Exam VII Flashcards
What comprises the telencephalon?
cerebral cortex, subcortical white matter, basal ganglia
Lobes in each cortex
frontal, parietal, occipital, temoral, insula, & “limbic”
Layers of the cerebral cortex
molecular, external granule, external pyramidal, internal granule, internal pyramidal, multiform
Supragranular layer
layers 1-4, primarily receive sensory information. Layers 1-3 non-specific, layer 4 = specific
Layers 5 & 3 of cerebral cortex contain…
cell bodies of motor neurons (pyramidal neurons) whose axons constitute the corticospinal, corticobulbar and corticopontine tracts.
Major sulci/fissures
lateral sylvian fissure, central sulcus, interhemispheric (longitudinal) fissure, transverse cerebral fissure.
Frontal lobe sulci
precentral (anterior to precentral gyrus), superior (superior frontal gyrus from middle frontal gyrus), inferior (middle frontal from inferior frontal gyrus)
Frontal lobe gyri/areas
pre-central gyrus, anterior aspect of paracentral lobule (brodmann area 4) = primary motor area
premotor area (Brodman area 6) = directs the primary motor area in execution of skilled motor activities
Primary motor area
Frontal lobe. Origin of corticospinal, corticobulbar, & corticopontine neurons which innervate SC, BS & pontine nuclei LMN’s
Premotor area
Frontal lobe. directs movement and planning of movements.
Supplementary motor area
involved in planning and initiation of movement
Broca’s motor speech area
(Frontal lobe # 44/45) 95% in left hemisphere Lesion = expressive aphasia (non-fluent aphasia)
Frontal eye field
Frontal lobe. posterior medial frontal gyrus, causes voluntary conjugate CL eye movements.
Cortical control of voluntary horizontal gaze�
Frontal eye fields –> axons cross brainstem & innervate CL abducens neurons, lateral rectus and internuclear neurons (MLF –> CL medial rectus). Right frontal eye field causes eyes to rotate to the left.
Lesion to frontal eye fiels
Deviation of eyes ipsilateral to lesion d/t opposite pathway’s tonic input still being intact
Frontal lobe: Brodmans areas 9. 10. 11. 12
judgement, rational thinking, projection into the future, social behavior and motivation.
What is located in the inferior surface of the frontal lobe?
oribital gyrus, and gyrus rectus: personality, emotions, and behavior.
Sulci of the Parietal lobe
post central (posterior to post-central gyrus), interparietal (separates the supraparietal lobule from the infraparietal lobule)
Areas of parietal lobe
Superior parietal lobule, Inferior parietal lobule, precuneus, paracental lobule, post-central gyrus
Superior parietal lobule
Brodmann areas 5,7: sensory associational cortex.
Astereoagnosis - w/o 3D knowledge
Inferior parietal lobule
supramarginal (40) and angular (39) gyri: interpretation of written and spoken language
Supramarginal gyrus
integrates kinesthetic memories with auditory commands. Lesion = ideomotor apraxia
Angular gyrus
integrates visual, auditory, & tactile information. Damage = inability to read and write (alexia/agraphia)
Precuneus
medial surface, sensory associational area.
Paracentral lobule (posterior region)
Part of primary sensory cortex, receives sensory input from most of the CL LE.
Postcentral gyrus
Brodmans areas 3,1, & 2. 1st somesthetic area (primary sensory cortex). Identifies the location of stimulus and the size and shape of objects.
Homunculus
map of the body determined by recording responses from awake individuals during surgery in which different areas are electrically stimulated, & stimulating areas in the body and recording from the cortex.
Sulci of the temporal lobe
Superior (separates the superior temporal gyrus from middle temporal gyrus) and inferior (separates the middle temporal gyrus from the inferior temporal gyrus)
Areas/gyri of temporal lobe
superior temporal gyrus, inferior surface of temporal lobe
Superior temporal gyrus
primary auditory area on superior surface (41/42), auditory associational area i.e. Wernickes area (22)
Lesion to Wernickes area
receptive aphasia (auditoru agnosia or FLUENT aphasia)
Inferior surface of temporal lobe
occipitotemporal gyrus (visual association), parahippocampal gyrus/uncus (limbic system)
Functions of the sense of smell
increase enjoyment and desire for food, increases awareness of potentially harmful substance,s, communication (pheromones)
What can anosmia and hyposmia be caused by?
nasal congestion, degeneration of olfactory epithelium from chronic exposure to toxic odorants, head trauma which damages axons of olfactory neurons as they travel through the cribriform plate, tumors in the anterior cranial fossa (may be initial symptom)
Seizures originating near the uncus may be preceded by the perception of unpleasant odors (uncinate seizures)
Decreased sense of smell –> malnutrition –> decreased energy for therapy
Insular lobe (island of Reil)
posterior wall of lateral sylvian fissure. Involved with localization of pain, though to provide emotionally relevant context to sensory experiences.
