Physiological Psych Exam 2 PDF

Chapter 3 up to page 76, skip chapter 4, chapter 5 up to page 151, chapter 6 up to page 171, stopping at where is talks about digestive details Chapter 3 Primary Motor/ Precentral Gyrus: is involved in voluntary motor control, to activate skeletal muscles ○ Does not control...

Chapter 3 up to page 76, skip chapter 4, chapter 5 up to page 151, chapter 6 up to page 171, stopping at where is talks about digestive details Chapter 3 Primary Motor/ Precentral Gyrus: is involved in voluntary motor control, to activate skeletal muscles ○ Does not control reflexes, this is controlled by the brainstem and spinal cord, (example: heart control, we can't change how our heart muscles contract because if we made a mistake we would be dead) ○ One hemisphere controls the opposite side of the body, the relationship between brain side and body side are crossed, this means that neurons found in the primary motor cortex in the right hemisphere are involved in controlling the left side body muscles ○ If damage occurs to on right motor cortex, there will be damage on left side ○ Topographical organization of body muscles, how body muscles groups are laid out on the body itself, kind of like drawing maps of places ○ Its as if you could read a map of how muscle groups are laid out in the body within that region ○ Probe different regions during surgery there is a map ○ Coronal section (going from dorsal to ventral), motor homunculus map (known as funny looking man), for the most part a true map of the body, all the body parts are for the most part in the correct order (this is what makes it a map) ○ What's wrong about this map? It's not in proportion, distorted. ○ Hands have way more motor control, we can do complicated motor stuff with them, so therefore the area is a lot bigger, are sophisticated ○ A huge chunk contains neurons that are associated with your mouth, speech, we are constantly contracting our muscles. This motor aspect of speech is super complicated, a huge part of the motor cortex ○ Paralysis if damage in this area Secondary Motor Areas ○ Programming of movement ○ Combine info from other neurons, must receive info from other areas to make a plan to assemble motor sequences ○ Assemble movement sequences ○ Programming motor sequences ○ Damage does not cause paralysis is this area, they can't organize motor sequences, they have uncoordinated activity Broca's area: anytime this patient tried to say something all he could say is the word ten  ○ When this patient passed, Broca performed an autopsy, he found evidence that the lesion was much smaller than he expected, only one small region in the left hemisphere only. (language is localized to the left side of the brain) ○ Classical language region, the speech, premotor area, puts together motor sequences involved in producing language ○ Damage will make it difficult to put together speech that had grammatical structure ○ Lateralized to the left hemisphere ○ Aphasia (impairment of speech) ○ Broca's Aphasia: impaired word production, unimpaired word comprehension Frontal Lobe (prefrontal cortex) ○ Its called prefrontal cortex because of a theory that it did not exist in primates, and it evolved later, it was added later ○ Think back to phineas gage, could not keep inhibit lid on aggressiveness, this part of the frontal lobe are involved in executive functioning ○ Behavioral planning/organization ○ Anticipated consequences of behavior ○ Decision making ○ Impulse control PostCentral Gyrus/ primary somatosensory cortex ○ Processes skin senses , body position, and movement ○ One hemisphere serves the other side of the body ○ Topographical organization ○ Somatosensory homunculus- the skin in our lips is the most sensitive i part of our body ○ We have much more sensory ability in our fingertips too, hands as well ○ Damage to this would result in inability to be able to feel anything ○ This cortex receives information, is also called a projection cortex Association Cortex/ Area (posterior parietal) ○ Not involved in anything primary ○ Receive information from other regions and start integrating/ summing it up ○ Integrated information from other senses to bring about more complex behavior ○ Further sensory info processing ○ Locations of objects in space ○ If you have damage you don't know where things are, difficulties in processing spatial information ○ Unilateral neglect: ignoring objects on the side opposite to the damage, visually, and audorially , can't direct focus attention to that side ○  ○ If you ask them to draw a clock,, they would only draw one side and claim they have drawn the whole thing (they are not blind just can't direct focus attention to the left anymore) Occipital Lobe ○ Contains the visual cortex- process visual information ○ Primary visual cortex (V1) Received visual input from the retina Processes simple features (eg orientation) Topographical organization of visual space (map of retina), you could see a map of the 2 retines on this section Another example of a projection cortex ○ Association area (V4-V5) Receive information from V1 Form shape, movement, color Temporal Lobe ○ Auditory Cortex (projection area) received auditory (hearing info) from the ears ○ Wernicke's area Language comprehension Lateralized in the left