Neuroscience - Block 3 - Part 2

davidwurbel7's version from 2016-04-04 03:53


Brodmann's Areas

Question Answer
Brodmann’s Areas 1/2/3Primary Sensory
Brodmann’s Area 4Primary Motor
Brodmann’s Areas 45/46Broca's Area
Brodmann’s Areas 22/39/40Wernicke's Area
Brodmann’s Area 17Primary Vision
Brodmann’s Areas 18/19Visual Association
Brodmann’s Area 41Primary Auditory
Brodmann's Area 42Auditory Association
Brodmann’s Area 8Frontal Eye Field
Brodmann’s Areas 9-12 Prefrontal Cortex
Brodmann's Area 46Orbitofrontal
Brodmann's Area 47Dorsolateral
Brodmann’s Area 5, 7 Somatosensory Association Cortex
Brodmann’s Area 20 Inferior Temporal Gyri
Brodmann’s Area 21Middle Temporal Gyri
Brodmann’s Area 22 Superior Temporal Gyri
Brodmann’s Areas 23, 24, 29-33 Cingulate Gyrus
Brodmann's Area 18Secondary Vison
Brodmann's Area 6Secondary Motor
Brodmann's Area 9Tertiary Motor
Brodmann's Area 34Primary Olfactory
Brodmann's Area 37Unknown


Question Answer
Those that connect the two hemispheres. Corpus callosum, anterior commissure, posterior commissure, and fornixCommissural Fibers
Connections within the same hemisphere. Short connect adjacent gyri, long connect different lobesAssociation Fibers
Those fibers that descend to brainstem/spinal cordProjection Fibers
Connect anterior part of frontal lobeRostrum and Genu
Connects posterior part of frontal lobe, parietal lobes, and superior part of temporal lobeTrunk
Connects occipital lobesSplenium
Genu also known asForceps Minor
Splenium also known asForceps Major
Connects the pretectal nuclei (tectum), for pupillary light reflex. Lesion results in loss of consensual, but not direct, light responsePosterior Commissure
Connects the hippocampus with contralateral mammillary bodyFornix
Some olfactory axons cross here, also some spinothalamic axonsAnterior Commissure
Connects frontal, parietal, and occipital lobesSuperior Longitudinal Fasciculus
Connects Werneke to BrocaArcuate Fasciculus
Connects cingulate gyrus to other limbic structuresCingulum
Connect nearby gyriArcuate Fibers
If going from the cortex (motor)Corticofugal
If going to the cortex (sensory)Corticopetal
Corticobulbar, corticospinal, Corticofugal for extrapyramidal tracts and 3rd order neurons from VPL and VPM of thalamus
go through this part of the internal capsule
Posterior Limb of the Internal Capsule
Corticostriate and corticopontine go through this part of the internal capsuleAnterior Limb of the Internal Capsule
Comprises 90% of the cerebral cortex; generally, almost interchangeable with cerebral cortexNeocortex
Part of the cortex that has six layersNeocortex
Subdivided into - Paleocortex (olfactory system) and Archicortex (hippocampus and related structures)Allocortex
Part of the cortex that has three layerAllocortex