Occipital lobe sulci
parieto-occipital, calcarine
Occipital lobe gyri
cuneus gyrus, lingual gyrus, brodmann area 17, brodmann area 18 & 19
Cuneus gyrus
Occipital lobe: Right sees inferior L visual field
Lingual gyrus
Occipital lobe: R sees superior L visual field
Brodmann area # 17
primary visual cortex - located in the walls of the calcarine sulcus & adjacent areas of cuneus & lingual gyri
Brodmann areas 18 & 19
Visual association
Optic nerve pathway
receptors –> bipolar cells –> ganglion cells –> optic nerve –> optic chiasm –> optic tract –> lateral geniculate nucleus –> pretectal area/superior colliculus –> occipital cortex (cuneus and lingual gyri)
Common eye disorders
monocular blindness, bitemporal hemianopsia, homonymous hemianopsia, macular degeneration, cataracts, papilledema, glaucoma
pathway for left visual field
located in the walls of the calcarine sulcus & adjacent areas of cuneus & lingual gyri
R temporal retina → optic nerve to R optic tract → R lateral geniculate nucleus → R cuneus/lingual gyri
Lesions in visual field
Monocular blindness, bitemporal hemoanopsia (tunnel vision) (optic chiasm lesion), Homonymous hemianopsia (optic tract lesion)
Homonymous hemianopsia
right homonymous hemianopsia = loss of rt visual field
Macular Degeneration
degeneration of centrally located photoreceptros, loss of central vision with increasing difficulty with reading, watching TV or recognizing faces
Cataracts
deterioration of the lens, gradual loss of vision with central vision lost first. Difficulty reading, needs to turn head often to locate items in the environment
Papilledema
papilla in the termination of the subarachnoid space at the beginning of the optic nerve, increased subarachnoid pressure can cause swelling in the optic disc
Glaucoma
increased intraocular pressure which can compress and cause degeneration of the retina –> blindness
Sympathetic innervation to the eye
pupilalary dilator muscles in the iris, muellers muscle in the upper eyelid, damaged in Horner’s syndrome
What makes a hemisphere “dominant”
the hemisphere with language comprehension and production. left in 95% R handed and 75% left handed people
Left hemisphere function
Handwriting Calculation Intelligence Rationalization Language comprehension Articulation
Right hemisphere function
Drawing/artistic skills Recognition of faces Intuition Gestures Spatial awareness and shapes of objects
Upper motor neuron
All the neurons that lead to innervation of the alpha and gamma motor neurons
UMN lesion
CVA, MS, AMLS, Tumors, TBI, SCI
Signs/Sx of UMN lesion
Spasticity, myoplasticity, hyperreflexia, no/minimal muscle atrophy, fibrillations, (+) babinski (corticospinal tract dysfunction)
Spasticity
NM overactivity d/t: hyperreflexia - reduced higher level inhibitory control, increased sensitivity to muscle stretch reflex. & UMN hyperactivity of reticulospinal and vestibulospinal tracts, clasped knife phenomena
Myoplasticity
adaptive muscular changes that occur in UMN diseases and in normally innervated but immobilized joints - increased # of weak actin/myosin bonds, selective atrophy of type I & II fibers, contracture
Modified Ashworth Scale: 0
no increase in tone -This scale does not differentiate between spasticity and contracture
Modified Ashworth Scale: 1
Slight increase tone with minimal resistance at end ROM
Modified Ashworth Scale: 1+
Slight increase tone with minimal resistance less than half of ROM
Modified Ashworth Scale: 2
More marked increase tone through most ROM; affected part easily moved
Modified Ashworth Scale: 3
Considerable increase tone; PROM difficult throughout ROM
Modified Ashworth Scale: 4
Rigid in flexion and extension
