The Pyramidal Cell

The pyramidal neuron in cortical tissue was first noticed by Ramon Y Cajal, who, staining and describing them in the late 19th century, opened the field of molecular neuroscience. The large cell body and the cell’s vertical orientation were both noticeable in Cajal’s preparations.

The pyramidal neuron of the neocortex sits in layer five, explores the four upper layers by way of an apical dendrite and sends an axon, as long a three feet, all the way into the motor tract of the spinal cord, thus producing direct cortical control of the skeletal muscles. This quick connection between the intelligent neural networks of the neocortex and the spinal cord is unique.

The pyramidal axon, in particular axons of anterior cortical cells, also invades the medullary brain structures which control non-oculomotor reflexes.

It is now thought the pyramidal cell has a great deal to do with consciousness, cognition and the smoothing of mechanical reflexes. Stuart Hameroff thinks horizontal spreading of pyramidal dendrites in layer five of the cortex causes consciousness.