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Gazzanigas Beginnings:The History of Cognitive Neuroscience Prof. DelaneyDanielle HernandezGettysburg College

Gazzanigas Beginnings: The History of Cognitive NeuroscienceThe beginning of modern cognitive neuroscience is sometimes cited as emerging with the publishing of Gazzanigas split brain study. It may seem that cognitive neuroscience is a very modern concept, yet since antiquity, humans have contemplated the mind. Although there was not quite a grasp on human cognition amongst early philosophers, there seemed to be some consideration that there was a source of reason that made humans different. For a long time, philosophy concerned itself with matter, alone, but soon, began to realize that there were two forces in the lives of humans: matter and mind. Aristotle studied the thoughts of his predecessors who found the root of life in elements such as water or fire. They stressed the observable world to be the sole truth. Aristotle, however, saw more to it (Marshall 2011). In a way, the establishment of what we today call cognitive neuroscience could begin with Aristotle. As cognitive neuroscience is an interdisciplinary field bridging psychology, neuroscience, biology, and even computer science, it can seem like a very medically related field of psychology. With this in mind, it is seems almost uncanny that the beginning of the field, in the fourth century BCE, began with the son of a physician. So Aristotle was raised by an expert physician, studied under Plato, and eventually began his own school of philosophy in Athens. He realized the importance of both the body and the mind, recognizing that the brain also plays as vital a role to human life as the soul and the heart (Marshall 2011). Aristotle acknowledged the brain, but fell short when he tried to surmise what its purpose was (Marshall 2011). By the first century AD, Galen of Pergamon continued to sharpen the understanding of the brain. As a philosopher very much educated in physiology, Galen pinpointed the brain as the origin of thoughts and mental activity. Previously, it was thought that the heart was the origin of thought and that the brain worked in a supportive role. Galen instead proposed that spirits resided within the structure of the brain and related information to the human and also to other parts of the body (Garebian 2014). Galen, in fact, set a firm foundation for the later works of Descartes who in the 17th century continued to understand the brain in terms of similar spirits that reached out from the brain to body parts pulling them and contracting various muscles. The modern notion of the reflex began to be understood (Goodwin 2010).By the 19th century, there was some understanding of the mind as a tool of rationality, reason, reflex, and although it was not yet fully understood, there was some sense of the brain and a nervous system being interconnected (Quick 2014) but until then, there had not been any focus on specialization of brain regions. Although today we understand that the brain is made up of myriad regions, pathways, neurotransmitters, and so forth, the brain was generally seen as one unit until the emergence of phrenology. Phrenology emerged from students of sciences and evangelists and carried itself across the world as a largely popular psychology (or what we might call today junk science). Tom Quick (2014) of University College London reflects today on phrenology as having been something of a rag-tag collection of beliefs and practices regarding the brain. 19th century phrenologists methods included using a generally standardized set of measurement tools to physically assess indentations and raised areas on the skull. These bumps and hollows reflected abundances and deficiencies of qualities, respectively, in domains represented by where on the head they were located. From this evaluation, phrenologists offered patients a horoscope-like forecast of what their life would be like given their strengths and weaknesses and offered advice about how to combat their poorer aspects of their personalities and enhance the better aspects (Quick 2014). Although we look back upon phrenology as problematic and even comical, its influence is not to be taken lightly. The proposed idea of specialization of regions of the brain was planted. In 1873, British physician John Hughlings Jackson published a groundbreaking paper titled On the Anatomical and Physiological Localization of Movements in the Brain. Jackson had studied under Thomas Laycock who did research no doubt influenced by Descartes on the brain and reflexesand was an ardent follower of Darwins newly proposed Origin of the Species (Smith 2012). In an added step to move away from phrenology, the French physiologist Pierre Flourens began exploring cerebral localization via surgical experimental methods. Working with pigeons, he studied split brain phenomena the effects of cortical ablations. Interestingly enough, he was also the main rival of Franz Joseph Gall who was considered the leading mind in the phrenology movement. Flourens and subsequent physiologists believing they had identified the connection between localized brain regions and motor functions attempted to stimulate movement in animal models using electric currents. Unfortunately, they were unsuccessful at the time (Hagner 2012). It wasnt until 1870 when Gustav Fritsch and Edvard Hitzig were able to successfully control motor functions with an electrical current. Nearly a century before them, Italian