Physiological Psychology: Biological Foundations of Behavior PDF

PRELIM PERIOD The Goals of Research CHAPTER I The goal of all scientists is to explain the Physiological Psychology: Biological phenomena they study. Scientific explanation takes Foun...

PRELIM PERIOD The Goals of Research CHAPTER I The goal of all scientists is to explain the Physiological Psychology: Biological phenomena they study. Scientific explanation takes Foundations of Behavior two forms: generalization and reduction. Chapter Objectives: Generalization 1. Describe the behavior of people with split. They explain particular instances of brains and explain what this phenomenon. behaviour as examples of general laws, contributes to our understanding of self- which they deduce from their experiments. awareness and the goals of scientific research. Reduction. They explain complex phenomena in 2. Learn the biological roots of physiological terms of simpler ones. psychology and the role of natural selection In the evolution of behavioral The TASK of the Physiological Psychologist traits. is to explain behavior in physiological 3. Discuss the value of research with animals terms. But physiological psychologists and ethical issues concerning their career cannot simply be reductionists. and the career opportunities in neuroscience. We must understand "psychologically" why a particular behavior occurs before Physiological psychology we can understand what physiological is the study of the physiological basis of events made it occur. how we think, connecting the physical operation of the brain with what we Behavioral Example actually say and do. Mice will build nests under two It is thus concerned with brain cells, brain conditions: when the air temperature is structures and components, brain low and when the animal is pregnant. chemistry, and how all this. leads to speech and action. Nest building can be studied as behavior related to the process of temperature It is also, of course, important to regulation, or it can be studied in the understand how we take in information context of parental behavior. from our five senses. Physiological mechanisms can tell us something Physiological psychology about psychological processes. It relates an activity to how the brain and other organs function, even at the cellular Damage to a specific part of the brain can and chemical levels. cause very specific impairments in a person's language abilities. The body is a machine and, like any other machine, it converts one kind of energy Damage to another region of the brain can into another kind of energy. Among other produce extreme difficulty in reading things, the body converts chemical energy unfamiliar words by sounding them out, into various kinds of brain activity and but it does not impair the person's ability into the movement of various parts of the to read words with which he or she is body. already familiar. Biological Roots of Physiological Psychology phenomenon as animal electricity. believing that he had discovered a distinct Rene Descartes form of electricity His speculations about the roles of the Johannes Muller mind and brain in the control of behavior provide a good starting point in the history He was a forceful advocate of the of physiological psychology. application of experimental techniques of physiology. To Descartes, animals were mechanical devices; their behavior was controlled by In his doctrine of specific nerve energies, environmental stimuli. Muller observed that although all nerves carry the same basic message - an His view of the human body was much the electrical impulse - we perceive the same: It was a machine. Reactions like messages of different nerves in different this did not require participation of the ways. mind; they occurred automatically. He called them reflexes. The answer is that the messages occur in different channels. DUELIST The portion of the brain that receives messages Descartes believed that each person from the optic nerves interprets the activity as possesses a mind - a unique human visual stimulation, even if the nerves are stimulated attribute that is not subject to the laws of mechanically. the universe. He was the first to suggest that a link exists between the human mind Because different parts of the brain receive and its purely physical housing, the brain. messages from different nerves, the brain must be functionally divided: Some parts perform some Model functions, while other parts perform others. is a relatively simple system that works on Marie Jean Pierre Flourens known principles and is able to do at least some of the things a more complex system was a French physiologist, the founder of can do. experimental brain science and a pioneer in anesthesia. Luigi Galvani Through the study of ablations on found that electrical stimulation of a frog's animals, he was the first to prove that the nerve caused contraction of the muscle to mind was located in the brain, not the which it was attached. heart. Contraction occurred even when the Jean Pierre Flourens removed various nerve and muscle were detached from the parts of animals' brains and observed their rest of the body, so the ability of the behaviour. This method is called muscle to contract and the ability of the experimental abolition. nerve to send a message to the muscle were characteristics of these tissues themselves. Thus, the brain did not inflate muscles by directing pressurized fluid though the nerve. Galvani referred to the Pierre-Paul Broca They applied weak electrical current to the exposed surface of a dog's brain and has been referred to as brilliant observed the effects of the stimulation.. neurologist, surgeon and anthropologist, a child prodigy. and a man well ahead of his They found that stimulation of different time. portions