Making Sense of the Senses
Bruce Johnson

We monitor our environment, the position of our limbs and the homeostatic internal condition of our bodies through sensory receptors that are sensitive to different forms of physical energy. All our different sensory receptors have similar ways of responding to the quality, intensity and time course of physical stimuli. In this exploration we will test a hypothesis addressing the question of how we discriminate the strength of a sensory stimulus. We will examine intensity coding and other basic properties of sensory reception by recording the electrical responses of a model sensory neuron: the stretch receptor of the crayfish tail. This receptor is responsible for reporting tail movements to the brain, much like the muscle spindles and related organs in our own muscles and ligaments report the position of limbs and the contraction state of our muscles.