hemisphere Can not understand the meaning of speech Lesion causes wernicke's aphasia (impaired word comprehension, can produce speech though) Unimpaired word production, however the sentences don't make any sense, world salad, don't understand what they are talking about but say a lot of jumped of words ○ Inferior Temporal Cortex Visual identification of familiar objects Can still describe things correctly or know what they are though touch Rest of the temporal cortex (an association region) Different modules for object recognition Fusiform face area/ module - very specific to ability to recognize familiar faces vs someone you don't know prosopagnosia : can't recognize the faces of familiar people they should know Corpus callosum ○ Large band of myelinated axons ○ Defining features that separated mammals from other vertebrates ○ Only mammals have one, in other non mammals the 2 hemispheres are much more isolated, mammals have more integration between two hemispheres ○ Highway of communication between the 2 hemispheres  Ventricles: cavities in the brain ○ Cavities get warped and shaped during different periods of growth ○ There are a total of 4 of them ○ Lateral Ventricles- present in both left and right hemispheres, the biggest, they are joined together by the third ventricle ○ Third ventricle: found right around the thalamus and hypothalamus, connects these two , part of the forebrain ○ Third ventricle narrow down to form the cerebral aqueduct, belongs to the midbrain ○ Cavity enlarges again near the hindbrain to form the fourth ventricle ○ Contain the cerebral spinal fluid, transport away waste products that is produced by metabolic processes, functions as a medium for the transportin away of these products ○ Also transports nutrients to the tissues of the central nervous system Thalamus and hypothalamus are also both in the forebrain, both made of sub clusters of gray matter Thalamus ○ Acts as a sensory relay station and filtering station- relays incoming sensory information to the cortex ○ Before information get to projection areas or association areas in the cortex, it first has to go through the thalamus ○ Sends the information to the correct region ○ Different parts of the thalamus are for different senses (olfaction and smell excluded) ○ Smell does not go through the thalamus as all before it goes to the cortex ○ Odors can be strongest sensory - can unlock an old memory, way more powerful because it is very direct and goes straight to the cortex ○ Different parts of a thalamus are called nuclei ○ ganglion - peripheral ns, gray matter cluster ○ Nucleus- central nervous system, cluster of gray matter Hypothalamus- made up of nuclei ○ Coordinates emotional and motivational functions (sex, eating, emotion, and aggression) ○ Also, controls the pituitary gland which controls the rest of the endocrine system (hormones) ○ Known as the master gland of them all ○ They is an anatomical connection between the two ○ Pituitary is not part of the forebrain, just connected to the hypothalamus which is a part of it. Midbrain  ○ Tectum: (dorsal side of midbrain) ○ Means roof in latin (tectum) ○ Two separate parts that make up the tectum Superior colliculus (2): vision (eye movement) goes from retina to this region in the midbrain, does not create any conscious vision at all The function is to coordinate the movement that controls the two eyeballs If a stroke happens in this region a patients will experience erratic and uncontrollable eye movements Inferior Colliculus (2 of them) : hearing (location of the sound) The ability to figure out where a sound comes from as soon as you hear it What ventricle is in the diagram? The fourth ventricle ○ Tegmentum (ventral side of midbrain) Control of movement Subtantria nigra - dopamine producing neurons Parkinson's disease, tend to show a premature degeneration of substantia nigra, neurons here die out earlier Patients experiences uncontrolled tremors, having issue with movement, rigid movements No current cure, you can give the patient extra dopamine, l'dopa ○ Ventral Tegmental Area Plays a major role in the rewarding effects of food, sex, drugs and rock and roll Will come back to this region Hindbrain ○ Pons (bridge) Sensory neurons pass through on the way to the thalamus, motor neurons pass through between cortex and cerebellum It is part of the reticular formation (sleep and arousal, circadian rhythms) ○ Cerebellum Little brain (lots and lots of neurons packed in here) Motor coordination and balance, motor learning, cognitive functions (even language, attention) Anytime we acquire a new motor skill we use this region learning how to walk, or ride a bike, lets us remember how we did this It is almost involved in anything we do, even highly abstract cognitive function Has become a hot area in research because it is so complicated and so large, not just purely a motor structure ○ Medulla No high level processing  Literally involved in keeping us alive, life sustaining Regulates heart activity, breathing Innate aspects of behavior Can be very lethal is anything happens to this area (acute alcohol poisoning is affected by this area) Spinal Cord: ○ cable of neurons, carry signals from the brain to muscles and glands (periphery) ○ Carries sensory information from the periphery (sense of organs) to the brain ○ Outside of it is made of white matter, inside is made of gray matter ○ The hub for reflex arcs (neural pathways that produce reflex acts) ○ Don't confuse these two, cant produce a reflex act (the behavior) without an reflex arc (the hardware that makes the behavior possible) ○ Nerves separate into two separate bracnhes, the dorsal root and ventral root ○ They are also separated functionally, ○ You can only find sensory neurons in the dorsal root of spinal nerves, the dorsal root has a bulge in it, it is causes by the fact that sensory neurons have their cell bodies clustered outside of the spinal cord ○ These is referred to as a spinal ganglion- cluster of gray matter outside of the central nervous system ○ Sensory neurons- info flows in through the dorsal root, the signal travels along this and will get to the spinal cord, then goes to the interneuron, then goes through the ventral root and travels out (motor neuron, output), then causes a movement or command ○ Muscle fiber of gland tissues- effector, cells or cell structures that take a signal and transform it to a response ○ All of the structures in the blue outlines are called a reflex arc ○ Reflex arc - a neural pathway that controls a reflex act ○ Hitting knee with mallet example at doctor ○ Reflex act: simple, automatic response to a sensory stimulus, there are reflexes that doesn't just involve muscle contractions, for example salivation, this becomes activated through a reflex arc ○ Includes muscle contraction or gland secretion), many of them ivolve activation of glands not just  Receptor: a cell in the body that is there to receive a stimulus, in other words some kind of energy in environment (skin or touch receptors embedded in the skin, eyes ears, nose and so on) ○ Transforms environmental energy into something the neurons can work with The motor neuron will make a synaptic connection with an effector ○ Effecortr: a structure in physiology, a muscle fiber to produce movement or a gland Reflex arc makes an reflex act possible Reflex arc is the hardware that makes the reflex act possible (outlines in blue on the diagram) Nerves that come out of the spinal cord are in the peripheral There are 3 membranes that wrap around the whole of the spinal cord and the whole of the brain (central nervous system) ○ These membranes collectively are known as the meninges ○ They provide some degree of structural support and protection to spinal cord and brain (limited) from shock ○ Both the meninges and fluid protect the CNS from trauma ○ In between the 2 innermost membrane there is a little bit of cerebrospinal fluid present, also provides a little protection from trauma Don't confuse the spinal cord (CNS) with the spinal column backbone(skeletal system) Is there is too much load exerted on a disk between two vertebrae, it will start to bulge out because it is flexible ○ This will start exerting pressure on to the roots and spinal nerves, irritate the sensory fibers, cause shooting pain down one leg, pressure being put on sensory neurons Blood Brain Barrier (not technically a part of the NS, part of the vascular system) ○ Prevents harmful substances (toxins) from entering the brain ○ Capillary membrane cells are so tightly packed together that they form a barrier to most molecules ○ Fat soluble substances freely pass through the barrier, because the blood brain barrier is made mostly of fat (phospholipid) Psychiatric substances have the reach the brain so they make them fat soluble Example: opiates ( heroin), not slowed down by the blood brain barrier ○ Other substances use special transport proteins to get through (amino acids, glucose), transmembrane proteins ○ Some areas of the brain are not protected by the blood brain barrier  The area postrema (in medulla) induces vomiting when certain toxins are in the bloodstream Blood brain barrier is somewhat leaky here, if toxins come in blood they will reach this area Through a reflex arc in the brainstem, they set off a very powerful reflexive behavior, when the postrema senses toxins in the person's blood it leads to projectile vomiting Why vomit? - toxins end up in blood through something we have ingested, so it makes perfect sense through a survival point of view why we engage in this behavior, prevents substances from getting all the way to the brain ○ If we remember, we have divided the peripheral nervous system into the cranial nerves (12 pairs) and the spinal nerves (31 pairs) Nerves come out of brainstem = cranial nerves Nerves come out of both ends spinal cord = spinal nerves Diagram 1 ○ Any blue arrow = carrying sensory information into the brain from the senses ○ Motor commands from the CNS outwards to muscle or glands are indicated by red arrow coming out of the brain ○ Don't need to know what part of the brain stem each nerve belongs to, don't need to know where all arrows go Diagram 2 ○ All fair game for test 2 ○ Know all of this info in this table ○ Include the number, “what is cranial nerve number 8?” There is another way of subdividing the peripheral nervous system that is based on a different criterion ○ So far we have looked at the anatomical way (cranial and spinal nerves) ○ There is another way, functional way to divide it, considering behavioral function