Cerebral Cortex Flashcards
Is the primary motor or sensory cortex considered the Agranular cortex?
Motor
Is the primary motor or sensory cortex considered the Granular cortex?
Sensory
This histological cerebral layer is considered the granular layer
Layer 4
This histological cerebral layer receives inputs from the thalamus
Layer 4, granular layer
This histological cerebral layer sends outputs to subcortical structures (other than the thalamus)
Layer 5, large pyramidal layer
Does layer 4 or 5 of the cerebum receive inputs from the thalamus?
4
Does layer 4 or 5 of the cerebrum send outputs to subcortical structures (other than the thalamus)
5
Association cortex integrates this type of information from a single sensory modality
Afferent
E.g. visual association cortex integrates information about form, color, and motion that arrives in the brain in separate pathways
This cortex has unimodal projection areas that send information to multimodal sensory association areas that integrate information about more than one sensory modality
Association cortex
Where is the primary motor cortex located?
Precentral gyrus
(frontal lobe)
Where is the premotor cortex, supplemental motor cortex and frontal eye field located?
Precentral gyrus and rostral adjacent cortex
(frontal gyrus)
Where is the frontal eye field located?
Superior, middle frontal gyri
Medial frontal lobe
Where is Broca’s area located?
Inferior frontal gyrus (frontal operculum)
Part of the frontal lobe that functions in voluntary movement and control
Primary motor cortex
Part of the frontal lobe that functions in eye movements
Frontal eye field
Part of the frontal lobe that functions in thought, cognition, movement, planning
Prefrontal association cortex
Part of the frontal lobe that functions in motor aspects of speech
Broca’s area
Primary motor cortex is known as this Brodmann’s area
4
Premotor cortex is known as this Brodmann’s area
6
Frontal eye field is known as this Brodmann’s area
8
Broca’s area is known as this Brodmann’s area
44
Prefrontal association cortex is made up of these Brodmann’s areas
9-12 and 45-47
Irritative lesions of this result in seizures that begin as a focal twitching and can spread to involve large muscle groups
Primary motor cortex
(frontal lobe)
Destructive lesions to this result in contralateral paralysis of affected muscle groups
Primary motor cortex (BA4)
What results from irritative lesions of the primary motor cortex?
Seizures that begin as a focal twitching and can spread to involve large muscle groups
What results from destructive lesions to the primary motor cortex?
Contralateral paralysis of affected muscle groups
Does destructive lesion to the primary motor cortex result in ipsilateral or contralateral paralysis of affected muscle groups?
Contralateral
A patient who is unable to perform activities of daily living, such as brushing teeth or combing hair, may have lesion to this
Premotor and/or supplementary motor areas (BA6) of frontal lobe
A patient who is unable to drink from a straw, whistle, or blow out candles may have suffered from a lesion to this
Premotor and/or supplementary motor areas (BA6) of frontal lobe
A patient who has primitive reflexes, such as grasp, suck, snout and root, may have a lesion to this lobe
Frontal lobe
(“Frontal release signs” - common in infants but may return in adults following frontal lobe lesions)
A patient with abnormal gait, involving shuffling, unsteadiness, or magnetic gait, may have suffered lesion to this lobe
Frontal lobe
Lesions to this may cause changes in personality, lack of judgement, organization and inhibitions
Intellectual capacity remains largely intact
Prefrontal association cortex
What results from a lesion to the prefrontal association cortex?
Changes in personality
Lack of judgement, organization, and inhibitions
Lobotomies to the prefrontal association cortex can be done, as well as to this structure that is still a viable treatment for major depression and obsessive compulsive disorder
Anterior cingulate cortex
(frontal lobe)
Where is the primary somatosensory cortex located?
Postcentral gyrus
(parietal lobe)
Where is the secondary somatosensory cortex located?
Superior bank of lateral sulcus, buried deep in the lateral sulcus
(parietal lobe)
Where is the posterior parietal association cortex located?
Superior parietal lobule
Where is the parietal-temporal occipital association cortex located?
Angular gyrus / supramarginal gyrus
(parietal lobe)
Where is the gustatory cortex located?