Cortex Structural Organization

Question Answer
External pyramidal layer and ganglionic layer (internal pyramidal layer) are these types of layersOutput Layers
External granular layer and internal granular layer are these types of layersInput Layer
This layer contains horizontal neuronsMolecular Layer (I)
Small, multipolar cellsCells of Martinotti
Huge pyramidal cells. Only found in motor cortexBetz cells
Non specific afferents from intralaminar nucleus of thalamus and brainstem areasMolecular layer (I)
Receives callosal and association afferentsExternal granule layer (II):
Association and commissural fibers originate hereExternal pyramidal layer (III)
Receives afferents from thalamic nuclei, ie. this is the termination point of thalamic relay neurons (specifically VPL and VPM for post central gyrus, LGN for visual cortex)Internal Granule Layer (IV)
Origin of corticospinal, corticobulbar, and corticostriatal fibersInternal pyramidal layer (V)
Also gives rise to some association and commissural fibers; most corticothalamic fibers originate hereMultiform layer (VI)
This layer is responsible for cortical consciousnessMolecular Layer (I)
This part of the brain is responsible for turning on cortical consciousnessReticular Formation of the Midbrain
This part of the brain is responsible for turning off the reticular formationReticular Formation of the Pons
Granular layers (2, 4) are very big, but pyramidal layers (3, 5) are not. This is the typical arrangement in major sensory areas (like postcentral gyrus)Granular Brain Tissue
Pyramidal layers (3, 5) are very big, but granular layers (2, 4) are not. Obvious example is precentral gyrusAgranular Brain Tissue
The functional units of the cortex arranged in vertical units of 300-500 neuronsCortex Column
Is the anteromedial portion of the premotor area (Brodmann 6)Supplementary Motor Area
Almost always the left (Because the world is 90%+ right handed). Almost all right handers are left hemisphere dominant. A little more variability exists in left handers. Dominant hemisphere has language, so Broca’s and Wernicke’s on dominant hemisphere onlyDominant Hemisphere
The formation of the idea of a complex purposeful motor act. This requires proper functioning of the dominant parietal lobe. Proper execution of the act requires intact frontal lobe functionPraxis
Inability to sustain the intent or desire the complete a series of movementApraxis
Executive function regulates and directs cognitive processes such as decision making, problem solving, learning, reasoning and strategic thinking and moderating correct social behaviorPrefrontal Cortex
This is the anterior 2/3 of the frontal lobePrefrontal Cortex
Loss of desire/ability to perform voluntary actionsAbulia
Involved in planning of movement, i.e. ‘integration of sensory and motor information for the performance of an action. That’s basically the definition for PraxisPremotor Cortex
Ask the patient to put their arms out straight, supinated. (Eyes closed). The affected arm will slowly pronate and moves away.Pronator Drift
Damage to this area on one side leads to hemianopia with macular sparing. Bilateral damage could cause other visual field deficitsArea 17
Damage to this area possible visual hallucinationsAreas 18, 19
Layer IMolecular Layer
Layer IIExternal Granular Layer
Layer IIIExternal Pyramidal Layer
Layer IVInternal Granular Layer
Layer VInternal Pyramidal Layer (Ganglionic Layer)
Layer VIMultiform Layer
Molecular LayerLayer I
External Granular LayerLayer II
External Pyramidal LayerLayer III
Internal Granular LayerLayer IV
Internal Pyramidal Layer (Ganglionic Layer)Layer V
Multiform LayerLayer VI

Headache and Migraine

Question Answer
Headaches not due to other causesPrimary Headache
Headaches due to tumor or other causeSecondary Headache
Migraine with auraClassic Migraine
Migraine without auraCommon Migraine
Set of symptoms that occur prior to the migraineAura
Subtle symptoms occuring 1-2 days before the attack; constipation, depression, drowsiness, diarrhea, food cravings, excitability or irritabilityProdrome
Visual most common, can also be sensory, motor, or verbal (dysphasic aura). ‘Scintillating scotoma’ is most common. ‘Fortification spectrum’ is one type of this (so named because it looks like a medieval fortress). 10-30 minutesAura
Can last 4-72 hoursAttack
1-2 days, feeling drained/exhaustedPostdrome