that the fibers in the nerves carry out ○ Somatic and Autonomic Branches ○ Somatic: Somatic includes all fibers in the nerves that are in involved in voluntary commands (muscle or sensory) Motor neurons- carry signals from CNS to skeletal muscles Sensory neurons- bring info from sensory organs into CNS Includes all fibers in all nerves that are involved in behavior that we are consciously aware (sensation) of or voluntary controlling (motor activity) ○ Autonomic: These fibers are involved in automatic aspects of activity that we don't have control over, Reflexes that happen automatically Regulating the body's general activity level Is what is keep our body alive digestions , granular activity, Controls smooth muscle, heart, glands ○ There are two further sub branches of the autonomic nervous system ○ Sympathetic Branch Speeds up bodily processes, such as heartbeat, respiration, blood pressure, sweat glands We can't control any of this (atomatic), it's good we can't change these things (ei we don't want to be able to control out heart) When would this be beneficial to an organism: in a fight or flight type of situation all of this is likely to happen Why is this good biologically? - all of these reactions are selected because they increase the chances of an organism to survive an encounter with a threatening situation Heartbeat goes up because it gets nutrients such as glucose and blood to the muscles so we can run Sweat glands: covering the surface of the skin with water (sweat) we can lower the temperature of the skin through evaporation, in turn will lower the temp of blood, and cool down the inner core temperature. Prevents us from passing out, so our body inner core does not get to high and cause us to faint Originate from the middle spinal cord, instead of end points Passes through the sympathetic ganglion chain (there are ganglia, cluster of gray matter outside of CNS) Fibers of sympathetic branch are all connected by the sympathetic ganglion chain, It is wired together to work as a unit, happens at once Simultaneous activation of organs- work as a unit ○ Parasympathetic Branch Slows body processed back down Originate from the ends of the spinal cord There is no ganglion chain here, the fibers are not all connected together, Don't need this because it is not relevant here for all the reactions slow down all at once They are free to slow down at separate rates  ○ These two branches don't work as mutually exclusive switches Both are active to some degree at all times In different conditions one of them will take the lead Body’s activity levels reflects the balance between the two Development of Nervous System ○ We start of as a neural tube ○ How do we go from the hollow tube, to a brain? (sagital plane) ○ 4 phases: ○ Orient ourselves with the diagram first: coronal section taken of the forebrain, ventricular zone will turn into 2 lateral ventricles, middle section turns into 3rd ventricle 1. Proliferation: neurons divide and multiply at extreme rate, regenerate themselves Proliferation happens above the ventricular zone only 2. Migration: neurons migrate to final location by climbing radial glial cells (these form a pathway for the neurons to follow on the way to their final destination), form the cortex 3. Circuit Formation: neurons send developing axons to make synapses with their target cells (other neurons somewhere else in the brain, can be close or far part) The goal is to make synaptic connections with other neurons Forms the corpus callosum in the forebrain in this process The brain wires itself Growth cone: develops at the tip of the developing axon and moves towards final targets using chemical and molecular signals The blob in the picture is the growth cone, in the membrane of the growth gone there are special kind of transmembrane proteins that act as receptors for chemical signals The growth cone knows that direction to go because it is following the direction of the chemical signals by the target cell Ultimately makes a synaptic connection, 4. Circuit Pruning: extra neurons that have developed die Aspect of elimination Eliminated a large number of extra synapses, r refines organization, optimized function of brain in relation to cost Purpose is to maximize the effectiveness of the final product of the brain Keeps biological cost of the brain within bounds, neurons use a whole lot of energy, use a ton of glucose  We dont want too many, but want to make sure there is still enough (evolutionary balance) These 4 are the classic phases of development, however one could argue there are actually 5. Plasticity can be considered a 5th stage 5. Plasticity: ability of synapses to be modified by experience, learning The brain is always changing when we learn more info Decrease with age, however it does not go away completely Old people can still learn new info, their plasticity just decreases Cortical association areas (ventral area temporal lobe, association area for somatosensory) are more likely to retain their plasticity, can rewire themselves better Different is neurology, ability for the brain to compensate for lost function after brain damage, other neurons in different regions can acquire and perform the function of neurons that have died out (recovery) Example: a person with damaged