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In comparison to other mammals, what do you have have a lot of and why?
- increased amounts of sulci and gyri to increase surface area
- humans have association areas which take primary info and further develop it
- this is not strictly due to enlarged motor or primary sensory areas
What makes up the striatum?
What makes up the lentiform nucleus?
What makes up the corpus striatum?
- caudate nucleus
- globus pallidus
What makes up the basal ganglia?
- caudate nucleus
- globus pallidus
What makes up the claustrum?
- caudate nucleus
- globus pallidus
- subthalamic nucleus
- substantia nigra
What makes up the paracentral lobule?
junction of pre and postcentral gyrus coming together on the medial surface
What is the precuneate?
continuation of the parietal lobe
What is the cuneate?
- lower visual field from opposite side
- is above the calcerine sulcus
What is the lingual gyrus
- upper visual field
- below the calcerine sulcus
What make up the walls of the 3rd ventricle?
thalamus and hypothalamus
What occurs at the optic chiasm?
retinal nasal fibers cross
What is the fornix?
where a bundle of fibers from the temporal lobe and hipppocampal region wrap across the dorsal aspect of thalamus before descending and terminating in the mamillary bodies of the hypothalamsus
What occurs with subthalamic nuclei lesions?
movement disorders characterized by contralateral hemiballisimus (violent or ballistic) or choreiform (jerky)
What is the septum pellucidum?
a thin tissue between the fornix and corpus callosum
What are the thalamic nuclei: VPL and VPM, associated with?
What are the thalamic nuclei- VL/VA associated with?
basal ganglia and cerebellum
What are the thalamic nuclei MGB and LGB associated with?
What are the thalamic nuclei- intralaminar and midline associated with?
paleospinothalamic and projections throughout the cortex
What are the three classifications of thalamic nuclei?
- relay nuclei
- association nuclei
- nonspecific nuclei
What is the significance of relay nuclei?
they have fairly well defined afferent and efferent groups
What is the significance of association nuclei?
- they have broader efferent outputs associated more with limbic system
- ex: emotional tone, primitive behaviors like eating behavior, sexual reproduction
What is the signficance of non-specific nuclei?
has widespread projections- specifically intralaminar nuclei and associations with paleospinothalamic pathways
What forms the medial and lateral boder of the inter medullary lamina?
- medial border: 3rd ventricle
- lateral border: internal capsule
What forms the gray matter of the cerebral cortex?
- archiocortex (3 layers)
- neocortex (6 cellular layers)
What/where makes up the archicortex?
- lies deep and close to midline
- has 3 cell layers
What makes up the neocortex (basic)?
- 6 cellular layers deep
- occupies vast majority of cortical region
What makes up the hippocampal fomration and what is its purpose?
- hippocampus + dentate gyrus
- archicortex wrapped around eachother
- important for storage/retrieval of memory
What is the fimbria of the fornix?
- it brings axons out of the hippocampal region and go around in the a big loop passing directly superior to the thalamus
- important for memory and emotion
What are the cell layers of the neocortex and their make up?
- molecular layer: mostly neuropil
- external granular layer: stellate cells
- external pyramidal layer: small pyramidal cells
- internal granular layer: stellate cells
- internal pyramidal layer: large pyramidal cells
- multiform layer: multiple cell types
What layer of the neocortex do cells from the VPL and LGB project to?
internal granular layer
What is the difference between INTRAcortical and INTERcortical ares of white matter?
- intracortical: are association fibers, they connect one area of the cerebral cortex to another region (communication within hemispheres)
- intercoritcal: are commisural fibers, they start on one side of the cerebral cortex and end on the other side (communication between hemispheres)
What are projection fibers?
- they start in the cerebral cortex and travel down to lower regions passing through the IC
- corticofugal fiber system
Where do primary sensory cortices receive information from and what are the different types?
- from the sensory thalamus (VPL/VPM, LGB/MGB)
- carry somatosensory, auditory, and visual sensory experiences
What is the purpose and where is the somatosensory cortice?
- tactile, some pain and temp
- primarily contralateral output
- parietal lobe
What is the purpose and where is the auditory/vestibular cortice?
- awareness of sound intensity and sound pitch
- head movement and position relative to gravity
- bilateral input
- superior temporal gyrus
What is the purpose of the visual cortice?
- light/dark, objects (horizontal/vertical lines), shape
- contralateral input
Where does the anterior limb of hte internal capsule lie?
between the caudate head and lentiform nucleus
Where does the posterior limb of hte internal capsule lie?
between the lentiform nucleus and the thalamus
What is at the intersection of the anterior/posterior limbs?
What are the 4 pathways the thalamus sends info to the cortex?
- superior thalamic radiation
- anterior thalamic radiation
- posterior thalamic radation
- inferior thalamic radiation
Where does the superior thalamic radiation send information to and from?
from the thalamus to the cortex and then terminates in layer 4 of the neocortex
Where does the anterior thalamic radiation send information to and from and what does it associate with?
