Which condition is characterized by abnormal upward movement of toes when the sole of the foot is stimulated?

The condition characterized by abnormal upward movement of the toes when the sole of the foot is stimulated is known as the Babinski reflex. This reflex is an important indicator of neurological function, particularly in assessing infants and individuals with central nervous system disorders. In infants, the Babinski reflex is considered a normal response, as their nervous systems are still developing. When the sole of the foot is stroked, the toes will fan out and move upward, which is a typical response due to incomplete myelination of pathways in the immature brain.

In adults, an upward response of the toes can indicate neurological damage, particularly to the corticospinal tract. A positive Babinski sign (upward movement of the toes) may suggest conditions such as multiple sclerosis, stroke, or a spinal injury.

The plantar reflex, on the other hand, normally results in curling of the toes when the foot is stimulated, particularly in adults. Decerebrate posturing and decorticate posturing are abnormal body postures seen in response to severe brain injury and involve specific arm and leg movements but do not relate to the stimulation of the foot in the same way.