Organization of Cerebral Cortex Flashcards
Bands of Baillarger are:
Present in layers:
Horizontal nyelinated fibers
4, 5
Pyramidal cells predominate in layers ___
3, 5
Order of layers of cortex (outside –> inside)
Plexiform Outer granule Outer pyramidal Inner granule Inner pyramidal Multiform
Short association fibers originate in layer ___
Connect neurons that:
2
Closely adjoining gyri of SAME lobe
Long association fibers originate in layer ___
Connect neurons that:
3
Widely separated cortical regions of the same hemisphere (connection b/w lobes)
Callosal fibers originate in layer ___
Connect:
Major examples:
3
Homologous parts of opposite hemispheres
Corpus callosum = all lobes except temporal
Anterior commissure = temporal lobe
Von Economo spindle neurons originate in layer ___ of _______ cortex Involved in:
5
Frontoinsular and anterior cingulate cortex
Empathy, social awareness, self-control
Corticostriate, corticopontine, corticobulbar, corticospinal neurons originate in layer ___
5
Corticothalamic neurons orgininate in layer ___
6
Thalamocortical projections from SPECIFIC thalamic nuclei target layer ___
4
Thalamocortical projections from ASSOCIATION specific nuclei target layers ___
1, 3, 5
Local intrinsic pathways connect ___
layers
Local circuit pathways connect ____
columns
Primary neurons respond to ____
Most input from:
ONLY single modality: somatosensory, olfactory, auditory, visual, gustatory, motor
Specific thalamic nuclei
Secondary (belt) areas of cortex respond to ____
Input from:
Single modality but perform more complex processing
Primary nuclei and some specific thalamic nuclei
Association areas of cortex are located ____
Receive input from:
Promotes:
Between adjacent secondary areas
Multimodal thalamic input from association thalamic nuclei (pulvinar), primary and secondary cortices and brainstem
Complex integrative functions
Frontal association cortex function:
plans appropriate behavioral responses to stimuli
Parietal association cortex function:
Attends to complex stimuli in external and internal environment
How you fit into world that you’re sensing
Temporal association cortex function:
Identifies nature of such stimuli
Apraxia
Deficits in spatial and construction
Agnosia
Deficit in recognition and categorization
Left or right hemisphere?
Language function
Left
Left or right hemisphere?
Spatial functioning
right
Left or right hemisphere?
Non-verbal functions
Right
Left or right hemisphere?
Concerned w/ objects or entities
Left
Left or right hemisphere?
Emotions associated w/ verbal stimuli
Left
Left or right hemisphere?
Emotions associated w/ nonverbal stimuli
Right
Small lesions of V1 produce ___
Larger lesions produce ____
Scotomas in the opposite visual field
Loss of contralateral visual field quadrants: quadrantopsia
Dorsal V3 receive input from ____
Respond to ____
Concerned with:
V1 and V2
Large scale motion
Object and relative body motion
Placing objects in external space
COntrol of visually guided eye movements
Ventral V3 receives input from ___
Involved in:
V2
Object recognition
V4 is concerned in:
Output to:
assemblage of object representations
Posterior inferior temporal lobe
Left inferior temporal involved in:
Processing feature information (color, texture, shape)
Symbols associated with language (writing)
Alexia
unable to understand written words
Agraphia
Loss in ability to communicate through writing
Alexia with agraphia caused by:
LEFT posterior inferior temporal lobe lesion
Agnosia
Inability to recognize objects, discriminate b/w simple geometric shapes and their orientation
Agnosia caused by:
Lesions of the ventromedial occipitotemporal cortex
Parietal eye fields function
Generate saccadic eye movements evoked by novel visual/auditory stimuli
Frontal eye fields function
Generate voluntary eye movements
V5 location:
Sends info to:
Involved in:
Posterior end of middle temporal gyrus
Frontal eye fields and posterior parietal cortex
Motion perception, assemblage of objects in visual space
Bilateral lesion of posterior parietal cortex near temporoparietooccipital junction causes:
Compromised by:
Deficits:
Balint’s syndrome
Watershed infarct b/w MCA/PCA –> posterior cortical atrophy
Simultanagnosia
Ocular apraxia
Optic ataxia
Simultanagnosia
Inability to perceive more than single object at a time
Ocular apraxia
absence or defect of controlled, voluntary and purposeful eye movement
Optic ataxia
lack of coordination b/w visual inputs and hand movements –> inability to reach and grab objects
Primary auditory cortex located in:
Inputs:
transverse temporal gyri (Heschl’s gyri)
Binaural input w/ contralateral dominance
Thalamic input from medial geniculate nuclei
Left auditory cortex involved:
decoding temporal aspects of sounds (sequence, duration, intervals b/w sound)
Right auditory belt cortex
Decodes spectral aspects of sounds (frequency, pitch, harmonics)
Predicts sound that should come next: filling in gaps
Auditory processing
The further from primary cortex, the less the ____ but the higher the ____
acoustic sensitivity
selectively response to more complex stimuli
Wernicke’s area is located (left/right) ____
Specialized in:
Active during:
Left posterior superior temporal gyrus
Decoding verbal information. Phonemic content
Gaps between speech sounds
Damage to Wenicke’s area leads to
Sensory aphasia: Speech sounds fluent, effortless and melodic but is jumbled and unintelligible
Cannot express themselves meaningfully using language
Similar area of Wernicke’s area on the right is involved in
Prsody: rhythms, intonations in normal speech
Lesions to right posterior superior temporal gyrus lead to
sensory aprosodia: inability to detect prosodic elements (humor, sarcasm) in speech
Ventral stream of auditory association pertains to:
Done by:
Recognition of words and their meaning
Lateral and inferior parts of the temporal lobe
Dorsal stream of auditory association pertains to:
Done by:
