Biopsychology

What makes you, you? What makes you unique from every other person?

The Mind is what the Brain does Specific areas of the brain and specific systems in the body are responsible for –Learning and Memory –Sensing and perceiving –Emotion –Personality –Planning –Attention and arousal –Motivation –Etc.

The building blocks of the brain The Neuron

Types of Neurons –Sensory neurons (carry messages from sense receptors towards the CNS) –Motor neurons (carry messages from CNS toward muscles and glands) –Interneurons (carry messages between nerve cells)

The Structure of a Neuron

Neural Communication Two states –Resting Potential  Negatively charged ions on inside; positively charged ions on outside; cell is negatively charged on inside relative to outside –Action Potential  Based on summation of excitatory and inhibitory signals  Cell depolarizes; i.e., cell becomes positively charged  Voltage change (electrical surge) travels down axon and causes release of neurotransmitter into the synapse

Neural Communication All or None Law –Neurons either fire or they don’t –Require a minimum amount of excitation or stimulation in order to fire –Once the minimum threshold has been reached, the neuron will fire –Regardless of the intensity of stimulation, the neuron will fire with the same intensity

Neural Communication If neurons always fire with the same intensity, how do we discriminate intensity of the stimulus? –The # of neurons stimulated by a single stimulus –Rate of firing (up to a maximum)

Neural Communication Once the neuron fires, it releases its Neurotransmitter into the synapse –Neurotransmitter  Chemical messengers that relay neural messages across the synapse Neurotransmitter fits in receptor like a key fits in a lock Neurotransmitter either excites or inhibits the post-synaptic cell by binding to its receptors

Neuron Demonstration

Neural Communication Methods to stop neural transmission –Reuptake –Degradation –Presynaptic autoreceptors

Seven Important Neurotransmitters Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins

Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Produces sensations of pleasure and reward; used by CNS neurons in voluntary movement Problems with Imbalance: Schizophrenia, Parkinson’s disease Substances that Affect: Cocaine, amphetamines, Ritalin, alcohol

Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Regulates sleep and dreaming, mood, pain, aggression, appetite and sexual behavior Problems with Imbalance: Depression, certain anxiety disorders, obsessive- compulsive disorder Substances that Affect: Prozac, hallucinogenics (e.g. LSD)

Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Controls heart rate, sleep, sexual responsiveness, stress, vigilance and appetite Problems with Imbalance: High blood pressure, depression Substances that Affect: Tricyclic antidepressants, beta blockers

Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Pleasurable sensations and control of pain Problems with Imbalance: Lowered levels resulting from opiate addiction Substances that Affect: Opiates: opium, heroin, morphine, methadone

Plasticity Plasticity – –Ability of the nervous system to adapt or change as the result of experience; sometimes helps the nervous system adapt to physical damage

The Organization of the Nervous System Nervous system Peripheral nervous system Central nervous system (CNS) Autonomic nervous system Somatic nervous system Sympathetic nervous system Parasympathetic nervous system

Divisions of the Nervous System Central Nervous System (CNS) –Brain and spinal cord Peripheral Nervous System (PNS) –Connects brain and spinal cord with the rest of the body

Peripheral Nervous System Somatic Nervous System –Carries incoming messages from sense organs –Carries outgoing messages to skeletal muscles; mobilizes voluntary movements Autonomic Nervous System –Carries signals from the CNS to the internal organs –regulates involuntary functions such as digestion, respiration, heart rate

Autonomic Nervous System Sympathetic Division –Mobilized under stress – (e.g., controls 4 F’s) Increases heart rate and respiration, increases muscle tension, shuts off digestion Parasympathetic Division –Responsible for basic processes or homeostasis Slows heart rate and respiration, increases digestive functioning

Example Hear rattlesnake –Somatic NS  orients eyes to sound to locate snake –Sympathetic Division of ANS  mobilizes fight or flight response (i.e., blood to skeletal muscles; increases respiration) –Somatic NS  initiates skeletal muscles to escape –Once escaped, Parasympathetic NS initiates relaxation response

The Endocrine System (the body’s chemical messenger system)

The Endocrine System Pituitary gland –Master gland; i.e., produces hormones that influence the secretions of all other endocrine glands –Attached to and controlled by hypothalamus

The Endocrine System Endocrine glands release hormones into bloodstream; circulate through body until target organ is reached Non-stress conditions  supports parasympathetic nervous system in maintaining basic processes or homeostasis Stress conditions  supports sympathetic nervous system through release of epinephrine (adrenaline)

Example Revisited Hear rattlesnake –Somatic NS  orients eyes to sound –Sympathetic Division of ANS  mobilizes fight or flight response –Somatic NS  initiates skeletal muscles to escape –Parasympathetic NS  initiates return to resting state, But, … –Endocrine system  release of adrenaline, explains why you feel edgy for a long time afterward

The Endocrine System GlandsSystems/ Processes regulated Anterior PituitaryOvaries and Testes, Milk production, metabolism, stress reactions Posterior PituitaryConservation of water, milk secretion, uterus contractions ThyroidMetabolism, physical growth & development ParathyroidCalcium levels PancreasGlucose (sugar) metabolism Adrenal glandsFight or flight response, metabolism, sexual desire (especially women) OvariesFemale sex characs., production of eggs TestesMale sex characs., sperm production, sexual desire

How Does the Brain Produce Behavior and Mental Processes? The brain is composed of many specialized modules that work together to create mind and behavior

Film on Structures of the Brain

Three Layers of the Brain Brain stem and cerebellum –Drive vital functions, such as heart rate, breathing, digestion Limbic system –Adds emotions, complex motives, increased memory abilities Cerebrum –Enables reasoning, planning, creating, problem solving

The Brain Stem and Cerebellum Thalamus Pons Cerebellum Medulla Brain stem

The Limbic System Hypothalamus – Serves as the brain’s blood- testing laboratory, constantly monitors blood to determine the condition of the body

The Limbic System Amygdala – Involved in memory and emotion, particularly fear and aggression

The Limbic System Hippocampus – Involved in establishing long-term memories

The Cerebrum Cerebrum – Topmost layer of the brain; the bulbous cap over the limbic system Cerebral cortex – Thin gray-matter covering of the cerebrum; carries on thinking and perceiving Cerebral hemispheres – The two walnut shaped halves of the cerebrum, connected by the corpus callosum

04.15 W. W. Norton

Phineas Gage

Specialization of the Cerebral Hemispheres Left Hemisphere Right Hemisphere Spontaneous speaking and writing Responses to complex commands Word recognition Memory for words and numbers Sequences of movements Feelings of anxiety Positive emotion Repetitive but not spontaneous speaking Responses to simple commands Facial recognition Memory for shapes and music Spatial interpretation Emotional responsiveness Negative emotion

Film on Split-Brain