of a specific region of the brain caused contraction of specific muscles on He applied the principle of experimental the opposite side of the body. ablation to the human brain. We now refer to this region as the His early scientific work focused on the primary motor cortex, and we know that histology of cartilage and bone, the nerve cells there communicate directly treatment of aneurisms, infant mortality, with those that cause muscular and cancer pathology. contractions. Also, a wonderful brain anatomist, he made contributions to understanding the limbic system. Broca was also responsible for his discovery of the speech center, known today as Broca's area. He studied the brain of aphasic patients, who were unable to talk. He observed the behavior of people whose brains had been damaged by strokes. Hermann von Helmholtz In 1861 he performed an autopsy on the brain of a devised a mathematical formulation of the man who had had a stroke that resulted in the loss law of conservation of energy, invented of the ability to speak. the ophthalmoscope (used to examine the retina of the eye), and devised an important and influential theory of color vision and color blindness, and studied audition, music, and many physiological processes. Helmholtz was also the first scientist to attempt to measure the speed of conduction through nerves. But Helmholtz found that neural conduction was much slower - only about Gustav Fritsch and Eduard Hitzig 90 feet per second. German physiologists who used electrical stimulation as a tool for understanding the physiology of the brain. Functionalism: Nature Selection and Evolution Mutations are accidental changes in the Charles Darwin chromosomes of sperms or eggs that join together and develop into new organisms. formulated the principles of evolution and natural selection, which revolutionized Most mutations are deleterious; the offspring either biology. fails to survive or survives with some sort of deficit. However, a small percentage of mutations He noted that across succeeding are beneficial and confer a selective advantage. generations, Individual members of a species spontaneously undergo structural Many different kinds of traits can confer a selective changes. advantage: resistance to a particular disease, the ability to digest new kinds of food, more effective If these changes produce favorable effects weapons for defense or for procurement of prey, that permit the individual to reproduce and even a more attractive appearance to members more successfully, some of the individual's of the opposite sex. offspring will inherit the favorable characteristics and will themselves Ethical Issues in Research with Animals produce more offspring. Any time we use another species of animals for our Darwin's theory gave rise to own purposes, we should be sure that what we are functionalism, a belief that characteristics doing is both humane and worthwhile. of living organisms perform useful functions. Ethical Issues in Research with Animals So, to understand the physiological basis of various Research with laboratory animals has produced behaviors, we must first understand what these Important discoveries about the possible causes behaviors accomplish. of potential treatments of produced important discoveries about the possible causes or potential We must therefore understand something about the treatments of neurological and mental disorders. natural history of the species being studied so that, including Parkinson's disease, schizophrenia, the behaviors can be seen in context. manic-depressive illness, anxiety disorders, obsessive-compulsive disorders, anorexia nervosa, The comerstone of this theory is the principle of obesity, and drug addictions natural selection. Briefly, here is how the process works: Every sexually reproducing multicellular Ethical Issues in Research with Animals organism consists of a large number of cells, each of which contains chromosomes. Some people have suggested that instead of using laboratory animals in our Chromosomes are large, complex molecules that research, we could use tissue cultures or contain the recipes for producing the proteins that computers. cells need to grow and to perform their function. The easiest way to justify research with In essence, the chromosomes contain the blueprints animals is to point to actual and potential for the construction (that is, the embryological benefits to human health. development) of a particular member of a particular species. If the plans are altered, a different organism is produced. The plans do get altered; mutations occur from time to time. Careers in Neuroscience Physiological psychologists study behavioral phenomena that can be observed in nonhuman animals. They attempt to understand the physiology of behavior: the role of the nervous system, interacting with the rest of the body (especially the endocrine system, which secreles hormones), in controlling behavior. CHAPTER II equation when drawing conclusions about this relationship. FUNCTIONAL NEUROANATOMY: THE NERVOUS SYSTEM AND BEHAVIOR CHAPTER OBJECTIVES 1. Pinpoint the parts of the neuron and give their functions. 2. Identify the different cranial and spinal nerves and give its corresponding functions. 3. Recognize the significant function of each part of the nervous system and know its effects on NEURON behavior. the basic cellular structure of the nervous system, The way structures in the developing brain are transmits nerve impulses throughout a complex related to changes in psychological and cognitive network of interconnecting brain cells. The brain development is of interest to child contains approximately 180 billion cells, 50 billion neuropsychologists. There are several ways that of which transmit and receive sensory-motor this relationship can be explored, including: signals in the central nervous system (CNS) via 15,000 direct physical connections (Carlson, 2007). 