Cortical Organization - E2 Flashcards
What is the localization theory?
Specific functions are assigned to regions of the cerebral cortex and they operate independently of each other
Broadman’s areas 41, 42, and 22 basic disorders, dysfunction and region of brain
Temporal lobe
Disorders of auditory sensation and perception. Dysfunction: Unilateral lesion –> partial hearing loss in CL ear
What deficits would you find from damage to the R temporal lobe (per the Localization Theory)?
R:
- 41,42,22: L hearing loss
- Long term memory: Nonverbal (designs, what you did)
Bil:
- Selective attn, distractibility
- Change in personality/affect
- Changes in sexual activity
What deficits would you find from damage to the R frontal lobe (per the Localization Theory)?
R:
- 4: L hemiparesis/plegia
Bil:
- 6 (lateral): PMA
- 6 (medial): SMA
- Impaired response inhibition (distractable, dec. : judgement, consid of outcomes, elabo.)
- Impaired social behaviour (apathy, dec. initiation, no social graces)
- Altered Sexual Behaviour
- Dec. behav. spontaneity
- Poor recency memory
Function of PMA vs SMA
PMA is planning and production of complex motor tasks by SMA is planning and execution of complex motor behaviour
What deficits would you find from damage to the L frontal lobe (per the Localization Theory)?
L:
- 4: R hemiparesis/plegia
- 44: Broaca’s area - Expressibe aphasia
Bil:
- 6 (lateral): PMA
- 6 (medial): SMA
- Impaired response inhibition (distractable, dec. : judgement, consid of outcomes, elabo.)
- Impaired social behaviour (apathy, dec. initiation, no social graces)
- Altered Sexual Behaviour
- Dec. behav. spontaneity
- Poor recency memory
What deficits would you find from damage to the L temporal lobe (per the Localization Theory)?
L:
- R hearing loss (41, 42, 22)
- Long-term memory: Verbal
- 22: Wernicke’s Area - Receptive aphasia
Bil:
- Selective attn, distractibility
- Change in personality/affect
- Changes in sexual activity
What deficits would you find from damage to the R Parietal lobe (per the Localization Theory)?
R:
- Short term memory: Non-verbal
- L sided neglect
- Spatial apraxia
- Disorders of spatial ability
- Disorders of drawing
Bil:
- 3,1,2: Sensation
- 5,7: Stereognosis
- 39,40: Cross-modal matching (visual, sensory, auditory)
- Disorders of body image
What deficits would you find from damage to the L Parietal lobe (per the Localization Theory)?
L:
- Short-term memory: Verbal
- Apraxia
- Disorders of language
- Acalculia
- R/L confusion
- Disorders of writing
Bil:
- 3,1,2: Sensation
- 5,7: Stereognosis
- 39,40: Cross-modal matching (visual, sensory, auditory)
- Disorders of body image
Which side of the brain is associated w/non-verbal disorders?
Non-dominant or Right hemisphere
Which side of the brain is associated w/verbal disorders?
Dominant or Left hemisphere
What part of the brain is associated w/disorders of spatial ability?
Non-dominant or Right Parietal lobe
Which part of the brain is associated w/…
a) long term
b) short term
Memory?
a) Temporal = Long
b) Short = parietal
Which hemisphere is more…
a) logical
b) creative
a) Dominant (Left) = logical
b) Non-dominant (Right) = creative
Where in the brain do you get hearing disorders?
Temporal lobes: areas 41,42,22
Where in the brain do you get sensory disordres?
Parietal lobe 3,1,2
Where in the brain do you get motor disorders?
4: Hemiparesis
6: lateral PMA medial SMA
Where and what is area 44?
What does damage to that area cause?
Dominant (left) frontal lobe - Broca’s area
Damage = expressive aphasia
Where and what is area 4?
What does damage to that area cause?
Primary Motor Cortex in R and L frontal lobes
cause hemiparesis or hemiplegia of CL side
Where and what is area 3,1,2?
What does damage to that area cause?
Primary Somatosensory Cortex in R and L parietal lobes w/3 more “ant”
Damage causes disorders of tactile dysfunction and perception and sensation
Where and what is area 39 and 40?
What does damage to that area cause?
Sensory association area in Parietal Lobe
Damage causes Impaired cross modal matching (visual, aud, and sesnory together)
Where and what is area 6?
What does damage to that area cause?
Medial is SMA and Lateral is PMA in frontal cortex R and L
Damage causes disorders of planning, production, organization, and execution of complex motor behaviours
Where and what is area 5,7?
