DOCSLIB.ORG

Learning Learning Habituation Sensitization

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Learning Learning Habituation Sensitization Learning • Adaptive change in behavior that results from past experiences Learning • Nonassociative Learning – Habituation – Sensitization • Classical Conditioning • Instrumental Learning/Operant Conditioning Habituation Sensitization • Ability to discontinue • Increase in response to highly responsiveness as repetitive stimuli result of • Sokolov (1963) – repeated application of – Delayed Train stimulus – aversive stimulus Habituation can be short-term or long-term, depending on Habituation and Sensitization presentation and interval between stimuli. Characteristics of Habituation and Sensitization Short-term habituation: -rapid presentations of a stimulus with a short interval Time course between presentations -results in habituation quickly but see spontaneous Sensitization is usually temporary recovery -sensitization can last for up to a week but not -the degree of spontaneous recovery depends on length generally a long-term effect. of rest interval. -with a stronger stimulus, the effects last longer. 1 1. Short-term habituation 2. Spontaneous recovery 3. Long-term habituation Long-term habituation: -one stimulus presentation a day -see more long-term effects -see less spontaneous recovery 4. Rate of habituation faster for short ISI 7. Habituation is specific – generalization gradient 5. Rate of habituation faster for weaker stimuli 8. Dishabituation 6. Below-zero habituation 9. Habituation of dishabituation Habituation/Dishabituation Stimulus specificity Habituation is stimulus-specific • GSR measured at -if you change the stimulus, see recovery of the onset of either high or response low tone – Tone gradually elicits Sensitization is not highly stimulus-specific less anxiety -if an animal is aroused, it is usually aroused to a th •15 trial is the variety of cues opposite tone – high for low group & low for high group 2 Effects of strong extraneous stimuli Habituation and Sensitization in Aplysia If you change the nature of the eliciting stimulus you see recovery of the habituated response. Can also see recovery of the response if the animal is given a rest period = spontaneous recovery. The response can also be restored by presenting a strong stimulus— this is called sensitization Dishabituation refers to recovery of the response to the habituated stimulus following presentation of a different, novel stimulus. Habituation of the gill withdrawal reflex results from changes in the S-R pathway Sensitization Less transmitter After the gill withdrawal reflex has habituated, a shock to released here the tail sensitizes the gill withdrawal reflex elicited by touching either the mantle or siphon Skin SN MN Gill Sensitization occurs because tailshock augments the release of neurotransmitter from the Habituation vs. Sensitization sensory neuron Habituation Sensitization Tail FN • Decrease in strength • Increase in strength of behavior of behavior • Typically low-intensity • Typically high- stimuli intensity stimuli Skin SN MN • Stimulus-specific • Nonspecific generalization generalization • < neurotransmitter • > neurotransmitter Gill 3 Pavlov Classical Conditioning • Process by which a neutral stimulus (CS) comes to be associated with another stimulus (UCS) that elicits a response (UCR) • Results in elicitation of response by CS Pavlov paired the clicking of a metronome with food. Clicker Food (never used a bell) Dogs normally salivate with food but not with the clicker After a few of these pairings, dogs began to salivate when the metronome came on. Four major terms apply to Pavlovian Conditioning experiments Sequence in Conditioning Stimuli Responses • Initially the neutral UR US stimulus elicits no Unconditioned response Unconditioned stimulus The unlearned response response Biologically potent stimulus that triggered by the US reliably evokes an unlearned or • UCS elicits reflexive Powerful and reflexive response (UCR) reflexive reaction (i.e., food) (i.e., salivation to food) • Pair NS w/ UCS & elicit UCR CS CR Conditioned stimulus Conditioned response • CS elicits salivation Biologically weak stimulus It is elicited by the CS and – UCR=CR salivation The CS may evoke an orienting represents the learned behavior response, but not the strong response evoked by the US (i.e., salivation to the Metronome) (i.e., metronome) 4 Appetitive & Aversive Timing Conditioning Appetitive Aversive • US is an event the • US is an event the organism seeks out & organism avoids & considers