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TAMU PSYC 340 - 5A – Phenomena

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Pages: 13
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5A – PhenomenaInstrumental Conditioning- Criteria: o 1. The behavioral modification depends on a form of neural plasticityo 2. The modification depends on the organism’s experiential history o 3. (a) The modification outlasts (extends beyond) the environmental contingencies used to induce it. (b) The experience has a lasting effect on performance.o 4. Imposing a temporal relationship between a response and an outcome alters the response.- Studying Instrumental Behavioro 2 types of relationships: 1. Receive reinforcement 2. No reinforcemento 2 types of reinforcement 1. Appetitive (good) 2. Aversive (bad)o 4 total training paradigms: 1. Reward Learning- Description: if you preform response, you get the reinforcement- Examples of appetitive reinforcement:o 1. food Requires: dieto 2. Press lever and receive food- Leads to a(n) increase in the response 2. Omission Training- Description: if they perform the response, you omit the food- What kind of behaviors should we target? natural- Leads to a(n) reduction in the response 3. Aversive/Punishment- Description: if they perform the response, they get an aversive reinforcer (shock)- Leads to a(n) reduction in the response 4. Escape- Description: perform the response in order to avoid aversive stimuli- Usually studied using:o 1. Shuttle boxo 2. Wheel turn chamber- Leads to a(n) increase in the responsePhenomena- Common Behavioral Principleso Preparedness Description: pigeons can key peck for grain and treadle to turn off shock but can’t switch themo Undermining the US Description: extra exposure to US outside of CS undermines conditioning or the RO relationship, undermines acquisition- Learned Helplessnesso Generated in instrumental paradigms by: pre-exposing rats to the reinforcer/aversive stimulus (shock)o Induces a behavioral phenomenon known as: learned helplessness1 Can last for: dayso Usually studied using:  Triadic Design: wheel turn chamber- 1. Master (escapable)o Receive: controllable shock, have behavioral control- 2. Yoked (inescapable)o Receive: have no behavioral control, uncontrollable shocks- 3. Unshocked o Receive: stay in chamber How do we test if learned helplessness if due to the shock itself, or from the perception of control? Compare master and yoked group- Train rats using the: wheel turn- Test rats using the: shuttle avoidanceo This is an avoidance task o We add a(n) auditory cue o How can rats avoid the shock? Respond during the toneo FR1 schedule: walk over once Results: no differences between master and yoked animalso FR2 schedule:  Results: master rats can learn but yoked can’t - Does the learning deficit depend on behavioral control or the amount of shock? It is due to behavioral control of the shocko Learned Helplessness Hypothesis (Maier and Seligman) Hypothesis: the cognition of no control would reduce the organism’s incentive to escape and undermine the subject’s motivation to respond - Two deficits:o 1. Motivational deficito 2. Associative deficit o Immunization and Therapy Therapy: need a problem first- Groups:o 1. Restrained - restrainedo 2. Inescapable shock – escapable shock (experimental group)o 3. Inescapable shock – inescapable shocko 4. Inescapable shock – restrainedo Left side: tail shock, right side: wheel turn- After 24 hours, test on the shuttle avoidance task- Results: animals given behavioral therapy learn the task Immunization- Groups: o 1. Restrained - restrainedo 2. Escapable shock – inescapable shock (experimental)o 3. Inescapable - inescapableo 4. Restrained – inescapable shock - Results: groups that received immunization therapy are protected from deficito Role of Endogenous Opioids Question: do the inescapable rats fail to learn because they’re analgesic  This would undermine which deficit? motivation Tested using: tail flick2- Results 24 hours after training: no differences between groups- Results after 5 FR1’s: inescapable rats show enhanced analgesia, master rats do not This analgesia is mediated by: endorphins/opioids - What happens to the shuttle avoidance task if we give the rats naltrexone prior to training? Analgesia is blocked but doesn’t reverse the learning deficito Why? Associative deficit This may provide a model for: human depressiono Helplessness and the Immune System Description: rats exposed to uncontrollable stressor were less able to reject cancerous cells and had increased mortality rates, whether aversive stimulus have aversive consequences depends on whether you perceive them as controllable or uncontrollableo Helplessness and Anxiety  3 conditions associated with PTSD- 1. Heightened arousal or anxiety- 2. Re-experiencing- 3. Numbing of general responsiveness Evidence for enhanced anxiety- Two tests:o 1. Social interaction test Anxiety behavior: reduced or no social interactiono 2. Elevated plus maze Anxiety behavior: rats hide in the dark arms or don’t moveo Neural Structures Involved in Learned Helplessness 1. DRN- Results from stimulation: produce learned helplessness- Results from lesion: no learned helplessness- Serotonin, prozac 2. vmPFC- Relationship with DRN: through GABA, inhibitory relationship- Results from stimulation: block learned helplessness- Results from lesion: rats will learn the task but still show learned helplessness35B – Mechanisms OutlineInstrumental Learning within the Spinal Cord- Methods o What surgery must the rats have to separate the brain from the lower spinal cord? Upper thoracic transectiono Instrumental Contingency Response: rat lowers leg Outcome: foot shock Result: rat learns to keep his leg up, no conscious control- Triad Designo Results from training Master result: keep legs up Yoked result: don’t learn/keep leg up Unshock result: don’t keep leg upo Results from test using controllable shock Master result: keep legs up, learn, reduce net shock exposure Yoked result: don’t learn, imperative learning, learned helplessness in spinal cord Unshock result: learno Learned helplessness can last: 48 hours- Therapy and Immunizationo Description: transected animals show the same effects as intact animals when given behavioral therapy, learned helplessness in spinal cord can be reversed by controllable shock and be prevented by controllable shock- Clinical Implicationso Description: just six minutes of uncontrollable stimulation after a contusion injury can impair long term

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