Psychology 4. Brain and Nervous System

BRAIN & NERVOUS SYSTEM WHO STUDIES BEHAVIORA psychologist is someone who studies the mind and behavior. While talk therapy is often the only thing associated with the word psychologist, this profession actually encompasses a wide range of specialty areas, including animal research and organizational behavior. NATURAL SELECTION TODAYNatural Selection remains true today. In a world where we've tamed our environment and largely protected ourselves from the vagaries of nature, we may think we're immune to the forces of natural selection. But, studies find that the process that drives evolution was still shaping us as recently as the 19th century. PHYSIOLOGICAL PSYCHOLOGYPhysiological psychology is a subdivision of behavioral neuroscience (biological psychology) that studies the neural mechanisms of perception and behavior through manipulation of animal brains in controlled experiments. NERVOUS SYSTEMThe nervous system is the body's main communication system; it gathers, synthesizes, and uses data from the environment. The most basic unit of the nervous system is the neuron, which serves as both a sensor and communicator of internal and external stimuli. MYELINATIONMyelination is the process of creating the myelin sheath that surrounds the axons of the nerves, forming an electrically insulated layer (think of the rubber coating that insulates copper wire). Myelin is an outgrowth of the glial cells. ALL-OR-NONE AND SUMMATION● ALL-OR-NONE LAWThe all-or-none law is a principle that states that the strength of a response of a nerve cell or muscle fiber is not dependent upon the strength of the stimulus. If a stimulus is above a certain threshold, a nerve or muscle fiber will fire. ● SUMMATION- Summation, also known as frequency summation, is the method of signal transduction between neurons. It also determines whether or not action potential will be triggered by the summation of postsynaptic potentials. Neurotransmitters emitting from the terminals of a presynaptic neuron fall under one of two categories. CENTRAL NERVOUS SYSTEMThe central nervous system (CNS) is composed of the brain and spinal cord. The CNS receives sensory information from the nervous system and controls the body's responses. THE HINDBRAINThe hindbrain (developmentally derived from the rhombencephalon) is one of the three major regions of our brains, located at the lower back part. There are three main parts of the hindbrain the pons, cerebellum, and medulla oblongata. Most of the 12 cranial nerves are found in the hindbrain. THE COLLICULIThe superior colliculus (SC) is a structure in the midbrain that is part of the brain circuit for the transformation of sensory input into movement output. Its major function is orienting the animal, particularly with eye movements, to objects of interest in the outside world. CEREBRUMThe cerebrum is the largest and most highly developed area of the brain. All parts work together and share responsibility for the regulation of the higher cognitive and emotional functions of the brain such as perception, motor functions, and even intelligence. HEMISPHERIC SPECIALIZATIONHemispheric specialization, also referred to as cerebral dominance or lateralization of function, is a defining characteristic of the organization of the human brain. When task demands are high, the brain's processing capacity is increased by interaction between these two processors. THE ENDOCRINE SYSTEMThe endocrine system is a series of glands throughout the body that secrete chemicals, or hormones, into the bloodstream. In turn, those hormones affect body functions.