Insular cortex, frontoparietal operculum
The gustatory cortex is this Brodmann’s area
43
The parietal-temporal occipital association cortex is in these Brodmann’s areas
39-40
Irritative lesions of this cause paresthesias on contralateral body
Primary somatosensory cortex
(parietal lobe)
Destructive lesions of this cause impairments in sense and cutaneous sensation
Primary somatosensory cortex (parietal lobe)
What results from irritative lesions to the primary somatosensory cortex?
Paresthesias on contralateral body
What results from destructive lesions to the primary somatosensory cortex?
Impairments in sense and cutaneous sensation
Irritative lesions to the primary somatosensory cortex results in paresthesias on the ipsilateral or contralateral body?
Contralateral
Lesions to this result in tactile agnosia and asteregnosis
Unimodal somatosensory association cortex
Deficit in the ability to combine touch, pressure, and proprioception input to interpret sensory information
Seen in lesion to unimodal somatosensory association cortex
Tactile agnosia
Inability to recognize an object placed in the hand without the use of sight
Seen in lesion to unimodal somatosensory association cortex
Astereognosis
Lesion to this causes difficulty with visual spatial analysis, can cause contralateral neglect syndrome
Multimodal somatosensory association cortex
In lesions to multimodal somatosensory cortex, does the dominant or non-dominant hemisphere play a larger role?
Non-dominant (usually right) hemisphere
Condition where stimuli in the environment on the contralesional side can be ignored or “neglected”
Contralateral neglect syndrome
Seen in lesion to Multimodal somatosensory association cortex (of parietal lobe)
Where is the striate cortex (primary visual cortex) located?
Banks of calcarine fissure (cuneus and lingual gyrus)
Where are the secondary and tertiary visual cortices located?
Surround striate cortex
Part of the occipital lobe that functions in processing of visual stimuli
Striate cortex (primary visual cortex)
Part of the occipital lobe that functions in depth of vision
Secondary visual cortex
Part of the occipital lobe that functions in color, motion and depth of vision
Tertiary visual cortex
Part of the parietal lobe that functions in stereognosis and perception
Posterior parietal association cortex (BA5,7)
Part of the parietal lobe that functions in perception, vision, reading, speech
Parietal-temporal occipital association cortex (BA39,40)
Irritative lesions to this cause flashes of light in vision as well as rainbows, brilliants stars and bright lines
Primary visual cortex
Destructive lesions to this cause Anopias and Anton-Babinski syndrome
Primary visual cortex
Condition that may result from destructive lesion to primary visual cortex, involving cortical blindness though patient says that they are capable of sight
Although rare, we are seeing it more with current treatments for MS (natalizumab)
Anton-Babinski syndrome
A patient who believes they are capable of sight when they are not may have this condition
Anton-Babinski syndrome
Associated with destruction lesion to primary visual cortex
What results from an irritative lesion to the primary visual cortex?
Flashes of light
Rainbows
Brilliant stars
Bright lines
What results from a destructive lesion to the primary visual cortex?
Anopias (loss of vision)
Anton-Babinski syndrome
Lesions to this result in visual agnosis (inability to recognize objects despite intact vision), deficits in moving eyes with a target, and disorders of visual organization
Visual association cortex
Inability to recognize objects, despite intact vision
Can result from lesion to visual association cortex
Visual agnosis
Lesions to this pathway can cause prosopagnosia (inability to recognize faces) and achromatopsia (cortical colorblindness)
Ventral “what” pathway
This is an inability to recognize people by their faces
Is seen in lesion to the ventral “what” pathway
Prosopagnosia
This is cortical colorblindness, which may be seen after lesion to the ventral “what” pathway
Achromatopsia
Balint’s syndrome results from lesion to this
Dorsal “where” pathway
(dorsolateral parieto-occipital cortex)
Condition caused by lesion to the dorsal “where” pathway
Involves simultanagnosia, optic ataxia and ocular apraxia
Balint’s syndrome
Inability to perceive parts of a scene as a whole
Seen in Balint’s syndrome (lesion to dorsal “where” pathway)
Simultanagnosia
Difficulty reaching in space under visual guidance
Seen in Balint’s syndrome (lesion to dorsal “where” pathway)
Optic ataxia
Difficulty voluntarily directing gaze towards objects in the periphery
Seen in Balint’s syndrome (lesion to dorsal “where” pathway)
Ocular apraxia
Where is the primary auditory cortex located?
