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AP Notes, ’15: Chapter 2 – Neuroscience and the Brain Central principle: ultimate challenge: recency – phrenology… Neural Communication – bottom up (top down is chapter 6…) -Neurons – dendrite (cell body) axon; myelin sheath, multiple sclerosis; -action potential details: chemistry to electricity, sodium pump, ions, resting potential, selectively permeable, depolarization, refractory period; cell body decision -- excitatory versus inhibitory signals: all-or-none response -synapse / synaptic gap / synaptic cleft – neurotransmitters, release / reuptake – from vesicles in the terminal buttons (of axon!) -major neurotransmitters: acetylcholine, dopamine, serotonin, norepinephrine, GABA, glutamate, endorphins /morphine – and basics for each agonists, antagonists: blood-brain barrier; L-dopa The Nervous System – CNS, PNS (figure 2.7, 2.8) -Peripheral Nervous System: somatic (AKA voluntary), autonomic composed of sympathetic and parasympathetic -composed of sensory (in), motor (out) -Central Nervous System: interneurons - reflex (figure 2.9) -neural networks -The Endocrine System: hormones – pituitary gland! (versus neurotransmitters…) – others, figure 2.11 -The Brain: what, where, how do we know… -The Tools of Discovery – clinical observation, lesions, stimulation – EEG (electroencephalogram), CT scan (computed tomography), PET scan (positron emission tomography, MRI (magnetic resonance imaging), fMRI (functional magnetic resonance imaging) – what and how for each Structures: (mostly on the handout…) -size, complexity -The Brainstem – medulla, reticular formation (AKA Reticular Activating System), pons, thalamus, cerebellum -The Limbic System: hippocampus, amygdala, hypothalamus, pituitary gland – reward deficiency syndrome -Cerebrum Cerebral Cortex: glial cells, lobes – frontal, parietal, occipital, temporal (FPOT); motor cortex, sensory cortex, neural prosthetics, association areas, Phineas Gage!; -Neural Networks: reading / language circuit: aphasia; angular gyrus Wernicke’s area Broca’s area motor cortex -plasticity, hemispheres – corpus callosum, split brain patients – hemispherectomy -left hemisphere: -right hemisphere: - organization, function, complexity – “Left Brain / Right Brain” article issue; left-handedness AP Notes, ’15 Chapter 2 – Neuroscience and the Brain – with spaces Central principle: ultimate challenge: recency – phrenology… Neural Communication – bottom up (top down is chapter 6…) -Neurons – dendrite (cell body) axon; myelin sheath, multiple sclerosis; -action potential details: chemistry to electricity, sodium pump, ions, resting potential, selectively permeable, depolarization, refractory period; cell body decision -- excitatory versus inhibitory signals: all-or-none response -synapse / synaptic gap / synaptic cleft – neurotransmitters, release / reuptake – from vesicles in the terminal buttons (of axon!) -major neurotransmitters: acetylcholine, dopamine, serotonin, norepinephrine, GABA, glutamate, endorphins /morphine – and basics for each agonists, antagonists: blood-brain barrier; L-dopa The Nervous System – CNS, PNS (figure 2.7, 2.8) -Peripheral Nervous System: somatic (AKA voluntary), autonomic composed of sympathetic and parasympathetic -composed of sensory (in), motor (out) -Central Nervous System: interneurons - reflex (figure 2.9) -neural networks -The Endocrine System: hormones – pituitary gland! (versus neurotransmitters…) – others, figure 2.11 -The Brain: what, where, how do we know… -The Tools of Discovery – clinical observation, lesions, stimulation – EEG (electroencephalogram), CT scan (computed tomography), PET scan (positron emission tomography, MRI (magnetic resonance imaging), fMRI (functional magnetic resonance imaging) – what and how for each Structures: (mostly on the handout…) -size, complexity -The Brainstem – medulla, reticular formation (AKA Reticular Activating System), pons, thalamus, cerebellum -The Limbic System: hippocampus, amygdala, hypothalamus, pituitary gland – reward deficiency syndrome -Cerebrum Cerebral Cortex: glial cells, lobes – frontal, parietal, occipital, temporal (FPOT); motor cortex, sensory cortex, neural prosthetics, association areas, Phineas Gage!; -Neural Networks: reading / language circuit: aphasia; angular gyrus Wernicke’s area Broca’s area motor cortex -plasticity, hemispheres – corpus callosum, split brain patients – hemispherectomy -left hemisphere: -right hemisphere: - organization, function, complexity – “Left Brain / Right Brain” article issue; left-handedness Chapter 2 Neuroscience