Cerebrum Flashcards
main function of the cerebrum
center of consciousness
1. sensory processing
2. motor planning
3. consciousness
4. memory
what side of the body do the cerebral hemispheres control
contralateral
structure of the cerebrum
telencephalon: cerebral hemispheres, basal nuclei, rhinencephalon
diencephalon: thalamus, hypothalamus
gray matter of the cerebrum
cortex and basal nuclei
primary type of neuron in the cerebral cortex
pyramidal neurons
white matter of the cerebrum
myelinated axons projecting from cells in the gray matter
short association axons
connect adjacent gyri (same lobe)
long association axons
connect gyri of different lobes (same hemisphere)
projection axons
connect cerebrum to thalamus/brainstem
commissural axons
connect cerebral hemispheres
- corpus collosum
- rostral commissure
neocortex
frontal, parietal, temporal, and occipital lobes
contain all 6 cell layers (molecular, ext granular, ext pyramidal, int granular, int pyramidal, multiform)
archicortex
limbic system; hippocampus
contains 3 cell layers
paleocortex
piriform lobes, olfactory gyrus
contains 3 cell layers
primary cortical areas
six specific areas that intake/output information
- olfactory region
- frontal lobes
- parietal lobes
- temporal lobes
- occipital lobes
- limbic system
olfactory region
paired olfactory bulbs, tracts, and piriform lobes
- includes CN I
- has connections to limbic system
processes OLFACTION
(does NOT get processed by thalamus)
frontal lobes
primary MOTOR cortex
- origin of corticospinal tract
- somatotopic organization (motor homunculus)
behavior and judgement
somatotopic organization
specific cortical areas are associated with specific body surfaces
parietal lobes
SOMATOSENSORY (conscious proprioception and nociception)
- receives contralateral sensory information
- somatotopic organization (sensory homunculus)
temporal lobes
AUDITORY cortex
- receives fibers from MEDIAL geniculate
- fibers decussate 2x (ends up ipsilateral)
occipital lobes
VISUAL cortex
- receives fibers from LATERAL geniculate
- fibers decussate (ends up contralateral)
limbic system
brain function, emotion, behavior
- integrates emotional, visceral, and autonomic responses
- 4 Fs - fear, flight, food, reproduction
hippocampus, amygdala, cingulate gyrus, mammillary bodies, septal nuclei
association cortexes/areas
areas that are associated with primary cortical areas that integrate the stimuli
- problem solving
- creative thinking
- decision making
recognizes information and forms associations with the senses perceived by the primary areas
rhinencephalon
“smell brain” - has an olfactory and non-olfactory portion
olfactory: bulbs, tracts, piriform lobes
non-olfactory: amygdala, septum, hippocampus
amygdala
large nucleus located dorsally to the piriform lobe
function: emotion (anxiety, fear, anger)
receives afferents from: cerebral cortex, piriform lobes, thalamus, hypothalamus
septal nuclei
located midline and ventral to corpus callosum between the lateral ventricles
function: autonomic functions, behavior, emotion
receives afferents from: olfactory bulb, amygdala
hippocampus
loops are rostral/caudal colliculi and thalamus/hypothalamus to attach at mammillary bodies
function: learning and memory; governs aggression and behavior
receives afferents from: neocortex, amygdala, contralateral hippocampus
projects efferents to: hypothalamus, cingulate cortex
basal nuclei
subcortical nuclei in each cerebral hemisphere
function of basal nuclei
modulate cortical signals for voluntary movement
INHIBITS unwanted movement to release wanted movement
- caudate nuclei
- putamen
- globus pallidus
- claustrum
cerebral dysfunction: history
SEIZURES
behavioral changes:
- abnormal urination
- vocalizing
- aggression
- reduced consciousness
seizures
clinical manifestations of excessive, synchronous, neuronal firing
- paroxysmal
- involuntary movements
- altered consciousness
- autonomic signs (drooling, urination/defecation)
cerebral dysfunction: mentation
normal, obtunded, demented
cerebral dysfunction: posture
head turn (NOT tilt) towards side of lesion
decerebrate rigidity (opisthotonus, all 4 limbs)
coma
cerebral dysfunction: gait
gait is NORMAL; may express:
compulsive walking/pacing
head pressing
circling toward lesion
contralateral hemiparesis (if corticospinal tract is damaged)
NO paresis or paralysis
cerebral dysfunction: cranial nerves
central blindness (contralateral vision loss)
menace deficits
contralateral perceptual deficits
NORMAL PLRs
cerebral dysfunction: postural reactions
contralateral deficits on all
cerebral dysfunction: spinal reflexes
normal
cerebral dysfunction: palpation
apparent pain in cranium/cervical spine due to meninges stretching
hemi-inattention syndrome
patient with cerebral disease ignores input from one half of the environment (ignores the side that is contralateral to side with lesion)
- able to perceive stimuli but cannot localize it
basal nuclei dysfunction
neurodegeneration of basal nuclei
unable to initiate movement - animal wants to/tries moving forward but is able
