Neuroscience - Block 3 - Neuro Pathologies - Part 2

davidwurbel7's version from 2016-04-06 17:02


Question Answer
Ptosis, mydriasis, diplopia. Eye is ‘down and out’ due to unopposed actions of lateral rectus and superior obliqueDamage to CN III
Lack of abduction, medial deviation at rest (strabismus). Horizontal diplopia only, when looking in direction of lesionDamage to CN VI
Damage to abducens nucleus may only affect the lateral rectus itself. However, it may also affect the connections of abducens nucleus to the contralateral CN III subnucleusOne and a Half Syndrome
A lesion here prevents the eyes from looking to the rightLeft Frontal Eye Field Lesion or Right Nuclear CN VI and MLF Lesion
A lesion here prevents the eyes from looking to the leftRight Frontal Eye Field Lesion or Left Nuclear CN VI and MLF Lesion
Damage to this can cause paralysis of vertical (upward) gazeRostral MLF
Destruction of frontal eye field results in conjugate deviation of the eyes towards the lesioned side, and inability of the eyes to look voluntarily to the opposite sideSupranuclear Ophthalmoplegia
Disruption or demyelination of the medial longitudinal fasciculus interrupts connections between CN III, IV, VI, and VIIIMLF Syndrome
Damage here results in decreased eye movements towards the opposite side (i.e. left side damage, decreased eye movements towards right), and neglectParietal Eye Field
Patient will tilt head forward to compensate for difficulties in depressing the eyeVertical Diplopia
Patient will tilt head to the side to compensate for rotational problems. Head tilt is towards a nucleus, and away from a nerve, lesion. Or stated differently, head tilt is always away from affected eyeTorsional Diplopia
Bilateral damage of lingual gyrusUpper Altitudinal Hemianopia
Upper altitudinal hemianopia is caused by bilateral damage to thisLingual Gyrus
Bilateral damage of cuneus gyrusLower Altitudinal Hemianopia
Lower altitudinal hemianopia is caused by bilateral damage to thisCuneus Gyrus
Paralysis of horizontal gazeFrontal Eye Fields (Brodman's Area 8).
Paralysis of vertical gazePontine Tegmentum
Lesions of this will affect consciousness. The effects depend where the lesion isARAS
Loss of consciousnessMidbrain Lesions
Constant wakefulnessPons lesions
5-HT depletionInsomnia
Produces coma or slow-wave sleep as a result of a disconnection of the ARAS from cortexMidbrainTransection
ARAS functions normally. Paralysis below the level of the injuryCord Transection
Constant wakefulness. ARAS is unable to induce sleepMidpontine Transection
Damage to axons in cerebral, brain stem, and possibly cerebellar white matter resulting from major head injury, involving rapid acceleration /deceleration along with rotational forces. ‘Shearing’ forces, i.e. the brain is ‘twisted’ and nerve fibers (white matter) is torn/damagedDiffuse Axonal Injury
Chronic disease characterized by severe bilateral stenosis or occlusion of the arteries around the Circle of Willis with prominent collateral circulationMoya Moya Disease

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