and Behavior – complete notes Body composed of cells; nerve cells that conduct electricity Biological psychologists are concerned with the links between biology and behavior Phrenology: bumps on head correspond to personality traits… wrong! I. Neural Communications Body built of neurons (interconnected cells) We are biopsychosocial systems Similarities in humans and monkeys allow researchers to study relatively simple animals (i.e. squid) -Animal nervous system and neural systems are similar Objective: People’s thoughts and emotions interact with their biology and person history to produce a unique individual. Scientists gain much of their study of neural systems in other mammals because humans and animals have similar neural systems A. Neurons Body built of neurons nerve cells Dendrite; bushy fibers, receive information and conducts it towards the body Axon; pass information from dendrite to other neurons sometimes very long Motorneurons control muscles The myelin sheath fat that insulates the axons of some neurons (protects your brain; fat head, literally) - Multiple sclerosis is a result of the deteriorating myelin sheath, slows all communication to the muscles along with loss of muscle control Brain activity measured in milliseconds A neuron fired (an impulse) when it receives signals from sense receptors stimulated by pressure, heat or light If stimulated by chemical messages from other neurons it is called action potential Neurons generate electricity from chemical events The fluid below a resting axon has an excess if negatively charged ions The fluid outside the axon has positively charged ions Positive outside negative inside is called resting potential A resting axon has gates that block positive sodium ions -The axons surface is selectively permeable Axons gates open positive charged sodium ions flood through the membrane Depolarizes the axon the axon’s next channel opens During resting, pause; (refractory period) neuron pumps positively charged sodium ions back -Excitatory; pushing a neurons accelerator -Inhibitory; pushing its break (stopping it) Threshold- the level of stimulation required to trigger a neural impulse Increasing the stimulus above the threshold does not increase the action potential; it either happens or not – all-or-none Objective: Body’s circulatory system consists billions of cells; neurons, they send signals through their axon (sometimes encased in the myelin sheath). Receive signals through the dendrites and their cell body. If strong enough, signal fires, transmitting and electrical impulse (action potential). B. How Neurons Communicate Synapse; synaptic gap or cleft The junction between the axon tip of the sending neuron and the dendrite receiving neurons Synapse is the reason for the pause of electrically charge Action potential reaches its end point, triggering neurotransmitters Objective: When action potential reaches end of the axon, they stimulate the release of neurotransmitters. They carry messages from the sending neuron across a synapse to a site on a receiving neuron. Again, if strong enough it generates its own action potential and sends the messages to other cells. C. How Neurotransmitters Influence Us Neural pathway in the brain may only use only one or tow neurotransmitters (ACh)Acetylcholine -Neurotransmitters Neurotransmitters Acetylcholine (Ach) Dopamine Serotonin Norpinephrine GABA Glutamate Function Enable muscle action, learning memory Influences movements, learning, attention, emotion Example Alzheimer’s disease, ACh neurons deteriorate Mod, hunger sleep, arousal depression Controls alertness and arousal adrenaline Major inhibitory neurotransmitter STOP Major excitatory neurotransmitter, memory Undersupply linked to depression, to raise levels take Prozac Not enough can cause depression Excessive leads to schizophrenia, tremors and decreased mobility Parkinson’s Not enough can cause seizures, tremors and insomnia Over supply can over stimulate brain, producing migraines, seizures (people avoid MSG) Ach: Role of learning and memory Messenger at every junction between a motor neuron and skeletal muscle (If blocked, muscles cannot contract.) Candace Pert and Solomon Snyder discovery -Radioactive tracer to morphine, show where it takes up room in brain Morphine bound to receptors in areas linked with mood and pain sensations Endorphins; “Morphine within” Brain contains many neurotransmitters like morphine Objective: Each neurotransmitter has an effect on behavior and emotions. ACh, affects muscle action, learning and memory. Endorphins are natural