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The Biological Basis of Behavior. Neurons: The Messengers. Neurons vary in size and shape All are specialized to receive and transmit information. Myelinated neuron (Fig. 2-1). Three Types of Neurons. Sensory (afferent) neurons: Carry messages from sense organs to the spinal cord or brain
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Neurons: The Messengers • Neurons vary in size and shape • All are specialized to receive and transmit information
Three Types of Neurons • Sensory (afferent) neurons: • Carry messages from sense organs to the spinal cord or brain • Motor (efferent) neurons: • Carry messages from the spinal cord or brain to the muscles and glands • Interneurons (association neurons): • Carry messages from one neuron to another
Glial Cells • The nervous system also contains glial cells, or glia, which: • Hold neurons in place, provide nourishment, and remove waste • Prevent harmful substances from passing from the bloodstream into the brain • Form the myelin sheath
Major Neurotransmitters • Acetylcholine • Dopamine • Serotonin • Norepinephrine • Endorphins
Neural Plasticity • The brain has the ability to be changed by experience. • Rosenzweig (1984)
The Central Nervous System • The nervous system has two parts: • The central nervous system (CNS) • the brain and spinal cord • The peripheral nervous system (PNS) • linking all of the body's parts to the CNS
The Limbic System The structures listed below are often considered to constitute the limbic system. This system is involved in olfaction, emotions, learning, and memory. The limbic system was introduced as a concept by Paul MacLean in 1952 and was long considered the seat of the emotions. Though some of the structures included in this system are in fact involved in some emotional responses, we now know that it does not correspond exactly to any of the multiple emotional systems in the brain.
Hemispheric Specialization • Cerebrum has two separate cerebral hemispheres • Connected by the corpus callosum • Split-brain research
Processing of speech and language Language
Tools for Studying the Brain • Microelectrode techniques • Macroelectrode techniques • Structural imaging • Computerized Axial Tomography scanning (CT) • Nuclear Magnetic Resonance Imaging (MRI) • Functional imaging • Electroencephalograph (EEG) • Magnetoencephalography (MEG) • Magnetic Source Imaging (MSI) • Positron Emission Tomography (PET) scanning
Peripheral Nervous System • The peripheral nervous system (PNS) contains two types of neurons: • afferent neurons • efferent neurons • The PNS is divided into two subsystems • Somatic nervous system • Autonomic nervous system
The Endocrine System • Endocrine Glands: • Tissues that produce and release hormones • Hormones: • Chemical substances released by glands that help regulate bodily activities
Endocrine Glands • Pituitary gland • Pineal gland • Thyroid gland • Parathyroids • Pancreas • Adrenal glands • Adrenal cortex • Adrenal medulla • Gonads
Genes, Evolution, and Behavior • Behavioral Genetics • What is the relationship between heredity and behavior? • Evolutionary Psychology • What are the origins of behavior, and what adaptive value do they provide?
Genetics • Genes • Chromosomes • Deoxyribonucleic acid (DNA)
Patterns of Inheritance • Dominant genes, recessive genes • Polygenic inheritance • Genotypes and phenotypes
Behavior Genetics • A variety of methods are used to study the contribution of genes • Animal behavior genetics • Strain studies • Selection studies • Human behavior genetics • Family studies • Twin studies • Adoption studies
Average Risk of Schizophrenia Among Biological Relatives of People with Schizophrenia Average risk of schizophrenia among biological relatives (Fig. 2-19)
Social Implications • New challenges have arisen as a result of our better understanding of genes. • Modern prenatal screening • Over-simplified reporting of genetic technologies in mass media
Evolutionary Psychology • Examining adaptive value of behaviors from an evolutionary perspective • Common applications • Language • Mate selection • Criticisms