1. correlating structural changes in the developing brain with behavioral changes, 2. investigating behavioral changes and making inferences about structural maturation of the brain, and 3. studying brain dysfunction and its relationship to behavioral disorders (Kolb & Fantie. 1989). Although these approaches can yield useful information about the developing brain, they are not without shortcomings. For example, because of the plasticity of NEURONS AND NEUROGLIA the developing brain following damage, injury in a specific brain region may The CNS is comprised of two major cell types, produce behavioral losses that vary greatly neurons and neuroglia (Carison, 2007). While depending on the age of the child. neurons conduct nerve impulses, the neuroglia ("nerve glue") provide structural support and Environmental factors, such as enrichment insulate synapses (the connections between opportunities and social-cultural neurons). experiences, also influence the developing brain and the manner in which behaviors are expressed (Baron, 2004). Thus, the study of the brain- behavior relationship is particularly complex in children, and these factors must enter the GLIAL CELLS These star-shaped glial cells attach to capillary blood vessels and cover Gilal cells make up about 50 percent of the total approximately 80 percent of each volume of the CNS. Glial cells serve various capillary. functions, including transmission of signals across neurons, structural support for neurons, repair of Oligodendroglia cells form and maintain injured neurons, and production of CNS fluid the myelin sheath and, when injured, swell (Carlson, 2007). in size. Tumors rarely occur in oligodendroglia cells; when they do, they Neuroglia infiltrates or invades surrounding fissue grow slowly and are found primarily in in both the gray and white matter, and in rare the cortex and white matter. instances these cells replicate uncontrollably during tumor activity (Nortz, Hemme-Phillips, & Ris. While about 40-60 percent of these tumors 2007) can be detected by skull X-rays after they calcify (Cohen & Duggner, 1994), radionuclide brain scans, angiography, and computed tomography scans have been helpful in the diagnostic phase of tumor processes. Microglia cells are predominantly found in the gray matter (Carlson, 2007). Following disease or injury, microglia proliferate, move to the site of injury, and perform a phagocytic function by cleaning TYPES OF NEUROGLIA up damaged tissue. Tumors rarely occur in microglia cells. The neuroglia cells serve a number of important functions in the CNS: GRAY MATTER AND WHITE MATTER (1) providing structural support to neurons; (2) aiding in the regeneration of injured nerve Gray matter is located in the core of the CNS, the fibers; corpus striata at the base of the right and left (3) occupying injured sites by producing scar hemispheres, the cortex that covers each tissue, and hemisphere, and the cerebellum (Carlson, 2007). (4) transporting gas, water, and metabolites from The cell bodies, the neuroglia, and the blood and removing wastes from nerve cells (Carlson, vessels that enervate the CNS are gray-brown in 2007). color and constitute the gray matter. The three major types of neuroglia (astrocytes, oligodendroglia, and White matter covers the gray matter and long axons microglia) have distinct functions and extending out from the neuron. serve multiple purposes in the CNS Astrocytes have three primary functions: (1) forming the blood-brain barrier; (2) supporting the cellular structure of the brain, and (3) directing the migration of neurons during early development. Astrocytes are the largest in size and the most abundant type of neuroglia (Carlson, 2007). AXONS RNA RNA, the site of protein synthesis, transmits Axons are generally covered by a myelin sheath, instructions from DNA directing the metabolic which contains considerable amounts of neuroglia functions of the neuron. and appears white upon inspection. White matter has fewer capillaries than gray matter (Carlson, Biochemical processes of the neuron, which take 2007). As the basic functional unit of the CNS, the place in the cytoplasm of the cell body, include the neuron transmits impulses in aggregated energy- producing functions, the self- reproducing communities or nuclei that have special behavioral functions, and the oxidating reactions, whereby functions. energy is made available for the metabolic activities of the cell (Carlson, 2007) Neurons can be modified through experience, and they are said to learn, to remember, and to forget as a result of experiences (Hinton, 1993). DENDRITES CELL BODY OR SOMA Dendrites branch off the cell body and receive impulses from other neurons (Carlson, 2007). The cell body, or soma, is the frophic or center of Dendrites are afferent in nature and conduct nerve neuron. Cell bodies vary in size and shape and impulses toward the cell body. contain the ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) of the neuron. Dendritic spines are the major point of the synapse, the area of transmission from one cell to another. Individuals with cognitive retardation have fewer spines or points of contact across neurons (KleinTasman, Phillips, & Kelderman, 2007). Dendrites can transmit neuronal impulses across neurons through either temporal or graded potentials. AXON HILLOCK The axon hillock is a slender process close to the cell body where action potentials arise. The axon hillock is highly excitable and is activated through electrochemical processes, thereby "turning on" the neuron (Carlson, 2007). NODES OF RANVIER Axons allow the nerve cells to transmit impulses rapidly, particularly along the Nodes of