Significance of location and motion of the sound source
Posterior parietal cortex function
Left caudal parts of lateral and inferior temporal lobe important for:
retrieval of general names of objects
Left anterior parts of lateral and inferior temporal lobe important for:
retrieval of proper nouns that denote unique entities (individuals, places)
Lesions of left lateral and inferior temporal lobe lead to:
Anomia: naming defects w/ severity increasing with lesions closer to temporal pole
Right lateral and inferior temporal lobe involved in:
Recognition of objects, retrieval on non-verbal information pertaining to these objects
Medial temporal lobe includes (3)
Critical for: (3)
parahippocampal gyrus, hippocampus, amygdala
Memory formation, emotion, sexual behavior
Agraphesthesia
Inability to recognize written letters or numbers traced on the skin
Astereognosis
Inability to identify an object by active touch of the hands without other sensory input
Lesions affecting the ventromedial parietal lobe lead to:
tactile agnosia: cannot recognize objects by touch or cannot name them
Lesions affecting dorsomedial parietal lobe lead to:
Constructional apraxia: difficulty with simple drawings, assembling blocks
Right inferior parietal lobule plays a critical role in:
Self-perception and position of body in external space
Visuospatial tasks and using spatial knowledge to perform complex tasks
Damage to right inferior parietal lobule leads to ___
Hemispatial neglect: left side of bodyd ignored
Visual neglect of left visual field
Left inferior parietal lobule involved in:
Language functions
Lesions in left supramarginal gyrus (IPL) have:
impairments in verbal working memory
Lesions of both supramarginal and angular gyri cause:
Agraphia: loss of ability to write
Acalculia: loss of ability to understand math
Finger agnosia: inability to distinguish own fingers and fingers of others
Gerstmann’s syndrome
Agraphia + acalculia + finger agnosia + impaired verbal working memory
Small lesions of V1 produce ___
Larger lesions produce ____
Scotomas in the opposite visual field
Loss of contralateral visual field quadrants: quadrantopsia
Ventral V3 receives input from ___
Involved in:
V2
Object recognition
V4 is concerned in:
Output to:
assemblage of object representations
Posterior inferior temporal lobe
Left inferior temporal involved in:
Processing feature information (color, texture, shape)
Symbols associated with language (writing)
Right inferior temporal involved in:
holistic non-verbal perception; face recognition
Alexia
unable to understand written words
Agraphia
Loss in ability to communicate through writing
Alexia with agraphia caused by:
LEFT posterior inferior temporal lobe lesion
Agnosia
Inability to recognize objects, discriminate b/w simple geometric shapes and their orientation
Agnosia caused by:
Lesions of the ventromedial occipitotemporal cortex
Parietal eye fields function
Generate saccadic eye movements evoked by novel visual/auditory stimuli
Frontal eye fields function
Generate voluntary eye movements
V5 location:
Sends info to:
Involved in:
Posterior end of middle temporal gyrus
Frontal eye fields and posterior parietal cortex
Motion perception, assemblage of objects in visual space
Bilateral lesion of posterior parietal cortex near temporoparietooccipital junction causes:
Compromised by:
Deficits:
Balint’s syndrome
Watershed infarct b/w MCA/PCA –> posterior cortical atrophy
Simultanagnosia
Ocular apraxia
Optic ataxia
Simultanagnosia
Inability to perceive more than single object at a time
Ocular apraxia
absence or defect of controlled, voluntary and purposeful eye movement
Optic ataxia
lack of coordination b/w visual inputs and hand movements –> inability to reach and grab objects
Primary auditory cortex located in:
Inputs:
transverse temporal gyri (Heschl’s gyri)
Binaural input w/ contralateral dominance
Thalamic input from medial geniculate nuclei
Left auditory cortex involved:
decoding temporal aspects of sounds (sequence, duration, intervals b/w sound)
Right auditory belt cortex
Decodes spectral aspects of sounds (frequency, pitch, harmonics)
Predicts sound that should come next: filling in gaps
Auditory processing
The further from primary cortex, the less the ____ but the higher the ____
acoustic sensitivity
selectively response to more complex stimuli
Wernicke’s area is located (left/right) ____
Specialized in:
Active during:
Left posterior superior temporal gyrus
Decoding verbal information. Phonemic content
Gaps between speech sounds
Damage to Wenicke’s area leads to
Sensory aphasia: Speech sounds fluent, effortless and melodic but is jumbled and unintelligible
Cannot express themselves meaningfully using language
Similar area of Wernicke’s area on the right is involved in
Prsody: rhythms, intonations in normal speech
Lesions to right posterior superior temporal gyrus lead to
sensory aprosodia: inability to detect prosodic elements (humor, sarcasm) in speech
Ventral stream of auditory association pertains to:
Done by:
Recognition of words and their meaning
Lateral and inferior parts of the temporal lobe
Dorsal stream of auditory association pertains to:
Done by:
Significance of location and motion of the sound source
Posterior parietal cortex function
Left caudal parts of lateral and inferior temporal lobe important for:
retrieval of general names of objects
Left anterior parts of lateral and inferior temporal lobe important for:
retrieval of proper nouns that denote unique entities (individuals, places)
Lesions of left lateral and inferior temporal lobe lead to:
Anomia: naming defects w/ severity increasing with lesions closer to temporal pole
Right lateral and inferior temporal lobe involved in:
Recognition of objects, retrieval on non-verbal information pertaining to these objects
Medial temporal lobe includes (3)
Critical for: (3)
parahippocampal gyrus, hippocampus, amygdala
Memory formation, emotion, sexual behavior
