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PSY 190: General Psychology Chapter 3: Biological Psychology “So why do we have to study biology in a psych class?” Let me use Phineas Gage to help answer this question… “He was no longer Gage…” Several different angles of where the rod passed through his skull There is a Phineas Gage display in the Warren Medical Museum at Harvard University This is what went through his brain (see below)… 3½ feet in length; 1¼ inch in diameter Some history buffs travel to the tiny town of Cavendish, VT Biological Roots of Behavior Franz Gall (1758-1828) – Austrian physicist who invented phrenology – He felt that bumps on the skull could reveal our mental abilities and character traits. – Introduced as being scientific – Although, ill-fated theory was laughed at by scientific community of that day – it may have had some validity – Localization of brain functions somehow hit the mark The Nervous System Electrochemical communication system that enables us to think, feel, and behave Complex beyond comprehension Although, human brains are more complex our nervous systems and those of animals operate in a similar fashion Major Components Neurons – Rapidly respond to signals and quickly send signals of their own Afferent – sensory neurons Efferent – motor neurons Glial cells – Help neurons to communicate, keep chemical environment stable, secrete chemicals to help restore damage, and respond to signals from neurons – enable neurons to function Axons Function – Carries signals away from the cell body – Pass information along to other neurons, or to muscles or glands – Wrapped tightly with white, fatty myelin This insulates the axon Synapse Very small gap between neurons For communication to occur between cells, the signal must be transferred across this gap Function – Provides an area for the transfer of signals between neurons, usually between axon and dendrite Dendrite Function – Detects and carries signals to the cell body Type of Signal Carried – The postsynaptic potential, which is an electrochemical signal moving toward the cell body Receptors Function – Proteins on the cell membrane that receive chemical signals Type of Signal Carried – Recognizes certain neurotransmitters, thus allowing it to begin a postsynaptic potential in the dendrite Transmitting information A neuron: – – – Receives signals form other neurons through its branching dendrites and cell body Then combines these signals in the cell body And then transmits an electrical impulse down its axon Transmitting Information Type of Signal Carried – The action potential, an all-or-nothing electrochemical signal that shoots down the axon to vesicles at the tip of the axon, releasing neurotransmitters Neurotransmitters Neurotransmitters are chemicals made by neurons (nerve cells) and used by them to transmit signals to the other neurons – A chemical message telling the next cell to fire or not to fire its own action potential – More than 200 in our body all with different functions Lets briefly discuss some of the most important ones… Serotonin Facilitates a relaxed, sleepy feeling – Tryptophan an amino acid found in dairy products and turkey is converted into serotonin in the body Some Illnesses Associated With Serotonin Depression – Low levels Anxiety Disorders – Low levels Obesity – Low levels Dopamine High levels lead to pleasure – Makes person feel happy and active Dopamine raises the body's temperature and increases metabolic rate Gives you euphoric feelings and allows you to be active Drug and alcohol abuse will block dopamine receptors and therefore a person needs to take more to get the same effect Some Illnesses Associated With Dopamine Parkinson’s Disease – low levels Schizophrenia – high levels Tourette’s Disorder – high levels Norepinephrine Stress hormone that plays a role in attention and arousal Used by sympathetic nervous system to prepare us for action – Along with epinephrine underlies the fight-or-flight response (increase HR, increase of glucose, increase blood flow, etc.) Some Illnesses Associated With Norepinephrine Depression – low levels chronic stress depletes this neurotransmitter and can lead to depression Note: – Aerobic Exercise is found to protect the brain from this depletion Schizophrenia – Specificially, akathisia (inner restlessness; inability to sit still) – high levels Epinephrine (adrenaline) Involved in energy and glucose metabolism – Increases heart rate, contracts blood vessels, dilates air passages Used by sympathetic nervous system to