Lecture 1: Cerebrum Overview Flashcards
Parts of cerebrum
Telencephalon and diencephalon
Parts of telencephalon
Cerebral cortex and subcortical regions
Parts of diencephalon
Thalamus and hypothalamus
Parts of CNS
Cerebrum, cerebellum, brainstem, spinal cord and roots
The thalamus and hypothalamus lie where?
Lateral to the 3rd ventricle
The cerebrum develops from what?
Prosencephalon (single vesicle)
As the ______ grows, it surrounds the ______
Telencephalon
Diencephalon
Single brain vesicle (prosencephalon) will divide into ______?
telencephalon and diencephalon
What happens to the cortex when the sulci and gyri form?
It remains as one continuous sheet
What is considered the “hidden” lobe of the cerebral cortex?
Insular lobe
Where is the insular lobe located?
Within the lateral fissure
What are the deep subcortical structures of the telencephalon and where are they located?
Basal ganglia and claustrum (insular and frontal lobes)
Amygdala (medial temporal lobe)
Hippocampal complex (medial temporal lobe)
What is the primary sensory cortex?
Region receiving sensory input
Visual
Area 17 - striate cortex, input from lateral geniculate nucelus
Somatosensory
Postcentral gyrus, input from VPL/VPM thalamic nuclei
Auditory
Transverse gyri in the lateral fissure, input from medial geniculate nucleus
Vestibular
Insular/parietal cortex in lateral fissure, input from VPL thalamic nuclei
Taste
Insular/parietal cortex in lateral fissure, input from VPM thalamic nuclei
Olfactory
Multiple cortical (and subcortical) regions, input from olfactory tract
What is the primary motor cortex?
Origin of corticospinal/corticonuclear projections
Mainly pre central gyrus and frontal eye fields for Oculomotor UMNs
Secondary (unimodal) association cortex
Input from/to primary cortex, one kind of sensation
Sensory and motor
Motor: plans motor movements, projects to primary motor cortex
Which cortex area processes complex information?
Secondary association cortex
Tertiary (hetero/multi-modal) association cortex
Input from unimodal association cortex of more than one sensory/motor system
Ex. Wernicke’s area (language): auditory, visual, and sometimes touch (Braille)
Which cortex processes input from more than one sensory/motor system?
Tertiary association cortex
Thalamocortical fibers
Somatosensory input and cerebrocerebellar system
Corticocortical afferents
Input to cortex from other regions
Interneurons
Short/local projections within the same cortical region, filter information
Projection fibers
Corticospinal, corticobulbar, corticopontine (output from cortex)
Corticocortical efferents
Output from cortex
Diffuse neurochemical system input
Ach, dopamine, norepi
Cortical histology: name the 6 lamina of the cortex from superficial to deep
- Molecular layer
- External granular layer
- External pyramid layer
- Internal granular layer
- Internal pyramid layer
- Polymorphic layer
Where is there laminar variability?
Across cortical regions
What is Brodmann’s map?
Separates the brain into functional areas histologically
Cerebral hemispheres are connected by what 2 major white matter tracts?
Corpus callosum and anterior commissure
Parts of corpus callosum
Rostrum, genu, body, splenium
What does the anterior commissure connect?
Temporal lobes and olfactory bulbs
Superior longitudinal fasciculus
Connects occipital, parietal, and frontal lobes
Inferior fronto-occipital fasciculus
Connects frontal and occipital lobes?
Uncinate fasciculus
Connects temporal and frontal lobes
Arcuate fasciculus
Connects language areas (Wernicke’s and Broca’s)
Inferior longitudinal fasciculus
Connects occipital and frontal lobes
Cingulum bundle
Connections throughout cingulate and parahippocampal gyri
Short association fibers
Connect neighboring gyri (of same hemisphere), aka U fibers, arcuate fibers
Motor projections descend through the internal capsule to the ______, onward through the basilar pons, pyramids, LCST
Cerebral peduncle (crus cerebri)
Regions of supratentorial
Telencephalon, diencephalon
What do we test for in the supratentorial compartment?
Awake and oriented, mental status, CN 1 and 2, olfactory and visual systems, language, cognition, memory, emotional and behavioral regulation, and hypothalamic/pituitary functions
Regions of infratentorial compartment
Brainstem and cerebellum
What do we test for in the infratentorial compartment?
CN 3-12, motor coordination and balance
Vertebral compartment contains what? And what is tested?
Spinal cord, dorsal and ventral roots
Motor and somatosensory exams, reflexes
Peripheral level: nerves and autonomics tests for what?
Somatic and visceral nerves, reflexes
Unique functions of supratentorial
Olfactory and visual systems, language, cognition, memory, emotional and behavioral regulation, hypothalamic/pituitary functions
Longitudinal functions of supratentorial
Awake and oriented, mental status
Brainstem-thalamus-cortex network
Cranial nerves UMNs are located where?
Supratentorial compartment - cortex
Motor systems of supratentorial
Strength and coordination
Corticospinal, corticobulbar/corticonuclear, cerebrocerebellar (coordination), and basal ganglia (coordination)
Somatosensory systems of supratentorial
ALS and DC-ML
Course of MCA
From circle of willis over insular to lateral cerebral surface
What artery supplies the medial and dorsolateral parts of frontal, parietal, and cingulate gyrus?
ACA
What artery supplies ventral and some lateral surface of temporal and occipital lobes? (and some lateral cortex)
PCA
Arterial supply of orbitofrontal cortex
ACA
There are watershed regions where?
Borders of middle and anterior arteries
Arterial territories contain what
Some white matter deep to cerebral cortex
What are borderline zones of arterial territories where smaller branches can anastomose called?
Watersheds
______ border in the anterior end of the temporal lobe has variable location: ___ may cover all of ventral and medial surface, or ___ anterior division may reach this surface
PCA-MCA border
PCA
MCA
Collateral blood flow
One artery can compensate for impaired blood flow in another
Watershed infarct
When anastomoses collapse during hypotension/hypovolemia
Transient episodes of _____ can selectively produce a watershed infarct
Hypoxia
Anastomoses of the circle of willis are most important when which arteries are compromised?
One of the cerebral arteries
Tumors typically _____ local function, but can also
Suppress, stimulate/irritate
Temporal profile of tumors
Insidious onset
Pathology type of tumors
Focal, with localizing signs
The amygdala sits mostly rostral to the ______, but also extends caudally and just superior/dorsal to the ______
Hippocampus
What region is critical for long term memory, helps cortex store memories, regulates emotion and stress responses, and interacts with the hypothalamus?
Hippocampus
What structure is station adjacent to the 3rd ventricle, superior to the midbrain, and adjacent to several other subcortical structures (parts of basal ganglia or basal nuclei) specifically caudate nucleus and putamen
Thalamus
Visual nucleus of thalamus
LGN - lateral geniculate nucleus
Auditory nucleus of thalamus
MGN - medial geniculate nucleus
Somatosensory nucleus of thalamus
VPL and VPM - ventral posterior lateral/medial
Taste nucleus of thalamus
VPM - ventral posterior medial
Motor nuclei of thalamus
VA and VL
VL = cerebrocerebellum, both part of feedback loop between cortex and basal ganglia (nuclei)
