NE Stephen's High Yield Exam 2 Deck Flashcards
What lobe is responsible for Emotion, motivation, personality, initiative?
Frontal lobe
What cortex for tactile and proprioception information?
Primary somatosensory cortex
What lobe is responsible for processing complex aspects of learning, memory and emotion?
Limbic lobe
Includes Cingulate gyrus & Parahippocampal gyrus
What lobe is responsible for taste processing?
Insular Lobe
What are the three ascending tracts in the SC and what information do they relay?
o Posterior columns
▪ Convey ipsilateral proprioceptive, tactile and vibratory information from the body (not the face) (ipsi before decussating in medulla
o Spinocerebellar tracts
▪ Information relays to cerebellum, thalamus, and motor cortex to influence efficiency of motor activity
o Anterolateral System
▪ Relays pain and temperature and non-discriminative touch from the body (not the face)
What are the three descending tracts in the SC and what actions do they elicit?
o Corticospinal tract
▪ Controls voluntary, fine movements of the musculature
o Vestibulospinal tract
▪ Influence motor neurons innervating primarily axial and neck musculature
o Rubrospinal fibers
▪ Excite flexor motor neurons and inhibit extensor motor neurons
Blood plasma vs. CSF concentrations of ions and substances
Equal concentrations: Na+ and HCO3
CSF higher: Mg2+, Cl-, and CO2
CSF lower: K+, Ca2+, protein, and glucose
Flow of CSF
o Lateral ventricles🡪 interventricular foramen🡪 third ventricle🡪 cerebral aqueduct🡪 fourth ventricle🡪 Cisterna magna(median aperture) and Subarachnoid space (lateral aperture)
o Ends w/ absorption by arachnoid granulations/arachnoid villi (bulk flow & pinocytosis)
What are the circumventricular organs?
Posterior pituitary aka Neurohypophysis (neural tissue)
Releases hormones into blood
Area Postrema (Close to surface of medulla) Vomiting
OVLT/Subfornical organ
Control of the body water/thirst/blood volume control. Need access to blood to detect osmolarity levels.
Lateral Spinothalamic Tract (LSTT)
Spinothalamic = ALS
Contralateral pain/temp 2 sensory dermatomes below lesion
Lateral Corticospinal Tract (LCST)
Contralateral Spastic paralysis Dorsal root (DR)
- because it is BEFORE the decussation (at inferior medulla- pyramids). CST lesion would be ipsilateral if it was AFTER the decussation.
also hyperreflexia, hypertonia, Babinski sign, clonus, and disuse atrophy.
Fasc. Gracilis
Ipsilateral Proprioception/2-pt lower limb
Fasc. Cuneatus
Ipsilateral Proprioception/2-pt upper limb
Anterior White Commissure (AWC)
Bilateral Pain/temp anesthesia
(in shoulders/upper limb - may be part of syringomyelia)
Destruction of the anterior white commissure results in a bilateral loss of pain
and temperature sensations to the upper extremities (“yoke-like” anesthesia).
Anterior Horn (AH)
Ipsilateral LMN paralysis
LMN paralysis results from the destruction of the lower motor neurons or the axons of one or more of the cranial or spinal motor nuclei. LMN paralysis is characterized by flaccid paralysis, areflexia. atonia, atrophy and fasciculations
ALS
LMN and UMN paralysis
Corticospinal Tract Lesion above decussation
Contralateral Spastic Hemiplegia
Note: Corticospinal tract are UMN. Lesions also lead to hyperreflexia, hypertonia, paralysis & disuse atrophy.
The CST conveys descending motor information from the motor cortex. In the midbrain the CST comprises the middle 3/5’s of the crus cerebri. In the pons it is split into numerous fascicles by the pontine nuclei and pontocerebellar fibers. In the medulla, the CST forms the pyramids which partially decussate in the lower medulla. A unilateral lesion of the corticospinal tract is classically described as a contralateral spastic hemiplegia.
Medial Lemniscus
Contralateral Proprioceptive/2-pt tactile Hemianesthesia
The ML conveys proprioceptive, vibratory, and two-point tactile discriminative information from the opposite 1⁄2 of the body. At the level of the upper pons and midbrain the ML also contains fibers that convey taste information from the ipsilateral 1⁄2 of the tongue and pharynx.
Spinal Lemniscus
Contralateral Hemianalgesia (pain) & Hemianesthesia (sensory) (ONE SIDE OF BODY)
The SL conveys pain and temperature information from the opposite 1⁄2 of the body.
