Cerebellum, Taste, GVA Clinical Application

Where is the lesion if a dog presents with hypermetria, intention tremors that disappear at rest, and a wide-based stance?

Cerebellum

What system is affected in a cat with normal strength but severe ataxia and dysmetria?

Cerebellar coordination pathways (not UMN or LMN)

What is the most likely lesion if an animal overshoots food when reaching but is mentally alert?

Cerebellar cortex

Loss of which cerebellar cell type leads to intention tremors and ataxia?

Purkinje cells

What neurotransmitter deficiency is most associated with cerebellar dysfunction?

GABA

What condition is most likely in a young animal with congenital ataxia that is non-progressive?

Cerebellar hypoplasia

Why do cerebellar tremors disappear at rest?

Cerebellum modulates voluntary movement, not involuntary activity

What deficit would a lesion of the fastigial nucleus most likely cause?

Impaired balance, posture, and eye movements

Which movements would be affected by a lesion of the interposital nucleus?

Proximal and distal limb movements

What deficit results from damage to the dentate nucleus?

Loss of skilled and precise voluntary movements

What information is disrupted by a lesion of the caudal cerebellar peduncle?

Proprioceptive afferent input from spinal cord and medulla

Does a cerebellar lesion cause ipsilateral or contralateral deficits?

Ipsilateral deficits

Which cerebellar region is likely involved in a dog presenting with head tilt, nystagmus, and ataxia?

Flocculonodular lobe (vestibulocerebellum)

What effect does a lesion affecting Purkinje cells have on brainstem nuclei?

Loss of inhibitory control leading to dysregulated motor output

Which cerebellar zone is affected in an animal with truncal sway and loss of equilibrium of the entire body?

Medial zone (vermis)

Which cerebellar zone is affected in a horse with poor regulation of skilled limb movement but normal truncal posture?

Lateral zone

Which structure is involved if a dog presents with vomiting due to toxin exposure that bypasses the BBB?

Area postrema

Why is the area postrema clinically important?

It lacks a blood-brain barrier and detects blood-borne toxins

Why does a cow undergoing rumenotomy show no signs of pain?

Visceral afferents do not convey sharp or localized pain

What type of afferent fibers are responsible for poorly localized abdominal pain in a dog?

General visceral afferents (GVA)

Which functions would a lesion in the nucleus tractus solitarius most affect?

Visceral sensory processing and autonomic reflexes

Which cranial nerve function is disrupted by a lesion affecting the nodose ganglion?

Vagus nerve visceral afferents

Which cranial nerve carries baroreceptor information from the carotid sinus?

Glossopharyngeal nerve (CN IX)

Which cranial nerve carries baroreceptor information from the aortic arch?

Vagus nerve (CN X)

What sensation is impaired by damage to the geniculate ganglion?

Facial nerve visceral sensation and taste

Which pathway is affected in a dog that has difficulty sensing fullness and visceral discomfort?

General visceral afferent pathway

Why does referred pain occur?

Visceral and somatic afferents enter the same spinal cord segments

Which nerve is involved in taste from the rostral two-thirds of the tongue?

Facial nerve (CN VII)

What indicates damage to the glossopharyngeal nerve (CN IX)?

Loss of taste from the caudal third of the tongue

Which nerve carries taste sensation from the larynx?

Vagus nerve (CN X)

What sensory modality may be affected in a dog with oral trauma that refuses food but has intact motor function?

Special visceral afferents (taste)

Damage to which receptor type suggests loss of sweet and umami taste?

G-protein coupled receptors

Dysfunction of which taste bud cell type suggests loss of salt taste?

Type I taste cells

Dysfunction of which taste bud cell type suggests loss of sour taste?

Type III taste cells

In which brainstem nucleus do taste fibers synapse?

Nucleus tractus solitarius (NTS)

What is the final cortical destination of taste sensation?

Insular cortex

What sensory system is evaluated in a patient who fails a two-bowl test?

Gustatory (taste) system