Neuroscience Chapter 1

Neuroscience Chapter 1U0

IntroductionAnimism is the philosophy that the physic and chemistry of the world were governed by spirits.The Mind-Body question is the debate of the mind; does it control the nervous system, part of the nervous system, physical or tangible? Not an easy debate to deliberate on since non-physical phenomena cannot be detected in the laboratory. Dualism is the belief in dual nature of reality. The concrete separation of the body and the mind, where the first is made of ordinary matter and the second is not. Monism is the belief that everything in the universe consists of matter and energy. Mind is a phenomenon produced by the workings of the nervous system.Consciousness is the ability for humans to be aware of our thoughts, perceptions, memories and feelings. This can be considered and attributed to our elaborate evolution, our invention of language and our establishment of our behaviours. Hypothesized that consciousness is a physiological function like behaviour.Blindsight is the phenomena where the brain may intercept and interpret our perceptions without the perceptions entering consciousness. Two main brain divisions can be made based on evolution. The primitive visual systems evolved in fish and frogs is devoted to controlling eye movements and bringing our attention to fast moving objects. This system is not directly connected to consciousness but rather to brain regions in control of hand movements. The mammalian system developed afterwards is responsible for our consciousness and our ability to perceive things around us. Directly connected to consciousness. Therefore, blindsight suggests that consciousness is not a property for all parts of the brain.Split Brains are obtained when cerebral hemispheres are no longer able to communicate with each other. This is done by cutting the corpus callosum, a large bundle of nerves that connect corresponding parts of one side of the brain to the other. Cutting the corpus callosum in a split-brain operation is done for severe epilepsy when only one side of the brain will stimulate the other side to become overactive. Cutting it will greatly reduce the frequency of epileptic seizures. Sensory perception and movement control are connected contralaterally. The opposing cerebral hemispheres become independent in perceiving the information. Patients find that their left hand will have a mind of its own. Olfactory sensory, however, is connected ipsilaterally. Therefore, if an odour enters the left nostril, the patient will be able to describe it. However, language is lateralized mostly to the left hemisphere. When you speak with a split brain patient, you are only talking to the left hemisphere. Since sensory information are only noted when they reach the left hemispheres verbal and language region, we can say that consciousness is situated there.Unilateral Neglect is the phenomenon where the patient ignores objects and movements specifically on the left side. Caused by damage to the parietal cortex, which receives somatosensory information as well as auditory and the analyses of movement and location of visual information. Neglect of the left halves of things in the environment and neglect of the left half of ones own body. Note that permanent neglect only occurs to the left side, caused by right parietal cortex damage. Patients with unilateral neglect are neither dumb or numb on one side. They can see things located on their left and feel when one touches them on their left, but normally they ignore such stimuli and are not conscious to them. Note that it is not simply the left perception field that is inactive as certain patients only neglect the left side of an object. To be able to leave out the left side of an object, one must first perceive the full object. The neglect to the left side of objects and vision even extends to visual imagery and recollections. The rubber hand illusion concluded that the parietal cortex analyses the sight and feeling of brush strokes, interrelates them, and then sends it to the premotor cortex if they are congruent.Physiological psychology stems from the foundation that the ultimate function of the nervous system is behaviour. The primary function of the brain is to control movement through the perception of what is happening around us.Goals of research is to explain scientific phenomena. A scientific explanation can take two forms Generalization is the general conclusion of a scientific event based on many observations of the similar phenomena Reduction is the underlying descriptions of a scientific event. The explanation of a complicated phenomena with easier and basic events. We must first understand why a particular behaviour occurs psychologically before we can understand it physiologically.Ancestral roots for physiological psychology: The Egyptians, Indians and Chinese cultures believed that the heart was the seat of thought and emotions However, Hippocrates challenged this in 460-370 BC and gave the role to the brain. French philosopher Decartes denoted reflexes as actions that did not require the participation of the mind, an automatic action. Although a dualist, Decartes suggested a link between the ordinary human body and the extraordinary human mind: the brain. He suggested that the body supplied the information to the mind through its sensory organs, the mind would communicate to the body through the pineal gland. Inspired by the Royal Gardens west of Paris, he thought that the nervous system functioned on hydraulics from the ventricle system in the brain. He established the first mechanical model for the explanation of the nervous system He was quickly proven wrong by Galvani, who was able to stimulate muscles that were detached from the CNS. A scientific model is a simple, physical analogy for a complicated physiological process. German physiologist Muller pushed experimental physiology from observations and classifications to experimental testing of animal organs. He established the doctrine of specific nerve energies: in which he concluded that all nerves carry electrical impulses as messages. French physiologist Flourens introduced experimental ablation, which is the research method in which brain function in a specific region is inferred by observing the behaviours of an animal that is missing the specific region of the brain. Fritsch and Hitzig used electrical stimulations on the primary motor cortex and found stimulations in the muscles on the contralateral side of the dog. Broca, through indirect experimental ablation observations in humans, determined that language and speech was focused to the cerebral cortex on the left side, now named Brocas area. Helmholtz was the first scientist to attempt to measure the speed of conduction of a neuron.Darwins theory of evolution and a species inherent survival behaviours gave rise to functionalism, which is a belief that characteristics of living organisms perform useful functions. This principle aims to bets understand a biological phenomenon by understanding its useful function for the organism. Functional analysis experiment was done by Blest. Butterflys and moths had eye spots on the back of their wings to defer birds from eating them. Several evolutionary traits had benefited the homo sapiens and allows them to house a bigger brain: To harbour a larger brain requires a larger skull. The more intellectual brain also has less percentage of its neurons dedicated to analysing and sending motor and sensory information, but more for learning, remembering, reasoning and making plans. Our brains are able to develop larger because of the phenomenon called neoteny, which is a prolonged period of neural maturation, allowing more time for brain growth.Ethical Issues in Research with AnimalsPhysiological psychologists study all behavioural phenomena that can be observed in nonhuman animals.