NEUROSCIENCE AND BEHAVIOR CHAPTER 2 NEUROSCIENCE AND BEHAVIOR

Phrenology A theory of personality formulated in the 18th and 19 centuries by German physician Franz Joesf Gall. It stated that specific abilities or personality traits are represented by specific areas of the brain. The size of these brain areas determines the degrees of the corresponding skill or trait. Although wrong in most respects, the theory suggested the idea of localization of function.

Biological Psychology (a.k.a. biopsychology/psychobiology): The study of psychological processes from a biological point of view

NEURONS Nerve cells that run throughout our body. They send and receive messages from other structures in the body such as muscles and glands. Neurons receive, integrate and transmit information in the form of signals. There are 3 main types of neurons: sensory neurons, interneurons, and motor neurons

A “TYPICAL” NEURON Neuron: an individual nerve cell. Neurons are the basic building blocks of the nervous system. They receive, integrate and transmit information in the form of signals. It is estimated that humans have 100-180 billion.

Components of a Neuron Soma (Cell Body): Contains the nucleus (a body within the soma that contains the cell’s hereditary material of the cell) it produces energy that fuels the activity of the cell

Components of a Neuron Dendrites: The short, branched projections of a neuron that receive impulses from axons terminal on other neurons and conduct them toward the cell body.

Components of a Neuron Axon: The long projection that transmit impulses away from the cell body to the synapse.

Components of a Neuron Myelin Sheath: A white fatty substance that insulates and protects the axon. The myelin helps speed the impulses. The loss of muscle control seen with multiple sclerosis is due to a degeneration of myelin sheath.

Components of a Neuron Nodes of Ranvier: the regularly spaced gaps in the myelin sheath. The gaps permit the nerve impulses to leap from one node to the next thus speeding the transmission of the message

Components of a Neuron Axon Terminals (Terminal Buttons): The endings on axons. They are small knobs that secrete chemicals called neurotransmitters.

Who wants to be a mill-neuron-aire? http://opl.apa.org/contributions/EC/Million.htm

Neural Communication Action Potential: A brief electrical charge that travels down the axon of a neuron. It works its way from the dendrites to the axon terminal, much as a bite of swallowed food makes its way from your mouth to your stomach. http://www.youtube.com/all_comments?v=U0NpTdge3aw

Neural Communication Selectively Permeable: allows some particles to pass in and out while blocking other. The selectively permeable surface of the axons allows positive ions in Ions: molecules that carry positive or negative electrochemical charge Stimulus Threshold: The minimum level of stimulation required to activate a particular neuron

http://www.youtube.com/watch?v=ifD1YG07fB8

Neural Communication All-or-None-Law/Principle: The principle stating that either a neuron is sufficiently stimulated, and an action potential occurs or a neuron is not sufficiently stimulated and an action potential does not occur. A neuron always fires at the same intensity; all action potentials have the same strength

Neural Communication Refractory Period: A short period between action potentials; it is so short that a neuron can send action potentials down its axons at rates of up to 1000 per second.

How Neurons Communicate Synapse: The tiny gap between the axon terminal of the sending neuron and the dendrites of the receiving neuron It is across this tiny gap that neurons communicate with one another

Neurotransmitters Neurotransmitters are chemical messengers released from the axon terminals. Neurotransmitters will bind only to specific receptors on the postsynaptic membrane that recognize them.

How Neurotransmitters Influence Us Acetylcholine (ACh): A neurotransmitter that causes excitation at synapses between motor neurons and skeletal muscles, causing the muscle to contract. It also plays a crucial role in learning and memory. Insufficient supply of Ach is related to Alzheimer’s disease.

How Neurotransmitters Influence Us Endorphins: found mainly in the pituitary gland they are the natural opiates released in response to pain and vigorous exercise. The release of endorphins during vigorous exercise explains a “runner’s high” and their release in response to pain explains why some injured people are indifferent to pain.

Table 2.1 Myers: Psychology, Eighth Edition Copyright © 2007 by Worth Publishers

How Drugs & Other Chemicals Alter Neurotransmission What happens when the brain is flooded with drugs such as heroin and morphine? The brain may stop producing its own natural opiates, and withdrawal of these drugs may result in discomfort until the brain resumes production of its natural opiates

How Drugs & Other Chemicals Alter Neurotransmission Agonists: A drug that boosts the effect of a neurotransmitter. For example, Prozac reduces depression by enhancing the availability of serotonin at the synapse. Prozac, therefore, is a serotonin agonist.

