Higher Order Cerebral Function Flashcards
What are the 6 layers of the neocortex
- Dendrites and axons from other layers
- Cortical to cortical connections
- Cortical to cortical connections
- Receives inputs from thalamus
- Sends outputs to subcortical structures (other than thalamus)
- Sends outputs to thalamus
What is included in the primary cortex?
- Primary sensory cortex (somatosensory, visual, and auditory)
- Primary motor cortex
What is included in the association cortex?
- Unimodal association cortex: area adjacent to primary cortex involved in processing for a SINGLE sensory or motor modality (somatosensory, visual, auditory, premotor cortex, supplementary motor area)
- Heteromodal association cortex: integrating functions from MULTIPLE sensory and/or motor modalities (prefrontal cortex, parietal, and temporal heteromodal association cortex
What are Brodmann’s Areas?
- Cortex is divided based on microscopic appearance
- Correlates well with functional areas of the cortex
How is cortical sensory processing relayed?
- Sensory input travels to the primary sensory cortex via thalamic relay
- Primary cortices relay to unimodal and heteromodal association cortices
The primary somatosensory cortex (S1) receives input from where?
- Ventral posterior nucleus of the thalamus
- Ventral medial nucleus of the thalamus
What does the secondary somatosensory cortex (S2) respond to?
Responds to touch, pressure, limb position, and pain from both sides of the body
Describe the inputs as in pertains to parallel processing from Brodmann’s areas in the primary somatosensory cortex
- Muscle spindle afferents synapse in area 3a
- Cutaneous afferents synapse in areas 1 and 3b
- Joint receptors synapse in area 2
What symptoms may be seen with a lesion in the primary somatosensory cortex (S1)?
- Impaired 2 point discrimination
- Impaired localization of stimuli
- Impaired position sense
What does the unimodal association cortex do in terms of somatosensory perception?
- Found in brodmann’s area 5
- Receives input from the primary somatosensory cortex (S1)
- Integrates information between body segments and somatosensory modalities
- Process of stereognosis occurs here
What does the heteromodal association cortex do in terms of somatosensory perception?
- Found in brodmann’s area 7
- Receives input from brodmann’s area 5 and visual information
- Controls eye-limb processing for most visually triggers or visually guided movements
What does the primary visual cortex do?
- Found in brodmann’s area 17
- Receives input from the lateral geniculate nucleus of the thalamus
- Integrates information from both eyes about shape, color, size, location, and direction of movement for the contralateral half of the visual field
What is the difference in function between the dorsal and ventral pathways of the heteromodal visual association areas?
- Dorsal: analysis of motion and spatial relations (where are things around you?)
- Ventral: analysis of form and color (what are the things around you?)
Describe the primary auditory area (A1)
- In transverse temporal gyri
- Found in brodmann’s area 41
- Receives input from medial geniculate nucleus of the thalamus
- Responsible for sound frequency and location from both ears
Describe the secondary auditory area (A2)
- In transverse temporal gyri
- Found in brodmann’s area 42
- Receives input from medial geniculate nucleus of the thalamus
What does the auditory unimodal association area do?
- In transverse temporal gyri
- Found in brodmann’s area 22
- Interconnects with the medial geniculate nucleus of the thalamus
- Discriminates auditory frequencies , sequence, or pattern
- Projects to heteromodal association areas in prefrontal and parietotemporal areas
What is hemispheric specialization?
There is mostly symmetrical anatomy and functions of the left and right hemisphere, but some marked asymmetries functionally, which may eliminate communication delays between the hemispheres
Which hemisphere is typically dominant and why?
- Left hemisphere is typically dominant
- Controls simple movements for contrlateral limb and skilled tasks for both limbs (90% of people are right-hand dominant)
- Language center
What is lateralization and what makes it clinically relevant?
- Lateralization is the development of a “dominant” hemisphere that usually occurs before 3-4 years of age
- If damage occurs early in lateralization, language and handedness function can shift to the other hemisphere
- If damage occurs too late, function will not shift
What structures are involved in the core language circuit?
- Wernicke’s area
- Broca’s area
- Arcuate fasciculus
What is Wernicke’s area?
- Found in brodmann’s area 22
- Posterior 2/3 of superior temporal gyrus in the dominant hemisphere
- Adjacent to the primary auditory cortex
- Responsible for language processing to enable sequences of sounds and writing to be identified and comprehended as meaningful words
- Adjacent association cortex assist in language processing
What is Broca’s area?
- Found in brodmann’s areas 44 and 45
- Opercular and triangular portion of the inferior frontal gyrus
- Motor program to activate sequences of sound to produce words and sentences are formulated here and communicated to the face region of the primary motor cortex
- Adjacent areas assist with the production of speech