broca's area, other neurons in nearby regions will now be able to perform the function of the damaged neurons, allowing him to speak again (recovery) Chapter 5 (Psychoactive Drugs) Drug: a chemical substance that changes the body and its functioning ○ Psychoactive Drugs: drugs that have psychological effects (anxiety relief, hallucination, reduce pain, increased happiness) ○ Agonist: mimics or enhances the effects of a neurotransmitters Having the same effect on receptor as NT (mimics), drug chemical composition is so similar in NT composition, that it can directly substitute for the NT and impact the same channel that a NT does Have a very fast effect, because they are direct All opiates (morphine) are direct agonist to endorphins, lack on to the endorphins receptors, by directly mimicking endorphins Increasing the effect of NT on receptor Example: Alcohol (ethanol) is not a direct substitute, it CANT latch the the same receptor that Gaba locks in to Indirect Agonist When Gaba and Ethanol are present together, Ethanol helps Gaba open up the channel even wider than normal The effect that Gaba has on its own channel is greater than it would be without ethanol there  Blocking reuptake or degradation of NT (indirect) ○ Will lead to an increase in a neurotransmitter signal in the cleft ○ Still counts as an agonist, just very indirect Antagonist: block or reduce the effect of a NT ○ They are different ways that can acts as antagonist (direct or indirect) ○ Block = direct ○ Reduce = indirect Direct Antagonist: drug looks similar enough chemically to NT that it can bind to the receptor site of NT, but then it does not open the channel (ends up blocking the site and not allows the NT to latch on) Indirect Antagonist: reducing the availability of NT (reducing the production/ release of NT from presynaptic terminals) Drug Abuse Terminology: ○ Addiction: criteria to determine if someone is addicted 1. Preoccupation with obtaining a drug (spends lot of time energy resources in daily lives trying to get access to drug) 2. Compulsive use of drug (individual realizes that it is not good for them but they feel that they have no choice in order to not feel worse), inevitable that they must use 3. High tendency to relapse after quitting Relapsing is an integral part of addiction, there is no shame to relapse after trying to stop for the first time It is not a sign of weak character, patients must come to terms with this Withdrawal: negative reaction when drug use it stopped ○ Many symptoms, physical and psychological ○ Symptoms often opposite of the effects of the drug (eg withdrawal from elation producing drugs = depression) Dependence: need to keep using the drug to avoid withdrawal Tolerance: increasing amounts of the drug are required to produce the same results ○ A point is reached where the drug does have nearly the same effect as it used to ○ Mostly due to the reduction in number or sensitivity of receptors to the drug ○ In extreme cases receptors can end up falling off Opiates ○ Derived from opium poppy (poppy plant) ○ opium = dried up resin Abused since around 5700 B.C  One of the oldest psychoactive drugs ○ Morphine (derived from opium) Early 1800s, effective treatment of intense pain Often used in cancer patients for chemo ○ Heroine: Late 1800s - initially sold as an over the counter analgesic Was an attempt to make something less dangerous than morphine This sort of backfired bc its is very dangerous, they just didn't know this ○ Codeine Cough suppressant Not nearly as powerful as Heroin or Morphine Only available as prescription, bc highly addictive, can lead to later use of other stronger opiates Exposing young children can increase risk of developing opiate addiction later in life, this is why they made in prescription ○ Variety of effects Analgesic (pain relieving) Hypnotic (sleep inducing) Produce euphoria (intense since of happiness) ○ Side Effects Addictive Heroin: highly soluble in lipids, crosses the blood brain barrier easily, and reach brain cells super fast Major danger is overdose Drug to pure (concentrated higher than they are used to) Tolerance (he or she feels like they need to increase their dose) ○ Bind to opiate receptors Acts as direct agonist of endogenous opiates -endorphins (pain relief) Depressants ○ Reduce the activity of the central nervous system (inhibitory effect) ○ Ethanol (alcohol, booze) Produced from fermented fruits, grains etc (ie waste products of bacteria, yeasts, etc) Complex action High doses: sedative (calming), hypnotic Low doses: “stimulant” How is this explained? - not all parts of the brain are equally impacted by alcohol, some areas are impacted first  Prefrontal is impacted first by ethanol at small doses ○ Highly Addictive ○ Withdrawal symptoms are super dangerous (tremors, anxiety, mood and sleep disturbances Delirium tremens (trembling craziness) in the worst cases - hallucinations, seizures even death ○ Acts as an antagonist of glutamate (most prevalent excitatory NT) ○ Acts as an agonist of GABA by binding to GABA a (chloride channels) receptors Ethanol is an indirect agonist of Gaba, ethanol will latch one to one part of the channel and GAba will latch on to another receptor, combined effect will stretch open the channel even wider Ethanol needs Gaba to be