Lecture 3 - The Biology of Behavior (1) PDF

The Biology of Behavior (1) What is Psychology? Many people mistakenly believe that psychology only involves psychological disorders and therapies In fact, psychology is the scientific study of thought, behavior, and emotion Why do people behave, think, and feel the way the...

The Biology of Behavior (1) What is Psychology? Many people mistakenly believe that psychology only involves psychological disorders and therapies In fact, psychology is the scientific study of thought, behavior, and emotion Why do people behave, think, and feel the way they do? ©2022 Keiko T. Brynildsen  Modern psychological perspectives Biological/neuroscientific How physical systems (e.g., the brain) affect behavior, feelings, and thoughts Evolutionary Natural selection of traits Behavior genetics Contribution of genes and environment to behavior ©2022 Keiko T. Brynildsen  Modern psychological perspectives cont’d. Psychoanalytic/psychodynamic Unconscious dynamics within the individual Behavioral Learning via reinforcements and punishments Cognitive How people reason, remember, interpret Sociocultural How social and cultural forces shape individuals’ behavior ©2022 Keiko T. Brynildsen  Why Do Psychologists Study the Brain? Thoughts, feelings, and behaviors can be traced to electrical and chemical signals traveling through the brain and body  How Does the Brain Work? Nervous system – complex communication network made up of neurons  Nervous System Cells Neuron – specialized cell that transmits neural messages to other neurons, glands, and muscles Dendrite – receives neural messages from other neurons Cell body (soma) – houses DNA Axon – thin tube that transmits messages  Nervous System Cells Glial cells (glia) Provide structure for neurons Some glial cells form blood-brain barrier (prevents some toxins from entering brain) Some glial cells form myelin sheath - specialized cells that are wrapped around the axon to help transmit message  How Do Neurons Communicate? 2 steps: 1) Electrical signal within a neuron (action potential) 2) Chemical signal between neurons (neurotransmitters)  How Do Neurons Communicate? Action potential – electrical impulse that travels from the cell body down to the end of the axon (neural firing) Threshold – level of electric charge needed to stimulate action potential All-or-none response – once the electric charge of the neuron reaches a certain threshold, it fires an action potential  How Do Neurons Communicate? Synapse – junction between 2 neurons Messages are transmitted across synapse via neurotransmitters Neurotransmitters – chemical messengers that travel across synapse from sending neuron to receptors on receiving neuron Reuptake – sending neuron reabsorbs excess neurotransmitters  How Do Neurons Communicate? Excitatory signals – increase likelihood that neuron will fire Inhibitory signals – decrease likelihood that neuron will fire  Specific Neurotransmitters Acetylcholine (ACh) – involved in muscle action, learning, memory Endorphins – reduce pain and promote pleasure Dopamine – involved in voluntary movement, reward, learning, memory  Specific Neurotransmitters Serotonin – involved in sleep, appetite, mood Glutamate – excitatory – learning, memory enhancement GABA – inhibitory – calms Epinephrine and norepinephrine – involved in stress response  Drugs and Neurotransmission Agonists – increase normal activity of a neurotransmitter Antagonists – decrease activity of a neurotransmitter The Nervous System (organization)  Types of Neurons Motor neurons – carry signals from brain or spinal cord to muscles, skin, and glands Sensory neurons – carry messages from receptors to spinal cord and brain  The Nervous System Central nervous system – brain and spinal cord Responds to sensory information Sends messages to muscles, glands, organs Spinal cord – extension of the brain Handles both incoming and outgoing messages Acts as bridge between brain and body below neck Spinal reflexes – automatic responses that  The Nervous System Peripheral nervous system All of nervous system outside brain and spinal cord Allows communication between CNS and sensory systems Contains somatic and autonomic nervous systems  The Peripheral Nervous System Somatic nervous system (voluntary) Sensory and motor pathways Autonomic nervous system (automatic) Sympathetic nervous system – increases physiological arousal Parasympathetic nervous system – decreases arousal  The Endocrine System Hormones – chemicals secreted by endocrine glands into bloodstream Hypothalamus (brain structure) – controls pituitary gland Pituitary gland – “master gland” Adrenal glands – important in mood, energy level, stress response Pineal gland – regulates circadian rhythm