Historical Contributions from Philosophy PDF

Foundations of Physiological Psychology Historical Contributions from Philosophy  According to Stanley Prusiner, an American Neurologist, neuroscience is by far the most exciting branch of science because the brain is said to be the most fascinating object in the universe....

Foundations of Physiological Psychology Historical Contributions from Philosophy  According to Stanley Prusiner, an American Neurologist, neuroscience is by far the most exciting branch of science because the brain is said to be the most fascinating object in the universe. Every human brain is different and that the brain makes each human being unique and defines who a person is. Psychology emerged as a separate discipline way back in 1879 when Wilhelm Wundt established the first psychology laboratory in Leipzig, Germany. Recently, the many information discoveries from experimental biology, chemistry, animal behavior, psychology, computer science, and many other fields has contributed to the diverse interdisciplinary field of behavioral neuroscience.  There are two forms of scientific explanation: One is the so- called Generalization which refers to explanations as examples of general laws revealed by experiments. The other is Reduction which refers to explanations of complex phenomena in terms of simpler ones. Nevertheless, the field of behavioral neuroscience is growing and has been formed by scientists combining experimental methods of psychology and physiology. Researches in neuroscience could range from topics such as perceptual processes, control of movement, sleep and waking, reproductive behaviors, ingestive behaviors, emotional behaviors, learning and language, substance abuse, neurological and mental disorders.  During the Renaissance Era from 1400 to 1600 AD, it was the time of artistic expansions, world explorations as well as of scientific curiosities. As human beings during the early days have believed in the possession of a mind, or a soul or a spirit. We also have a physical body with muscles for movement and sensory organs like the eyes, ears, that perceive information about the world around us. Within our bodies, the nervous system plays a vital role in receiving information from the sensory organs and controlling the movements of the muscles. The mind-body question has been historically puzzling in the earliest history of civilization.  The Physical Model of Behavior of Descartes, he used a hydraulic model to explain the brain's activity influenced by his observations of the statues in the Royal Gardens of Saint Germain. Using this model, he reasoned that the nerves were also hollow tubes and the fluid they carried were not water but animal spirits which flowed from the brain and inflated the muscles to produce movements. He viewed the human body as a machine and that some movements were automatic and involuntary. Say for example a person who happened to touch a hot object would immediately withdraw from the source of stimulation. These reactions did not require the participation of the mind; they are automatic and he called these reflexes. Descartes believed that the "soul" now called the mind controls the movements of the muscles through its influence on the pineal body. Based on his theory, the eyes sent visual information to the brain where it could be examined by the soul. Thus, when the soul decided to act, it would tilt the pineal body which divert pressurized fluid through the nerves to the appropriate muscles.  Behavioral neuroscientists believed that with the resolution of the mind and body question based on the approach, as human beings we can already explain how we perceive, think, remember and behave.  The first proponent in the development of experimental physiology was Luigi Galvani an Italian Physiologist who lived in the year 1737 to 1798.  The frog leg experiment of Galvani is contrary to Descartes' discovery that the brain inflate the muscles by directing pressurized fluid through the nerves. His experiment inspire others to study the nature of the message transmitted by the nerve and the means by which muscles contracted. Another most influential figure in the development of experimental physiology was a German Physiologist back in 1805 to 1858, Johannes Muller.  How can different sensations arise from the same basic message? Johannes Muller's answer was that the messages occur in different channels. For example, messages carried by the optic nerves produce sensations of visual images, and those carried by the auditory nerves produce sensations of sounds. The portion of the brain that receives messages from the optic nerves interprets the activity as visual stimulation, even if the nerves are actually stimulated mechanically. Say for instance, when we rub our eyes, we see flashes of light. The reason for this is because different parts of the brain receive messages from different nerves. Thus, the brain must be functionally divided which would mean that some parts perform some functions, while other parts perform others.  