How Drugs & Other Chemicals Alter Neurotransmission Antagonists: A drug that blocks the effects of a neurotransmitter. For example, ACh triggers muscle contraction. Some native tribes in S. America use a poison called curare, to coat the tips of the darts they use in their blowguns. When these darts strike an animal, the result is paralysis, because the curare molecules fill the receptor sites on dendrites that normally receive ACh, but the curare molecules do not stimulate an action potential in the receiving neuron the way ACh would. This means the ACh is blocked from doing its job and movement ceases. Therefore curare is an antagonist.

The Nervous System A complex combination of cells that allows you to gain information about what is going on inside and outside your body and to respond appropriately It is comprised of the Central Nervous System and the Peripheral Nervous System

The Nervous System http://www.youtube.com/watch?v=4Gdjcd68sGE

Peripheral Nervous System Nerve cells that send messages between the CNS and all the parts of the body, such as muscles, organs, and skin receptors.

Peripheral Nervous System Somatic Nervous System Autonomic Nervous System Controls involuntary actions. It regulates the body’s vital functions: breathing, digestion, blood pressure, etc. It is also involved in emotions Controls voluntary activities It serves arousal functions

Peripheral Nervous System AUTONOMIC NERVOUS SYTEM Parasympathetic Nervous System Sympathetic Nervous System Calms the body after emergencies. Restores the body’s energy Prepares the body for fight-or flight response

The Peripheral Nervous System

Three Types of Neurons Sensory Neurons Carry information from the sense receptors to the spinal cord and brain. Motor Neurons Nerves that carry information away from the brain and spinal cord to the muscles and glands so they can takes action Interneurons Nerve cells in the brain & spinal cord that are responsible for processing information, they are neither sensory nor motor but connect other neurons within the CNS

Central Nervous System Brain and the Spinal Cord

Central Nervous System Reflexes: (1st proposed by R. Descartes) Automatic responses to stimuli. A simple spinal reflex pathway is composed of a single sensory neuron and a single motor neuron. They often communicate through an interneuron.

Which Nervous System? Which nervous system is involved in allowing you to shoot a basketball, smell freshly baked bread, and push the keys on a piano? Somatic Nervous System

Which Nervous System? The digestion of last night’s dinner is most directly controlled by which nervous system? Autonomic

Which Nervous System? The voluntary command Zelda uses to raise her hand in class would travel through which nervous system from the spinal cord to the muscles that control movement? Somatic

Which Nervous System? When a man grabbed Zoe’s purse, she ran after him, tackled him, and retrieved her purse. Then she realized that her heart was racing, her breathing was irregular, and she was trembling. Which of Zoe’s nervous systems was responsible for this reaction? Sympathetic

Which Nervous System? You woke up late for your big job interview! You are running and your heart is beating fast! Which nervous system governs your running? Somatic Which nervous system governs your heart rate? Autonomic (Sympathetic)

Which Nervous System? Zeon had a long, difficult day at school. As he sits down on the sofa, his heart rate and breathing slow down, his muscles relax, and his digestive system starts getting ready for food. Which of Zeon’s nervous systems has been activated? Parasympathetic

The Endocrine System The endocrine system contains hormones which stimulate growth and many kinds of reactions. Hormones have specific receptor sites. Hormones are produced by glands such as the pituitary gland, the thyroid gland, the adrenal gland, the testes, and the ovaries.

Hormones are to the endocrine system as ______________ are to the _________________

The endocrine system is faster/slower than the nervous system

Thyroid Gland: Secretes hormones involved in metabolism Hypothyroidism (too little thyroxin) leads to being overweight Hyperthyroidism (too much thyroxin) leads to weight loss, inability to sleep, excitability, etc.

Adrenal Gland: The outer layer of the adrenal glands secretes cortical steroids which increase resistance to stress and promote muscle development. Cortical steroids also release stored sugar, making energy available for emergencies.

Pituitary Gland: is also known as the “master gland” because it secretes many hormones that affect a wide range of behaviors such as growth, pregnancy, mothering, etc.

