Cerebral Cortex - Overview

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The cerebral cortex of the mouse covers the cerebral hemispheres. The mouse cerebral cortex is lissencephalic: It has no gyri and sulci, in contrast to the cerebral cortex of higher animals, including humans. The cerebral cortex of the mouse, like that of other mammals, comprises three parts, the evolutionarily newest of which is the neocortex (isocortex). The neocortex coordinates sensory and motor information and consists of six layers (I-VI), though in the mouse layers II and II cannot be identified separately and are referred to as layer II/III. Layer I (molecular layer) is located underneath the meninges and consists of neuropil and few cell bodies of neurons. Layer II/III contains many granule (stellate) cells (small interneurons) and numerous cone-shaped cell bodies of small pyramidal cells. Layer IV (internal granular layer) is composed of granule cells. Layer V (internal pyramidal layer) contains cell bodies of large pyramidal cells. Layer VI (fusiform or multiform layer) is dominated by elongated spindle-shaped (fusiform) cells.

The 4X micrograph is a sagittal section of the cerebral cortex, showing the meninges, layers I through VI of the neocortex, and white matter. The 10X micrograph exhibits layers I through V in more detail. The 20X and 40X micrographs display the cells present in layers I and II/III.