prepare us for action – Along with norepinephrine underlies the fight-or-flight response Some Illnesses Associated With Epinephrine Depression – low levels Anxiety Disorders – high levels ADHD – high levels Acetylcholine Involved in voluntary movement, learning, memory, and sleep – Helps parasympathetic nervous system to slow our heart rate Some Illnesses Associated With Acetylcholine Alzheimer’s Disease (and other dementias) – low levels Note: – Unfortunately, drugs used to increase acetylcholine to help restore normal levels appear to have small effects on improving memory Myasthenia Gravis – autoimmune neuromuscular disease leading to fluctuating muscle weakness and fatigability – low levels GABA Inhibits excitation and anxiety Illnesses Associated With GABA Anxiety disorders – low levels Huntington’s Disease – low levels Huntington's disease is a hereditary disorder characterized by memory loss, abnormal movement and premature death – GABA systems aren’t working and this allows dopamine systems to run wild Epilepsy – low levels Glutamate Main excitatory neurotransmitter in the brain Very important in learning and memory Illnesses Associated With Glutamate Depression – Low levels in prefrontal cortex Alzheimer’s Disease – low levels in hippocampus Strokes – high levels can cause neurons to die ALS (Lou Gehrig’s Disease) – high levels causes death in neurons in the spinal cord and brainstem Endorphins Involved in pain reduction and pleasure – They enhance the release of dopamine – These natural opiates are released in response to pain and vigorous exercise Some Illnesses Associated With Endorphins Eating Disorders – Low levels Drug addiction – Low levels Use of artificial opiates can cause body to stop manufacturing its own later leading to withdrawal symptoms Divisions of the Nervous System Consists of two systems – Central Nervous System Brain and spinal cord – Peripheral Nervous System Which connects the CNS to the rest of the body Organization of the Nervous System Peripheral Nervous System Two components: – Somatic Nervous System Transmits sensory input to the CNS from the outside world and directs motor output – Autonomic Nervous System Controls glands and muscles of our internal organs – “automatic pilot” Autonomic Nervous System Dual system: – Sympathetic Nervous System Arouses the body – Parasympathetic Nervous System Calms us down Studying the Brain Clinical observations – Check trauma or disease Experimenting with the brain – Electroencephalograph (EEG) – Brain-Imaging Techniques Computerized axial tomography (CT scan) Positron emission tomography (PET scan) Magnetic Resonance Imaging (MRI) Functional Magnetic Resonance Imaging (fMRI) Cerebral Cortex Makes us distinctively human – much higher developed than in animals – Motor Cortex – involved in the conscious initiation of voluntary movements in specific parts of the body including hand, knee, foot and head Fritsch and Hitzig (1870) Delgado (1969) Cerebral Cortex Sensory Cortex – receives information from our senses Visual cortex – visual info Auditory cortex – auditory info Somatosensory cortex – info from skin Association cortex – involved in complex cognitive tasks associating words with images Broca’s area (aphasia) Wernicke’s area (aphasia) Recent Examples of Aphasia Click on pictures above for video clips How does the brain govern behavior? 3 Principle layers of the brain: – Hindbrain (Brainstem) – Limbic System Hippocampus Amygdala Hypothalamus – Cerebral Cortex Hindbrain The brain’s innermost region… – Begins where the spinal cord enters the skull and swells slightly forming the medulla – Towards the rear of the brainstem is the cerebellum – this is linked to memory and its major function is muscular control Limbic System Limbic System Hippocampus – This structure plays a key role in allowing us to store new information – Problems here may cause Alzheimer's – these individuals have trouble processing declarative memories – Milner (1968): the classic case of H.M. – Only in 2008 (at the time of his death at age 82), was his name revealed as Henry Molaison See article about H.M. on my website and read pp. 242-243 in textbook. Limbic System Amygdala – Emotional control center of the brain – major influence on aggression and fear – Emotional memories as well – Alzheimer’s ??? Kluver and Bucy (1939) Demasio (1994) Limbic System Hypothalamus – Major influence on hunger, thirst, body temperature, and sexual behavior Olds and Milner (1954) Brain Reorganization: Synaptic Plasticity Synaptic Plasticity – Often when