pleasant considers unpleasant –food – shock –physical touch – painful stimulus –warmth – air puff in eye Phases of Learning Extinction • Acquisition – phase • Diminishment of response when reinforcement w/strengthening of is discontinued response through repeated reinforcements Acquisition & Extinction Acquisition and Extinction • Spontaneous Recovery 5 What is learned? Pavlov • Stimulus-Stimulus Associations • Stimulus-substitution theory CS – CS becomes directly associated with the UCS – A connection forms in the brain between the CS and the UCS and so elicits a similar/related response to the UCS activation sites – When the CS is activated UCR UCR alone following acquisition, it will automatically activate the • Stimulus-Response Associations UCS site in the brain – Therefore, the CR should be CS – CS becomes directly associated with the UCR almost identical to the UCR and so elicits the same response as the UCR (because the connection UCS between UCS and UCR in the brain is hardwired) UCR/CR Support: Stimulus Substitution Against Stimulus Substitution • Water Group • CR not always the same as UCR – CS(light)ÆUCS(water) Water Grain – Pigeons tried to “drink” the – When tone paired with shock, rats will jump to lit key the UCS (shock), but the CR is typically • closed beak and open eyes freezing • Grain Group – CS(light)ÆUCS(grain) CS – Pigeons tried to “eat” the lit key UCS • Open beak and closed eyes Jenkins & Moore (1973) CR UCR Other stimulus-response models Siegel (1972) • Preparatory Response Model –Kimble • Gave rats repeated – CR is a response that serves to prepare the organism for the injections (CS) of insulin upcoming UCS (UCS) – Insulin’s effects are to – CR eyeblink may actually prepare the person for the upcoming reduce the level of airpuff such that the eye would be partially closed when the glucose in the blood airpuff occurs (UCR) • Compensatory Response Model • Give rats injection of saline – Siegel – Measured the CR (change in blood glucose – Learned association between CS and UCS serves to elicit a CR levels) that compensates for effects of UCS • Glucose levels increased – Sometimes CR=UCR • CR ≠ UCR, and the CR was – Sometimes CR opposite of UCR definitely compensatory • Evidence for compensatory response model 6 Conditioned Drug Tolerance • Siegel, et al., 1978 45 – Experimental Group: CS (light change & noise w 40 reduction) paired with UCS 35 (injection of morphine) for 9 30 days 25 – Placebo Control Group (CS 20 paired with injection of saline) 15 – Unpaired Control Group 10 •Test: present CS, inject Pa Lick to Latency Mean 5 every rat with morphine, 0 place rat on hot surface Placebo Experimental Control – Measure latency to lick their paws (lick when they feel pain) 7.
Load more

Recommended publications
  • A Psychological Approach to Musical Form: the Habituation–Fluency Theory of Repetition
    A Psychological Approach to Musical Form: The Habituation–Fluency Theory of Repetition David Huron With the possible exception of dance and meditation, there appears to be nothing else in common human experience that is comparable to music in its repetitiveness (Kivy 1993; Ockelford 2005; Margulis 2013). Narrative arti- facts like movies, novels, cartoon strips, stories, and speeches have much less internal repetition. Even poetry is less repetitive than music. Occasionally, architecture can approach music in repeating some elements, but only some- times. There appears to be no visual analog to the sort of trance–inducing music that can engage listeners for hours. Although dance and meditation may be more repetitive than music, dance is rarely performed in the absence of music, and meditation tellingly relies on imagining a repeated sound or mantra (Huron 2006: 267). Repetition can be observed in music from all over the world (Nettl 2005). In much music, a simple “strophic” pattern is evident in which a single phrase or passage is repeated over and over. When sung, it is common for successive repetitions to employ different words, as in the case of strophic verses. However, it is also common to hear the same words used with each repetition. In the Western art–music tradition, internal patterns of repetition are commonly discussed under the rubric of form. Writing in The Oxford Companion to Music, Percy Scholes characterized musical form as “a series of strategies designed to find a successful mean between the opposite extremes of unrelieved repetition and unrelieved alteration” (1977: 289). Scholes’s characterization notwithstanding, musical form entails much more than simply the pattern of repetition.