Ranvier. The Nodes of Ranvier are gaps in the myelin and during cell activation, nerve impulses skip from node to node. ALL OR NOTHING RULE Myelinated axons permit more rapid transmission of signals, and anesthetics seem to be more The impulse must be of sufficient strength for the effective at the Nodes of Ranvier. The terminal neuron to "fire." branches of the axon end at the synaptic telodendria Axons follow an "all or nothing" rule; if the impulse is not strong enough the neuron will not fire and, thus, will not transmit the message to another neuron. After the neuron fires, there is a period of time when it will not fire again as the neuron "recovers." MYELIN SHEATH Axons are covered by a myelin sheath made up of neurilemma (or Schwann cells), which surround the SYNAPSE axon. The presynaptic and postsynaptic sites are both The myelin sheath gives the axon a white referred to as the synapse. Synapses are specialized appearance and constitutes most of the white matter for the release of chemicals known as in cortical and subcortical areas. neurotransmitters. Neurotransmitters are released from synaptic knobs at the end foot of the neuron in Most axons are myelinated at birth particularly in the presynapse, and they activate neurons at the areas necessary for survival (motor-sucking: tactile postsynapse sensitivity to hot, cold, and pain; auditory, and vision). Some axons continue to myelinate throughout development with myelinization not complete in the frontal lobes until well into the third decade of life. TYPES OF SYNAPTIC CONNECTIONS about tone) in the auditory system that project into the temporal cortex, and pain, touch, temperature, Synapses are quite large for motor neurons and are and pressure sensors in the skin that project into the smaller in the cerebellum and other cortical parietal cortex regions. Synapses usually occur between the axon of one cell and the dendrite of another (axondendritic connections). Although they can connect onto the soma or cell body of another neuron (axosomatic connection), synapses rarely occur from axon to axon (axoaxonal connections). NEUROTRANSMITTERS Neurotransmitters are released from the presynapse (neuron A), travel across the synaptic cleft, and influence the activity of the adjoining neuron (neuron B). TYPES OF NEURONS There is a collection of vesicles at the synaptic knob at the end of each synapse, where Efferent neurons originate in the motor cortex of neurotransmitters are stored. Most neurons have the CNS, descend through vertical pathways into thousands of synapses, and each dendritic spine subcortical regions, and culminate in the body's serves as a synapse that is excitatory in nature, muscles (Gazzaniga, Ivry, & Mangun, 2002). which causes neurons to fire. These large descending tracts form columns from Neurotransmitters the motor cortex connecting higher cortical regions through the brain stem and spinal cord, to the body Chemical messengers for transmission of for the activation of single muscles or muscle information across synapses to dendrites groups. Various motor pathways begin to develop prenatally, while postnatal development is marked by changes in primitive reflexes (the Babinski reflex) and automatic reflexes (head and neck righting) (Swaiman et al., 2006). Afferent neurons, sensory receptors found throughout the body, transmit sensory information into specific cerebral areas. For example, afferent neurons consist of rods and cones (cells that convey information about color or black/white) in the visual system that project into the occipital cortex; hair cells (convey information  ANATOMY OF THE BRAIN ANATOMY OF HINDBRAIN ANATOMY OF THE FOREBRAIN CEREBRAL CORTEX CEREBRAL CORTEX ANATOMY OF THE LIMBIC SYSTEM SPECIALIZATION OF LEFT HEMISPHERE ANATOMY OF MIDBRAIN  SPLIT BRAIN STUDY Postmortem Studies Identify disorder and then examine brain after death Young, Holcomb, Yazdani, Hicks, & German (2004) Found depression is associated with a greater number of nerve cells in the thalamus being devoted to emotional regulation Supported idea that structural abnormality may lead to depression SPLIT BRAIN METHODOLOGY Corpus callosum severed Animal Studies Techniques used test each half-brain Single-cell recordings SPLIT BRAIN DEMONSTRATION Monitor activity of a single neuron What would a split-brain patient say they saw? Selective lesioning What would a split-brain patient point to Surgically removing or damaging part of with their left hand? the brain Lobes of the Cerebral Cortex Genetic knockout procedures Create animals that lack certain kinds of cells or receptors in the brain 1. Example: Single-Cell Recording 2. Disterhoft & Matthew (2003) 3. Young versus old rabbits compared in 4. learning of eye-blink conditioning 5. Hippocampal pyramidal neurons were monitored 6. Typically, aging animals cannot learn the task 7. Metrifonate, galanthamine, and CI- 8. 1017 injected into the aging rabbits Viewing Structures and Functions of the Brain 9. This led aged rabbits to learn as quickly as young controls 1. Postmortem studies 2. Studying live, non-human animals Human Studies 3. Studying live humans Electrical recordings Electrical recordings Record of a small change in the brain's Static imaging techniques electrical activity in response to a Metabolic imaging stimulating event EEG waves are averaged over many trials to reveal ERPS Dehaene-Lambertz et al. (2004) Examined the language abilities of Infants using EEG  Intelligence and Neuroscience Functional magnetic resonance imaging (fMRI) Takes a series of images of the brain in quick succession and then statistically analyzes the images for differences. Brain areas with more blood flow have been shown to have better visibility on MRI images Better visibility is thought to be correlated with brain activation