Chapter 1 Neuroscience Past Present and Future Monday January 6 2014 The Origins of Neuroscience Our prehistoric ancestors knew that the brain was vital to life Preformed skull surgeries by drilling holes in the head Ancient Egyptians believed that the heart was the seat of feeling emotion and the soul not the brain The Greek philosopher Hippocrates believed that the brain was the seat of intelligence However Aristotle concurred with the Egyptians and hypothesized that the brain s function was to cool down the blood by the overheating heart The Roman physician Galen dissected sheep s brains and established two major parts of the brain the cerebrum front and the cerebellum back He found that when cut open the brain has hollow spaces called ventricles led with uid The Cerebrum is the seat of sensation and memory The Cerebellum is where movement is controlled Galen believed that the cerebellum controlled movement by pumping uids down from the ventricles to the limbs Reinforced by French Anatomist Vesalius s Fluid mechanical theory in the 16th century Rene Descartes agreed withe the Fluid mechanical theory but said that humans possessed a soul unlike animals and that the pineal gland is the gateway to god During the 18th century scientists discovered that brain tissue is composed of gray matter and white matter They concluded that white matter serves to bring information to and from the gray matter 1 Monday January 6 2014 By the End of the 18th century the nervous system had been completely dissected and it was established that the nervous system has two divisions the Central Nervous System CNS and the Peripheral Nervous System PNS The CNS consists of the brain and the spinal cord The PNS consists of the network of nerves and nerve cells that are found outside of the brain and spinal cord During the end of the 18th century it was discovered that every individual brain had the same pattern of bums gyri and grooves ssures and sulci This made it possible for the cerebrum to be broken down into lobes At the beginning of the 19th century Luigi Galvani and Emil du Bois Reymond showed that when certain areas of the brain are electrically stimulated muscles twitch In 1810 Charles Bell and Fran ois Magendie showed that just before nerves connect to the spinal cord they divide into two branches one going in the front ventral root and the other in the back dorsal root of the spinal cord Bell found that when only the ventral roots were cut paralysis occurred Therefore the ventral roots carry motor bers Magendie later showed that the dorsal root carried sensory information The Dorsal roots carry sensory bers From these ndings Bell proposed that the cerebrum is the destination of the sensory bers and the cerebellum as the origin of motor bers A French physiologist named Marie Jean Pierre Flourens practiced the experimental ablation method which is when you destroy parts of the brain to test what functionality is lost The Brain utilizes lateralization and localization Lateralization is the crossing over of information from one side of the brain to the other side via the corpus callosum Information from the right eye and hand is sent to the left hemisphere of the brain and information from the left eye and hand is sent to the right hemisphere of the brain Localization is the principle that different areas of the brain have speci c functions 2 Monday January 6 2014 Franz Joseph Gall wrote a book on phrenology which sought to establish a connection between certain personality traits with the shape of the skull was rejected by the results of Flourens experimental ablation Broca s area is the seat of spoken or written language in the brain When Broca s area is damaged the victim cannot talk in correct grammar however they can still comprehend what is being said or written by others expressive aphasia When Wernicke s area is damaged the victim cannot understand written or spoken language and does not comprehend or make understandable speech receptive aphasia The goal of neuroscience is to learn how the nervous system functions 3