Week 9 Flashcards
(16 cards)
What is disconnection and disconnection syndrome?
Disconnection is cutting off cerebral connection ( leads to dysfunction)
Disconnection syndrome is a collection of neurological symptoms via lesions to associational or commissural nerve fibres
What is the function of the corpus callosum?
a broad band of nerve fibers that connects the left and right hemispheres of the brain that ensures both sides of the brain can communicate and send signals to each other
What are the three major types of neural fiber pathways that connect the neocortex?
Association, projection, and commissural fibres.
What are the functions of association, projection, and commissural pathways?
Association pathway are long fibres that connect distant neocortical areas and also short subcortical, U-shaped fibres that connect adjacent neocortical areas
Projection pathways are ascending fibres from lower brain centers to the neocortex, such as projections from the thalamus and descending fibers from the neocortex to the brainstem and the spinal cord.
Commissural pathways connect the two hemispheres and include the corpus callosum, interior commissure, and hippocampal commissures.
When is commissurotomy used for therapeutic purposes?
Commissurotomy (split-brain) procedure can be used as an adjunct to anticonvulsants for the control of seizures in patients whose epilepsy cannot be relieved by anticonvulsants alone.
What happens to vision when the commissures are disconnected?
Visual information from one eye can project only to the ipsilateral hemisphere
If the ipsilateral hemisphere contains an intact amygdala, the circuit for activating species- typical behavior is _______ and behavior will be ________ and if the amygdala in the hemisphere is not intact, visual information will be ________ from motor systems and _____ elicit species-typical behavior.
a) Complete b) incomplete c) atypical d) typical e) disconnected g) cannot f) can
answer : a, d, e, g
Brain networks can be extracted using imaging data from?
EEG
CT
DTI
DTI (diffusion tensor imaging tractography)
Under which three conditions would the hemisphere become completely separated?
In humans, the interhemispheric fibers are sometimes resected as a therapy for epilepsy (commissurotomy)
Second, people are born with congenitally reduced or absent inter-hemispheric connections, or callosal agenesis (a condition called calluses agenesis).
Third. in animals, disconnections are performed to trace functional systems, to model human symptoms, and to answer basic questions about interhemispheric development.
Name the neurological syndromes that arises from inter or intra-hemispheric disconnections
Alzheimer’s disease
Define the terms Ipsilateral, Contralateral, and Bilateral
Bilateral
something that occurs on both hemispheres of the brain.
Contralateral
one side of the body sends information to the opposite side of the body
Ipsilateral
one side sends information the same side
What are the white matter tracts?
These are collections of myelinated axons extending from the cell bodies.
Damage to the right parietal lobe can lead to _________
a. Hemispatial neglect
b. Contralateral neglect
c. Bilateral neglect
d. Sensory neglect
B
The brain has ____ control of the facial muscle
a. Ipsilateral
b. Contralateral
c. Bilateral
c. Bilateral
T/F: After surgery, split-brain patients have impaired intellect and motivation
False
T/F: Normally, a split-brain patient should be able to name an object flashed to the left visual field
False
