eye

- animal should pull head and neck away and blink

-afferent: CN II

-efferent: cervical cord LMNs and CN VII (medulla)

Dazzle reflex

-how to preform

-what should be the response

- afferent nerve

-efferent