Browsing by Subject "Classical conditioning"

Now showing 1 - 4 of 4
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    The effects of alcohol odor cues on food and alcohol attentional bias, cravings, and consumption
    (2015-07-08) Karyadi, Kenny; Cyders, Melissa A.; Stewart, Jesse; Mosher, Catherine Esther; Grahame, Nicholas J.
    In order to elucidate the role of classical conditioning in food and alcohol co-consumption, the present study examined: (1) the effects of alcohol odor cues on alcohol and food cravings and attentional bias (bias in selective attention toward either food or alcohol pictures relative to neutral pictures); and (2) the role of alcohol odor cue elicited cravings and attentional biases on subsequent consumption. Participants (n = 77; mean age = 30.84, SD = 9.46; 51.9% female, 83.1% Caucasian) first completed the lab portion of the study. In this portion, they were exposed to alcohol and neutral odorants, after which their food and alcohol cravings and attentional bias were assessed. Participants then received an online survey the next day, on which they reported their level of food and alcohol consumption following the lab portion of the study. Using repeated measures analysis of covariance, alcohol odor cues were differentially effective in increasing food and alcohol attentional bias and cravings (Fs= 0.06 to 2.72, ps= 0.03 to 0.81). Using logistic and multiple regressions, alcohol odor cue elicited alcohol attentional bias, food attentional bias, and food cravings were associated with later alcohol consumption, but not with later food consumption or concurrent consumption (βs = -0.28 to 0.48, ps = 0.02 to 0.99; Exp(B)s = 0.95 to 1.83, ps = 0.33 to 0.91). Overall, alcohol odor cues can become conditioned stimuli that elicit conditioned food-related and alcohol-related responses, both of which persist long enough to motivate later alcohol consumption; however, these conditioned responses might not persist long enough to motivate later food or concurrent consumption. These findings serve as a first step in clarifying the role of classical conditioning in concurrent consumption. In particular, they suggest that additional empirical investigations are needed to: (1) clarify the classical conditioning mechanisms underlying concurrent consumption; and (2) examine whether interventions targeting classical conditioning mechanisms are effective for reducing alcohol use.
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    Embryonic Methamphetamine Exposure Inhibits Methamphetamine Cue Conditioning and Reduces Dopamine Concentrations in Adult N2 Caenorhabditis elegans
    (Karger, 2016-05) Katner, S.K.; Neal-Beliveau, B.S.; Engleman, E.A.; Psychology, School of Science
    Methamphetamine (MAP) addiction is substantially prevalent in today's society, resulting in thousands of deaths and costing billions of dollars annually. Despite the potential deleterious consequences, few studies have examined the long-term effects of embryonic MAP exposure. Using the invertebrate nematode Caenorhabditis elegans allows for a controlled analysis of behavioral and neurochemical changes due to early developmental drug exposure. The objective of the current study was to determine the long-term behavioral and neurochemical effects of embryonic exposure to MAP in C. elegans. In addition, we sought to improve our conditioning and testing procedures by utilizing liquid filtration, as opposed to agar, and smaller, 6-well testing plates to increase throughput. Wild-type N2 C. elegans were embryonically exposed to 50 μM MAP. Using classical conditioning, adult-stage C. elegans were conditioned to MAP (17 and 500 μM) in the presence of either sodium ions (Na+) or chloride ions (Cl-) as conditioned stimuli (CS+/CS-). Following conditioning, a preference test was performed by placing worms in 6-well test plates spotted with the CS+ and CS- at opposite ends of each well. A preference index was determined by counting the number of worms in the CS+ target zone divided by the total number of worms in the CS+ and CS- target zones. A food conditioning experiment was also performed in order to determine whether embryonic MAP exposure affected food conditioning behavior. For the neurochemical experiments, adult worms that were embryonically exposed to MAP were analyzed for dopamine (DA) content using high-performance liquid chromatography. The liquid filtration conditioning procedure employed here in combination with the use of 6-well test plates significantly decreased the time required to perform these experiments and ultimately increased throughput. The MAP conditioning data found that pairing an ion with MAP at 17 or 500 μM significantly increased the preference for that ion (CS+) in worms that were not pre-exposed to MAP. However, worms embryonically exposed to MAP did not exhibit significant drug cue conditioning. The inability of MAP-exposed worms to condition to MAP was not associated with deficits in food conditioning, as MAP-exposed worms exhibited a significant cue preference associated with food. Furthermore, our results found that embryonic MAP exposure reduced DA levels in adult C. elegans, which could be a key mechanism contributing to the long-term effects of embryonic MAP exposure. It is possible that embryonic MAP exposure may be impairing the ability of C. elegans to learn associations between MAP and the CS+ or inhibiting the reinforcing properties of MAP. However, our food conditioning data suggest that MAP-exposed animals can form associations between cues and food. The depletion of DA levels during embryonic exposure to MAP could be responsible for driving either of these processes during adulthood.
