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Biomedical subjects

P Badia

Publications and source records attributed to P Badia.

At least 55 records · Page 3Linked to original sources
PubMed1987

Control of masseter muscle tension during sleep.

This study evaluated whether muscle tension could be controlled during sleep. Twelve volunteers were assigned to an experimental condition or to a no treatment control group. Experimental subjects were instructed to reduce the tension in their masseter (jaw) muscle when signalled with an auditory tone. These subjects demonstrated cue-controlled tension reductions during awake training sessions. Although both groups evidenced muscle tension increases in response to the tones presented during sleep, experimental subjects produced significantly smaller increases in response to tone stimuli than did control subjects. More importantly, experimental subjects sustained lower tonic levels of muscle tension throughout the sleep sessions than did control subjects. Sleep was moderately disrupted for subjects in both groups. However, experimental subjects evidenced the greatest tension reductions during those responses in which they shifted to a lighter stage of sleep rather than fully awakening. These data suggest that muscle tension can be moderated during sleep.

Adolescent↗
PubMed1985

Behavioral responsivity during recovery sleep.

Previous research has shown that REM-deprived subjects are more likely than non-REM-deprived subjects to perform an operant response during subsequent REM sleep when punishment (full awakening) for failure to respond was used. The present study used the same punishment procedure while attempting to extend these findings to other sleep stages. Response latencies were compared for six subjects under each of two conditions: Normal sleep occurring from 2300 to 0700 and recovery sleep occurring from 0700 to 1300 after 24 hr of continuous wakefulness. Alpha activity, EMG increases, stage shifts, and body movements were assessed to determine the amount of arousal associated with behavioral responding under both conditions. In general, response latencies lengthened during recovery sleep indicating a diminished ability to respond while no differences in arousal were evident.

Arousal↗
PubMed1984

Sleep fragmentation and daytime sleepiness.

It has been noted that clinical populations complaining of excessive daytime sleepiness (EDS) frequently have disrupted or fragmented nocturnal sleep. The relation between sleep fragmentation and daytime sleepiness has not been systematically studied. This study was designed to use correlational techniques evaluating the relation between these variables in patients complaining of EDS, patients complaining of insomnia, and asymptomatic controls. The four groups studied included patients complaining of EDS with sleep apnea (n = 15) or with periodic leg movements (n = 15), patients complaining of insomnia (n = 15), and healthy volunteers with no sleep complaint (n = 10). One night of polysomnography followed by a Multiple Sleep Latency Test was obtained for each subject. Each recording was evaluated using standard criteria and also by a four-level arousal scoring system. Across all subjects, the total number of arousals correlated significantly with sleepiness index (r = 0.48, p less than 0.001). Closer analysis of the data shows that, depending upon the sleep complaint, different types of arousals are predictive of degree of daytime sleepiness. It is concluded that the number and type of nocturnal arousals play an important role in subsequent daytime sleepiness.

Adult↗
PubMed1984

Choosing between predictable shock schedules: Long- versus short-duration signals.

Two experiments assessed the relative aversiveness of different duration preshock signals (5 and 20 seconds) and different duration stimuli identifying shock-free periods. In the first experiment, the responding of 15 of 18 rats was maintained when it produced changes from a predictable-shock condition with a 5-second preshock signal to an identical schedule with a 20-second preshock signal; responding was not maintained when it produced the opposite changes. These results occurred with intershock intervals of both 120 seconds and 240 seconds. The second experiment assessed whether changing to the 20-second schedule was maintained by properties of the preshock signals identifying the shock periods or by properties of the stimuli identifying the shock-free periods. Four subjects were given training with the two signaled schedules in an operant chamber and then later given off-baseline preference tests in a shuttlebox. When given a choice between preshock signals, subjects chose the 5-second signals over the 20-second signals. However, when given a choice between stimuli identifying shock-free periods, subjects chose the stimulus identifying the shorter shock-free periods (i.e., the one previously correlated with the 20-second signals). These findings are discussed within the Rescorla and Wagner model of stimulus compounds and within the context of safety as a contrast phenomenon.