    [Show full text]
  • Modeling the Dishabituation Hierarchy: the Role of the Primordial Hippocampus*
    Biol. Cybern. 67, 535-544 (1992) Biological Cybemetics Springer-Verlag 1992 Modeling the dishabituation hierarchy: The role of the primordial hippocampus* DeLiang Wang and Michael A. Arbib Center for Neural Engineering, University of Southern California, Los Angeles, CA 90089-2520, USA Received January 30, 1992/accepted in revised form April 6, 1992 Abstract. We present a neural model for the organiza- orienting response to a certain stimulus applied at a tion and neural dynamics of the medial pallium, the given location, the response can be released by the same toad's homolog of mammalian hippocampus. A neural stimulus applied at a different retinal locus (Eikmanns mechanism, called cumulative shrinking, is proposed 1955; Ewert and Ingle 1971). (2) Hierarchical stimulus for mapping temporal responses from the anterior tha- specificity. Another stimulus given at the same locus lamus into a form of population coding referenced by may restore the response habituated by a previous spatial positions. Synaptic plasticity is modeled as an stimulus. Only certain stimuli can dishabituate a previ- interaction of two dynamic processes which simulates ously habituated response. Ewert and Kehl (1978) acquisition and both short-term and long-term forget- demonstrated that this dishabituation forms a hierarchy ting. The structure of the medial pallium model plus the (Fig. 1A), where a stimulus can dishabituate the habitu- plasticity model allows us to provide an account of the ated responses of another stimulus if the latter is lower neural mechanisms of habituation and dishabituation. in the hierarchy. Computer simulations demonstrate a remarkable match A model developed by Wang and Arbib (1991a) between the model performance and the original exper- showed how a group of cells in the anterior thalamus imental data on which the dishabituation hierarchy was (AT) could respond to stimuli higher in the hierarchy based.
    [Show full text]
  • Intensive Auditory Comprehension Treatment for People with Severe Aphasia
    Intensive Auditory Comprehension Treatment for People with Severe Aphasia: Outcomes and Use of Self-Directed Strategies A dissertation proposal submitted to the Division of Graduate Education and Research Of the University of Cincinnati in partial fulfillment of the requirements of the degree of DOCTOR OF PHILOSOPHY In the Department of Communication Sciences and Disorders In the College of Allied Health Sciences Dissertation Committee: Aimee Dietz, Ph D., chair Lisa Kelchner, Ph.D. Robin Thomas, Ph.D. Pete Scheifele, Ph.D 2012 by Kelly Knollman-Porter Intensive Auditory Comprehension Treatment Abstract The purpose of this study was to determine the efficacy of an intensive (2 hours/day, 5 days/week for 3 weeks) treatment protocol on individuals with severe, chronic speech perception or auditory comprehension deficits associated with aphasia. Two experiments were implemented to examine this purpose. Experiment I: Single Word Comprehension Approach (SWCA) established the effectiveness of an intensive treatment protocol on single word auditory comprehension (n = 6). Alternatively, Experiment II: Speech Perception Approach (SPA) examined the outcomes of an intensive treatment protocol on speech perception in individuals with profound global aphasia (n = 2). The researcher employed an ABA single subject design for both experiments, and examined the following variables: (1) changes in single word comprehension (SWCA) or speech perception (SPA); (2) the number of self-initiated requests for repetition and lip-reading cues; (3) the effectiveness of repetition and lip-reading cues; (4) the indirect effects of the protocols on verbal expression (SWCA – naming; SPA – repetition; Both – narrative skills); (5) and generalization to functional communication environments. Results revealed that all participants enrolled in the SWCA or SPA exhibited a lack of awareness regarding their comprehension impairment at the onset of treatment.