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    Pairing Neutral Cues with Alcohol Intoxication: New Findings in Executive and Attention Networks
    (Springer, 2018-09) Oberlin, Brandon G.; Dzemidzic, Mario; Eiler, William J.A.; Carron, Claire R.; Soeurt, Christina M.; Plawecki, Martin H.; Grahame, Nicholas J.; O’Connor, Sean J.; Kareken, David A.; Psychiatry, School of Medicine
    Rationale: Alcohol-associated stimuli capture attention, yet drinkers differ in the precise stimuli that become paired with intoxication. Objectives: Extending our prior work to examine the influence of alcoholism risk factors, we paired abstract visual stimuli with intravenous alcohol delivered covertly and examined brain responses to these Pavlovian conditioned stimuli in fMRI when subjects were not intoxicated. Methods: Sixty healthy drinkers performed task-irrelevant alcohol conditioning that presented geometric shapes as conditioned stimuli. Shapes were paired with a rapidly rising alcohol limb (CS+) using intravenous alcohol infusion targeting a final peak breath alcohol concentration of 0.045 g/dL or saline (CS−) infusion at matched rates. On day two, subjects performed monetary delay discounting outside the scanner to assess delay tolerance and then underwent event-related fMRI while performing the same task with CS+, CS−, and an irrelevant symbol. Results: CS+ elicited stronger activation than CS− in frontoparietal executive/attention and orbitofrontal reward-associated networks. Risk factors including family history, recent drinking, sex, and age of drinking onset did not relate to the [CS+ > CS−] activation. Delay-tolerant choice and [CS+ > CS−] activation in right inferior parietal cortex were positively related. Conclusions: Networks governing executive attention and reward showed enhanced responses to stimuli experimentally paired with intoxication, with the right parietal cortex implicated in both alcohol cue pairing and intertemporal choice. While different from our previous study results in 14 men, we believe this paradigm in a large sample of male and female drinkers offers novel insights into Pavlovian processes less affected by idiosyncratic drug associations.
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    Suppressing fear in the presence of a safety cue requires infralimbic cortical signaling to central amygdala
    (Springer Nature, 2024) Ng, Ka; Pollock, Michael; Escobedo, Abraham; Bachman, Brent; Miyazaki, Nanami; Bartlett, Edward L.; Sangha, Susan; Psychiatry, School of Medicine
    Stressful events can have lasting and impactful effects on behavior, especially by disrupting normal regulation of fear and reward processing. Accurate discrimination among environmental cues predicting threat, safety or reward adaptively guides behavior. Post-traumatic stress disorder (PTSD) represents a condition in which maladaptive fear persists in response to explicit safety-predictive cues that coincide with previously learned threat cues, but without threat being present. Since both the infralimbic cortex (IL) and amygdala have each been shown to be important for fear regulation to safety cues, we tested the necessity of specific IL projections to the basolateral amygdala (BLA) or central amygdala (CeA) during safety recall. Male Long Evans rats were used since prior work showed female Long Evans rats did not acquire the safety discrimination task used in this study. Here, we show the infralimbic projection to the central amygdala was necessary for suppressing fear cue-induced freezing in the presence of a learned safety cue, and the projection to the basolateral amygdala was not. The loss of discriminative fear regulation seen specifically during IL->CeA inhibition is similar to the behavioral disruption seen in PTSD individuals that fail to regulate fear in the presence of a safety cue.