Can't Get Enough Of Those Monkeys

A study was done on the 4 contraversial Silver Springs monkeys who had had their arm nerves cut twelve years previously. Pons' expectations of confirming earlier results were confounded when he discovered that the face region of the cortex had completely taken over what was once the amputated arm's cortex (Pons, 1995). In all four subjects, stimulation of the face brought response from the face as well as the hand and arm area of the homunculus.

This amount of neural reorganization would be impossible if the brain were hardwired. So how can this be explained? One potential answer is that new axonal branches had actually sprouted up from the facial cortex, across the amputated limb's area.

Pons speculated that his experiments can be explained by more moderate neural growth somewhere farther down the touch pathway. An area where this could occur is the thalamus.

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