jimtrue.com : school : PSY1012 : Chapter Two: Neuroscience & Behavior

Posted by Jim True on February 6, 2006 5:29 PM. Last Updated October 22, 2006 9:23 PM

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Chapter Two: Neuroscience & Behavior

Angel class enabled. Next unit's Powerpoint online on Angel. http://angel.spcollege.edu, We are section 1508.

Service-Learning Details: goodbread.beth@spcollege.edu

In Class Discussion

Neural Communication

• Biological Psychology
• Branch of psychology concerned with th links between biology and behavior
• some biological psychologists call themsselves behavioral neuroscientists, neurophysicists, behavior geneticists, physiological psychologists, etc.
• Neuron
• A nerve Cell
• the basic building block of the nervous system
• diagram of Neuron on Page 59
• Dendrites receive messages from other neurons. Message goes into cell body traveling down the axon heading to the terminal branches (electrical using ions) - the end parts are synapses (chemical). Neuro-transmitters at synapses are the chemical messengers. Brain is densely packed in the brain, nerves are often not myelinated as no distance to travel. Neurons that have to travel a long distance are highly myelinated. Breakdown in myelin sheath disrupts the signal; an example of this is MS.
• Nervous system is the body's speedy electro-chemical messenging system. If you deplete electrolytes (sodium and potassium) are important to keeping nervous system functioning.
• Action potential - like the wave at a ball game. All or None.
• a neural impulse; a brief electrical charge that travels down an axon.
• generated by the movement of positively charged atoms in and out of channels in the axon's membrane.
• electrical release is what triggers the release of the neurotransmitter at the synapses.
• Threshold
• the level of stimulation required to trigger a neural impulse. What's required to start the Action Potential.
• Neuro-Transmitter Details
• Picture on Page 61 shows Neuro-transmitter detail. (From A&P, there are more synapses in the human brain than there are stars in the milky way galaxy.
• Neurotransmitters circulate in different pathways within the brain. Graph of Neurotransmitters from page 62 in book. First discovered in 1921. They are either excitatory or inhibitory (they either create or quiet down impulses). ACh (excitatory muscle contractions); Dopamin (inhibits muscle movement, emotion). L-Dopa used to be used to treat low dopamine levels in Parkinson's Disease patients. Serotonin is our 'feel-good' transmitter; prozac and other increase levels of serotonin in depression patients.
• Acetylcholine - a neurotransmitter that, among its functions, triggers muscle contraction
• Endorphins
• "morphine within"
• natural, opiatelike neurotransmitters
• linked to pain control and to pleasure -- when are they most usually released? (exercize)
• Agonists or Antagonists - neuro-transmitters are like a lock and key arrangement; neurotransmitter molecule fits on a receptor site on receiving neuron. Agonist mimics the neurotransmitter and activates the receptor site (also increases the level of the neurotransmitter in the nervous system, because they replace the active neurotransmitter) [cocaine and amphetamines are agonists for Acetylcholine, as is nicotine]; antagonist blocks the neurotransmitter, bind on the receptor site and block the neurotransmitter from being released (antagonist example is cobra venom an antagonist for acetylcholine... first symptom is double-vision, later paralysis; botox is a neurotox that paralyzes the muscles where the wrinkles would show).
• Antidepressants are agonists but work in a different way; neurotransmitters are stored in the synaptic vesicles at the axon terminal. When the electrical impulse fires the neurotransmitter they bind on the receptor sites and once they've activated, they are 'reuptaked' into the synaptic vesicles. SSRI - Selective Serotonin ReUpdate Inhibitors. Ecstasy floods the brain, SSRI's prevent the reuptake from working, so the serotonin are not taken back; they stay on the receptor site longer.

The Nervous System

• Nervous System
• the body's speedy electrochemical communication system
• Consists of all the nerve cells of the peripheral and central nervous systems
• Central Nervous System (CNS)
• the brain and spinal cord
• Peripheral Nervous System (PNS)
• the sensory and motor neurons that connect the CNS to the rest of the body
• Nerves
• neural "cables" containing many axons
• part of the peripheral nervous sytem
• connect the CNS with muscles, glands and sense organs
• Sensory Neurons
• neurons that carry incoming information from sense receptors to the central nervous system. INPUT
• Interneurons
• CNS specific neurons that internally communicate and intervene between the sensory and motor neurons. INTERMEDIARY
• Motor neurons
• Carry outgoing information from CNS to muscles and glands. OUTPUT
• Somatic Nervous System
• Division of the PNS that controls body's skeletal muscles. Skeletal nervous system is same as Somatic Nervous System.
• Autonomic Nervous System
• Division of the PNS that controls the glands and the muscles of the internal organs (such as the heart). Further broken down into:
• Sympathetic Nervous System
• AROUSES the body, mobilizing it's energy in stressful situations
• affects adrenal glands releasing adrenaline and cortisol
• Adrenaline release causes faster breath rate, heart rate, digestion stops and pupils dilate (better vision); the fight or flight response.
• Parasympathetic Nervous System
• CALMS the body, conserving it's energy.
• Our bodies like to be in equilibrium or homeostasis, so parasympathetic system brings the excited (sympathetic) system back into homeostatis.