    [Show full text]
  • Classical Conditioning Without Awareness: an Electrophysiological Investigation
    Classical conditioning without awareness: An electrophysiological investigation A Thesis Presented to The Division of Philosophy, Religion, Psychology, and Linguistics Reed College In Partial Fulfillment of the Requirements for the Degree Bachelor of Arts Jasmine Huang December 2016 Approved for the Division (Psychology) Timothy Hackenberg Michael Pitts Acknowledgements There is no way to express the amount of gratitude I feel towards every single person who has contributed to my growth as a student and as a human being, but I will try. My family, who has worked tirelessly to support me through life and years of school, I will never know how to repay that debt. My advisors, who have endlessly encouraged me and provided me with every opportunity I could have wished for. Tim who has believed in and supported me from my first year at Reed right up until the end. Enriqueta who was always willing to discuss experiments outside of class (even when I wasn’t in her class to begin with). Michael who inspired me every day with his unending enthusiasm and drive for research. The amazing psychology department staff who are always making sure that everything is running as smoothly as it can be. Joan, our silent hero who puts out the metaphorical fires every day. Greg, one the most lively presences in the animal colony, whose love for all of the critters is unparalleled. Chris, whose attention to detail and patience for dumb questions were invaluable to me during this process. Lavinia, whose realism and dark humor made for the best introduction into real labwork that I could have asked for.
    [Show full text]
  • Impact of a Reminder/Extinction Procedure on Threat-Conditioned Pupil Size and Skin Conductance Responses
    Downloaded from learnmem.cshlp.org on March 28, 2020 - Published by Cold Spring Harbor Laboratory Press Research Impact of a reminder/extinction procedure on threat- conditioned pupil size and skin conductance responses Josua Zimmermann1,2 and Dominik R. Bach1,2,3 1Computational Psychiatry Research, Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric Hospital, University of Zurich, 8032 Zurich, Switzerland; 2Neuroscience Centre Zurich, University of Zurich, 8057 Zurich, Switzerland; 3Wellcome Centre for Human Neuroimaging and Max Planck/UCL Centre for Computational Psychiatry and Ageing Research, University College London, London WC1 3BG, United Kingdom A reminder can render consolidated memory labile and susceptible to amnesic agents during a reconsolidation window. For the case of threat memory (also termed fear memory), it has been suggested that extinction training during this reconso- lidation window has the same disruptive impact. This procedure could provide a powerful therapeutic principle for treat- ment of unwanted aversive memories. However, human research yielded contradictory results. Notably, all published positive replications quantified threat memory by conditioned skin conductance responses (SCR). Yet, other studies mea- suring SCR and/or fear-potentiated startle failed to observe an effect of a reminder/extinction procedure on the return of fear. Here we sought to shed light on this discrepancy by using a different autonomic response, namely, conditioned pupil dilation, in addition to SCR, in a replication of the original human study. N = 71 humans underwent a 3-d threat condition- ing, reminder/extinction, and reinstatement, procedure with 2 CS+, of which one was reminded. Participants successfully learned the threat association on day 1, extinguished conditioned responding on day 2, and showed reinstatement on day 3.
