8.1.1 The cerebral Cortex Flashcards
What is the fine structure of the cerebral cortex?
6 layers containing cell bodies and dendrites
What are most outputs from the cortex?
Axons of pyramidal neurones e.g. UMNs in primary motor cortex are pyramidal neurones
What can outputs from the cortex be?
- Projection fibres going down to brainstem and cord
- Commissural fibres going between hemispheres
- Association fibres connecting nearby regions of cortex in same hemisphere (arcuate fasciculus)
Where are most inputs from?
Thalamus and other cortical areas
Where are most outputs from?
Pyramidal cells
What functions are affected with cortical damage of the frontal lobe?
- Higher cognition
- Impulse control and social- damage leads to impulsive, disinhibited behaviours e.g. sexual inappropriateness and agression
- Voluntary motor control- contralateral weakness
- Speech- Broca’s area is here, can result in expressive dysphasia
- Eye movements- contains the frontal eye fields, conjugate gaze
- Continence- contains paracentral lobules (responsible for continence maintenance)
H- Higher cognition
I- impulse and social control
V- voluntary motor control
Extremely - eye movements
Serious - speech
Shit - continence
What functions are affected with parietal lobe damage?
- Sensory- contains PSC, may lead to contralateral anaesthesia affecting all modalities (converge at cortex)
- Comprehension of speech- contains part of Wernicke’s area, damage to left parietal lobe can cause receptive dysphasia
- Body image and awareness of external environment - damage to right parietal lobe can cause neglect, in and outside the body
- Calculation and writing- works with frontal lobe to perform these tasks, can affect calculation ability but may also be frontal lobe
- Superior optic radiations pass through here
STEMI
Sensory
Talking
Eyes
Maths
Image
What functions are effected with temporal lobe damage?
Taste
Emotion- contains limbic structures e.g. hippocampus and amygdala, lesions are complex but may be related to pathogenesis of some psychiatric disorders
Memory- hippocampus crucial for consolidating declarative memories, two hippocampi one in each lobe
Petrous- (Hearing), primary auditory cortex sits on superior surface of temporal near to wernickes area, may also cause auditory hallucinations
Olfaction- primary olfactory cortex sits on inferio-medial aspect, uncus
R-Adiations- inferior optic radiations
Language
TEMPORAL
What can cause deja vu?
Temporal lobe epilepsy can trigger memories leading to a feeling of deja vu
Where do inputs arise from?
Population of inputs arise from the reticular formation, maintaining cortical activation (conciousness)