- from thalamus to frontal lobe, passing thru the anterior limb of the IC
- associates with emotional, tone behavior connections (or the frontal lobe which is a component of the limbic system)
Where does the posterior thalamic radiation send info to and from and whats another name for it?
- optic radiation
- from LGB to primary visual cortex
Where does the inferior thalamic radiation send infor to and from and what's another name for it?
- auditory radiation
- from MGB to superior temporal gyrus in the primary auditory cortex
What is the purpose of sesnory association cortices?
- allows for a richer sensory experience
- puts meaning to our sensory experiences by integrating color, tone, language, textures, and memory comparisons
Why do all the sensory association areas begin to come together?
- so when you see, hear, or feel something, you can put some sort of meaning to it
- ex. you hear something and then can look for something or you see something and then you can ascribe some touch meaning to it
What does damage to the primary somatosensory cortical area cause?
loss of tactile localization and conscious proprioception
What does damage to the primary auditory cortical area cause?
loss of localization of sound
What does damage to the primary vestibular cortical area cause?
change in awareness of head postion and movement
What does damage to the somatosensory association area cause?
astereognosis (the inability to identify an object by touch)
What does damage to the visual association area cause?
What does damage to the auditory association area cause?
What is the purpose of the primary motor cortex?
- contralateral fine movements
What are the different areas of the primary motor cortex and their purpose?
- supplemental area: initiation of movement
- premotor area: axial and girdle mm
- brocas area: speech (non-verbal communication)- primarily in dominant hemisphere
- frontal eye fields: volitional (directed) gaze
What does damage to the primary motor cortex cause?
- loss of motor control, spastic dysarthria
- contralateral paralysis with damage to primary motor area
Damage to what two areas in the motor cortex causes apraxia?
premotor area and supplementary motor area
What does damage to Broca's area (dominant hemisphere) cause?
expressive non-fluent aphasia
What does damage to the frontal eye fields cause?
- force gaze to same direction; tracking of objects affectedd
- irritation force gaze away from affected side
What is the purpose of the prefrontal association?
- goal oriented behavior
- self awareness
- emotional control
What is the purpose of the parietotemporal association?
- parietal, temporal and part of occipital lobe come together
- sensory integration
- problem solving
- understanding language
- spatial relationships
- in dominant hemisphere- take auditory input and ascribe meaning and language to it
What is the purpose of the limbic association?
- processing of memory
What does damage to the dorsolateral profrontal association cause?
losse of executive functions and divergent thinking
What does damage to the parietotemporal association in the dominant hemisphere cause?
What does damage to the parietotemporal association in the non dominant hemisphere cause?
neglect or difficultly understanding nonverbal communication
What does damage to the limbic association cause?
disturbance of personality and emotions
What are the for main Brodmann areas?
- primary motor cortex
- primary somatosensory cortex
- primary visual cortex
- primary auditory cortex
Where is the anterior commissure and what is its purpose?
- inferior and middle temporal gyri, olfractory areas
- brings smell sensation from one side to the other side
Where does the posterior commisure lie and what is its purpose?
- preoptic nuclei
- connects visual areas associated with the tectum
What commissure is associated with the pupillary light reflex and visual convergence?
What does the habenular commisure help more with?
habenular nuclei- part of the epithalamus
What is the purpose of the corpus callosum, and what are its parts?
- connects the hemispheres (rostrum, genu body, and splenium)
- anterior forceps/posterior forceps
How does the corpus callosum work- where does info go, what if it's damaged?
- see something in L hemisphere --> R occipital lobe --> through posterior forceps to L side --> association fibers bring it to the language area to be named
- if posterior foceps are damaged, see something in L visual field --> R occipital lobe --> then can't identify object because it can't go through posterior forceps to be named on L side
- if seen in the R visual field, can still be named because doesn't have to cross
What is considered the language dominant hemisphere?
What is agnoisa?
damage to areas that transmit image over to language center and prevent language from naming it
What do short association fibers connect?
connect adjacent fibers
What are the long association fibers and what do they connect?
- superior longitudinal fasiculus: connects occipital lobe to frontal lobe
- inerior longitudinal fasiculus: connects temporal to occipital
- arcuate fasiculus: connects primary auditory region to language region to primary motor region (broca's)
- cingulum: septal area, cingulate, & parahippocampal gyri
- unicate fasiculus: orbital frontal gyri to temporal lobe
Damage to which long association fibers causes aphasia?
What is the difference between fluent and non-fluent aphasia?
- Fluent/receptive aphasia: affects primary auditory cortex (wernickes); have a fluent response but doesn't make sense
- Non-fluent/Expressive aphasia: affects primary motor cortex (brocas); can understand but can't physcially get response out
What is the difference between dysarthria and aphasia?
dysarthria: hoarsness, damage to CN IX, X
What are projection fibers?
arise from layer 5 of the cortex and pass inferiorly through the cortex as they are fanned out (corona radiata)
How is the cortical function organized?
- in precentral gyrus in the primary motor strip
- face is lateral --> fingers --> UE --> trunk --> knee --> toes