    [Show full text]
  • Gabab Regulation of Methamphetamine-Induced Associative Learning
    Loyola University Chicago Loyola eCommons Dissertations Theses and Dissertations 2010 Gabab Regulation of Methamphetamine-Induced Associative Learning Robin Michelle Voigt Loyola University Chicago Follow this and additional works at: https://ecommons.luc.edu/luc_diss Part of the Pharmacology Commons Recommended Citation Voigt, Robin Michelle, "Gabab Regulation of Methamphetamine-Induced Associative Learning" (2010). Dissertations. 38. https://ecommons.luc.edu/luc_diss/38 This Dissertation is brought to you for free and open access by the Theses and Dissertations at Loyola eCommons. It has been accepted for inclusion in Dissertations by an authorized administrator of Loyola eCommons. For more information, please contact [email protected]. This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. Copyright © 2010 Robin Michelle Voigt LOYOLA UNIVERSITY CHICAGO GABAB REGULATION OF METHAMPHETAMINE-INDUCED ASSOCIATIVE LEARNING A DISSERTATION SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL IN CANDIDACY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY PROGRAM IN MOLECULAR PHARMACOLOGY & THERAPEUTICS BY ROBIN MICHELLE VOIGT CHICAGO, IL DECEMBER 2010 Copyright by Robin Michelle Voigt, 2010 All rights reserved ACKNOWLEDGEMENTS Without the support of so many generous and wonderful individuals I would not have been able to be where I am today. First, I would like to thank my Mother for her belief that I could accomplish anything that I set my mind to. I would also like to thank my dissertation advisor, Dr. Celeste Napier, for encouraging and challenging me to be better than I thought possible. I extend gratitude to my committee members, Drs. Julie Kauer, Adriano Marchese, Micky Marinelli, and Karie Scrogin for their guidance and insightful input.
    [Show full text]
  • Amphetamine Sensitization Alters Hippocampal Neuronal Morphology and Memory and Learning Behaviors
    Molecular Psychiatry https://doi.org/10.1038/s41380-020-0809-2 ARTICLE Amphetamine sensitization alters hippocampal neuronal morphology and memory and learning behaviors 1,2,5 1,2 1 Luis Enrique Arroyo-García ● Hiram Tendilla-Beltrán ● Rubén Antonio Vázquez-Roque ● 1 3 3 3 1 Erick Ernesto Jurado-Tapia ● Alfonso Díaz ● Patricia Aguilar-Alonso ● Eduardo Brambila ● Eduardo Monjaraz ● 2 4 1 Fidel De La Cruz ● Antonio Rodríguez-Moreno ● Gonzalo Flores Received: 12 November 2019 / Revised: 29 May 2020 / Accepted: 3 June 2020 © The Author(s), under exclusive licence to Springer Nature Limited 2020 Abstract It is known that continuous abuse of amphetamine (AMPH) results in alterations in neuronal structure and cognitive behaviors related to the reward system. However, the impact of AMPH abuse on the hippocampus remains unknown. The aim of this study was to determine the damage caused by AMPH in the hippocampus in an addiction model. We reproduced the AMPH sensitization model proposed by Robinson et al. in 1997 and performed the novel object recognition test (NORt) to evaluate learning and memory behaviors. After the NORt, we performed Golgi–Cox staining, a 1234567890();,: 1234567890();,: stereological cell count, immunohistochemistry to determine the presence of GFAP, CASP3, and MT-III, and evaluated oxidative stress in the hippocampus. We found that AMPH treatment generates impairment in short- and long-term memories and a decrease in neuronal density in the CA1 region of the hippocampus. The morphological test showed an increase in the total dendritic length, but a decrease in the number of mature spines in the CA1 region. GFAP labeling increased in the CA1 region and MT-III increased in the CA1 and CA3 regions.
    [Show full text]
  • Journal of Neurobiology, Parametric Studies of The
    JOURNAL OF NEUROBIOLOGY,VOL. 1, NO. 3, PP. 345-360 PARAMETRIC STUDIES OF THE RESPONSE DECREMENT PRODUCED BY MECHANICAL STIMULI IN THE PROTOZOAN, Stentor coeruleus DAVID C. WOOD* Brain Research Laboratory, The University of Michigan, Ann Arbor, Michigan 43104 SUMMARY A decrement in the probability of eliciting a response is observed dur- ing the course of repetitive stimulation in many response systems of both metazoa and protozoa. Those forms of metazoan response decre- ment called habituation have recently been characterized behaviorally. In the studies reported here, the response decrement of the contractile protozoan, Stentor coeruleus, to repeated mechanical stimulation was systemically characterized to provide a comparison with metazoan habit- uation. This change in response probability was closely approximated by a negative exponential function after the first few stimuli. Animals responded to parametric variations of stimulus amplitude, interstimulus interval and retention period in a manner paralleling that observed in metazoa. However, neither interpolated large amplitude mechanical stimuli nor suprathreshold electrical stimuli produced dishabituation in Stentor though these stimuli are among the most effective dishabituating stimuli for metazoan tactile response systems. Behavioral analysis of the response decrement proceeded on the assumption that Stentor con- tains receptor and effector mechanisms only. Since the response decre- ment was not correlated with a change in responsiveness to electrical stimuli, the ability of the animal to contract appears to be unaltered by the process producing the response decrement. On the other hand, weak mechanical prestimuli were found to increase the rate of the response decrement which suggests that a process of receptor adaption is opera- tive.