The Brain

• Study brain by seeing the types of effects caused by a brain lesion (tissue destruction), naturally or experimentally caused destruction of brain tissue.
• Electroencephalogram (EEG)
• amplified recording of the waves of electrical activity that sweep across the brain's surface.
• waves are measured by electrodes placed on the scalp.
• CT (computed tomography) Scan
• series of x-ray photographs taken from different angles; the computer combines these scans into a representative 'slice' through the body. Also called the CAT scan.
• PET (Positron emission tomography) Scan
• visual display of brain activity that detects where radioactive glucose goes while the brain performs a given task. Shows function and activity.
• MRI (magnetic resonance imaging)
• technique using magnetic fields and radio waves to produce images that distinguish among different types of soft tissue; allows us to see structures within the brain. Shows structure.
• Cerebro spinal fluid in the ventrigals, much more space in schizophrenic patients, impacts pressure of fluid against the brain.
• Brainstem
• the oldest part and central core of the brain, beginning where the spinal cord sweels as it enters the skull
• responsible for automatic survival functions
• sometimes called the 'reptilian brain', oldest and most basic brain region.
• Broken down into:
• Medulla [mud-DUL-uh]
• base of the brainstem
• controls heartbeat and breathing
• Reticular formation (not reponsible)
• sleep cycle and level of arousal
• important role in controlling arousal, affected by alcohol for example
• Thalamus
• the brain's sensory switchboard, located on the top of the brainstem
• directs messages to sensory receiving areas in the cortex and transmits replies to the cerebellum and medullah
• Cerebellum
• the "little brain" attached to the rear of the brainstem
• helps coordinate volunatry movement and balance
• The Limbic System
• primarily responsible with emotions and memory
• doughnut-shaped neural structure at the border of the brainstem and cerebral hemispheres
• associated with emotions such as fear and agression and drives such as for food and sex
• During adolescence, emotions are high strung
• Includes the hippocampus, amygdala, and hypothalamus
• Amygdala [ah - MIG - dah - la]
• two almond shaped neural clusters that are components of the limbic system
• linked to emotions
• Hypothalamus
• neural structure lying BELOW (hypo) the thalamus
• directs several maintenance activities (eating, drinking, body temperature)
• helps govern the endocrine system via the piptuitary gland; plays a role is not controlling
• linked to emotion
• Pituitary Gland - Master Gland of the Endocrine System
• Hippocampus - linked to memory
• Cerebral Cortex
• highly complex; covers two cerebral hemispheres
• cross-lateralized - right controls left, left controls right.
• Newest most highly evolved portion of the human brain.
• Know the lobes and what they're responsible for:
• Frontal Lobes(speaking and muscle movements, planning and judgement)
• parietal lobes (sensory cortex);
• occipital lobes, straight in the back (visual areas, receive visual information from the opposite visual field)
• temporal lobes, located above the ears (include the auditory areas)
• Aphasia
• Any kind of difficulty with speaking or language; left hemisphere damage, Broca's area (impairing speaking); Wernicke's area (impairing understanding).
• Broca's Area
• area of left front lobe that directs muslce movements involved in speech. Would understand and know what they wanted to say, but be unable to speak.
• Wernicke's Area
• area of left temporal lobe involved in language comprehension and expression. Make all kinds of sounds, but not make any sense.

Divided Brain

• Corpus Callosum
• large band of neural fibers
• connects the two brain hemispheres
• carriers messages between the hemispheres
• "The Man Who Mistook His Wife for a Hat" - Written by Andrew Sachs as a case study for a man who, due to damage in the right hemisphere of his brain, was unable to distinguish faces; he could descibe concrete elements of the face, but could not see the face as a whole.
• The brain is cross-lateralrized; information comes in from the left side of the body, crosses the corpus callosum and is processed by the right side of the body.
• Disappearing Southpaws - the percentage of left-handers decreases sharply in samples of older people. There just really aren't that many to begin with. Left-handed people use both hemispheres equally when processing language.

Endocrine System

• Endocrine System
• The body's "slow" chemical communication system
• a set of glands that secrete hormones into the bloodstream
• Adrenaline is released quickly; corisol, also released by the adrenal glands hangs around and takes longer to breakdown. Also released when you're angry.
• hypothalamus controls the pituitary gland, which secretes many different hormones, some of which affect other glands. All works under the control of the nervous system.
• Thryoid gland issues: hypothyroid condition: low thyroxin; hyperthyroid condition: hi thyroxin

http://www.pbs.org/wnet/brain/3d/

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