Where is the Prefrontal Cortex located and much of the cortex is the PFC?
1/3 of human cortex
Name two scientists in the history of the prefrontal cortex
Fritsch and Hitzig - electrical stimulation
Ferrier - silent cortex (no motor actions)
Monakow - anatomic similarity to thalamus
Brodmann - current term: granular frontal brain region
Rose and Woolsey, Akert - defined prefrontal cortex
Van de Werd
Why do we use the term Prefrontal Cortex (PFC) and not frontal granular cortex or frontal association cortex anymore?
frontal granular cortex —> limits to areas with layer 4
frontal association cortex —> limits to one cognitive function
Which is included in the PFC? Premotor or motor cortex?
none, its excluded
What is the role of PFC in higher cognitive function?
organization of action and behavior (movements, language, …) in temporal domain
—> the longer the series —> more dependent on PFC
executive control (decision making and planning)
What is the Perception-Action Cycle?
interaction between perceiving the environment and taking actions based on those perceptions
transaction between executive and perceptual memory
blue: involved in sensory processing
red: forming meaningful output, motor
—> meaningful responses and execution = PA cycle
hierachically organized channels form a medial (internal signals as emotions, feelings) - lateral (external signals) division
Ontogeny: How does the PFC develops from child to adult?
first: motor and sensory cortex
cognitive cortical association areas (inkl. PFC) are last to myelinate —> complex built
lateral PFC (external/environmental signals) later than medial and inferior PFC (emtions, …)
changes will stop in the ages 20-30
PFC is one of the most likely brain regions to show age-related cell loss and degeneration (“cortical thinning”)
Which Broca areas are in the PFC?
B44/45/47
In which functional areas can the PFC be divided?
dorsolateral (dl) & dorsomedial (dm)
ventrolateral (vl) & ventromedial (vm)
OFC - orbital frontal cortex
ACC - anterior cingulate cortex
What is the cytoarchitecture of the PFC and which is the most prominent layer in the homotypical isocortex?
I. Molecular layer
II. External granular layer
III. External pyramidal layer
IV. Internal granular layer
V. Internal pyramidal layer
VI. Multiform layer
—> prominent granular IV (small granule neurons)
What is the differnece of PFC in humans and rodents?
rodents don’t have granular areas (all are Agranular) —> no strong layer 4
—> cant fuse and integrate the input information
Do rodents have a prefrontal cortex?
YES! a medial PFC
but not a lateral PFC
but its behavior, not the cortex that is selected by evolution
How does the damage of PFC shows in a patient?
deficits in:
executive functions (planning, decision-making, …)
affect, emotion and social behavior
language
intelligence
What tests can be done to show PFC damage?
Wisconsin Card Sorting Test
shows ability to form concepts and stick/shift concepts when a rule shifts
—> sort cards by rule; when rule changes, patients can not adapt to that rule
Bi-stable vision
see pictures that can be multiple things
—> patients cannot switch btw. ambigious figures
What insight could be gained from experiments such as rule-switching-task and match-to-numerosity-task with monkeys?
Single PFC neurons represent abstract rules.
—> one neuron for match rule and one for non-match
—> match rule is preferred
Individual neurons are tuned to numerosity.
What is the main function of PFC?
brain’s center for organizing behavior
orchestrates thought and action with internal goals / behavior in temporal domain
What are three axes in the PFC and their functions?
medio-lateral axis (emotional internal vs. sensory, environmental external signals)
ventro-dorsal axis (what and where a object is)
rostro-cordol axis (more and less abstract)
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