there to be able to do anything (open CL receptors) Facilitates the opening of CL channel, hyperpolarization of postsynaptic membrane Barbiturates ○ Derivatives of barbituric acids ○ Complex action: High doses: sedative and hypnotic Low doses: inhibit cortical centers that inhibit behavior, talkativeness ○ Acts as an antagonist of glutamate ○ Acts as agonist of Gaba by binding to Gaba a (different receptor site than ethanol) In high doses they be direct agonist and open chloride channels on their own even without GABA, can potentially be very dangerous (even coma and death) Chance of accidental overdose is even higher Benzodiazepines ○ Similar to barbiturates but safer Cannot open chloride channels on their own, need GABA to be there ○ Produce anxiolytic (anxiety reducing), sedative, ant seizure, and muscle relaxing ○ Addictive Stimulants ○ Increase the activity of the central nervous system ○ Cocaine: She don't lie, she don't lie.. Cocaine (Eric Clapton) Produces euphoria, increases alertness, relief from fatigue Coca plant- South American tribes in the Andes  Used to be legal as an ingredient in over the counter medication and Coca-Cola (60 mg per bottle) Sigmond Freud- addiction to cocaine, recommended it to friends and family as a miracle as a cure, eventually realized there were dangers (addiction) Acts as an agonist of dopamine and serotonin by blocking their reuptake, which in turn causes a build up of them in the cleft Addictive withdrawal symptoms include depression and anxiety Can cause brain damage: loss of gray matter in the prefrontal and temporal areas (impairments in executive functioning, impulse control, decision making and in memory) ○ Amphetamines Synthetic drugs (methamphetamine: speed crack, crystal) Produce euphoria, increase in confidence, alertness and concentration Acts as agonist of dopamine and norepinephrine by increasing their release in the synaptic cleft In high doses can cause hallucination, delusions and other psychotic symptoms Chronic use effects: significant loss of gray matter in multiple areas ○ Nicotine Primary psychoactive and addictive agent in tobacco Legal - not as dangerous Complex action: Short puffs - stimulating effects Long puffs- relaxing effects Acts as a direct agonist of acetylcholine (activates muscles, increases alertness) and dopamine (positive mood effect) Highly addictive, rates of relapse are very high Withdrawal symptoms include anxiety, nervousness, drowsiness, lightheadedness, headaches ○ Caffeine Primary psychoactive agent is coffee, tea, etc Produces increased arousal, alertness, and decreased sleepiness Relatively safe, however, one can overdose on it Acts as indirect agonist of dopamine and acetylcholine by increasing their release (exocytosis) Due to blocking the receptors of adenosine (produced by the degradation of AMP,ADP), which has sedative/ depressive effects Caffeine blocks adenosine receptors  Withdrawal symptoms includes headaches, fatigue, anxiety, shakiness, craving Psychedelics ○ Cause perceptual distortions (of objects, time, self, often accompanied by euphoria In extreme cases can turn into full blown hallucinations ○ Became very popular in the 1960’s (Pink Floyd was part of the psychedelic movement) many artist were experimenting with them because they were interesting in a creative point of view, can change their perceptual experience Used them as tools to increase creativity ○ LSD: produces sensory distortion, hallucinations Direct serotonin agonist , binds to serotonin receptors ○ Ecstasy (MDMA) At low doses increased energy, sociability and sexual arousal At high doses has similar effects to LSD, hallucinations and distortions Indirect agonist- blocks reuptake of dopamine, norepinephrine and serotonin In high doses/ extensive use can kill serotonin neurons in monkeys, damage to hippocampus in humans ○ Angel Dust (PCP) Ketamine: dissociative effects (separated or disconnected from their own body) produce schizophrenia like symptoms in humans in high doses Inhibit NMDA glutamate receptors, leads to schizophrenia symptoms Synthesized in the lab Marijuna ○ Dried and crushed leaves and flowers of Indian hemp plant ○ Major psychoactive ingredient: THC Particularly concentrated in the dried resin of the plant- hashish ○ THC acts as direct agonist of NT anandamide and 2-AG by binding to their receptors (cannabinoid receptor), Cannabinoid receptors are widely distributed across the CNS Found on axon terminals: cannabinoids released by postsynaptic neurons and act as retrograde messengers, regulate the presynaptic neurons release of neurotransmitters (dopamine) Andmaide and 2 AG are produced in the postsynaptic (cell body or dendrite), and then they are sent out to the presynaptic cell, and then they can reach receptors sites (CB1), this is why they are called retrograde because they go the opposite direction (postsynaptic to presynaptic), sevres as neuromodulator  Anandamide and 2ag may play important role in the regulation of mood, memory, appartute, and pain perception- effects of marijuana Withdrawal symptoms anxiety, irritability, stomach cramps Withdraw Avoidance Hypothesis ○ Addiction is caused by desire to avoid withdrawal symptoms Withdraw is the negative reaction when drug use is stopped ○ Must people agree this is not