one area of the brain is damaged, other areas may in time reorganize and take over its function It is not uncommon for stroke patients who have lost the ability to speak or to move a limb to regain function after several weeks of convalescence How does the brain recover? Essentially what is occurring is a “remodeling” of the cerebral cortex after an injury in which sometimes a large part of it simply dies – This is the exception and not the rule For example, not all stroke victims recover Even better chances: Plasticity in children The brain has extraordinary powers of reorganization, especially when damaged before it is fully developed Case Study: Christina Santhouse Click on picture for article The Split-Brain Phenomenon Corpus Callosum – Large band of neural fibers that connects the two brain hemispheres The two sides of our brains serve different functions (lateralized or specialization of tasks): – Left hemisphere: Language, math, logic – Right hemisphere: spatial abilities, face recognition, visual imagery, musical and artistic abilities, emotional tasks. This is the case for almost all right-handers (about 96%) and about half of left-handers Split-Brain Experiments Vogel and Bogen (1961) Sperry and Gazzaniga – Conducted many experiments from 1960’s through the 1980’s Important aspects of this divided brain phenomenon Information from left half of field of vision is received only by your right hemisphere, and information from the right half of your field of vision is received only by your left hemisphere – Don’t get confused here as each eye receives sensory information from both right and left visual fields. But this information is only transmitted from a particular visual field to a particular brain hemisphere Important aspects of this divided brain phenomenon The left hemisphere receives information from and controls movements of the right side of the body, whereas the right hemisphere receives input from and controls movements of the left side of the body Important aspects of this divided brain phenomenon Hopkins (2006) – Tests show that almost all right-handers (over 96%) process speech in the left hemisphere – Left-handers are more diverse: 70% process speech in the left hemisphere 5% process speech in the right hemisphere 25% use both hemispheres about equally The Split-Brain Phenomenon FIELD OF VISION LEFT RIGHT When the patient is asked “What do you see?” They answer… LEFT HEMISPHERE RIGHT The Split-Brain Phenomenon LEFT FIELD OF VISION RIGHT When the patient is asked “What do you see?” They answer… LEFT HEMISPHERE RIGHT The Split-Brain Phenomenon LEFT FIELD OF VISION RIGHT The same patient who has just said they could not see the picture is now asked to take their left hand and touch the ‘happy face” picture… What happens now??? LEFT HEMISPHERE RIGHT The Split-Brain Phenomenon LEFT FIELD OF VISION RIGHT Now, with the object in the patient’s hand, he/she is asked “what is in your hand”…what is their answer this time??? LEFT HEMISPHERE RIGHT Split Brain Videos Click on pictures above for video clips Severed Corpus Collusom: Video 1st scene: – “Joe” is flashed words in his right field of vision (“storm” and “piano”) and has no trouble saying them – He is then flashed the word “phone” in the left field of vision…and he can’t say it – “didn’t see that” – But when asked to draw a picture of what he saw with his left hand…he draws a telephone but since its still in his left field of vision he still can’t verbalize what he just drew Severed Corpus Callosum: Video But then when asked to draw it with his left hand but in his right field of vision…he is able to say what he drew (“oh, phone”) – Very interesting… Severed Corpus Collusom: Video 2nd scene: – Joe is flashed words simultaneously in both fields of vision – “toad” in left field and “stool” in right field… – He can’t say “toad” but can draw it with left hand – He can say ‘stool” and by speaking it, he is able to let the right hemisphere in on the “secret” Severed Corpus Collosom: Video 3rd scene: – Again, two words simultaneously…”bell” appears in his left field of vision and “music” in his right field of vision – When asked to point with his left hand to what he saw, Joe points to a picture of a bell but is not really sure why so he makes up a story that seems to be plausible…he’s basically trying to figure out what's going on Severed Corpus Callosum: Video Joe’s left hemisphere is trying to interpret what is going on – trying to find a cause and effect – Left hemisphere is responsible for making sense out of