What does damage to that area cause?
It is in the parietal lobe for stereognosis
Damage causes visual or tactile agnosia
Where and what is area 17,18,19?
What does damage to that area cause?
Occipital Lobe
Damage causes visual problems
Where and what is area 22?
What does damage to that area cause?
Wernicke’s Area in L Temporal Lobe
Damage causes receptive aphasia
Where do you see disorder of music, pitch, rhythm?
in R (non-dom) hemisphere
Where do you see disorders of language?
In L (dom) hemisphere
What does focal damage to the face region in area 4 and area 3,1,2 cause?
dysarthria
What is the connectionism theory?
It is a theory of cortical organization based on neuroanatomy that states bundles of axons connect various brain areas together and allow an exchange of information b/t lobes/areas and b/t hemispheres
What are the commissural fibers in the connectionism theory?
ex?
(un)myelinated axons that cross the midline and interconnect the hemispheres
Ex) Corpus callosum (interconnects the frontal, parietal, temporal and occipital lobes)
What are the association fibers in the connectionism theory?
ex?
(Un)myelinated axons that interconnect areas of the same cerebral hemisphere
Ex) Arcuate fasciculus (connects temp, par & temp lobes w/in same hemi)
What are the projection fibers in the connectionism theory?
ex?
(Un)myelinated axons project up and down the neuroaxis (cranial <> caudal)
Ex) Internal capsule
What is the cellular connectionism theory
It is a theory of cortical organization that combines the localization and connectionism theory to state that:
All hemi fun. dependent on discrete, identifiable collections of cells that have integrated, specific connections w/in and across the hemispheres and in other parts of the brain and SC up and down the neuroaxis
What is example 1 of the Evidence of cellular connectionism theory?
The Wernicke-Geschwind Model of Language
What is the Wernicke-Geschwind Model of Language?
(Example 1 of the cellular connectionism theory)
Multiple areas and their inter-connections are responsible for the whole function of speech
What are the 8 components of the Wernicke-Geschwind Model of Language
- Visual input (17 primary & 18,19 association)
- Auditory input (41,42)
- Tactile/proprioceptive input SI (1,2,3)
- Left Wernicke’s area (22)
- Left angular gyrus (39)
- Left arcuate fasciculus
- Left pre- and post-central gyri (3,1,2 and 4)
- Left Broca’s area
Which area of the brain do you get x aphasia according to the Wernicke-Geschwind Model of Language?
a) receptive
b) conduction
c) expressive
a) wernicke’s area (22 - temporal)
b) arcuate fasiculus
c) broca’s area (44 - frontal)
What is example 2 of the Evidence of cellular connectionism theory?
5 cortical areas in motor control - produces visually and goal-oriented, voluntary movement
List the 5 cortical areas involved in motor control (Ex. 2 of Evidence of Cellular Connectionism Theory)
- Motor Cortex (MI aka B. 4)
- Sensory Cortex (SI aka B. 312)
- Pre-motor area (PMA 6 lateral, 8)
- Supplementary motor area (SMA B. 6 medial)
- Posterior Parietal Lobe (B. 5&7)
What does micro-stimulation of the MI/B4 cause?
Isolated contractions of individual mms
When is MI/B4 active?
Immediately before and during movement and is the last cortical area to “fire” prior to mvmt onset
What does the DC frequency of the CST neurons encode (from MI/B4)?
FORCE AND RATE OF FORCE prod used to move the limb
NOT corresponding to position changes of the limb
What does the Evarts 1968 study show?
(MI portion of 5 cortical areas for Ex 2 of Cellular Connectionism Theory)
Shows that the CST neurons in the MI region do not correspond with the direction of mvmt/position change of a limb, but rather with the force and rate of force being used (Wrist flexion w/extension load = Extensors active whereas flexion w/flexion load is flexion neurons active)
What does the Georgopolus 1982 study show?
(MI portion of 5 cortical areas for Ex 2 of Cellular Connectionism Theory)
Individual MI neurons are sensitive to a mvmt direction during a “center-out” task and fire predominately to mvmts in the preferred direction, but also to a lesser degree to mvmts in other directions
What are population vectors per Georgopoulos (1982)?
The vectorial summation of single-cell contributions to accurately predict the direction of mvmt in 2/3D space to represent firing intensity avg. over a specific temporal period. & the cells preferred direction
What is true of the PMA? (Cellular Connectionism Theory Ex. 2)
Activity proceeds MI by <= 1 second and it is responsible for planning and prod of purposeful, complex mvmts, esp. those visually and sensory guided.
