Talk:Brain Awareness Week 2012
From Embryology
Neural Plate | Neural Tube |
Cerebrum
Primitive vertebrates
- (hagfishes and lampreys)
- cerebrum is a relatively simple structure receiving nerve impulses from the olfactory bulb.
Some fish and amphibians
(Cartilaginous fish (sharks), lobe-finned fish, amphibians)
- remains mainly devoted to olfactory sensation.
- Cerebrum divided into 3 regions.
- ventral - forms the basal nuclei, and contains fibres connecting the rest of the cerebrum to the thalamus.
- lateral - forms the paleopallium.
- dorsal - forms the archipallium.
Ray-finned Fish
- Cerebrum lateral and ventral regions inner surfaces bulge up into the ventricles.
- these include both the basal nuclei and the various parts of the pallium (complex in structure in teleosts).
- Verebrum dorsal surface is membranous, and does not contain any nervous tissue.
In amniotes, the cerebrum becomes increasingly large and complex.
Reptiles
- paleopallium is larger than in amphibians, and its growth has pushed the basal nuclei into the central regions of the cerebrum.
- Grey matter is generally located beneath the white matter
- in some reptiles, grey matter spreads out to the surface to form a primitive cortex (anterior part of the brain).
Birds
- enlarged compared to reptiles, due to the basal ganglia.
- other areas remain primitive in structure.
- no expansion of the cerebral cortex
- above basal ganglia the HVC develops
- involved with learning complex tasks, such as song.
Mammals
- cortex covers almost the whole of the cerebral hemispheres (greatest in primates).
- paleopallium is pushed to the ventral surface of the brain, where it becomes the olfactory lobes
- archipallium becomes rolled over at the medial dorsal edge to form the hippocampus.
- corpus callosum connects the two hemispheres.
- surface folding found only in higher mammals.