PS261 Chapter Notes - Chapter 2: Fixed Action Pattern, Supernormal Stimulus, Reflex Arc
Document Summary
All animals react to events in their environment. Much behaviour is elicited, its simplest form being reflexive behaviour. A reflex involves two closely related events: an eliciting stimulus and a corresponding response that are linked. Presentation of stimulus is followed by response, response rarely occurs in absence of the stimulus. The specificity of the relation between a stimulus and its accompanying reflex response is a consequence of the organization of the nervous system. In vertebrates (inc humans) simple reflexes are mediated by 3 neurons: sensory neuron/affterent neuron: Transmits sensory message to the spinal cord: interneuron. Sensory and motor neurons rarely communicate directly, impulses relayed through interneuron: motor neuron/efferent neuron: These 3 neurons together constitute the reflex arc (represents the fewest neural connections necessary for reflex action) However, sometimes sensory messages may be relayed in the brain which may modify reflex reaction in various ways. In nursing mothers can be stimulated eventually by cues that reliably predict the infant"s suckling.
