Somatic Mechanical, thermal, chemical Mechanoreceptor, thermoreceptor chemoreceptor pain receptor eg. Each of the senses activates a separate area of the cerebral cortex, the sheet of neurons that makes up the outer layer of the brain's hemispheres. Approximate locations of the primary sensory areas are shown in color. Most of the activity takes place within convolutions that cannot be seen from the surface of the brain. Receptors transfer their stimulation to the sensory areas of the brain through several neuronal connections.
Neurons monitor the world by parceling it into small regions of space, known as receptive fields.
RFs are defined in terms of single neurons. RF location is related to stimulus modality. Due to the inhomogenous receptor density in the retina, only a small spot around fixation is seen sharply. Peripheral blur is counterbalanced here by enlarged letters. Consult the book.