Testosterone: A male sex hormone produced by the testes in the male. If, in the prenatal period, testosterone is secreted male sex organs develop. However, if testosterone is NOT secreted, female sex organs develop. In adolescence, testosterone aids in the growth of muscle and bone and in the development of primary and secondary sexual characteristics

Estrogen and Progesterone: female sex hormones secreted by the ovaries Estrogen is involved in the development of primary and secondary sexual characteristics

The Brain The Tools of Discovery Lesion: a naturally or experimentally caused destruction of brain tissue Clinical Observation: The oldest method of studying the brain. People with brain injuries or diseases and observe how these injuries effect their functioning. These clinical observations have helped scientists map the brain. (Ex. Phineas Gage)

METHODS OF STUDYING THE BRAIN Electroencephalogram (EEG): Records the electrical activity of the brain creating “brain waves” It is frequently used in studying sleep, monitoring the depth of anesthesia, diagnosing epilepsy, and other brain disorders or dysfunction, as well as studying normal brain function

METHODS OF STUDYING THE BRAIN Neuroimaging Techniques PET Scans: The test involves injecting a very small dose of a radioactive glucose into the vein of your arm. The glucose travels through the body and is absorbed by the organs and tissues being studied. Next, you will be asked to lie down on a flat examination table that is moved into the center of a PET scanner—a doughnut-like shaped machine. This machine detects and records the energy given off by the tracer substance and, with the aid of a computer, this energy is converted into three-dimensional pictures. A physician can then look at cross-sectional images of the body organ from any angle in order to detect any functional problems.

PET SCAN Image

METHODS OF STUDYING THE BRAIN Types of Scans CAT Scans: Produce a 3-dimensional view of the brain that can be displayed on a video monitor

This is what the image looks like taken by a CAT scan

This is NOT the type of CAT Scan to which I am referring

METHODS OF STUDYING THE BRAIN Types of Scans MRI: more powerful than a CAT Scan and can show detail more clearly

METHODS OF STUDYING THE BRAIN Functional Magnetic Resonance Imaging (fMRI) This technique can reveal the brain’s functioning as well as its structure. Blood goes where the brain is especially active. Therefore researchers can watch the brain light up as a person performs different mental functions.

Ten Amazing Facts About the Brain http://www.youtube.com/watch?v=wmcHH4wPpMU

ORGANIZATION OF THE BRAIN

Older Brain Structures The Brainstem: the oldest part and central core of the brain. It begins where the spinal cord swells as it enters the skull. It is responsible for automatic survival functions. It is comprised of… Medulla Pons http://www.youtube.com/watch?v=snO68aJTOpM

Older Brain Structures Brainstem Medulla: located at the base of the brainstem, it controls basic life support functions like heartbeat and breathing Pons: it works with the cerebellum in controlling equilibrium, and with the cerebral cortex in smoothing and coordinating voluntary movements.

Older Brain Structures Reticular Formation (Reticular Activating System: RAS): It is involved in arousal, alertness, and sleep-wake cycles. Alcohol can disrupt the activity of the RAS thus affecting alertness and reaction time. If the fibers from the RAS are disconnected from the brain, a person goes into a permanent coma

Older Brain Structures Thalamus: The brain’s sensory switchboard, located on top of the brainstem; it directs messages for all senses EXCEPT smell Cerebellum: (Latin for Little Brain): Helps coordinate voluntary movement and balance cerebellum

The Limbic System Limbic System: Contains Amygdala Hypothalamus Hippocampus (HAH!=Hippocampus, Amygdala, Hypothalamus)

The Limbic System Amygdala: An almond shaped neural cluster in the limbic system that controls emotional responses, such as fear, aggression and anger.

The Limbic System Hypothalamus: It helps regulate many of the body’s maintenance activities, such as eating, drinking, body temperature, sex drive, etc. It is also linked to emotions such as pleasure Reward centers are located in the hypothalamus. When allowed to trigger their own stimulation in these reward centers by pressing a pedal, rats would sometimes do so at a feverish pace until they dropped from exhaustion.

The Limbic System Hypothalamus Lateral Hypothalamus: Tells us we are hungry Ventromedial Hypothalamus Tells us we are full

The Limbic System Hippocampus: (Hippo is Greek for horse). The hippocampus is a horse shoe shaped structure that helps process new memories for permanent storage.

The Cerebral Cortex Cerebral Cortex: The brain’s wrinkled outer surface that make up the body’s ultimate control and information processing center. It is the largest and most complex part of the human brain, making up 2/3 of the weight of the entire nervous system. It is responsible for out most complex activities such as learning, remembering & thinking.

