No abstract

Binge eating disorder (BED) is characterized by periods of excessive food intake combined with subjective feelings of loss of control. We examined whether sucrose bingeing itself leads to uncontrolled or compulsive responding and whether this effect is magnified following a period of abstinence. We then assessed dopamine (DA) modulation of inhibitory synaptic transmission in the oval bed nucleus of the stria terminalis (ovBNST) as a neural correlate of compulsive responding and whether this behavioral effect could be disrupted by DA blockade in the ovBNST. Over 28 days, male Long-Evans rats (n = 8-16 per group) had access to 10% sucrose and food (12 or 24 h), 0.1% saccharin and food (12 h), or food alone (12 h). Compulsive responding was assessed following 1 or 28 days of sucrose abstinence using a conditioned suppression paradigm. Only rats given 12 h access to sucrose developed binge-like intake, manifested as copious intake within the first hour; compulsive responding was significantly elevated in this group following 28 days of abstinence. In parallel, the effect of DA on ovBNST inhibitory transmission switched from a reduction to a potentiation; the effect, although observable after 1 day, was more pronounced and sustained following 28 days of abstinence. Intra-ovBNST infusions of a DA D1 receptor antagonist (0.8 µg/µl SCH-23390) reversed the blockade of conditioned suppression, thereby confirming the causal relationship between ovBNST DA modulation of γ-aminobutyric acid transmission and alterations in conditioned suppression following binge-like intake of sucrose.

Men's sexual arousal is largely dependent on the actor's gender in a sexual stimulus (gender-specific), whereas for women, particularly androphilic women, arousal is less dependent on gender (gender-nonspecific). According to information-processing models of sexual response, sexual arousal requires that attention be directed toward sexual cues. We evaluated whether men's and women's self-reported attention to sexual stimuli of men or women were consistent with genital responses and self-reported arousal. We presented gynephilic men (n = 21) and women (n = 22) and androphilic men (n = 16) and women (n = 33) with audiovisual stimuli depicting men or women engaged in sexual activities. Genital responses were continuously recorded and, following each stimulus, participants reported the amount of attention paid to the video and feelings of sexual arousal. Self-reported attention was gender-specific for men and gender-nonspecific for women, and generally mirrored genital responses and self-reported arousal. Gender-specificity of genital responses significantly predicted gender-specificity of self-reported arousal; however, for men only, this effect was significantly mediated by gender-specificity of self-reported attention. Gender differences in gender-specificity of sexual arousal may be partially accounted for by differences in gender-specificity of self-reported attention, although attention may play a greater role in men's sexual arousal than women's.

Impulsive action, the failure to withhold an inappropriate response, is treated clinically with dopamine agonists such as amphetamine. Despite the therapeutic efficacy, these drugs have inconsistent effects on impulsive action in rodents, causing improvements or disruptions in different tasks. Thus, we hypothesized that amphetamine is producing an effect by altering distinct cognitive processes in each task. To test this idea, we used the response inhibition (RI) task and trained rats to withhold responding for sucrose until a signal is presented. We then varied the duration that subjects were required to inhibit responding (short ¼ 4 s; long ¼ 60 s; or variable ¼ 1-60 s) and examined whether this influenced the pattern of premature responses. We also tested the effects of amphetamine (0.0, 0.125, 0.25, 0.5, and 1.0 mg/kg) on each task variant. The probability of premature responding varied across the premature interval with a unique pattern of time-dependent errors emerging in each condition. Amphetamine also had distinct effects on each version: the drug promoted premature responding when subjects expected a consistent delay, regardless of its duration, but reduced premature responding when the delay was unpredictable. We propose that the ability to inhibit a motor response is controlled by a different combination of cognitive processes in the three task conditions. These include timing, conditioned avoidance, and attention, which then interact with amphetamine to increase or decrease impulsive action. The effect of amphetamine on impulsive action, therefore, is not universal, but depends on the subject's experience and expectation of the task demands.