Cerebrum Overview Flashcards
Telencephalon regions
Cerebral cortex
Subcortical regions
Diencephalon regions
Thalamus
Hypothalamus
What is lateral to the 3rd ventricle?
Thalamus
How does the cerebrum develop
It starts to envelope the more caudal regions
What does the prosencephalon divide into
Telencephalon and diencephalon
How is the cerebral cortex in the developed brain
One continuous sheet
Where is the insular lobe
Hidden in the lobe of cerebral cortex. Within the lateral fissure
What lobe is the uncut in
Medial temporal lobe
Where is the parahippocampal gyrus
Medial temporal lobe
Where is the isthmus of cingulate gyrus
Medial temporal lobe
Subcortical temporal lobe structures within the parahippocampal gyrus
- Amygdala within the uncus
- hippocampus
Region receiving sensory input
Primary sensory cortex
Where does input to the primary sensory cortex from the visual system project to
Lateral geniculate nucleus
Where does the somatosensory input to the primary sensory cortex come from
VPL/VPM thalamic nuclei
Where does the auditory input to the primary sensory cortex come from
Transverse gyri in lateral fissure, input from VPL thalamic nucleus
Where does vestibular input to the primary sensory cortex come from
Insular/parietal cortex in the lateral fissure, input from the VPM thalamic nucleus
Where does the taste input to the primary sensory cortex come from
Insular/parietal cortex in lateral fissure, input from VPM thalmic nucleus
Where does the olfactory input to the primary sensory cortex come from
Multiple cortical (and subcortical) regions, input from olfactory tract
Where are all upper motor neurons located
Primary motor cortex
What are the two main parts of the primary motor cortex
Precentral gyrus (mainly) and frontal eye fields (CN III UMNS)
Secondary association cortex, aka Uniondale association cortex
- input from/to primary cortex, 1 kind of sensation
- sensory functions: processes more complex info than primary cortex
- motor function: plans motor movements, projects to primary motor cortex
Tertiary association cortex, aka hetero/multi-modal association cortex
Input from unimodal association cortex of more than one sensory/motor system
-wernikes area, Braille
What are the 3 main areas for vision on the cortex
- lateral parietal and temporal heteromoal assoication cortex
- visual association cortex
- primary visual cortex
What fissure is the primary visual cortex in
Calcarine fissure
How many layers of the cortical layers are there
6
Thalamocortical fibers
Motor input to cortex (cerebrocellar system) and sensory input to cortex (somatosensory input)
Corticocortical afferents
Input to cortex from other cortical regions
Interneurons
Short/local projections within the same cortical region, filter info
Corticocortical efferents
Output from cortex
Diffuse neurochemical
System input of AcH, dopamine, norepinephrine
Is the histology the same all across the different regions of cortex?
No
Broadmen map of cortex
Cellular map of the brain
How are the cerebral hemispheres connected
Corpus collosum and anterior commisure
Genu of the corpus collosum
The most anteiror portion of the corpus collosum
What is the body of the corpus collosum?
The medial, superior region of the corpus colossum
What is the selenium of the corpus collosum
The most posterior portion of the corpus collosum
What is the rostrum of the corpus collosum
Anterior/inferior portion of the corpus collosum
Where do the cerebral hemispheres connect on the anterior commisure?
Circular cross section
Other than the cerebral hemispheres, what else connects at the anterior commisure
Olfactory bulbs
What are the deep white matter tracts within each cerebral hemisphere?
- superior longitudinal fasciculus
- inferior fronto-occipital fasciculus
- uncinate faciculus
- arcuate fasciculus
- inferior longitudinal fasciculus
- cingulum bundle
- short association fibers
Connects the occipital, parietal, and frontal lobes
Superior longitudinal fasciculus
Connects the occipital parietal, and frontal lobes inferiorly
Inferior fronts-occipital fasciculus
Connects the temporal and frontal lobes
Uncinate fasciculus
Connects the language areas (Wernicke’s and Broca’s areas)
Accurate fasciculus
Connects the occipital and temporal lobes
Inferior longitudinal fasciculus
Connections throughout cingulate and parahippocampal gyri
Congruous bundle
Connect neighboring gyri of same hemisphere
Short assoication fibers (U fibers, or arcuate fibers)
Is the cortex deep or shallow
Shallow
What kind of fibers are in the insular capsule
Descending and ascending
You can damage this without damaging other tracts and get weakness
When looking at a cross section of the cerebrum, what kind of radiations do you see?