Another two prominent figures in the development of experimental physiology were German Physiologists Gustav Fritsch (1838-1927) and Eduard Hitzig (1838-1907). They used electrical stimulation as a tool for understanding the physiology of the brain. They applied weak electrical current to the exposed surface of a dog's brain and observed the effects of the stimulation. They found that stimulating different portions of a specific region of the brain caused specific muscles to contract on the opposite side of the body. Nowadays, we refer this region as the primary motor cortex which communicate to cause muscular contractions.  Then we have the first scientist who attempted to measure the speed of conduction through nerves in the person of German Physicist and physiologist Hermann von Helmholtz way back in 1821 to 1894. Previous scientists believed that such conduction was identical to the conduction that occurs in wires, traveling at approximately the speed of light which was around 186,000 miles per second or 299,000 kilometers per second. But then, Helmholtz found that neural conduction was much slower which was only about 27.4 meters per second. This measurement proved that neural conduction was more than a simple electrical message.  Johannes Muller's advocacy of experimentation and the logical deductions from his doctrine of specific nerve energies set the stage for other scientists to perform experiments and this time directly on the brain. One of those scientists was Pierre Flourens (1794-1867) who was a French researcher. Flourens removed various parts of animals' brains and observed their behavior. By seeing what the animal could no longer do, he could infer the function of the missing portion of the brain. This method is called experimental ablation. He claimed to have discovered the regions of the brain that control heart rate and breathing, purposeful movements, and visual and auditory reflexes.  Paul Broca (1824-1880), a French surgeon, applied the principle of experimental ablation to the human brain.He did not remove parts of human brains to see how they worked but observed the behavior of people whose brains had been damaged by strokes. In 1861, he performed an autopsy on the brain of a man who had had a stroke that resulted in the loss of the ability to speak. Broca's observations led him to conclude that a portion of the cerebral cortex on the front part of the left side of the brain performs functions that are necessary for speech. This came to be known nowadays as Broca's area.  Jan Purkinje in 1787-1869 who was a Czech physiologist studied both the central and peripheral nervous systems in the middle of the nineteenth century. He discovered Purkinje fibers-neurons terminating on cardiac cells responsible for controlling contractions of the heart. With the use of a microscope he investigated the structure of neurons in many regions of the brain, which included discovering Purkinje cells in the cerebellum.  Spanish anatomist Santiago Ramon y Cajal in the late 19th century (1852-1934) used the Golgi staining technique to examine individual neurons of the brain. His drawings of neurons magnified through a microscope from the brain, spinal cord, and retina depicted the detailed structures of these cells for the first time. He proposed that the nervous system consisted of billions of discrete, individual neurons, in opposition to the predominant idea of the time that the nervous system was a continuous network. With his discovery, he was awarded the Nobel Prize for his work describing the structure of the nervous system in the year 1906.  In 2014 Nobel Prize was awarded to John O'Keefe (1939- ), May-Britt Moser (1963), and Edvard Moser (1962) for work on spatial positioning systems in the brain this was also called the brain's global positioning system, or GPS).  In the year 2014, Jeffrey Hall (1945- ), Michael Rosbash (1944-), and Michael Young (1949-) also received the Nobel Prize for their work describing the molecular mechanisms controlling circadian rhythms.  Nowadays, the field of behavioral neuroscience is already a diverse, international and interdisciplinary. The field of genetics also has encouraging discoveries such as the development of optogenetics which gives researchers with the ability to selectively activate single neurons and observe changes in behavior by the use of light. Another is the development of CRISPR-Cas9 techniques have which enabled precise editing of genetic material our (DNA). This technique is said to be using an enzyme (Cas9) to cut out pieces of DNA paired with a set of replacement directions (guide RNA) to create modified genes. The impact of this on behavioral neuroscience is just beginning to be understood. Then the field of epigenetics which focuses on the role of the environment in the expression of genes is also an emerging area in explaining human behavior.