Frontal Lobes Flashcards
Statistics of the frontal lobes
- 1/3 of the brain
- 20% of the brain’s oxygen
Frontal lobe maturation
Development comes in bursts all the way into one’s 20s. Due to the lateness of the development, the loves are individualised and specialised - environment influences development
Why are the frontal lobes historically considered silent?
Damage to the frontal lobes doesn’t present in an obvious way, the way that damage to other areas does. Speech, motor functions etc. remain intact.
What did Walter Freeman do in 1936?
Performed the first lobotomy
Define lobotomy
Psychosurgical procedure: severe the PFC and underlying structures, or destroy frontal cortical tissue.
Motivation for a lobotomy
It uncoupled the brain’s emotional centres from the seat of the intellect
Clinical reasoning behind silence of the lobes
The everyday behaviour was in tact. Namely, memory and intelligence. By this reasoning, FL lesions are asymptomatic
Changed view on the role of frontal lobes
With the advancing of testing tools, we can see that lesions:
- disrupt normal cognition
- produce a number of severe problems
Phineas Gage’s role
He was the first evidence that damage may be problematic, his personality changed and he became inappropriate in his behaviour
Modern understanding of frontal lobes
They act as conductors, guiding, directing, integrating and monitoring goal-directed behaviour
Interconnectedness of the frontal lobes
They are vastly interconnected, within and between hemispheres, as well as maintaining reciprocal connections across the brain. Consequently, frontal lobe deficits effects cross domains
Why do we take the syndrome approach to frontal lobe damage?
It’s a complex region, focusing on executive functions is difficult. It’s easy to look at certain regularities of frontal lobe pathology.
Two distinct anatomical and functional systems of the frontal lobes
- Dorsolateral
2. Ventral mesial (orbitofrontal/basal/medial)
Two sections of the ventral mesial system
- Ventral/orbitofrontal regions
2. Medial regions, including the anterior cingulate
Five parallel frontal-subcortical circuits
- Skeletomotor
- Oculomotor
- Orbitofrontal region
- Dorsolateral PF region
- Anterior cingulate
Neurological structure of the circuits
They all project from the frontal lobes to the basal ganglia, it’s a reciprocal projection. Each circuit returns via a specific thalamus nucleus