Heschl’s (transverse temporal) gyri and superior temporal gyri
Where is the secondary auditory cortex (association) located?
Heschl’s (transverse temporal) gyri and superior temporal gyri
Where is Wernicke’s area (higher order association cortex) located?
Superior temporal gyrus
Part of temporal lobe that functions in processing of auditory stimuli
Primary and secondary auditory cortices
Part of temporal lobe that functions in language comprehension
Wernicke’s area
Primary auditory cortex is this Brodmann’s area
41
Secondary auditory cortex is this Brodmann’s area
42
Wernicke’s area is this Brodmann’s area
22
Irritative lesions to this result in buzzing/roaring sensations
Primary auditory cortex
Destructive lesions to this result in unilateral decreased perception of sound or bilateral cortical deafness
Primary auditory cortex
What results from an irritative lesion to the primary auditory cortex?
Buzzing/roaring sensations
What results from a unilateral destructive lesion to the primary auditory cortex?
Decreased perception of sound
Somewhat worse in contralateral ear
What results from a bilateral destructive lesion to the primary auditory cortex?
Cortical deafness
Awareness of sound, but unable to identify nonverbal stimuli
A unilateral destructive lesion to the primary auditory cortex results in decreased perception of sound, somewhat worse in the ipsilateral or contralateral ear?
Contralateral
Lesion to this results in auditory agnosia and Wernicke’s aphasia
Auditory association cortex
Word deafness; patient can identify nonverbal auditory stimuli but cannot understand spoken words
Caused by lesion to auditory association cortex
Auditory agnosia
Auditory agnosia is due to an infarct in this structure of the dominant hemisphere extending into subcortical white matter, preventing hemispheric communication
Auditory association cortex
This is caused by lesion to the auditory association cortex, and involves an inability to understand language at all (reading, writing, listening)
Wernicke’s aphasia
In almost all right-handed people and most left-handed people, the main centers for language are in this hemisphere
Left
The location of this defines the dominant hemisphere
Language areas
Lesions to this cause Conduction aphasia (difficulty repeating words)
Arcuate Fasciculus
Lesions to Arcuate Fasciculus result in this
conduction aphasia (difficulty repeating words; comprehension and production of language are intact)
Lesion to pars triangularis or pars opercularis may cause this
Broca’s aphasia
(Expressive or motor aphasia
Nonfluent speech, difficulty with syntax, grammar, and production of individual words
Comprehension is intact)
Is comprehension intact in Broca’s aphasia?
yes
Is comprehension intact in Conduction aphasia?
yes
Is comprehension intact in Wernicke’s aphasia?