    [Show full text]
  • Verbal Language Spontaneous Recovery After Ischemic Stroke
    Arq Neuropsiquiatr 2009;67(3-B):856-859 VERBAL LANGUAGE SPONTANEOUS RECOVERY AFTER ISCHEMIC STROKE Gabriela Camargo Remesso1, Ana Lúcia de Magalhães Leal Chiappetta1, Alexandre Santos Aguiar2, Márcia Maiumi Fukujima3, Gilmar Fernandes do Prado3 Abstract – Objective: To analyze the spontaneous recovery of the verbal language on patients who have had an ischemic stroke. Method: Retrospective analysis of 513 medical records. We characterize referring aspects for data identification, language deficit, spontaneous recovery and speech therapy. Results: The average age was 62.2 years old (SD= ±12.3), the average time of academic experience was 4.5 years (SD=±3.9), 245 (47.7%) patients presented language disturbance, 166 (54.0%) presented spontaneous recovery, from which 145 (47.2%) had expression deficit (p=0.001); 12 (3.9%) had comprehension deficit and 9 (2.9%) had both expression and comprehension deficit. Speech therapy was carried with 15 patients (4.8%) (p=0.001). Conclusion: The verbal language spontaneous recovery occurred in most of the patients being taken care of at the stroke out clinic, and expression disturbance was the most identified alteration. As expected, the left hemisphere was associated with the deficit and smoking and pregressive stroke were the language alteration primary associated factors. KEY WORDS: aphasia, language, stroke, neuronal plasticity. Recuperação espontânea da linguagem verbal após acidente cerebrovascular isquêmico Resumo – Objetivo: Analisar a recuperação espontânea da linguagem verbal em pacientes que
    [Show full text]
  • The Brain That Changes Itself
    The Brain That Changes Itself Stories of Personal Triumph from the Frontiers of Brain Science NORMAN DOIDGE, M.D. For Eugene L. Goldberg, M.D., because you said you might like to read it Contents 1 A Woman Perpetually Falling . Rescued by the Man Who Discovered the Plasticity of Our Senses 2 Building Herself a Better Brain A Woman Labeled "Retarded" Discovers How to Heal Herself 3 Redesigning the Brain A Scientist Changes Brains to Sharpen Perception and Memory, Increase Speed of Thought, and Heal Learning Problems 4 Acquiring Tastes and Loves What Neuroplasticity Teaches Us About Sexual Attraction and Love 5 Midnight Resurrections Stroke Victims Learn to Move and Speak Again 6 Brain Lock Unlocked Using Plasticity to Stop Worries, OPsessions, Compulsions, and Bad Habits 7 Pain The Dark Side of Plasticity 8 Imagination How Thinking Makes It So 9 Turning Our Ghosts into Ancestors Psychoanalysis as a Neuroplastic Therapy 10 Rejuvenation The Discovery of the Neuronal Stem Cell and Lessons for Preserving Our Brains 11 More than the Sum of Her Parts A Woman Shows Us How Radically Plastic the Brain Can Be Appendix 1 The Culturally Modified Brain Appendix 2 Plasticity and the Idea of Progress Note to the Reader All the names of people who have undergone neuroplastic transformations are real, except in the few places indicated, and in the cases of children and their families. The Notes and References section at the end of the book includes comments on both the chapters and the appendices. Preface This book is about the revolutionary discovery that the human brain can change itself, as told through the stories of the scientists, doctors, and patients who have together brought about these astonishing transformations.