the best explanation for addiction Does not explain: Use of drugs before dependence develops Return to drug use after withdrawal has subsided Poor correlation between addictiveness of a drug and severity if withdrawal symptoms Different areas of the brain seem to be involved with withdrawal and addiction (they are separate physically in the brain, not all together like stated in the withdraw avoidance hypothesis) PeriVentricular/ Peri Aqueducatal Gray ○ Targeted this area in rats, injected tiny drops of opiates, then they injected a different compounds that would block the effect of morphine, suggesting they were going through withdrawal through their behaviors ○ Had evidence that this area was involved in withdrawal but not pleasure ○ Negative symptoms when you can't get the drugs Ventral Tegmental Area ○ When stimulated this area, demonstrated that rats would start pressing the lever vary rapidly to inject morphine over and over ○ However, blocking the effect of morphine did not result in withdrawal in this area ○ VTA, Medial Forebrain Bundle, Nucleus Accumbens (these three regions form a network that is called the mesolimbic pathway) ○ This pathways responds to dopamine ○ Mesolimbic Pathway- major hub in our brain for the experience of pleasure, signals the rewarding properties of any stimuli (Reward) ○ Did not evolve so we could get addicted to drugs, it evolved for creating the pleasure of good behaviors (eating, drinking, sexual activity) ○ Drugs hijack this system and make it go crazy Mesolimbic Pathway ○ Nucleus accumbens- (Nacc)- rich in dopamine receptors ○ Nearly all abused drugs increase dopamine levels in Nacc ○ Reducing dopamine levels in Ncaa decreased rewarding effects of the drugs ○ All three of those statements show that an increase in dopamine in NACcc may be the neural basis for rewarding effects of drugs Evidence that it is a part of a general reward system Electrical stimulation of the medial forebrain bundle is rewarding in rats Increased dopamine levels in NAcc Involved in rewarding effects of behaviors of basic importance (sex, feeding) ○ Increases dopamine level in NACC (both human and non) However, activity in MP (Reward) cannot account for all aspects of addiction ○ Many continue to use drugs even when the effects are no longer pleasurable Later stages of addiction: functional and structural changes in the mesocorticolimbic dopamine system ○ Includes also the amygdala and hippocampus, play valuable roles in addiction ○ Hippocampus- triggering storing and retrieving drug related memories, memories of drug experience ○ Amygdala- hub for emotions, has been shown to be involved in triggering emotional responses involved in drug use ○ When you compare someone who uses vs dont, there are plastic changes that happen in this network Changes in synaptic connections/signaling Increase for drugs and drugs related stimuli (they tend to experience a much higher level of reward for stimuli relating to drug use than other natural behaviors like eating and sex (receive a lower level of reward) Decrease for other normal stimuli Hypofrontality Reduced activity in frontal regions, impulsivity, which can lead to relapse Ending Dependence on Drugs Overcoming withdrawal symptoms ○ Difficult with nicotine and opiates (high relapse rates) ○ Potentially life threatening with alcohol (very severe including death) Fighting against relapse (integral part of addiction) ○ Freud- cocaine addiction willfully, trained neurologist, not even people like him were aware of the dangers, used it to enhance his ability to look into his own emotions ○ Later learned that it is addictive, according to his own dairy he said he was able to quit ○ However, he could never quit smoking cigars, so he was heavily addicted to nicotine, experienced the issue of relapse, ended up dying from mouth cancer Pharmacological Treatments for Dependence Agonist Treatments (drugs that has similar effects to the original drug) ○ Replace addicting drugs with another that has a similar effect ○ Can't just ask quit bc massive withdrawal, prescribe a different compound that has similar effects but not nearly as powerful or dangerous ○ Give me patients lower and lower access to the substituting drug, to where the patients can drop both the original drug and the substituting drug Nicotine gum Methadone for heroin addiction ○ Limitations? There is no pharmacological treatment that is a perfect solution “no silver bullet” Substituting one addiction for another, not necessarily good High rates of relapse, go back to the original drug These treatments statistically seem to have limited effect counterargument : drug is not as powerful and there is limited access (given by a doctor instead) Antagonist Treatments ○ Involves drug that blocks the effects of addicting drug ○ More modern treatments ○ If the patients takes in the addictive drug it won't have an effect bc the blocking molecule is there GABAa receptor blocker limit the effects of alcohol, bind to the ethanol receptor site, don't let ethanol bind ○ Can take alcohol but don't get the effects of it (reduces cravings and reinforcing effects of alcohol) ○ Limitations  Does not help the patient deal with withdrawal symptoms, still experience physical withdrawal symptoms Often give them another