Memory Cues for Parts of the Brain Term Keyword Meaning Your Mental Picture Broca’s Area Broken Directs muscles for speech production Imagine breaking a talking doll. If it gets broken (Broca), it won’t talk (speech) anymore Parietal Lobe Parent Sense of touch Imagine that a parent (parietal) is touching his/her baby’s forehead to feel if the baby has a temperature Cerebral Cortex Cereal Court Judgment You & a friend have a dispute over a box of cereal. So, you go to cereal court (cerebral cortex) and face a judge (judgment)

Memory Cues for Parts of the Brain Term Keyword Meaning Your Mental Picture Hypo- Thalamus Hypo-chondriac Hunger & Thirst Imagine a hypochondriac (hypothalamus) thinking they’re hungry & thirsty when they’re not Amygdala Armageddon Aggression & Fear In the Bible, Armageddon (amygdala) is the final battle between good and evil. Battles of full of aggression Frontal Lobe Front Impulse control Imagine a student losing patience & crowding to the front of the line. He has lost impulse control. Corpus Callosum Corpse Connects the 2 cerebral hemisperes Imagine a tiny corpse (corpus) lying across (connecting) the two cerebral hemispheres

Memory Cues for Parts of the Brain Term Key word Meaning Your mental picture Left Hemisphere Left Field Handles Language Imagine a Ryan Braun in left field talking (language) continuously during a game (for example, “swing, batter, swing batter, etc) Temporal Lobe Tempera Paints Hearing Imagine someone painting tempera paint (temporal) all over their ears (hearing) “These ears aren’t painted on,” she says Hippo- Campus Hippo Memories Imagine a hippo (hippocampus) wearing an elephant trunk as a Halloween costume. “It helps my memory!” he says

Structure of the Cortex Glia Cells: Cells in the nervous system that support, nourish, and protect neurons.

FOUR LOBES OF THE BRAIN PARIETAL LOBE FRONTAL LOBE OCCIPITAL LOBE TEMPORAL LOBE

Functions of the Cortex Motor Functions Motor Cortex: It initiates voluntary movements in specific parts of the body (right side of the brain controls the left side of the body, etc.)

Functions of the Cortex Mapping the Motor Cortex Those areas of the body requiring precise control (such as the fingers and the mouth) occupy the greatest amount of cortical space.

Functions of the Cortex Neural Prosthetics In an effort to find the source of motor control, researchers have recorded messages from brain areas involved in planning and intention, leading to testing of neural prosthetics for paralyzed patients. Paralyzed patients are now able to mentally to mentally control a television, play video games, etc. http://www.usatoday.com/money/industries/health/story/2011-10-15/robotic-touch/50774398/1

Functions of the Cortex Sensory Functions Sensory Cortex A region at the front of the parietal lobes, it registers and processes body sensations. The most sensitve body parts (i.e your finger tips) require the largest amount of space in the sensory cortex http://opl.apa.org/contributions/EC/Hom.htm

Functions of the Cortex Association Areas Association areas are found in all four lobes. They are involved in higher mental functions, such as learning, remembering, thinking, and speaking

Language Broca’s Area Wernicke’s Area

Language Aphasia: loss or impairment of the ability to understand language or express oneself through language due to brain injury or disease

Language Broca’s Area: (discovered by Paul Broca in the 1880s) directs the muscle movements involved in the production of speech (expressive language) Damage to Broca’s area (which often happens to stroke victims) results in difficulty with spoken languate. Stroke victims can form ideas but can’t turn those ideas into coherent speech Their comprehension of speech is fine and their ability to sing familiar songs are fine

Language Wernicke’s Area: (discovered by Carl Wernicke in 1874) it is involved with your ability to understand what someone else says (receptive language). Damage to Wernicke’s area might leave a person able to hear words but unable to comprehend the meaning of sentences created with the words.

Language Describe the 5 brain areas that would be involved if you read this sentence aloud. 1. registered in the visual area 2. relayed to the angular gyrus which transforms the words into an auditory code 3. the auditory code is received & understood in the nearby Wernicke’s area 4. it is then sent to Broca’s area 5. which controls the motor cortex as it creates the pronounced word

The Brain’s Plasticity Plasticity: the brain’s capacity for modification, as evident in brain reorganization following damage (especially in children)

Our Divided Brain Splitting the Brain: To control the disease of epilepsy, it is sometimes necessary to cut the corpus callosum so that seizures do not spread form one hemisphere to another Corpus Callosum: the wide band of axon fibers that connects the two brain hemispheres Split brain: a split brain is one whose corpus callosum has been severed

Studying Hemispheric Differences in the Intact Brain Laterization: the tendency for one cerebral hemisphere to excel at a particular skill compared with the other hemisphere

LANGUAGE ABILITIES Left Hemisphere: Language Functions are based in the left hemisphere for most people

LEFT VS. RIGHT HEMISPHERE Left: logic, problem solving, mathematical computation, etc. Right: imagination, art, feeling, and spatial relations However… People are NOT right or left brained. The hemispheres do NOT act independently of each other