26 Mar reflex

Responses to stimuli that are involuntary. The classic reflex is the knee-jerk response to a tap with a hammer. Reflexes are processed in the spinal cord rather than in the higher-level motor processing centers. Muscle memory, in which a part of the body has done a thing so many times that it can repeat the action without concentration, grows to behave like reflexes.
Keywords: stimulus
laughter
kinesthesia
expression
spinal cord
integration
perception
response
instinctive
References: brain physiology
neurons
neuroscience