lecture 16 Flashcards
what are the functions of the cerebrum?
conciousness, memeory, perception, skilled movements
what are gyri? sulci? fissures?
gyri: folds
sulci: grooves
fissures: deep grooves
what are the cerebral lobes?
frontal, parietal, occipital, temporal, insula, limbic
what is contained in the frontal lobes?
motor areas, CN I
what is contained in the parietal lobes?
somatosensory areas
what is contained in the occipital lobe?
visual areas
what is contained in the temporal lobes?
auditory areas
describe the insula?
maintains homeostasis by processing visceral sensations, taste, and ANS functions
-hidden by frontal, parietal, and temporal lobes
describe the limbic lobes?
- drives emotions, memory
- cingulate gyrus and parahippocampal gyrus
- encircles telencephalon and diencephalon junction
what are key components of the cerebral hemispheres?
- lateral ventricles
- corpus striatum
- white matter
- some limbic structures
- cerebral cortex
- CN I
the lateral ventricles are a landmark for what?
the study of brain sections
several regions of gray matter protrude into the lateral ventricles, what are they?
- caudate nucleus
- thalamus and interthalamic adhesion
- hippocampus
what is the caudate nucleus?
- functions in movement, memory, learning, reward, motivation, etc.
- forms lateral wall of body and anterior horn of lateral ventricles
- forms roof of interior horn
what is the thalamus?
- relays motor and sensory information to the cerebral cortex
- forms floor of body of lateral ventricles
what is the hippocampus?
- functions in learning and memory
- forms floor and medial wall of inferior horn of lateral ventricles
what is the corpus striatum?
collective name for caudate and lentiform nuclei
is the corpus striatum composed of white or gray matter?
gray
what is the corpus striatum a part of?
basal ganglia
why is it called the corpus “striatum”?
because it appears striated due to the bridges of gray matter than connect nuclei
what are the functions of the corpus striatum?
motor control and learning
the corpus striatum is divided into two parts, what are they?
neostriatum and paleostriatum
describe the neostriatum
- primary receiver (output info only goes to other basal nuclei)
- further divided into ventral striatum and dorsal striatum
describe the ventral neostriatum
- input from the limbic system, hippocampus and amygdala
- consists of nucleus accumbens and olfactory tubercle
where is nucleus accumbens? whats its function?
- in basal forebrain
- possible function in reward system
where is the olfactory tubercle? whats its function?
- near olfactory tract
- possible function in reward system and locomotion
describe the dorsal neostriatum
- fibres from cortex, substantia nigra and thalamus enter basal ganglia here
- consists of caudate and putamen
describe the caudate
- input: cortical association areas
- projects to prefrontal areas
- functions in cognition
- superior to putamen
describe the putamen
- input: motor and somatosensory areas
- projects to motor, pre-motor, and supplementary motor areas
- functions in movement and learning
- deep to insula
describe the paleostriatum
- input: neostriatum
- outpur: motor related areas
- consists of: globus pallidus
describe the globus pallidus
divided into globus pallidus externa (gpe) and globus pallidus interna (gpi)
do gpe and gpi have the same inputs? outputs?
similar inputs, different outputs
what separates gpe and gpi?
medial medullary lamina (white matter)
what is the lentiform nucleus?
anatomical groupung composed of the putamen and the globus pallidus
the corpus striatum has many surrounding structures, what are they?
- thalamus (medial to globus pallidus)
- white matter (internal capsule, external capsule, extreme capsule) (internal capsule divides caudate and putamen)
- claustrum (btwn external and extreme capsules)
- insula lobe
what is white matter in the cerebral hemispheres?
myelinated axon nerve fibers
what are the types of white matter in the cerebral hemispheres?
- association fibers
- commisural fibers
- projection fibers
describe association fibers
- paired
- 2 types: short or long
describe short association fibers
connect adjacent gyri (are located in the same lobe in the same hemisphere)
describe long association fibers
connect cerebral lobes (are located in different lobes in the same hemisphere)
can short fibers travel bidirectionally? can long?
short: no
long: yes
do short fibers have a distinct entry or exit? do long?
short: yes
long: no
list 4 long association fibers*
- cingulum (cingulate fasciculus)
- uncinate fasciculus
- superior longitudinal fasciculus
- inferior longitudinal fasciculus
describe the cingulate fasciculus*
connects frontal lobe, parietal lobe and parahippocampal gyrus
describe the uncinate fasciculus*
connects inferior frontal lobe and anterior temporal lobe
describe the superior longitudinal fasciculus*
connects frontal lobe, parietal lobe and occipital lobe
describe the inferior longitudinal fasciculus*
connects temporal and occipital lobe
describe commisural fibers
- connect equivalent regions btwn hemispheres
- not paired
list the two main commissural fibers
- corpus callosum
- commisure of the fornix
describe the corpus callosum
- connects the two cerebral hemispheres
- C shape: curves anteriorly towards olfactory tract, and posteriorly towards the temporal lobe
what are the components of the corpus callosum?
- rostrum (tip of C)
- genu (like head)
- body
- splenium (bottom of C)
what are the forceps minor?
- frontal fiber bundle of corpus callosum
- crosses midline at genu
what are the forceps major?
- occipital fiber bundle of corpus callosum
- crosses midline at splenium
describe the commissure of the fornix
- connects hippocampus to mammillary bodies (aka hippocampal commissure)
- formed by left and right cura od Fornix
what is the anterior commissure?
- anterior portion of commissure of Fornix
- connects olfactory regions
what is the posterior commissure?
- posterior portion of commissure of Fornix
- connects visual nuclei
describe projection fibers
- ascending and descending fibers interconnecting the cortex, thalamus, basal nuclei and brainstem
- composed of internal capsule and corona radiata
describe the internal capsule
- composed of anterior limb, genu and posterior limb
- communication pathway btwn brainstem and cortex
- separates caudate nucleus and thalamus from putamen and globus pallidus
describe the corona radiata
white matter tract that connects motor and sensory nerve pathways of the brainstem and cerebral cortex
what are the ascending projection fibers?
thalamocortical
what are the descending projection fibers?
frontopontine, corticobulbar, corticospinal
what are the key limbic structures?
outer arc: -cingulate gyrus -parahippocampal gyrus inner arc: -hippocampus other: -subcallosal gyrus -amygdala -anterior thalamus