drug to help w withdrawal so then they are responsible for remembering to take 2 drugs They have to motivate themselves to take this drug every single day, can't be forced High risk of relapse also, because they can dimply decide not to take pill Aversive Treatment ○ Cause negative reaction when person takes the addicting drug ○ Cause toxins to build up, reach the postrema, activate these neurons they will start to feel sick to stomach (throw up) ○ Use negative reinforcement to encourage the patient to stay away, every time I take the drug I feel sick Antabuse- prevents the breakdown of alcohol by products- makes you ill if you drink alcohol Want to make an negative association in their mind about alcohol “if i take this drug I will feel gross” ○ Limitations? Still have to remember to take the pill everyday Is it ethically okay for a doctor to prescribe this if they know it makes you ill? High relapse rates Antidrug vaccines ○ Stimulate the immune system to produce antibodies that break down the drug ○ Effects seem to be not as strong as needed, effect is not strong enough to keep the patients off the drug ○ More advantageous in theory, has the possibility to solve the limitations from earlier (once the patients has taken the vaccine, the patients can't decide to undo it) ○ Eliminates the problem of leaving it up to the patients to take the pill ○ Long term action (works for a long time) ○ Avoid side effects of other medicines ○ Pharmacological treatments are still somewhat controversial Motivation (set of factors that initiate, sustain and direct behavior) ○ Useful concept for organizing ideas about the sources of behavior ○ Inability to explain behavior solely in terms of external stimuli  ○ behaviorism - they did not talk about feelings emotions, subjective experiences, only wanted to look at outside overt behavior , this was a failure, you can't leave out the unobservable variables (inner workings of mind) Instinct (one of the simplest theories for motivation) ○ Complex behavior - not as simple as reflex ○ Automatic (one similarity of reflex) ○ Unlearned (innate) ○ Occurs in all members of a particular species in the same way ○ Humans have become specialist for the opposite, learned behavior ○ Reflex is not an instinct (know for test) ○ Applied geometry- amazing symmetric and complex structure of a spider web (innate) ○ There is not a lot of humans behaviors that fit into this category of instinct ○ birds - courtship behaviors, dances by males to convince females to mate (instinctive) ○ More found in other vertebrates but not useful for human behavior Drive Theory (simplest motivation theory that can apply to humans) ○ The body actively maintains physiological systems in a condition of balance - homeostasis ○ The body tries to maintain equilibrium state ○ Departure from homeostasis (eg lack of nutrients, drop in temp), will trigger an aroused condition called a drive ○ The function of a drive is to motivates the organism to engrave in appropriate behavior (eg drinking, eating seeking warmth) ○ This ultimately restores the homeostasis ○ Applies to behaviors directly involved in restoring basic tissue needs (drinking, temp regulation) ○ Does not apply to more complex behaviors like eating or sex, too complex Incentive Theory ○ Individuals are motivated by external stimuli, not just internal needs money, grades = incentives Arousal Theory ○ Individuals are motivated to maintain a preferred level of arousal ○ Not just sexual, more general sense ○ There is data to support this theory, individuals who don't like a high level of arousal at all in their lives, on the other end of the continuum there are people who don't feel well if they don't spend time doing exciting things “thrill seekers” ○ Different people have different optimal level of arousal Drive Theory (Revised ) ○ Drive = conditions of the tissues (original version)  ○ Drive = state of the brain (revised) ○ We don't know what the states of the brain are yet… this definition is still a bit to fuzzy ○ Some people think this revised drive theory becomes better at explaining more complex behaviors (sex and eating) Simple Homeostatic Drives Many physiological systems maintain a given condition within a narrow range (body temp, energy reserves) Control systems - operate on a negative feedback loop Feedback = process whereby some proportion of the output of the system is passed (fed back) to the input, capturing some info that coming out of system and making it go back into the system, this changes the output Negative feedback loop: feedback stabilizes the system at a given set point (small range of value) Inout = how much water is flowing in tank through the faucet output = how much water there is in the tank, how much energy is in the system Positive feedback loops- avalanche, economic collapse, explosion, crowd behavior, In a negative feedback loop, the system tries to counteract or "correct" a change, bringing things back to a stable state. In a positive feedback loop, the system amplifies or increases the change, pushing the system further away from its starting point. (child birth, blood clotting, usually to bring about the final end point) Negative feedback = stabilizing or reducing change. Positive feedback = amplifying or increasing change.