    [Show full text]
  • Comparison Between Two Methodological Paradigms of Conditioned Place Preference with Methlyphenidate
    East Tennessee State University Digital Commons @ East Tennessee State University Undergraduate Honors Theses Student Works 12-2013 Comparison between Two Methodological Paradigms of Conditioned Place Preference with Methlyphenidate. Bryce D. Watson East Tennessee State University Follow this and additional works at: https://dc.etsu.edu/honors Part of the Psychiatry and Psychology Commons Recommended Citation Watson, Bryce D., "Comparison between Two Methodological Paradigms of Conditioned Place Preference with Methlyphenidate." (2013). Undergraduate Honors Theses. Paper 89. https://dc.etsu.edu/honors/89 This Honors Thesis - Open Access is brought to you for free and open access by the Student Works at Digital Commons @ East Tennessee State University. It has been accepted for inclusion in Undergraduate Honors Theses by an authorized administrator of Digital Commons @ East Tennessee State University. For more information, please contact [email protected]. Watson 1 Comparison between Two Methodological Paradigms of Conditioned Place Preference with Methlyphenidate By Bryce Watson The Honors College Honors in Discipline Program East Tennessee State University Department of Psychology December 9, 2013 Russell Brown, Faculty Mentor David Harker, Faculty Reader Eric Sellers, Faculty Reader Watson 2 Abstract The aim of this thesis is to examine the mechanisms of Methylphenidate (MPH) on Conditioned Place Preference (CPP), a behavioral test of reward. The psychostimulant MPH is therapeutically used in the treatment of ADHD, but has been implicated in many pharmacological actions related to drug addiction and is considered to have abuse potential. Past work in our lab and others have shown substantial sex-differences in the neuropharmacological profile of MPH. Here a discussion of the relevant mechanisms of action of MPH and its relationship to neurotrophins and CPP are reviewed.
    [Show full text]
  • D, Dopamine Receptor Activation Is Necessary for the Induction of Sensitization by Amphetamine in the Ventral Tegmental Area
    The Journal of Neuroscience, April 1, 1996, 76(7):241 l-2420 D, Dopamine Receptor Activation Is Necessary for the Induction of Sensitization by Amphetamine in the Ventral Tegmental Area Paul Vezina Department of Psychiatry, The University of Chicago, Chicago, Illinois 6063 7 Repeated intermittent exposure to amphetamine produces injections of amphetamine. In the second experiment, locomo- long-term enhancements in the ability of this drug to produce tor sensitization induced by infusion of amphetamine into the locomotion and increase extracellular dopamine (DA) in the ventral tegmental area (WA) was blocked when these injections nucleus accumbens (NAcc). Three experiments were con- were preceded by systemic injections of SCH23390. Finally, in ducted to evaluate the role played by D, DA receptors in the experiment three, co-injecting SCH23390, but not its inactive production of these changes in response to amphetamine. Rats enantiomer, with amphetamine into the VTA during preexpo- were preexposed to amphetamine, alone or with a DA receptor sure prevented sensitization of the NAcc DA response to this antagonist, and tested for sensitization l-3 weeks after the last drug. These results indicate that while D, DA receptor activa- drug injection. On the test for sensitization, locomotor (experi- tion is not necessary for the induction of locomotor sensitiza- ments 1 and 2) and NAcc DA (experiment 3) responses of the tion to amphetamine, D, DA receptors located in the VTA play animals to a systemic amphetamine injection were assessed. In a critical role in the development of sensitized locomotor and the first experiment, systemic injections of the D, DA receptor NAcc DA response to this drug.
    [Show full text]