You see the internal capsule and then the coronal radiations off of that
How do motor projections descend in the internal capsule
Through the internal capsule to the cerebral peduncles, onward through the basilar pons, pyramids, LCST
What cranial nerves do we test in the supratentorial region
CN 1 and 2, and then UMN to ALL CRANIAL NERVES
What functions are tested in the supratentorial compartment
- awake and oriented, mental status
- CN1 and 2
- olfactory, and visual
- language, cognition, memory
- behavioral
Unique functions of the supratentorial compartment
Horizontal
- CN 1 and 2
- language, cognition, memory
- behavior
Longitudinal
- awake and oriented
- mental status
- brainstem-thalamus-cortex network
CN
-UMN to all cranial nuclei
Motor systems
- corticospinal system
- corticobulbar/corticonuclear
- cerebrocerebellar
- basal ganglia
Somatosensory
-ALS and DC-ML
What are the main types of pathology we see when dealing with the cerebrum
Vascular
Neoplasm
Degenerative
Seizures
What is the blood supply to the lateral surface of the brain
MCA
What is the blood supply to the parietal and frontal lobes
MCA
What is the blood supply to the medial surface of parietal and temporal lobes
PCA
This supplies the medial and dorsolateral parts of the frontal, parietal, and cingulate gyri
ACA
This supplies the ventral and some lateral surface of the temporal and occipital lobes
PCA
What are the borderline zones between the vascular territories on the cerebrum called
Watersheds, smaller branches anastomose here
PCA-MCA border
Varies in anterior end of temporal lobes
PCA border
May cover all of ventral and medial surfaces, or MCA inferior division may reach this surface
What do watershed territories include
White matter deep to cerebral cortex
Watershed infarcts
Anastomose between the major vasculature are small vessels and anastomoses can collapse during hypotension/hypovolemia causing a watershed infarct
What can transient episodes of hypoxia causes
Watershed infarct
What are the two main things that cause a watershed infarct
Reduction in flow or O2 levels
Are watershed areas restricted to gray matter?
No, they are wedge shaped territories that extend down into the white matter
Anterior (ICA) VS Posterior (vertebra-basilar) systems
Largely independent under normal conditions
-anastomoses through circle of willis are most important when one of the cerebral arteries is compromised
What two main blood supplies come off of the ICA
ACA and MCA
What main blood supply comes off of the vertebral artery
PCA
What do cerebral tumors do to function
Typically suppress local function, but can be irritative/stimulatory
What kind of presence do cerebral tumors show
Focal pathology (typically) with localizing signs
Temporal profile of cerebral tumors
Insidious onset
Abnormal electrical activity that transiently disrupts neural function
Seizures
Loss of consciousness in seizures
Differences in degree
How do seizures often appear as
Start as focal process, then may spread or ‘generalize”
How do you recognize the presentation pattern of seizures?
Must have a neuroanatomy knowledge
Temporal profile of seizures
Transient, aka paroxysmal, may recur
Prodrome and seizures
Often have a prodromal event or sensory “aura” immediately before onset
How does amygdala sit to the hippocampus
Mostly rostral, but extends caudally and just superior/dorsal to hippocampus
What structure is critical for long term memory
Hippocampus
What structure helps cortex store memories
Hippocampus
What structure helps regulate emotions and stress responses
Hippocampus
What structure does the hippocampus interact with
Hypothalamus
Major functions of the hypothalamic nuclei deep to 3rd ventricle
- neuroendocrine regulation
- regulates ANS
- thermoregulation
- energy/metabolism
- hunger/thirst
- cravings (Na+, fat)
- motivation
- behavioral regulation
Relationship of hypothalamus, thalamus, midbrain
All neighbors
What is the thalamus positioned adjacent to
3rd ventricle
Sensory nuclei through thalamus
- Visual: LGN
- auditory: MGN
- somatosensory: VPL and VPM
- taste: VPM
Motor nuclei through the thalamus
- ventral anterior nucleus
- ventral lateral nucleus
- part of the cerebrocerebellum circuitry
- part of the feedback loop between cerebral cortex and basal ganglia