Unit 4: Cerebrum pg 138 - 144 Flashcards
Medullary center of the cerebrum consists of what kind of fibers?
- Projection
- Commissaral
- Association
What kind of projection fibers are in the cerebrum?
- Corticopetal fibers (afferents to cerebral cortex)
- Corticofugal fibers (efferent of cortex)
Commissar also fibers
Connect an area of cortex in one hemi with similar area in opposite hemi
Association fibers
Connect cortical areas with single hemi
Cigulum
Associative fiber bundle of lambic lobe; deep inside cingulate gyrus
Superior longitudinal fasciculus (arcuate fasciculus)
Associative fiber bundle that provides connections between cortical areas of frontal, parietal, occipital, temporal and insular lobes
Connects motor and sensory language areas in “dominant” hemisphere
U-fibers
Short association fibers that connect adjacent gyri within same hemi
Neurons of cerebral cortex (3 types or names or neurons)
Pyramidal cells (unique to cerebral cortex)
Stellate
Fusiform
Archicortex
3 layered cortex
Paleocortex
5 layered cortex
Neocortex
90% of human cortex is comprised of 6 histological layers
Layers of neocortex from outermost to innermost layer:
[ outermost ] I. Molecular layer II. External granular layer III. External pyramidal layer IV. Internal granular layer V. Internal pyramidal layer VI. Multiform (fusiform) layer [ innermost — closest to medullary center ]
Afferent fibers synapse in what neocortex layers?
I-IV
Afferent fibers from sensory nuclei of thalamus terminate in which layer of the neocortex?
IV
This is large — 1˚ Sensory cortex. Brodmann map areas 1, 2, 3, 17, 41, 42
What layers of the neocortex are efferent fibers?
Layers V and VI
These are large areas. Brodmann map 4, 6, 8
Where are the 1˚ sensory cortex found on Brodmann map?
1, 2, 3, 17, 41, 42
Where are the motor cortex found in Brodmann map?
4, 6, 8
What layers of the cortex do efferent (corticofugal) fibers synapse?
V and VI
Corticofugal fibers =
Efferent
Corticopetal fibers =
Afferent
What layers of the cortex do afferent (corticopetal) fibers synapse?
IV
What are three important landmarks in the inferior frontal gyrus? (List from most anterior to most Posterior)
Orbital portion
Triangular portion
Opercular portion
The prefrontal cortex is involved with what activities?
Abstract thinking Judgment Foresight Behavior Attention Motivation Decision making
Patients with bilateral damage to prefrontal cortex experience profound changes in personality and behavior including:
Difficulty making good decisions
Neglect in setting goals or planning for the future
Lack of responsibility in personal affairs
Lack of good judgment
Dishonesty
(Sometimes) decrease in intellect
*example of Phineas Gage
Lesion of left hemisphere
Aphasia
Non-dominant hemisphere (right) is used for
3-dimensional/spatial relationships, prosody of speech
Broca’s Language Area corresponds to what Brodmann’s map area
44, 45
Broca’s area relates to what motor activity?
Muscles used in language expression
Includes: written, spoken, signed language
Motor/expressive language area also known as
Broca’s area
Sensory/receptive language areas:
Wernicke’s area
Where is wernicke’s area located?
Posterior part of superior temporal gyrus AND angular gyrus fo inferior parietal lobule
Disturbances of language areas =
Aphasia (negative speech)
Broca’s area lesion can lead to
Motor/expressive aphasia (Broca’s aphasia)
Motor/expressive aphasia (Broca’s aphasia) symptoms:
- impaired ability to speak fluently
- hesitant, disordered speech
- often present agraphia
- no impairment or comprehension
Lesion of wernicke’s area =
Sensory/receptive aphasia (Wernicke’s aphasia)
Sensory/receptive aphasia (Wernicke’s aphasia) symptoms
- Inability to comprehend spoken/signed language
- Inability to read = alexia: can see letters/symbols but not understand the meaning of symbols
- can hear sound but not understand meaning
- can spontaneously speak (if Broca’s unaffected) without understanding what they are saying
Alexia
Inability to read
Lesion of the arcuate fasciculus that connects wernike’s and broca’s is called
Conduction aphasia
Conduction aphasia symptoms
- language comprehension intact
- generally good language production with some errors
- difficulty repeating spoken language, reading aloud, responding to questions, copying written language
