Chapter 2 Psychology Condensed Powerpoint

Neurons: nerve cells; the basic elements of the nervous system Dendrites: fibers that receive electrical messages (impulses) from other neurons Axon: long extension that carries messages to other neurons Myelin sheath- Protective coat of fat that surrounds neurons for the muscles in our bodies to produce the complex movements that make up any meaningful physical activity, the brain has to provide the right messages to them and coordinate those messages. Such messages, as well as those which enable us to think, remember, and experience emotion, are passed through specialized cells called neurons. Perhaps as many as one trillion neurons throughout the body are involved in the control of behavior. How neurons fire All-or-none law The rule that neurons are either on or off. Resting State Before a neuron is triggered. Action potential An electric nerve impulse that travels through a neuron when it is set off by a “trigger,” changing the neuron’s charge from negative to positive. Mirror neurons Neurons that fire when a person enacts a particular behavior and also when a person views others’ behavior. Movement of the action potential across the axon. Just before Time 1, positively charged ions enter the cell membrane, changing the charge in the nearby part of the neuron from negative to positive and triggering an action potential. The action potential travels along the axon, as illustrated in the changes occurring from Time 1 to Time 3 (from top to bottom in this drawing). Immediately after the action potential has passed through a section of the axon, positive ions are pumped out, restoring the charge in that section to negative. Where Neurons Connect Synapse: the space between two neurons where the axon of the sending neuron communicates with the dendrites of the receiving neuron with chemical messages In a computer, each part is physically connected to the other part. In contrast, evolution has produced a neural transmission system that at some points has no need for structural connections between components. Instead, a synapse, a chemical connection, bridges the gap between two neurons. Neurotransmitters: the chemical messengers received at dendrites or cell body of receiving neuron Neurotransmitters are important for maintaining vital brain and body functions. As well, a deficiency or an excess of a neurotransmitter can produce severe behavior disorders. Deliver excitatory (make it more likely receiving neuron will fire) or inhibitory (make it less likely they will fire) messages Reuptake: terminal buttons of sending neuron reabsorb neurotransmitters (A) A synapse is the junction between an axon and a dendrite. The gap between the axon and the dendrite is bridged by chemicals called neurotransmitters (Mader, 2000). (B) Just as the pieces of a jigsaw puzzle can fit in only one specific location in a puzzle, each kind of neurotransmitter has a distinctive configuration that allows it to fit into a specific type of receptor cell (Johnson, 2000). 1. Chemicals that carry messages across the synapse to a dendrite of a receiving neuron are _____ 2. The following messages make it more likely that a receiving neuron will fire and an action potential will travel down its axon. _____ 3. The reabsorption of neurotransmitters by a terminal button is called _____ 4. Neurons in your brain connect to each other through a chemical connection called a _____ 5. The following messages provide chemical information that prevent or decrease the likelihood that the receiving neuron will fire. _____ Neurotransmitters Major neurotransmitters Acetylcholine (ACh): muscle movement, memory, cognitive functions; Dopamine (DA): movement, attention, learning; Serotonin: Sleeping, eating, mood, pain Endorphins: Pain suppression, pleasure, appetites neurotransmitters are a particularly important link between the nervous system and behavior. Not only are they important for maintaining vital brain and body functions, a deficiency or an excess of a neurotransmitter can produce severe behavior disorders. Central nervous system: the part of the nervous system that includes the brain and spinal cord Reflex: an automatic involuntary response to an incoming stimulus; some are controlled by the spinal cord Peripheral nervous system: the parts of the nervous system that includes the autonomic and somatic subdivisions; branches out from the spinal cord and brain and reaches the extremities of the body The nervous system is divided into two main parts: the central nervous system and the peripheral nervous system. The spinal cord is the primary means for transmitÝng messages between the brain and the rest of the body. However, it’s not just a communication channel. It also controls some simple behaviors on its own, with no help from the brain. Peripheral nervous system: the parts of the nervous system that includes the autonomic and somatic subdivisions; made up of neurons with long axons and dendrites, it branches out from the spinal cord and brain and reaches the extremities of the body Somatic division: specializes in the control of voluntary movements and communication of information to and from the sense organs Autonomic division: controls involuntary movement of the heart, lungs, and other organs of the body that keep you alive • Sympathetic • Parasympathetic The autonomic division plays a particularly crucial role during emergencies. The sympathetic division acts to prepare the body for action in stressful situations. This response is often called the “fight-or-flight” response. The parasympathetic division acts to calm the body after the emergency is ended. It also directs the body to store energy for use in emergencies. The sympathetic and parasympathetic divisions work together to regulate many functions of the body. Sympathetic • The part of the autonomic division of the peripheral nervous system that acts to prepare the body for action in stressful situations, engaging all the organism’s resources to respond to a threat. • “Fight-or-Flight Response” Parasympathetic • The part of the autonomic division of the peripheral nervous system that acts to calm the body after the emergency has ended. “Rest and Digest Response” The part of the nervous system that is composed of brain and spinal cord is The central Nervous system The part of the nervous system that includes the autonomic and somatic subdivisions, is made up of neurons with long axons and dendrites, and branches out from the spinal cord and brain to reach the extremities of the body is the peripheral nervous system The Endocrine system Endocrine system: chemical communication network that sends messages throughout the body through hormones in the bloodstream Hormones- chemical that circulate through the body via the bloodstream Pituitary gland The major component of the endocrine system, or “master gland,” which secretes hormones that control growth and other parts of the endocrine system. Another of the body’s communication systems, the endocrine system is a