Forebrain Procencephalon Forebrain The forebrain is the most
Forebrain Procencephalon
Forebrain The forebrain is the most anterior division of the developing vertebrate brain, containing the most complex networks in the central nervous system. The forebrain has two major divisions: the diencephalon and the telencephalon. The diencephalon is lower, containing the thalamus and hypothalamus (which together form the limbic system) The telencephalon is on top of the diencephalon and contains the cerebrum, the home of the highest-level cognitive processing in the brain.
Telencephalon It is the largest division of the human brain. It includes the two symmetrical cerebral hemispheres that make up the cerebrum Cerebral Hemispheres are coved by cerebral cortex and contain the limbic system & the basal ganglia (subcortical regions) • 3 mm thick approximately • Corrected for body size (deeply convoluted – increases the amount of cerebral cortex without increasing over all volume of the brain. Most mammals are Lissencephalic (smooth-brained) • Develops from inside to outside • First cells to be produced by the ventricular zone migrate a short distance and establish the first layer • The next cells pass through the first layer and form the second one What guides neurons to their final resting place? Rakic (1972, 1988): a special form of glial cell – radial glia – provides pathways that neurons follow during their migration. Patricia Goldman-Rakic
Cerebral Cortex Cerebral cortex consists mostly of glia and cell bodies, dendrites and interconnecting axos of neurons. Because cerebral cortex is composed predominantly of cells it has a grayish brown appearance and it is called gray matter. Underneath the cerebral cortex are millions of axons which connect with those located elsewhere in the brain. The large concentration of myelin around the axons gives this tissue an opaque white appearance – white matter
Cerebral Cortex (Lobes) The cerebral cortex is sub-divided into four areas or lobes • Frontal Lobe (the “front”): located in front of the central sulcus • Parietal Lobe (the “wall”): located just behind the central sulcus • Temporal Lobe (the “temple”): juts forward from the base of the brain • Occipital Lobe (latin: ob – “in back of” & caput “head”): lies at the back of the brain Neocortex: because of its relatively recent evolutionary origin (Northcutt & Kaas, 1995)
Frontal Lobe The frontal lobe is the largest lobe of the brain and makes up about a third of the surface area of each hemisphere. On the lateral surface of each hemisphere, the central sulcus separates the frontal lobe from the parietal lobe. The lateral sulcus separates the frontal lobe from the temporal lobe The frontal lobe includes • The primary motor cortex – cortical parts of the motor cortex, • The premotor cortex, and • The prefrontal cortex
- Slides: 8