the mystery – According to Gazzaniga: “the left hemisphere is where the action is” Severed Corpus Callosum: Video Final scene: – Pictures are shown of faces made out of fruit, meat, etc. – Right hemisphere specializes in locating faces and left is better at finding elements involved… So what happens? – Right hemisphere sees it as a face and left hemisphere sees it as a fruit Split-Brain Operations Today Effective medications have replaced this drastic procedure Nature or Nurture? What influences one’s behavior? – The age-old debate: Is it genes or is it the environment? An interaction? Goldie Hawn and Kurt Russell Kate Hudson Principle of Genetics Master plan for your body…. – 46 chromosomes 23 chromosomes carried in the egg are paired with 23 chromosomes brought to it by the sperm – Each is composed of a molecule called DNA DNA is made up of thousands of segments which are called genes Principle of Genetics Your sex is determined by the 23rd pair – the sex chromosomes… – From your mother always an “x” – From your father, you have a 50/50 chance of receiving an x making you a female (xx) – From your father, you have a 50/50 chance of receiving an y making you a male (xy) XX = female XY = male Twin Studies Monozygotic – Identical twins (one-egg) Dizygotic – Not identical (fraternal) twins Resemble one another as much as any brother or sister would Nature or Nurture? Question: – Do identical twins who are adopted by separate families act like one another more than say two adopted children into the same family who have no genetic influences? Lets look at some case study research to help us determine this… “The Jim Twins” Bouchard (1979) – Thomas Bouchard – University of Minnesota twin studies – extraordinary similarities between Jim Springer and Jim Lewis Uncanny coincidences? Any limitations to this study? Click on picture above for video clip The Jim Twins Tested at the Univ of Minnesota – Intelligence – Personality – Heart Rate – Brain waves All virtually alike as the same person tested twice Voice intonations and inflections were so similar that they could not tell each other’s Twins Oskar Stohr & Jack Yufe Bouchard (1979) – Part of Bouchard’s twins study… Oskar Stohl and Jack Yufe were raised in environments with more obvious differences Did these guys share a flushing the toilet gene? Oskar raised by Grandmother in Germany as a Catholic and a Nazi Jack raised by Father in the Caribbean as a Jew – Share traits and habits galore Love spicy foods Sweet liquors Fall asleep in front of the TV Flush the toilet before using it Store rubber bands on their wrists Dip buttered toast in their coffee Stohr is domineering toward women and yells at his wife as did Yufe before he and his wife separated Evolutionary Psychology These psychologists study ways in which adaptation and natural selection are connected with mental processes Men and women by nature must differ in their optimal mating behaviors – Women must be highly selective because they are biologically limited in the number of children they can bear and raise in a lifetime – Men can father an unlimited number of children and ensure their reproductive success by inseminating many women Gender Differences… The differences typically found between the sexes are small compared to the similarities… – But when it comes to casual sex… See next slides… “I have been noticing you around campus. I find you very attractive.” Clark & Hatfield (1989) – In this study, students were approached by another student of the opposite sex, who uttered the above statement… – This was followed by one of three invitations: “Would you go out tonight?” or “Would you come over to my apartment?” or “Would you go to bed with me?” Percent Saying “Yes” 100 Men were even more likely to say “yes” to the sexual invitation 80 60 About half of both sexes said “yes” to the date 40 20 0 Go Out Go to Apt. Go to Bed Not a single woman said “yes” to the sexual invitation The Burger King Study Townsend & Levy (1990) – Who would you prefer: a well-dressed unattractive person or a good-looking person in a Burger King outfit??? Burger King study: – Townsend and Levy (1990) looked at the effects of male status and ornamentation. – First, males were pre-rated into 2 groups: Handsome versus homely – Each were put into 1 of 3 costumes: Armani suit with Rolex (high status), white t-shirt (medium status), or Burger King uniform (low status) – They then did the same for females Handsome Homely Armani suit (high) White t-shirt (medium) BK outfit (low) What do you think happened?