"Even as our knowledge of the physical workings of the brain advanced during the last century, one old assumption remained firmly in place: most biologists and neurologists continued to believe, as they had for hundreds for years, that the structure of the adult brain never changed" (Carr 20).
You just never change your ways!
"The animals' neutral pathways have woven themselves into a new map that corresponds to the new arrangement of nerves in their hands" (Carr 25).
A neuroscientist named Mezernich conducts an experiment on monkeys, revealing that their neural pathways have the ability to reconstruct themselves correctly after the nerve system is damaged, reinforcing the growing theory that the brain does not stop growing after adulthood.
"In a slug's ordinary state about ninety percent of the sensory neurons in its gill have connections to motor neurons. But after its gill is touched just forty times, only ten percent of the sensory cells maintain links to the motor cells" (Carr 28).
Biologist Eric Kandel performs an experiment on a slug proving that "synapses can undergo large and enduring changes in strength after only a relatively small amount of training".