Cerebral Cortex Flashcards
What is the cerebral Cortex?
- largest, most evolved and interesting human brain region
- has 4 separate lobes - each specialised for a specific function- Functional localisation
What is functional localisation?
-Different lobes or regions which are specialised for a function
What is the cerebral cortex functional localisation for ?
- Special senses (e.g. somatic sensation or vision or hearing)
- Motor control (e.g. initiation of voluntary movements)
- Cognitive (e.g. different language or memory functions)
What are the primary areas of the cc?
-have matching pairs in each lobe and each cortical hemisphere e.g there is one primary area for a particular function in a lobe in a left cortex with a matching pair in the same lobe in the right cortex.
What is the reason of 2 primary areas in each lobe and hemisphere?
phenomenal on
- Functional Contra-laterality:
- involved with events occurring on the opposite side of the body or of external space ( left side brain controlling right side etc) - Topography: contain MAPS of the body or of external space in the primary area- primary areas contain a map of the opposite body surface or side of external space
What are the secondary association areas in the cerebral cortex ?
-lateralised to one hemisphere - known as cerebral dominance/functional asymmetry
for e.g left cc is dominant for language functions and right cc is dominated for spatial awareness/attention.
What is the old idea?
- phrenology- human beings posses 35 personality traits each of which to be ascribed to a particular region of the cc.
- idea behind phrenology- by filling around the surface of the skull- could detect bumps on it- which reflected enlargement of the gyrii of the brain undreneath- and when this was enlarged it reflected a increased development of particular characteristic to which that part of the brain was responsible
- same with the filling around the skull- there would be depressions of the bones- reflecting an underdevelopment of the gyro situated under- underdevelopment fo that personality trait
- as it happens - above the left ear- big lump of the surface of the skull- according to phrenologist - would mean you are secretive.
Where is the celebrellum ?
sticking out the back of the brain
What is the gyrii?
ridges on the surface of the cortex
What is sulci?
furrows in-between the ridges
What is the central sulcus?
major sulcus between the front and back of the brain
-divides the lobe of the cortex infront = frontal lobe from the lobe of cortex behind it called= parietal lobe
What is the frontal lobe?
- concerned with control and initiation of voluntary movements
- front
What does the parietal lobe do?
associated with somatic sensation
-back
What is the lateral sulcus?
- deep
- lateral surface of the coretx
- divides frontal and parietal lobe above from the temporal lobe below
What does the temporal lobe do?
associated with hearing / auditory functions
What is the occipital lobe?
- 4th lobe of the cortex
- situated at the back
- concerened with visual functions
What are the primary cortical areas?
-A small part of each lobe in each hemisphere, concerned with
the most basic or lowest levels of sensory or motor function;
- Primary Somatosensory (S1) Cortex (L & R parietal lobes)
- Primary Motor (M1) Cortex (L & R frontal lobes)
- Primary Auditory (A1) Cortex (L & R temporal lobes)
– Primary Visual (V1) Cortex (L & R occipital lobes)
Questions
Examine
- The organization of their detailed MAPS of the body/space
- How they acquire their specific functions (via the thalamus and long-range axon pathways in the white matter)
- Why they represent opposite side of the body/external space
- Anatomical/cellular basis of Functional Specializations
-How they acquire their specific functions (via the thalamus and long-range axon pathways in the white matter) e.g why is lumps of grey matter in occital lobes are essential for visual perception ?
they receive input from particular specialised nuclei of the thalamus that relays via long range axons projections travelling the white matter- info about vision to that particular part of the cerebral hemispheres
What is next to the central sulcus ?
continuous gyrus - long - starts at the bottom- goes all the way up lateral surface of the cortex and continues on the medial surface of the cortex where you can’t see behind the screen
Where is Postcentral gyrus ?
situated behind the central sulcus in the parietal lobe
-find the primary somatosensory (S1 cortex)
How do we know that the post central gyrus is a primary somatosensory cortex (S1 cortex)?
consequences of
-unilateral damage to that area - eg if you lose this in your left cordial hemisphere- you would lose all somatic sensation - loss of tactile, (touch) , thermal, pain & joint sensation, opposite side of body.- hemi- anaesthesia - i.e right
What is hemi-anaesthesia ?
lose all conscious sensations of the somatic senses
Why is it not just the left primary somatosensory cortex (S1 cortex)which receives sensory information from right side of body ?
because the postcentral gyrus contains a topographic representation or map of the body parts = Sensory homunculus- which is inverted and distorted