opiates release in repose of pain and exercise (runner’s high). D. How Drugs and Other Chemicals Alter Neurotransmission If the brain is filled with opiate drugs, can stop producing its own opiate Agonist mimics its effect or blocks its reuptake (Excites) Antagonists inhibits a neurotransmitters release (Inhibits) Blood brain barrier; enables brain to fence out unwanted chemicals circulating blood. Objective: drugs and other chemicals affect communication at the synapse. Agonists excite by mimicking neurotransmitters or block their reuptake. Antagonists (i.e. curare) inhibit neurotransmitters release or block its effect. II. The Nervous System Neurons are the elementary components of out nervous system Central Nervous system; Brain and spinal cord Peripheral Nervous system; Links the central nervous system with the body’s sense receptors muscles and glands Nerves are bundled axons. Sensory neurons Sends information from body’s tissues and sensory organs to the central nervous system (processes information) Motor neurons receive the information form the sensory neurons Interneurons communicate and intervene between the sensory input and motor output Objective: Divisions of the nervous system: central nervous system; consists of the brain and spinal cord. Peripheral nervous system; consists of the neurons that connect the CNS to the rest of the body. Sensory neurons carry information to the sense receptors in the CNS and motorneurons carry information from the CNS to muscles and glands. A. The Peripheral Nervous System Two components Somatic and autonomic Somatic; voluntary control of our muscles Autonomic; controls glands and muscles of out internal organs Operates on its own (unconsciously) Two parts of autonomic Sympathetic and parasympathetic Sympathetic; arousal -- adrenaline Parasympathetic; calming – conserves energy Objective: Somatic- voluntary control of the skeletal muscles. Autonomic sympathetic and parasympathetic controls involuntary control of skeletal. B. Central Nervous System Tens of bullions neurons, communications with other neurons C. The Spinal Cord and Reflexes An information highway—connects peripheral nervous system to the brain Ascendingsends up sensory information Descendingsends back motor control information Reflexes; automatic responses to stimuli, illustrate the spinal cord work Spinal reflex is composed of single sensory neuron and signal neuron Pain reflex; interneuron respond by activating motor neurons to the muscles in your arm To produce bodily pain or pleasure the sensory information must reach the brain D. The Brain and Neural Networks Brian; receives information, interprets it, decides responses Neuron connect with thousands of others (little brains within your big brain) Clustered neurons are in groups called neural networks Learning occurs as feedback strengthens connections that produce certain results Objective: Reflex pathways are automatic inborn responses to stimuli and they do not rely on conscious decisions made in the brain. A neuron can be excited by a stimulus and pass a message to an interneuron in the spinal cord, then causing a muscle reaction. Neural networks are bundles of neurons that strengthen with use, learning from experience. III. The Endocrine System The body’s “slow” chemical communication system Glands that secrete hormones into the bloodstream Hormones; originate in tissuetravel through blood stream affect tissue/brain Very slow system Are chemically identical to neurotransmitters Hormones influence our interest in food, sex, and aggression Hormones influence our growth, reproduction, metabolism, and mood Keeps everything in balance while we respond to stress Adrenal glandslocated on top of the kidneys Releases epinephrine and norepinephrine (Adrenaline and noradrenalin) Increase heart rate, blood pressure, blood sugarENERGY Pituitary gland; pea-sized structure located in the core of the brain Controlled by he hypothalamus Brainpituitaryother glands hormonesbrain Neurotransmitters can drift in the brain fluid’s to nerve receptors Affecting the overall alertness or mood transmitters Objective: Set of glands the secrete hormones into the bloodstream. Chemical messengers travel through the body and affect other tissues- the brain. Some hormones are chemically identical to neurotransmitters; the endocrine system mater gland is the pituitary system which influences the hormones release by other glands. Hypothalamuspituitaryother glandsinfluences the brain. IV. The Brain Enables the mind—seeing, hearing, smelling, feeling, remembering, thinking, speaking, dreaming A. Tools of Discovery Lesion; tissue destruction Usually naturally or experimentally cause by destruction of brain tissue 1. Clinical Observations Right side of the body is weird to the left side of the brain, the left side of the brain is weird to the right side of the brain. Back of the brain vision Left frontal part of the brain speech 2. Manipulating the brain Scientists can chemically or magnetically stimulate carious parts of the brain and note the effects. 