physician Luigi Galvani had accidentally caused a dead frogs leg to move with an electrical current to the sciatic nerve, but it had yet to be narrowed down and controlled. Fritsch and Hitzig stimulated various parts of a dogs cerebral cortex and noted subsequent motor activity. The two were able to successfully cause and predict various movements at different locations on the brain. The two successfully became the first scientists to begin truly mapping the brain and labeling specific areas with their correct functions (Gross 2007). But even before this study had been conducted, the famous discovery of Paul Broca had already been made.By the time of the renowned discoveries of Broca and Wernicke, there was already a developed understanding that the body and mind were specifically connected. The parts of the brain that modern cognitive neuroscientists associate with language were first understood in the mid- to late 19th century by French physician, Paul Broca and German neurologist, Carl Wernicke. Brocas famous patient called Tan after the only morpheme he could speak. The patient seemed to have full cognizant recognition and understanding of his surroundings and of language presented to him, but although he comprehended questions asked to him, his only response was tan. Some sources indicate that, when unsettled, Tan would sometimes be able to vocalize a curse in French (sacr nom de Dieu); however, this is actually a misattribution. Broca became fully engrossed in this case, unsuccessfully pinpointing what was wrong with the patient until postmortem autopsy revealed a malformation in the posterior infernal frontal gyrus of the Tans left hemisphere. Modern studies of his brain which is still preserved today reveal that the malformation was actually deeper than Broca believed, perhaps explaining why the patient also became increasingly paralyzed on the right side of the body as he neared death. Of course, this split brain phenomenon (of the side of the brain correlating with the opposite side of the body) had yet to be understood (Domanski 2013). Carl Wernicke was very much influenced by Broca as well as by Hitzig and Frisch to take part in the exciting new field of neuroscience. His discovery of a different type of aphasia on the side of the brain opposite Brocas area showed that both sides of the brain have their own unique functions which became important in future split brain research. The most important part of his legacy was not only the discovery of his namesake language brain area, but also his explanation for his findings. Wernicke was the first to mention the interconnectedness of the brains neural pathwaysthe communication from part to part to make a working whole (Pillmann 2003). With the discoveries of Brocas and Wernickes areas and the initial mapping of the cerebral cortex came a very important subsequent contribution to the blossoming field of neuroscience. German neurologist Korbinian Brodmann published images of the brain, labeling them, and creating a physical map of the human brain. The map, called the cytoarchitectonic map of the human brain, displayed real images of 43 separately functioning areas of the cerebral cortex. Not only did Brodmann give psychology these important images, but he also discovered that the cerebral cortex in humans was markedly different than those in primates and other animalsit seemed to be more complex and, so to speak, evolved. Versus humans 43 cerebral cortical areas, primates only show 30. The differences were especially noticeable in the olfactory, limbic, and insular cortices (Zilles & Amunts 2010). The rest of the 19th century consisted of a further explosion of research leading quickly up to what we consider the cognitive revolutionan important foundation for Gazzaniga and the establishment of cognitive neuroscience as a field of psychology. Hermann von Helmholtz followed in the paths of the experimenters of electricity and especially Galvani. Taking a frog and administering a shock, Helmholtz timed how long it took for the targeted muscle to contract. His particular contribution was in nervous functioning. Helmholtzs research showed that when travelling a shorter path from place of stimulation to place of action, there was a shorter reaction time. Nerve impulses followed physically set pathways (de Kock 2014). Following this contribution emerged research from Mnsterberg and Jamesboth of whom are the intellectual predecessors of Gazzaniga, himself.For much of the end of the 19th century, psychologists battled between whether psychology should be applied or kept a pure science. The proponents of keeping psychology pure stressed the importance of introspectionclearly not of much use to neurologists who are so very founded in physiology. Mnsterberg and James were two hefty proponents of the movement toward applied psychology. Hugo Mnsterberg actually began his career in vehement opposition to applied psychology like Titchener and other predecessors (Benjamin 2006). However, as time went on and he began to broaden his understanding of what psychology could be applied to. Mnsterberg ended up founding the schools of forensic, industrial/organizational, and clinical psychology. He also had his own thoughts on consciousness, believing it to be a voluntary state, directly relating the brain and the body. William James, the father of American psychology and paver of the road toward functionalism also favored application of psychology to many experimental methods that preceded him. He was