What are the four types of glial cells? What are the four lobes of the brain? What are the four types of receptors lie within and just below the dermal layer of skin? What is sensory homunculus? What are the five recognized taste sensations? What are the three auditory ossicles? If the lower motor neuron of the corticospinal tract is severed, will it result in complete paralysis? Why or why not? What are the three types of memory? What is the difference between facilitation and potentiation? What are the three layers of membrane that cover the brain?.