3. Recording the Brains Electrical Activity The electroencephalogram (EEG) reads the electrical activity waves. Able to filter out brain activity unrelated to the stimulus people can identify the electrical wave evoked by the stimulus Used for epilepsy 4. Neuroimaging Techniques PET (position emission tomography) scan; visual display of brain activity that detect a brains area of glucose consumption Active neurons are glucose hogs MRI (Magnetic resonance imaging) scans; using magnetic fields and radio waves generates images distinguishing different types of soft tissue Can reveal enlarges fluid filled brain areas in some patients who have a disabling psychological disorder (Schizophrenia). fMRI (Functional MRI) Can reveal the brains functioning as well as its structure Can detect blood rushing to the back of the brain as a person performs different mental functions such as looking at a persons face Snapshots are taken showing the brains changing activity CT scans-computed topography; photograph of the brain Objective: EEG, MRI and fMRI all reveal general effects of damage to various parts of the brain. Lesioning or electrically simulating specific brain areas, by recording the brains surface electrical activity by neural activity with brain scans, neuroscientist are now able to make connections between the brain, mind and behavior. B. Older Brain Structures 1. The Brainstem The brainstem is the oldest and innermost region Begins where the spinal cord enters the skull; slightly swelling to the medulla Brainstem is responsible for automatic survival functions If the brainstem is cut off the animal will still be able to breath and live. Above he medulla sits the pons; helps coordinate movements Brainstem is also the crossover point Between the ear lies the reticular “netlike” formation; a network of neurons that extend from the spinal cord to the thalamus Controls arousal Giuseppe Moruzzi and Horace Magoun; discovered that electrically stimulating the reticular formation of a sleeping cat instantly produced an awake alert animal 2. 3. Our brains are not idle when we sleep The Thalamus Egg shaped structure that sits on top of the brainstem Directs messages to the sensory receiving areas in the cortex and transmits to the cerebellum and medulla Receives information from all the senses except smell The Cerebellum Extends from the rear of the brainstem “little brain” Coordinates movements, nonverbal learning and movements, judge time, alter our emotions and tell apart sounds and textures. “Our brain processes most information outside of our awareness” Objective: brainstem survival functions. Medulla (heartbeat, breathing), pons (coordinate movements), reticular formation (arousal). The thalamus is the brain’s sensory switchboard. Cerebellumcoordinates muscle movements, help process sensory information C. The Limbic System Doughnut shape, borders the brainstem and cerebral hemisphere Associated with emotions; fear and aggression and drives for food and sex 1. The Amygdala Influence aggression and fear both involve neural activity in all levels of the brain Lesions of the amygdala can change a mammal from calm to violent 2. The Hypothalamus A neural system lying below the thalamus Directs several maintenance activities (eating, drinking, body temperature) Helps govern the endocrine system- pituitary gland is linked to emotion Monitors blood chemistry and takes orders from other parts of the brain Cerebral cortex; can stimulate hormones James Olds and Peter Milnerrat experiment; stimulate upon a brain center that provides a pleasurable. Addictive disorders ma stem from reward deficiency syndrome; genetically disposed efficiency in the neural brain systems for pleasure Objective: Located between the brainstem and cerebral cortex. Linked to emotions, memory, and drives. Amygdala, the hypothalamus; pleasurable rewards, hormonal system. Pituitary gland “master gland” controls it by stimulating it to trigger the release of hormones. Hippocampusmemory (Hippo on campus thinking). D. The Cerebral Cortex Intricate covering of interconnected neural cells that form a thin layer on your cerebral hemisphere Body’s ultimate control and information processing center Larger cortexincreased capacities for learning and thinking, more acceptable. 