interested, however, in both schools of thoughtboth in mental processes and behaviors. James saw the two as essentially inseparable. He believed that studying both was not detracting from psychology as either applied science or pure science, but understood it as supporting psychology as a practical science. His famous textbook includes a chapter on The Functions of the Brain outlining the roles of different brain areas and the spinal cord in human consciousness and motor activity as well as paramount to development of personality and sense of self. James used the actions reflected through neurophenomenology as a means of coming to conclusions and making predictions about neurobiological processes (Smith & Thompson 2015).Although behaviorism as a field of psychology has largely died out today, its very problems were vital to the thriving of cognitive neuroscience. John B. Watson, the founder of behaviorism went against the increasing support for neurological psychologies. Watson argued that only what is observable should be studied, that anything further is surmise, and that behavior held all the answers we needed in psychology. For a short period of time, behaviorism gained much recognition, but with the recognition came heated opposition. Using Watsons behaviorism as a foil, proponents of neuroscientific study of psychology pointed out that behavioral observations cannot explain phenomena like thought and memory. Additional controversial statements made by Watson only further hurt his reputation and, in turn, behaviorisms reputation. He began commenting on parenting suggesting that mothers should show their children no affection, and the sort (Harzem 2001). This sort of advice and other polemic arguments made by Watson on behalf of behaviorism only acted to further bolster the cognitive revolution in psychology. With the cognitive revolution giving neuroscience the all clear to continue its growth, the neuron doctrine was established by Cajal and Golgi during their research of neurons in the brain. The term neuron had also been officially coined at the time of their work. The word first came about in 1891 by a German anatomy professor, Wilhelm Waldeyer. Cajal and Golgi, using the new terminology to their advantage, received the 1906 Nobel Prize for Physiology or Medicine for their work in developing the silver staining method, the discovery that neurons are connected to each other in the cytoplasm, and the realization that electric signal could only travel one way down a neuron path (Bock 2013). With this neuronal basis established, widely recognized and lauded, research continued to further specify functions of the brain.In the early to mid-twentieth century, Wilder Penfield made his notable contribution to the field soon to be called cognitive neuroscience. He studied under Harvey Cushing, a clinical neuroscience, who instilled in him a passion to explore the parts of the brain never before explored. It was reported that Penfield craved exploration of the brain as someone might an undiscovered country. He wanted to help patients with neurological disorders and thus went about exploring functions of the cortex with electrical impulses as did his predecessors. Penfield extensively explored the sensory-motor cortex and came up with the visual homunculusan artistic representation and character of a human used to convey the relationship between parts of the motor cortex and related musculature systems. His hope for the future of the field was for it to become interdisciplinaryeffectively fusing together neurology, neurosurgery, neuropsychology, neurophysiology and neuropathology to help patients. It was clear that it was important for the science of the twentieth century to be not only verifiable, but practical. Application of psychology toward the fifties became more and more recognized and accepted in practice. Psychologists were employed to help in war efforts, theories were used to try to understand the Soviet Union (Parker 2007), and most of the 19th century psychologists had faded away from the public eye and ear leaving neuroscience wide open for reception (Rodkey 2011). In 1951, R.H. Stetson, a student of Mnsterberg and James published a book titled Motor Phonetics. In it, one will discover an explanation of speech as it related to cognitive control of muscle control in the chest, lungs, and mouth. Many had ignored the physiological processes related to such processes as speech, yet Stetson persevered, supported by his clinically-minded mentors. Although Stetsons name is often lost in the history of cognitive neuroscience, his role was pivotal (Lfqvist 1989). One of his students, Roger Walcott Sperry was inspired by Stetson to pursue psychology. After being under his tutelage, Sperry needed to know where behavior came from and what the purpose of consciousness was. He studied psychology, neuroembryology, and zoology, morphing together these disciplines as predicted and hoped for by Penfield. Two prominent figures in neurology at the time, Weiss and Lashley, viewed neural passageways as interchangeable and unfixed. As Sperry conducted studies on neurological development in fish, amphibians, and primates, however, he realized that these structures were established early in development, were very much fixed, and therefore, had to be interchangeable to allow for learning and development. His interest in neural pathways brought him to research the corpus collosumthe structure which connects the two hemispheres of the brainin 1953. What he