Answer:
The best answer to the question: Month´s after Tina´s left index finger was severed in a factory accident, she noticed an increase in the sensitivity of the fingers near the missing one. The increased sensitivity is caused by:___, would be: the area in the somatosensory cortex once occupied by the missing index finger is now receiving input from the adjacent fingers.
Explanation:
One vital thing to know about our brains is that it will always have a full map of all our body parts due to nerve connectivity between all these body parts, and the brain. Particularly in the cortex, where most of the integration of both sensations and reactions takes place, this map is a constant. When a part of our bodies is missing, like in the case of Tina, the nerve endings that once serviced the finger might be missing, but there were other related innervations connected to those that were not removed from her. Also, our somatosensory cortex does not lose the neurons that were once taking care of that particular anatomical part. What Tina is experiencing can sometimes be known as the ghost limb, or the ghost body part. This is because in neuronal connectivity, there are many more nerve connections than the ones that reach the severed part. This is why the first one is the best answer.
