Effects of signaled and unsignaled shock on schedule-controlled lever pressing and schedule-induced licking: Shock intensity and body weight

Schedule-controlled lever pressing and schedule-induced licking were studied in rats under a multiple fixed-interval fixed-interval schedule of food reinforcement. Following acquisition of stable rates of pressing and licking, a multiple variable-time variable-time schedule of electric-shock delivery was superimposed upon the baseline schedule. In only one component of the multiple schedule, a 5-sec stimulus preceded each shock (signaled shock). In the other component shock was unsignaled. Several shock intensities (Experiment 1) and body weights (Experiment 2) were studied. Lever pressing and licking were affected similarly by experimental manipulations, although with parametric differences. Depending upon shock intensity and body weight, rates of lever pressing and licking were hardly suppressed, suppressed primarily in the unsignaled shock component (differential suppression), or markedly suppressed in both components. Differential suppression during components with signaled and unsignaled shock and conditioned suppression of responding during the preshock stimulus appeared not to be functionally related. Differential suppression depended more on the discriminability of shock-free time, and on shock intensity, body weight, and the type of response than on the “preparatory” behavior preceding shock.     

Long-term smoking intervention at the worksite: effects of quit-smoking groups and an "enriched milieu" on smoking cessation in adult white-collar employees

Maximizing the potential of worksites for smoking intervention remains elusive. We hypothesized that long-term effectiveness of group intervention would be enhanced when offered within an "enriched milieu" (full program) compared with relative isolation (group only). The data failed to support the hypothesis. Although sustained abstinence rates were higher at full-program sites (50%) than at group-only sites (44%), the difference did not achieve statistical significance. Initial (35% vs. 47%) and 12-month (18% vs. 22%) quit rates at full-program and group-only sites also failed to demonstrate the "benefit" of the "enriched milieu."     

Overcoming fixation with repeated memory suppression

Fixation (blocks to memories or ideas) can be alleviated not only by encouraging productive work towards a solution, but, as the present experiments show, by reducing counterproductive work. Two experiments examined relief from fixation in a word-fragment completion task. Blockers, orthographically similar negative primes (e.g., ANALOGY), blocked solutions to word fragments (e.g., A_L_ _GY) in both experiments. After priming, but before the fragment completion test, participants repeatedly suppressed half of the blockers using the Think/No-Think paradigm, which results in memory inhibition. Inhibiting blockers did not alleviate fixation in Experiment 1 when conscious recollection of negative primes was not encouraged on the fragment completion test. In Experiment 2, however, when participants were encouraged to remember negative primes at fragment completion, relief from fixation was observed. Repeated suppression may nullify fixation effects, and promote creative thinking, particularly when fixation is caused by conscious recollection of counterproductive information.     

Differential effects of assisted cycling therapy on short-term and working memory of adolescents with Down syndrome

Persons with Down syndrome (DS) suffer from prefrontal cortex dysfunction and deficits in executive functions. The current study examined the effects assisted cycling therapy (ACT) on short-term (STM) and working memory (WM) in adolescents with DS. During ACT, the cadence of participants on a stationary bicycle was augmented with an electrical motor to 180% of the voluntary cadence. Participants completed eight weeks of ACT (n?=?17), eight weeks of voluntary cycling (VC) at their own preferred cadence (n?=?16), or eight weeks of no cycling (np?≥?.149) and working memory improved only in the ACT group (Hedge’s g?=?1.66; p?=?.003). The results indicate that assisted high-cadence cycling (i.e. ACT) produces superior neural benefits in the dorsolateral prefrontal cortex compared to VC.     

Effects of response-dependent and independent electric shock on schedule-induced polydipsia

In Experiment I, lever pressing by rats was maintained by the delivery of food pellets under a 45-sec fixed-interval schedule. Fixed-time 180-sec and fixed-interval 180-sec schedules of shock delivery were systematically superimposed on the baseline food schedule to study effects on schedule-induced water intake. Response-dependent shock had little, if any, effect on water intake, whereas shocks independent of lever pressing attenuated fluid intake. In Experiment 2, rats received food pellets under a fixed-time 60-sec schedule. Electric shock delivered concurrently under a variable-time 180-sec schedule, but never while the animal was licking or within 5 sec after licking terminated, led to similar attenuation of water intake. These findings suggest that schedule-induced polydipsia is sensitive to differences in the functional properties of response-independent and dependent electric shock.     

Effects on responding of mixed and multiple schedules of signalled and unsignalled response-dependent electric-shock delivery

Responding in two rats was maintained under mixed and multiple variable-interval 35-sec variable-interval 35-sec food delivery schedules. Similar rates and patterns of responding occurred in each component of the two schedules. Mixed and multiple variable-interval 65-sec variable-interval 65-sec schedules of response-dependent shock delivery were super-imposed on the mixed and multiple baseline food schedules, respectively. In one component, a 5-sec stimulus was presented on the average of once every 65 sec. Offset of the stimulus arranged that the next response would produce shock. In the other component, no stimulus was presented during the 5-sec period. The mixed schedule of signalled and unsignalled dependent shock delivery yielded similar degrees of response suppression in each component, but the multiple schedule of shock delivery revealed differential degrees of response suppression. Considerably more suppression occurred in the component not associated with the preshock stimulus, thus implicating the discriminative functions of the correlated stimulus.     

Unimanual and bimanual continuous movements benefit from visual instructions in persons with down syndrome

ABSTRACT The authors' aim was to understand how persons with Down syndrome (DS) perform different tasks and to assess if there were any differences in performance based on the type of instructions. This is important because of neurological differences in persons with DS and neurological demands for performing different types of tasks. Twenty right-handed participants with DS, 20 chronological age-matched (CA), and 20 mental age-matched (MA) performed unimanual, bimanual, discrete, and continuous drumming following visual, auditory, and verbal instructions. Overall, discrete drumming was performed with shorter movement times than continuous drumming and unimanual drumming was performed with shorter movement amplitude than bimanual drumming. With respect to instructions, persons with DS performed with smaller amplitudes, thus more efficient movements, following the visual instructions than auditory and verbal instructions for all types of tasks, whereas CA performed similarly with all instructions and MA performed with smaller amplitudes with visual instructions than auditory instructions. These results suggest that visual instruction provides the best information for people with DS to aid in performance of many different types of movements.     

Look before you regulate: differential perceptual strategies underlying expressive suppression and cognitive reappraisal

Successful emotion regulation is important for maintaining psychological well-being. Although it is known that emotion regulation strategies, such as cognitive reappraisal and expressive suppression, may have divergent consequences for emotional responses, the cognitive processes underlying these differences remain unclear. Here we used eye-tracking to investigate the role of attentional deployment in emotion regulation success. We hypothesized that differences in the deployment of attention to emotional areas of complex visual scenes may be a contributing factor to the differential effects of these two strategies on emotional experience. Eye-movements, pupil size, and self-reported negative emotional experience were measured while healthy young adult participants viewed negative IAPS images and regulated their emotional responses using either cognitive reappraisal or expressive suppression. Consistent with prior work, reappraisers reported feeling significantly less negative than suppressers when regulating emotion as compared to a baseline condition. Across both groups, participants looked away from emotional areas during emotion regulation, an effect that was more pronounced for suppressers. Critically, irrespective of emotion regulation strategy, participants who looked toward emotional areas of a complex visual scene were more likely to experience emotion regulation success. Taken together, these results demonstrate that attentional deployment varies across emotion regulation strategies and that successful emotion regulation depends on the extent to which people look toward emotional content in complex visual scenes.