Lecture 7: Brain Wiring Flashcards
What are the 3 types of White Matter Tracts?
- Projection Type
- Association Type
- Commissural Type
Where is the Projection Type?
Extend vertically between higher and lower brain areas and spinal cord center and carry information between the cerebrum and the rest of the body
Where is the Association Type?
Connect different regions within the same hemisphere of the brain
Where is the Commissural Type?
Cross from one cerebral hemisphere to the other through bridges called commissures
What is Long Association Fibers?
Connect different lobes of a hemisphere to each other in the Association Type
What is Short Association Fibers?
Connect different gyri within a single lobe in the Association Type
What do Fluorescent Dyes do?
Identifying neuron dendritic and axonal processes by staining with fluorescent dyes and viewing under ultraviolet illumination
What are Intra-Hemispheric Tracts?
Tracts that remain within a single hemisphere
What are Inter-Hemispheric Tracts?
Tracts that cross from one hemisphere to another
What are Tracts?
Tracts are defined in the brain as bundles of myelinated axons that carry information from one brain another distal region
What is the Superior Longitudinal Fasciculus? (SLF)
A long, bi-directional bundle of axons connecting distal regions of the ipsilateral cortex, including frontal, occipital, parital, and temporal lobes
The anterior extreme consists of white matter radiations in the frontal libe
The posterior extreme consists of white matter radiations in the posterior parietal
What are the 4 Main Divisions of the SLF?
SLF I
SLF II
SLF III
Arcuate Fasciculus (AF)
What is SLF I?
Dorsal component and originates in the superior and medial parietal cortex, passes around the cingulate sulcus, and terminates in the dorsal and medial frontal lobe (BA 6, 8, and 9) and the supplementary motor cortex (MII)
What is SLF II?
Middle component. It originates in the caudal-inferior parietal cortex and terminates in the dorsolateral prefrontal cortex (BA 6, 8, and 46)
What is SLF III?
Ventral Component. And originates in the supramarginal gyrus of the inferior parietal lobe and terminates in the ventral premotor and prefrontal cortex (BA 6, 44, and 46)
What is Arcuate Fasciculus (AF)?
Originates in the caudal superior temporal gyrus superior temporal sulcus and passes next to SLF II axons around the Sylvian fissure to terminate in the dorsal prefrontal cortex (BA 8, 46)
What is the Function of SLF I?
Aids in regulating motor beahviour (e.g seslecting amongst completeing tasks)
What is the Function of SLF II?
Aids in the selection and retrieval of spatial information to focus spatial attention
What is the Function of SLF III?
Aids in the transfer of somatosensory information (including speech articulation)
What is the Function of Arcuate Fasciculus?
Associated with transmission of auditory information between cortical areas associated with language comprehension
What are the Long Intra-Hemispheric Tracts?
Emanating from the occipital-paretal region: The fronto-occipital fasciculus
Emanating from the temporal lobe: the uncinate fasciculus
Emanating from the occipital-temporal region: The inferior longitudinal fasciculus
Emanating from the cingulate gyrus: The cingulum bundle
What is the Uncinate Fasciculus associated with?
Play some role in learning and memory
Damages: It also affects name retrieval, personality changes, and social-emotional problems
What is the Inferior Fronto-Occipita Fasciculus (IFOF) associated with?
Associated with semantic language processing and goal oriented behavior
What are the 6 Brain Commissures Crossing the Midline?
Corpus Callosum
Anterior Commissure
Hippocampal Commissure
Habenular Commissure
Posterior Commissure
Supraoptic Commissure
What is the difference between Structural Connectivity vs. Functional Interdependence?
Structural Connectivity: What neurons connect to
Functional Interdependence: The degree to which changes in the neural activity of one brain region result in associated changes in the neural activity of another region
What is the Default Mode Network?
A brain network who elements are active when an individual is awake and at rest and focused internally oriented tasks such as day dreaming, envisioning the future, etc…
What is Dorsal Attention Network?
A brain network activated by voluntary orientation of attention and reorientation to an unexpected visual event
What is Ventral Attention Network?
Large scale brain network that activates when an unexpected event occurs
What is Salience Network?
A network that monitors the degree to which an external stimulus (or internal state or thought) can attract an individual’s attention
What is Fronto-Parietal Network?
A large scale neural network that initiates cognitive activity
What is Lateral Visual Network?
A network important in activating brain processes in the presence of complex stimuli that evoke emotional responses
