Lecture 5: Cerebral Hemispheres Flashcards
List the important sulci?
Lateral Sulcus
Central sulcus
Parieto-occipital Sulcus
Cingulate Sulcus
Where is the lateral sulcus?
Between temporal & frontal/parietal lobes
Where is the central sulcus?
On the lateral/superior surface and a little bit on the medial
It separates the parietal and frontal lobes
Where is the parieto-occipital sulcus?
On the medial surface separating the parietal and occipital lobes
Where is the cingulate sulcus?
On the medial surface separating the temporal lobe from the frontal/parietal lobes.
What are the important gyri to remember?
- Pre- and Post- Central gyri (i.e. in front and behind the central sulcus)
- Sup/middle/inf Frontal Gyri
- Sup/middle/inf temporal gyri
- Sup/Inf Parietal Lobules
How are the two cerebral hemispheres connected?
By the Corpus Callosum, which is bundle of commissural fibres (Type of white matter)
What are the types of white matter tracts?
Commissural - Connect two hemispheres
Association - From one part of the hemisphere to another (long or short)
Projection - Between Cerebral Cortex and subcortical centres i.e. sensory fibres coming in or motor fibres going out
What do the projection fibres form within the cerebrum?
The internal capsule
A small area of white matter.
Seen on a transverse section of the cerebrum lateral to the thalamus/caudate nucleus and medial to the lentiform nucleus
Why is the blood supply to the internal capsule important?
The middle cerebral artery, because if its affected by embolism it will affect most of the fibres entering or leaving the brain, whereas embolism to specific part of the cerebrum would only cause a localised stroke
Explain the dominant hemisphere?
One of your cerebral hemispheres is dominant to the other. This one contains more complex lobes such as Wernicke’s area in the dominant temporal lobe
Explain the difference between primary sensory areas and adjacent association areas?
A primary sensory area is the region that detects basic sensory stimulation.
The Association areas are around the primary sensory area and are essential for more complex mental function such as Wernicke’s area allows processing of sound as language
What is each lobe responsible for?
Frontal - Motor function and intellect
Parietal - Somatosensory
Occipital - Vision
Temporal - Hearing & Smell
What are the main functional areas of the frontal lobe?
- Area 4, the Precentral Gyrus or Primary Motor Cortex
- Area 6, The Pre-motor cortex and Supplementary Motor Area
- Area 44/45, the Inf. Frontal Gyrus or Broca’s Area of Motor Speech
- Prefrontal Cortex
Whats the function of the Primary Motor Cortex?
Area 4 i.e. Precentral Gyrus
Involved in most physical movement, it is where signals regarding movement are turned into activation of the motor neurons
Contains the Motor Somatotopic representation of the contralateral half of the body
What is the Inferior Frontal Gyrus responsible for?
Area 44/45 i.e. Broca’s Area of Motor Speech
Determines the physical production of speech
What is the prefrontal cortex responsible for?
Higher order intellect:
- Judgement
- Prediction
- Planning
What are the main functional areas of the parietal lobe?
- Areas 1-3, Post-Central Gyrus or Primary Sensory Area
- Areas 5 & 7, Posterior Parietal cortex
- Superior Parietal Lobule- sensory association areas
- Inferior Parietal Lobule
What is the function of the primary sensory area?
Areas 1-3 or Post Central Gyrus
It recieves general sensory info from the contralateral half of the body and produces the Sensory Somatotopic representation of the body
What does the superior parietal lobule do?
Responsible for interpreting general sensory info and your conscious awareness of the body
What does the inferior parietal lobule do?
It interfaces between the somatosensory cortex, visual and auditory areas.
In the dominant lobe its an associated area that contributes to language