no
Lesion of language systems that involves nonfluent speech, difficulty with syntax, grammar, and production of individual words
Broca’s aphasia
Lesion of language systems that involves fluent speech, syntax, and grammar, and structure of words is intact
Wernicke aphasia
impairment in reading ability caused by central language processing deficits
Alexia
impairment in writing ability caused by central language processing deficits
Agraphia
Gerstmann’s syndrome involves agraphia, acalculia, right-left disorientation, and finger agnosia, and is caused by lesion to this
Dominant inferior parietal lobule (in the region of the angular gyrus)
Lesions of dominant inferior parietal lobule, in the region of the angular gyrus may cause this condition, characterized by agraphia, acalculia, right-left disorientation, and finger agnosia
Gerstmann’s syndrome
Gerstmann’s syndrome is caused by lesions of the dominant inferior parietal lobule, in the region of this
Angular gyrus
Subcortical fibers that interconnect areas within a hemisphere
Association fibers
Subcortical fibers that connect similar functional areas in two hemispheres
Commissural fibers
Subcortical fibers that travel to or from the cortex
In the Corona Radiata and converge into the internal capsule
Projection fibers
White matter fibers that provides important sensory communication between the parietal, occipital, and temporal lobes and the cortex of the frontal lobe so that appropriate action can be performed
Superior longitudinal fasciculus
White matter fibers that connects two major language areas in the dominant hemisphere
Arcuate fasciculus
Procedure that results in:
Inability to write (agraphia) with the left hand
Inability to name objects (anomic aphasia) placed in the left hand with the eyes closed, and
Inability to read (alexia) in the left hemi-field
Corpus callosotomy
(the right hemisphere is unable to access language functions in the left hemisphere)
Corpus callosotomy results in the inability to do these 3 things
Write with left hand
Name objects placed in left hand with eyes closed
Read in left hemi-field
Intractable complex or grand mal seizures that have an epileptogenic focus on one hemisphere may be treated by severing this
Corpus callosum
Intractable complex or grand mal seizures that have an epileptogenic focus on one hemisphere may be treated by severing the corpus callosum in this procedure
Corpus callosotomy
Damage to this structure can result in “Alien hand syndrome”, where patient’s hand may act without being guided by the patient’s own will
Corpus callosum
What is the arterial supply to the anterior limb of the internal capsule?
Lateral striate branches of MCA
Medial striate branches of ACA
What is the arterial supply to the genu of the internal capsule?
Lateral striate branches of MCA
Anterior choroidal
What is the arterial supply to the posterior limb of the internal capsule?
Lateral striate branches of MCA
Anterior choroidal
What is the arterial supply to the sublenticular part of the internal capsule?
MCA
What is the arterial supply to the retrolenticular part of the internal capsule?
PCA
Small branches from anterior choroidal
Which component of the internal capsule receives blood supply from lateral striate branches of MCA and medial striate branches of ACA?
Anterior limb
Which component of the internal capsule receives blood supply from lateral striate branches of MCA and anterior choroidal?
Genu
and posterior limb
Which component of the internal capsule receives blood supply from only MCA?
Sublenticular part
Which component of the internal capsule receives blood supply from PCA and small branches from anterior choroidal?
Retrolenticular part
What two types of fibers does the anterior limb of the internal capsule contain?
Corticopontine
Thalamocortical
What three types of fibers does the posterior limb of the internal capsule contain?
Corticopontine
Thalamocortical
Corticospinal
What type of fibers does the genu of the internal capsule contain?
Corticobulbar
What type of fibers does the sublenticular part of the internal capsule contain?
Acoustic radiation
What type of fibers does the retrolenticular part of the internal capsule contain?
Optic radiation
What artery supplies the motor and sensory cortices (lower limb)?
ACA
What artery supplies the supplemental motor area?
ACA
What artery supplies the prefrontal cortex?
ACA
What artery supplies the internal capsule (anterior limb)?
ACA
What artery supplies the occipital lobe?
PCA superficial branch
What artery supplies the splenium of corpus callosum?
PCA superficial branch
What artery supplies the inferior and medial parts of temporal lobe?
PCA superficial branch
What artery supplies the thalamus?
PCA deep branch
Alexia (inability to read) without agraphia (inability to write) is seen in lesion to this
Splenium of corpus callosum
Lesion to this relay center for descending and ascending information, as well as integration of cerebral cortex and the rest of the CNS, results in contralateral hemi-sensory loss
Thalamus
Prosopagnosia can be caused by lesions to the ventral “what” pathway of the occipital lobe, as well as parts of this structure
Inferior and medial parts of temporal lobe
Lesion to this part of MCA causes right face and arm weakness
Left MCA superior division
(UMN; also Broca’a aphasia)
Lesion to this part of MCA causes right face and arm cortical sensory loss, and right homonymous hemianopia
Left MCA inferior division
(also Wernicke’s aphasia)
Lesion to this part of MCA causes right hemiplegia
Left MCA deep territory
(UMN)
Lesion to this part of MCA causes a combination of right hemiplegia, right hemianesthesia, right homonymous hemianopia and global aphasia
Left MCA stem