Brain Tumors

Question Answer
Incidence 8 cases/100,000. Rarely metastasize. Adults supratentorial; pediatrics infratentorialPrimary Brain Tumor
Astrocytoma (all grades), Ependymal (ependymoma) and Oligodendroglioma are examples of these tumorsGlial Tumors
Neuroblastoma, pinealoma, ganglioneuroma, Meningeal (meningioma), Pituitary adenoma, Craniopharyngioma, chordoma, colloid cyst, CNS lymphoma are example of these tumorsNon-glial Tumors
20% primary intracranial neoplasms. Life expectancy approximates 5 years, worse prognosis if transformation to glioblastoma multiforme occurs. Four grades...with grade IV being GBMAstrocytoma
Tumor crosses the corpus callosumButterfly Tumor
5% of glial tumors. Mostly middle aged, F>M. Usually present with seizures frontal lobe. Fried egg appearanceOligodendroglioma
60% to 75% are located in the spaces of the posterior fossa, may also be found within the spinal cord or in the region of the cauda equina. Seen most frequently in children or young adults. Lesions in supratentorial locations may produce signs and symptoms reflecting their location, for example, hydrocephalus in the case of blocked CSF flow or seizure activity. Lesions in infratentorial locations frequently cause nausea and vomiting, headache, other signs and symptoms related to hydrocephalus, and cranial nerve signs and symptoms indicative of compression of, or tumor infiltration into, the brainstemEpendymoma
More often occur in the fourth ventricle (50% to 60%) but may also be found in the lateral and third ventricles. Present with signs and symptoms of increased intracranial pressure (headache, nausea, vomiting, lethargy), hydrocephalus (excessive production of CSF), or deficits of eye movement due to pressure on the roots of III, IV or VIChoroid Plexus Tumors
Second most common primary intracranial neoplasm (account for 20%). Tumor is external to the brain (displaces brain tissue). More common in women than men (3:1). Most often occurs after the age of 40. Originates in the arachnoidal cells. Considered a benign, slowly growing tumor. Can erode contiguous bone. Can be seen in association with NF-2 (neurofibromatosis). Can be induced by radiation therapyMeningioma
Tumor derived from Schwann cells. Acoustic neuromas may cause tinnitus, deafness, compression of other CNs. Surgery usually results in cure (RT also used, can observe) NF2 (neurofibromatosis) is characterized by bilateral acoustic neuromas (autosomal dominant syndrome)Schwannoma (acoustic neuroma)
2% of primary brain tumors. Often young children. Suprasellar, calcify. Can cause hypothalamic problems, visual problems, hydrocephalusCraniopharyngioma
1% of primary brain tumors. Present with hydrocephalus and brainstem compression. Parinaud’s syndrome. Elevated human chorionic gonadotropin (HCG) or alpha fetoproteinPinealoma
Can acutely obstruct 3rd ventricle when leaning forwardColloid Cyst
Second most common pediatric BT after gliomas, but can affect adults. Affects cerebellum (hemispheres and vermis). Can get vermal symptoms, acute obstructive hydrocephalus. SeedMedulloblastoma
Often syndromic and hereditary (associated with von Hippel-Lindau Syndrome). Can secrete erythropoietin and induce polycythemia. Highly vascularized. Seed. Originates in the cerebellum. Treated by EmbolizationHemangioblastoma
Primary cerebral lymphoma – HIV, immunosuppressive related. Steroid sensitive. Chemo (methotrexate based)+/- XRT (no surgery except biopsy). Cognitive impairment. Poor outcomePrimary Cerebral Lymphoma
Lesions usually multiple. Come from Breast (20%), Melanoma, Kidney, GI, Thyroid, Lung (40%), Ovarian, TesticularBrain Metastes
Between the meninges and spine bonesExtradural
Within meningesIntradural Extramedullary
Inside the cordIntramedullary
The most common form of herniation. Presence does not necessarily lead to severe clinical symptomatology. Present clinically as headache and as the herniation progresses, contralateral leg weaknessSubfalcine Herniation
Subset of transtentorial herniations. The medial part of the temporal lobe, is displaced into the suprasellar cistern. As the herniation progresses, pressure on the midbrain, producing contralateral hemiparesisUncal Herniation
The pupils become irregular and then fixed at midposition. Oculocephalic movements become more difficult to elicit. Extensor posturing appears spontaneously. Motor tone is increased and plantar responses are extensorCentral Herniation
The cerebellar tonsils move downward through the foramen magnum causing compression of the medulla oblongata and upper cervical spinal cord. May cause cardiac and respiratory dysfunctionTonsillar Herniation

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