1. Structure of the Cortex Eighty percent of the brain’s weight lies in the left and right cerebral hemispheres- filled with axon connections Glila cells are cell in the nervous system that support, nourish and protect neurons “glue cells” FPOT “Flower pot” as Mr. Craig would say Frontal lobe; lying above the forehead speaking and muscle movements Parietal lobes; at the top and to the rearreceives sensory input for touch and body positions Occipital lobes; at the back of your head visual areas Temporal lobes; on the sides above the earsauditory 2. Functions of the Cortex Partially paralyzed/speechlessdamaged cortical areas 3. Motor Functions Stimulation caused movement only when applied to an arch-shaped region at the back of the motor cortex An area at the rear of the frontal lobes that controls voluntary movements Fritch and Hitzig mapped the motor cortex according to the body parts they controlledThe fingers and the mouth occupy the greatest amount of cortical space 4. Sensory Functions Parallel to the motor cortex is the sensory cortex; registers and processes body touch and movement sensations More sensitive a body regionthe larger area of sensory cortex devoted to it 5. Association Areas Neurons in the association areas integrate information Associate various sensory inputs with stored memories; very important part of thinking Damage to frontal lobe can result in altered personality, unable to plan ahead to begin tasks 6. Language Aphasia impaired use of language Speak fluently- cannot read Comprehend what they read-cannot speak Can write but not read... ect. Broca’s area; controls language expression, an area of the frontal lobe Directs the muscle movement involved in speech Wernicke’s area; speaking only meaningless words Reading aloud involves a third brain area; angular gyrus Read aloud; register in the visual area relayed to second brainunderstood by Wernicke’s areasent to Broca’s areacontrols the motor cortex; creates pronounced word Damage to the angular gyrus-unable to read but can understand Wernicke’s area-disrupts understanding Broca’s area- disrupts speaking Objective: Language read aloud; visual cortex, angular gyrus; transforms visual representation into auditory codes, Wernicke’s area; interprets codes sends to Broca’s area; controls motor cortexpronounced word. 7. The Brain’s Plasticity Plasticity; ability to modify itself after some types of damage Some neural tissue can reorganize in response to damage If one hemisphere is damaged in early life, others will pick up many of its functions Neurons transfer to other areas V. Our Brain Divided A. Splitting the Brain Corpus callousum; large brand of neural fibers connecting the two brain hemispheres and carrying fibers between them Vogel and Bogen; reduce patients seizures; with uncontrollable epilepsy Spilt brain; two hemisphere of the brain are isolated by cutting the connecting fibers between them Each hemisphere reports only what it sees Split brain patients report seeing portions of the word transmitted If pictures is flashed in the middle patients are not able to describe the object “two separate minds” Both hemispheres can comprehend and follow an instructions Left hemisphere is the interpreter B. Studying Hemispheric Differences in the Intact Brain Person performs a perceptual talkbrain waves, blood flow and glucose consumption reveal increased activity in the right hemisphere Hemispheric specialization, called lateralization People tend to recognize a picture faster when flashed to the right hemisphere People tend to recognize a word faster when flashed to the left hemisphere Stroke in the left hemisphere will disrupt a deaf persons signing just as it would disrupt a hearing person’s speaking Broca’s area spoken and signed speech Objective: left cerebral hemisphere is crucial for language. Research of split brain have confirmed that in most people the left hemisphere is the more verbal and the right excels in the visual perception and recognition of emotion. People who are healthy show that each hemisphere makes unique contributions to the integrated functioning of the brain. C. Brain Organization and Handedness About 10 percent of us are left-handed; they tend to die younger!!! Right-handers process speech process speech in the left hemisphere So do left-handers The remainder of left-handers split evenly the processing language in the right hemisphere