Which area is responsible for…
a) proximal and axial mm control
b) bimanual control
A) PMA
B) SMA
What is true of the SMA? (Cellular Connectionism Theory Ex. 2)
It has a role in more complex mvmts (Sequencing) & is active even during imagined, complex mvmts
What is true of the Posterior Parietal Lobe? (Cellular Connectionism Theory Ex. 2)
It is esp. involved w/visually guided mvmts and is responsible for spatial rlns. Helps w/sensorimotor transformations
Info on occipital lobe…
a) dorsal pathway
b) ventral pathway
(end destination and what each does)
a) to parietal lobe (spatial relations b/t obj. and self and to e.o.)
b) to ant, inf. temporal love (what are the physical qualities of the object)
What is the cortical lateralization or asymmetry of function theory?
States that each hemisphere processes the same info, just differently & is analyzed for different content depending on the hemisphere
What is the Right hemisphere responsible for according to the cortical lateralization theory?
Holistic logic
- spatial org. of sensory info
- symbolic and tonal communication
- drawing
What is the Left hemisphere responsible for according to the cortical lateralization theory?
Sequential logic
- ability to use syntactic rules for communication and math calculations
- organize events in a temporal sequence
- spoken and written word
What does the theory of brain development by Kolb and Whishaw state?
Supports cortical lateralization theory and states that both hemi are specialized at birth, but can assume some of the fun. performed by the missing hemisphere b4 age 5 (equipotentiality and parallel-development theories)
What is the equipotentiality theory
One of the theories of brain development by Kolb and Whishaw that states either hemi has equal potential for developing a certain function (b4 age 5)
What is the parallel-development theory
One of the theories of brain development by Kolb and Whishaw that states both hemispheres are destined to specialize for a certain function
What does the theory of brain development by Moscovitch state?
Supports cortical lateralization theory and states that there is a possibility that one hemisphere will inhibit the other hemisphere from developing similar functions & begins at age 5, which is why there is less plasticity after this age
What is reaction time?
The time b/t the stimulus being received and movement initiation beginning
What is movement time?
The time b/t movement initiation and mvmt termination
What is the Cognitive Stages of Motor Processing Theory
A theory that states there are 7 stages of cognitive processing that occur during the reaction time in order to produce a motor behaviour
List the 7 stages of cognitive processing according to the Cognitive Stages of Motor Processing Theory
- Detect
- Identify
- Memory Search
- Decision
- Response Selection
- Response Organization
- Response Execution
What is the encoding period?
Steps 1 and 2 (detect and identify) in the 7 cognitive stages of motor processing
What occurs in Stage 1: Detect with regard to: capacity code type, and decay rate
- visual:
capacity: 17 letters/words/symbols
code type: physical
decay rate: 200msec - auditory
capacity: 5 syllables/words/sounds
code type: physical
decay rate: 1500msec
What occurs in Stage 2: Identify with regard to: capacity code type, and decay rate
Capacity: chunks (3 if pure working, 7 if use LTM)
Code type: semantic/symbolic
decay rate: 7 seconds
What is Stage 1: Detect?
It is for image store, both visual and auditory
What is Stage 2: Identify
It is for working memory (recognizing or perceiving the image)
What is stage 3: Memory Search
It is the idea of “stacking” a network of related serial chunks into LTM
What occurs in Stage 3: Memory Search with regard to: capacity code type, and decay rate
Capacity: Infinite
Code type: Semantic
Decay: Infinite/N/A
What is stage 4: Decision?
Deciding whether or not the individual should act at the time - may include whether it is appropriate or not to act
What neuro population might have difficulty with stage 4: decision?
Individuals w/TBIs
What is Stage 5: Response Selection?
Choosing from a number of alternate motor responses (following Hicks Law)
What is Hick’s Law?
A law that states the more alternatives = the longer the reaction time (logarithmically)
What is Stage 6: Response Organization?
Organizing motor output as movement distance, direction, and speed
What is Stage 7: Response Execution
Executing the motor output as to mm, forces, and rate of force
Name a test of executive function for adults 18+
Trail Making Test part B (#s and As): Requires working mem, processing speed, visuospatial skills, selective and divided attn, and psychomotor coordination
What are some problems you may see w/impaired executive function?
Apathy
Lack of goal-directed behaviour (no cooperation &/motivation)
- lack of behavioural flexibility (alt. solns)
What are some of the executive functions?
- Decide on goal
- Plan for goal
- Execute goal
- Monitor execution
