Biological motion is a term used by social and cognitive neuroscientists to refer to the unique visual phenomenon of a moving, animate object. Often, the stimuli used in biological motion experiments are just a few moving dots that reflect the motion of some key joints of the moving organism. Gunnar Johansson invented these point light displays.
Early work suggested that the brain may contain mechanisms specialised for the detection of other humans from motion signals, but over the years this claim has been scaled down to the point where some authors now suggest that we have more generalised detectors tuned simply to the characteristic signal generated by the feet of a locomoting animal.
Perception of biological motion depends both on the motions of individual dots and the configuration/orientation of the body as a whole, as well as interactions between these local and global cues. Similar to the Thatcher Effect in face perception, inversion of individual points is easy to detect when the entire figure is presented normally, but difficult to detect when the entire display is presented upside-down.
The superior temporal sulcus is known to be activated for biological motion perception. Also, premotor cortex is important, which indicates that the mirror neuron system is recruited for "filling in" the dots.
In a large study with stroke patients, regions that emerged to be statistically associated with deficient biological motion perception included the superior temporal lobe sulcus and premotor cortex. The cerebellum also is important.
A recent study on a patient with developmental agnosia found intact biological motion, but deficient perception of non-biological form from motion 
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