True or False: Pyramidal cells generally relay information locally within the cerebral cortex functioning as interneurons while granule cells (i.e. non-pyramidal cells) function as the major output system for the cerebral cortex.
False
What are some general characteristics of pyramidal neurons?
pyramidal cell body
apical and basal dendrites
spiny dendrites
output cells
axons make up white matter
What are some general characteristics of non-pyramidal neurons in the cerebral cortex?
i.e. granule cells
e.g. Stellate, basket, and chandelier cells
spiny or non-spiny dendrites
local interneurons
relay information locally
In which layers of the neocortex do cortico-cortical afferent fibers synapse/terminate?
layer II
layer III
In which layers of the neocortex do thalamo-cortical afferent fibers synapse/terminate?
layer III
layer IV
In which layers of the neocortex do cortico-cortical efferent fibers originate?
layer II
layer III
layer V
layer VI
In which layers of the neocortex do cortico-thalamic efferent fibers originate?
layer VI
In which layers of the neocortex do corticobulbar, corticospinal, corticopontine, corticoreticular, and corticostriatal efferent fibers originate?
layer V
True or False: The neocortex makes up about 90% of the cerebral cortex and is organized into 6 layers based on neuronal inputs and outputs, with layer I being just deep to the pial surface and layer VI being just superficial to the white matter boundary.
True
What are the inputs and outputs of the parietal association cortex?
inputs:
somatosensory
auditory
visual
vestibular
motor outputs
outputs:
(strong connections) frontal cortex
cingulate gyrus
cerebellum
basal ganglia
Anosognosia (i.e. lack of awareness of illness or condition) and astereognosis (i.e. inability to identify object by touch without visual input) are associated with damage to which area of the brain?
parietal association cortex
What are some functions of the parietal association cortex?
spatial relations, including extrapersonal space and body image (non-dominant hemisphere esp. important)
development of movement plan
higher sensory function (polysensory)
stereognosis
language function (especially inferiorly, close to Wernicke's area)
Which hemifields do each of the parietal association areas represent in spatial representation?
left parietal association area: represents right hemifield
right parietal association area: represents left hemifield AND right hemifield
(i.e. with spatial orientation there are 2 cortical representations of the right hemifield but only 1 representation of the left hemifield)
What type of neurons are responsible for encoding upcoming saccade direction during delay periods and play a role in the development of a movement plan?
lateral intraparietal (LIP) neurons
(parietal association cortex)
What part of the cerebral cortex, specifically, is associated with intended movements and awareness of movement?
posterior parietal cortex
Unconscious movement is produced when what part of the cerebral cortex is stimulated?
premotor cortex
What are the inputs and outputs for the prefrontal cortex?
inputs:
sensory cortices
dopamine signals (SNpr)
cingulate gyrus
hippocampus
amygdala
basal ganglia
outputs:
motor cortices
cingulate gyrus
basal ganglia
hippocampus
amygdala
What are the 2 regions of the prefrontal association cortex and what are their respective roles?
dorsolateral: strategic planning for higher motor and cognitive behavior, working memory (lesion --> impulsiveness, disinhibition)
What are some of the functions of the prefrontal association cortex?
persistent activity: maintenance of task-relevant information in working memory
flexible encoding of behaviorally relevant information (context, "rules")
encode category information (unlike visual cortex)
planning complex cognitive behaviors
personality expression
decision making
moderating correct social behavior
orchestration of thoughts and actions in accordance with internal goals
mirror neurons (encode goals/intentions; understand intentions of others' movements)
restraint, initiative, order
What may result from lesions in the prefrontal association cortex?
cognitive deficits
problems with "working memory"
deficits with strategic planning, judgment
deficits with "flexibility" of behavior (context, rules)
personality/emotional changes
autism-like symptoms
What function do mirror neurons in the prefrontal cortex serve?
mirror neurons help encode goals/intentions and also help understand the inentions of others movements
mirror neurons may play a role in language learning, empathy
damage: autism-like symptoms
Agnosias are generally associated with damage to which part of the cerebral cortex?
temporal association cortex
What functions are associated with the temporal association cortex?
object recognition (higher order visual processing)
face recognition (bilateral)
verbal memory (left)
musical discrimination (right)
some olfactory function
consolidation of memories (bidirectionally linked with hippocampus)
What are the inputs and outputs of the temporal cortex?
inputs:
primary and secondary auditory cortex
Wernicke's area
visual form/color information
limbic system
basal ganglia
prefrontal cortex
outputs:
Wernicke's area
basal ganglia
prefrontal cortex
True or False: Single cells in face-selective patches in the temporal cortex respond preferentially to faces.
True
Verbal memory problems (e.g. aphasias) and visual discrimination problems (e.g. prosopagnosia) are generally associated with damage to which area of the cerebral cortex?
temporal association cortex
What are the 3 "types" of cerebral cortex and their components?
neocortex: 90% of cortex; 6 layers
paleocortex: olfactory areas at base of telencephalon; 3 layers
archicortex: hippocampus; 3 layers
(allocortex = archicortex + paleocortex)
What are the 3 major types of connecting fibers in the cortex, what do they connect, and what is an example of each?
association fibers: connect structures within same hemisphere (e.g. arcuate fasciculus, SLF, cingulum)
projection fibers: connect cortical structures with subcortical structures (e.g. corticospinal, corticobulbar, corticopontine, corticostriate, corticothalamic, and thalamocortical tracts)
commissural fibers: connect symmetrical structures from each cerebral hemisphere (e.g. corpus callosum, anterior and posterior commissures)
What type of fiber bundle is the superior longitudinal fasciculus (SLF) and what does it interconnect?
association fiber bundle
interconnects frontal, temporal, parietal, and occipital lobes (includes arcuate fasciculus)
What is the name of the structure through which projections fiber bundles run on their way to the brainstem?
internal capsule
From which cortical layers do projection fiber bundles originate?
layers V and VI
The central sulcus demarcates which 2 association cortices?
primary somatosensory (postcentral gyrus)
primary motor (precentral gyrus)
What gyrus is associated with the primary auditory cortex?
anterior transverse temporal gyrus
Where is the primary visual association cortex located?
occipital lobe (medial aspect of calcarine fissure)
Where is the olfactory cortex?
prepyriform cortex at junction of orbitofrontal and temporal lobes
Where is the premotor cortex?
posterior part of superior and middle frontal gyri (e.g. frontal eye fields)
sometimes included as a part of the association cortex
While speech comprehension and expression may be localized to the temporal lobe of a person's dominant hemipshere, the equivalent region in the non-dominant cortex is responsible for what?
prosody in language (i.e. variations in pitch, rhythm, stress, and inflection)
Which 2 gyri generally compose Wernicke's area?
superior temporal gyrus (temporal lobe)
supramarginal gyrus (parietal lobe)
What pathways interconnect the amygdala and prefrontal cortex?
direct pathways
pathway via mediodorsal nucleus of thalamus
Which are of the cortex has the highest level of dopaminergic innervation?
prefrontal region
Which area of the prefrontal cortex is associated with depression? with mania?
depression: left frontal lobe
mania: right lobe
What are the 2 areas of the occipital lobe and what are their respective functions?
dorsal occipital lobe: "where" stream concerned with location and movment of visual objects and spatial relationships among self, objects, and the environment
ventral occipital lobe: "what" stream concerned with identification of objects
Bilateral damage to the fusiform gyri of the occipital lobe will result in what deficit?
prosopagnosia
Achromatopsia (i.e. inability to perceive color) is associated with damage to which area of the brain?