discovered was groundbreaking. When the corpus collosum was severed, both hemispheres of the brain continued to workeach side having their own distinct functions. He noticed that the right brain correlated with the left side of the subjects body and that the left brain correlated with the right side of the subjects body. At the same time, Sperry also found that this split brain operation relieved seizures in patients with epilepsy. He continued research of the split brain, primarily of cats, in a 50-year research program during which one of his students was Michael Gazzaniga (Puente 1995; ). During his mentorship, Gazzaniga worked very closely with Sperry who didnt have a large research team or staff to help him run his split-brain experiments. Most of the work was done by Gazzaniga himself, helping him learned immensely about the split-brain and also fostering a very strong mentor-mentee relationship between Sperry and Gazzaniga (D'Esposito 2004). At the time of Gazzanigas research on The Split Brain in Man, the field of cognitive neuroscience still had yet to be named (D'Esposito 2004). But name or no name, Gazzaniga pushed forward extending his research past what his mentor had taught him. In 1967, he began researching in humans what his mentor researched in cats. When the cats brains were split down the corpus collosum, they had trouble completing tasks that required recognition of the full visual field. Gazzaniga wondered what it was that made the brain function almost as two separate entities and was curious whether, when split, the patient would express the right hand not knowing what the left was doing (Gazzaniga 1967). Gazzaniga had previously observed no noticeable change in behavior, personality, or intelligence in the few human patients he had worked with who had received this operation (i.e. after war-related injuries). One thing that was noticed was that patients began favoring one side of the body over the other and responded more to sensory stimuli on a single side of their field of vision. When they saw a light presented only in their left field of vision, there was no recognition that it had appeared, yet, contrary to surmise, there was no blindness in the eye, just a lack of processing. They called this phenomenon bisected brain syndrome (Gazzaniga 1967). In his 1967 experiment, Gazzaniga took a group of these patients and planned to flash them visual or written information to only the left or right eye. At this point in neuropsychology, it was understood that the left side of the brain related to the right side of the body and that the right side of the brain related to the right side of the body. What he found was that when a word or an image of an object appeared on a screen, the participant could pick that object up out of an assortment of objects with the hand on the same side of the body as the eye that received the visual cue. However, while they can retrieve this object (showing recognition and disproving any blindness), the participant could not verbally tell the researcher what they saw or picked up. They saw nothing. Although this process of cross-cuing revealed that language and object recognition do not occur in the same way in both hemispheres, it is difficult to assume that the right hemisphere is specifically for language and the left hemisphere is not. In fact, although the participants could not say what object they picked up with right hemisphere cues, Gazzaniga believes there is a small signal transmitted to the left hemisphere but, without the corpus collosum, the signal is too weak to have a significant effect (Gazzaniga 1967). Next, in a drawing task, Gazzaniga presented participants with images to copy of houses or prisms. Since past studies showed that split brain patients had difficulty arranging blocks with their right hand to match a visual cue, Gazzaniga believed the same would hold true for drawing. Participants were able to draw with both hands; however, the right handed drawing came out distorted while only the left handed drawing accurately reflected the visual cue.So what role does the corpus collosum play? Gazzaniga tested neural activity in his subjects similar to the way they were tested for cats in previous studies and found that the corpus collosum plays an important role in visual pattern information transmission between hemispheres. Instead of each hemisphere having to learn to view the world on its own, they two, bound together with the corpus collosum, learn to work and discern together. Although Gazzaniga recognizes that there are definitely unique qualities in the hemispheres, he concludes that it is important to proper processing that the brain be intact, allowing neural flow and communication between sides, uninterrupted (Gazzaniga 1967). Following The Split Brain in Man, came the official coining of the term cognitive neuroscience in the 1970s accompanied by Gazzanigas subsequent founding of the first journal for cognitive neuroscience, the Journal of Neuroscience (DEsposito 2004). ReferencesBenjamin, L. J. (2006). Hugo Mnsterberg's attack on the application of scientific psychology. Journal of Applied Psychology, 91(2), 414-425.Bock, O. (2013). Feature: Cajal, Golgi, Nansen, Schfer and the neuron doctrine. Endeavour, 37228-234.De Kock, L. (2014). Voluntarism in early psychology: The case of Hermann von Helmholtz. History of Psychology, 17(2), 105-128.D'Esposito, M. (2004). Interview: Mark D'Esposito with Michael S. Gazzaniga. 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