It is either lateral or posterolateral to the medial lemniscus.
Descending Tract of V
Ipsilateral Hemianalgesia : (FACE)
Alternating hemianalgesia
- Alternating hemianalgesia is due to a lesion of the descending tract of V and the spinal lemniscus. This pattern is part of CPA and Wallenberg syndromes, which are discussed in NE2.
Note: a lesion of V would result in complete anesthesia (FACE) and paralysis of the muscles of mastications.
The descending tract of V (trigeminal) conveys ipsilateral pain and temperature information from the face. It is located in the postero-lateral area of the medulla. The descending tract of V and the underlying descending nucleus of V are adjacent to the spinal lemniscus, which is slightly deeper. The descending tract and nucleus form the topographical structure called the trigeminal eminence. The fibers (primary axons) course just beneath the surface of the medulla and may be surgically cut for treatment of trigeminal neuralgia. The tract may be involved in Wallenberg and CPA syndromes
Vestibular nuclei
Ipsilateral Vestibular signs (nystagmus, vertigo, nausea, etc.)
Inferior cerebellar peduncle
Ipsilateral Cerebellar signs (+ Romberg, ataxia, dysmetria, etc.)
Tract NOT involved in spinal cord lesions?
Corticospinal tract (located above the pyramidal decussation). Forms:
Lateral corticospinal tract, which would be involved before it is in Spinal cord
Ventral Roots
Cause a LMN paralysis of associated motor dermatome: atonia, areflexia, fasciculation, and flaccid paralysis.
Corticobulbar Tract
*used for rehab post neurologic event (ex. stroke)
go to somatic motor, not parasympathetic.
so nerves like IV, VI
Supranuclear Facial Palsy
- any lesion above CN V
- needs to be intact for pt to listen and do the CN test. Pt needs to be attentive (tells go ahead and do action)
- Corticobulbar fibers originate in the head region of precentral gyrus,
- Course through the genu of the internal capsule and cerebral peduncles as uncrossed CBT
• Unilateral lesions of uncrossed CBT result in contralateral supranuclear facial palsy - Decussate in lower pons (between V and VI) and descend in the lower brainstem as crossed CBT
• Unilateral lesions below the decussation may result in some ipsilateral cranial nerve palsies.
a. Unilateral lesions of the corticobulbar fibers result in denervation of the brainstem motor nuclei below the level of the lesion. Some motor nuclei such as part of the facial motor nucleus receive fibers from both hemispheres and, therefore, are not affected by unilateral lesions of the head region of the motor cortex or CBT.
b. Unilateral lesions of the CBT above the level of the decussation results in a contralateral paralysis or paresis of the mimetic muscles of the lower half of the face (supranuclear facial palsy) as well as other cranial palsies due to denervation of the abducens nucleus, hypoglossal nucleus and the nucleus ambiguus. Lesions below the decussation result in ipsilateral cranial nerve palsies.
Lateral Lemniscus
Unilateral lesions of the lateral lemniscus, inferior colliculus, brachium of the inferior colliculus and medial geniculate body result in:
Bilateral diminution of hearing with a more prominent hearing loss in the contralateral ear.
The LL conveys bilateral auditory information, but predominantly information from the opposite ear. It is located in the lateral aspect of the brainstem
Medial longitudinal fasciculus
Internuclear Opthalmoplegia
Named for side of the non-adducting eye.
Patients with this syndrome have an abnormal response to horizontal gaze in the direction opposite the side of the lesion. Unilateral lesions of the MLF result in an impairment or loss of adduction (MR) of the ipsilateral eye, and a nystagmus of the abducting eye
Ex. Left INO
Patient shows normal horizontal gaze to the left. However, during horizontal gaze to the right, the left eye does not adduct and the right eye shows nystagmus.
MLF conveys vestibular influences from
the maculae utricle and saccule, and cristae ampullaris to the cranial nerves III, IV, VI;
and fibers for the oculomotor system.
- Critical in aligning gaze with head position.
Optic tract
Contralateral homonymous hemianopia. Unilateral lesions of the lateral geniculate body, complete optic radiations or visual cortex result in a contralateral homonymous hemianopsia. The figure shows a left homonymous hemianopia, which would indicate a lesion on right visual pathway, i.e., optic tract, lateral geniculate body or complete optic radiations.
