During the 18th Century science began to be big in the history of cognitive neuropsychology. The first big advance was in human reflexes. These bodily reactions to stimuli or outside forces are observed and measured. This was found by studying axons and learning how signals travel in the human body. Before this, science and technology were not advanced enough, but the 17th Century changed this. In fact, the development of the microscope helped as well. The brain's nerve fibers could now be seen and described. Cerebrospinal fluid (CSF) was also found in the spaces of the brain and spinal cord. With that, the physiology of psychology began to take control of cognition. These findings are all still true today.