chemical communication network that sends messages throughout the body via the bloodstream. Its job is to secrete hormones, chemicals that circulate through the blood and regulate the functioning or growth of the body. It also influences—and is influenced by—the functioning of the nervous system. Pituitary gland The major component of the endocrine system, or “master gland,” which secretes hormones that control growth and other parts of the endocrine system. Studying the brain Electroencephalogram (EEG) -electrical activity Positron emission tomography (PET) scan -biochemical activity Functional magnetic resonance imaging (fMRI) -3D image of brain by using a powerful magnetic field Transcranial magnetic stimulation (TMS) -magnetic field cause brief interruption in brain activity While the capabilities of the human brain far exceed those of the brain of any other species, humans share some basic functions, such as breathing, eating, and sleeping, with more primitive animals. The part of the brain known as the central core is quite similar in all vertebrates (species with backbones). Its evolution can be traced back some 500 million years to primitive structures found in nonhuman species. The electroencephalogram (EEG) records electrical activity in the brain through electrodes placed on the outside of the skull. Although traditionally the EEG could produce only a graph of electrical wave patterns, new techniques are now used to transform the brain’s electrical activity into a pictorial representation of the brain that allows more precise diagnosis of disorders such as epilepsy and learning disabilities. Positron emission tomography (PET) scans show biochemical activity within the brain at a given moment. PET scans begin with the injection of a radioactive (but safe) liquid into the bloodstream, which makes its way to the brain. By locating radiation within the brain, a computer can determine which are the more active regions, providing a striking picture of the brain at work. Functional magnetic resonance imaging (fMRI) scans provide a detailed, three-dimensional computer-generated image of brain structures and activity by aiming a powerful magnetic field at the body. With fMRI scanning, it is possible to produce vivid, detailed images of the functioning of the brain. Transcranial magnetic stimulation (TMS) is one of the newest types of scan. By exposing a tiny region of the brain to a strong magnetic field, TMS causes a momentary interruption of electrical activity. Researchers then are able to note the effects of this interruption on normal brain functioning. The procedure is sometimes called a “virtual lesion” because it produces effects analogous to what would occur if areas of the brain were physically cut. The enormous advantage of TMS, of course, is that the virtual cut is only temporary Our old brain Central core: controls basic functioning, such as eating and sleeping and is common to all vertebrates Hindbrain:  Medulla: important functions include breathing and heartbeat  Pons: integrates movement between right and left side of the body, regulates sleep  Cerebellum: part of the brain that controls bodily balance The limbic system is involved in several important functions, including self-preservation, learning, memory, and the experience of pleasure. The limbic system is sometimes referred to as the “animal brain” because its structures and functions are so similar to those of other mammals. Injury to the limbic system can cause marked changes in behavior. An animal that once was docile can turn into a savage. An animal that once was savage can become completely gentle. The Limbic System Limbic system: control a variety of basic functions relating to emotion, learning, memory, pleasure, and self-preservation (ex., eating, aggression, reproduction); includes the amygdala and hippocampus The cerebral cortex is referred to as the “new brain” because of its relatively recent evolution. It consists of a mass of deeply folded, rippled, convoluted tissue. Although only about one-twelfth of an inch thick, it would, if flattened out, cover an area more than 2 feet square. This configuration allows the surface area of the cortex to be considerably greater than it would be if it were smoother and more uniformly packed into the skull. The uneven shape also permits a high level of integration of neurons, allowing sophisticated information processing. Cerebral cortex Cerebral cortex: responsible for sophisticated, uniquely human information processing Lobes: The four major sections of the cerebral cortex: Frontal lobes, Parietal lobes, Temporal lobes, Occipital lobes Motor area The part of the cortex that is largely responsible for the body’s voluntary movement. Sensory area The site in the brain of the tissue that corresponds to each of the senses, with the degree of sensitivity related to the amount of tissue allocated to that sense. Association areas One of the major regions of the cerebral cortex; the site of the higher mental processes, such as thought, language, memory, and speech Hemispheres: left and right halves of the brain; each controls motion and sensation in the opposite side of the body (“right brain” and “left brain”) Lateralization: dominance of one hemisphere in specific functions, such as language The most recent development, at least in evolutionary terms in the organization and operation of the human brain probably occurred in the last million years: a specialization of the functions controlled by the left and right sides of the brain. Despite the appearance of similarity between the two hemispheres, they are somewhat different in the functions they control and in the ways they control them. The differences in specialization between the hemispheres are not great, and the degree and nature of lateralization vary from one person to another. Both hemispheres function in tandem. Neuroplasticity and the Brain Neuroplasticity: changes in the brain over the lifespan having to do with the addition of new neurons (neurogenesis), new interconnections between neurons, and the reorganization of information-processing areas Scientists have learned in recent years that the brain continually reorganizes itself in a process termed neuroplasticity. Although for many years conventional wisdom held that no new brain cells are created after childhood, new research finds otherwise. Not only do the interconnections between neurons become more complex throughout life, but it now appears that new neurons are also created in certain areas of the brain during adulthood— a process called neurogenesis. In fact, new neurons may become integrated with existing neural connections after some kinds of brain injury during adulthood (Bhardwaj et al., 2006; Jang, You, & Ahn, 2007; Poo & Isaacson, 2007). Biofeedback—a procedure in which a person learns to control through conscious thought internal physiological processes such as blood pressure, heart and respiration rate, skin temperature, sweating, and constriction of particular muscles.