Journal Article↗
PubMed1984

Preference for signaled over unsignaled shock schedules: Ruling out asymmetry and response fixation as factors.

Experiment 1 tested whether a "symmetrical" choice procedure yields results different from those previously reported using the "unidirectional" standard changeover procedure (e.g., Badia & Culbertson, 1972). Subjects could change at any time from unsignaled to signaled shock by pressing a lever and from signaled to unsignaled shock by pressing a second lever. Results were identical to those of the standard procedure and showed that the standard procedure is fully adequate. Experiment 2 tested whether choice of high density signaled shock over low-density unsignaled shock (Badia, Coker, & Harsh, 1973) resulted from initial training with equal-density schedules. Subjects were trained and tested with signaled shock twice as dense as unsignaled shock. Three of four subjects strongly preferred the signaled condition, thus ruling out carry-over and "response fixation" as alternative explanations.

Journal Article↗
PubMed1984

Signal modality and choice between signaled and unsignaled food.

Choice between signaled and unsignaled response-independent food schedules was assessed in three experiments using a commitment procedure. In Experiment 1, subjects tested with a 5-s visual signal consistently changed from the signaled to the unsignaled schedule. Changing from the unsignaled to the signaled schedule was observed only occasionally and only at low levels. The same outcome was observed in Experiment 2 with different types of visual signals and with different stimulus combinations identifying the signal period, the signal-absent period, and the unsignaled schedule. In Experiment 3 the visual signal was replaced with an auditory signal for four of the subjects tested in Experiment 2. The subjects then changed from the unsignaled to the signaled schedule or showed a substantial reduction in choice for the unsignaled schedule. The data were assessed using a conditioned-reinforcement interpretation of choice.

Journal Article↗
PubMed1983

Factors affecting choice of signaled or unsignaled food schedules.

Choice between signaled and unsignaled food schedules was assessed in two experiments using a shuttlebox. Experiment 1 examined preference with both a five-second signal and a thirty-second signal. Subjects preferred the unsignaled side with a five-second signal but preferred the signaled side with a thirty-second signal. Experiment 2 assessed preference using either a commitment procedure (a shuttle response resulted in exposure to the schedule for a fixed time) or a noncommitment procedure (each shuttle response changed the schedule in effect). Subjects preferred the signaled condition with the commitment procedure but the unsignaled condition with the noncommitment procedure. These results indicate that the discrepant findings of earlier studies are due to procedural differences involving signal duration and choice commitment. The data are consistent with a conditioned reinforcement interpretation of choice.

Journal Article↗
PubMed1981

Choosing schedules of signaled appetitive events over schedules of unsignaled ones.

Two experiments were completed allowing albino rats to choose between signaled and unsignaled reward conditions. These experiments examined the effects on preference of (1) response dependent versus response-independent reward and, (2) food pellets versus chocolate milk as the reward. All subjects preferred the signaled condition over the unsignaled condition, whether exposed to response-dependent, or to response-independent delivery of rewards. Preference was controlled most effectively by presenting both the signal itself and the correlated stimulus identifying the signaled condition. The signal presented alone (Extinction 3) controlled preference more effectively than did the stimulus correlated with the signaled condition (Extinction 2). The second experiment showed that the quality of the reinforcer (pellets and chocolate milk) did not affect preference for signaled reward since all subjects preferred the signaled condition at levels comparable to those observed in Experiment 1, with food pellets. These results, along with others, argue against species differences, response-dependency, and reinforcer quality as variables affecting the direction of preference.

Journal Article↗
PubMed1979

Choice for signaled over unsignaled shock as a function of signal length.

Subjects chose between signaled and unsignaled shock conditions while signal length was varied between .5 and 2.0 seconds in steps of .5 seconds in both ascending and descending series. Preference for the signaled condition failed to develop initially for five of six subjects when signals were .5 or 1.0 seconds but became strong for all subjects when signals were 2.0 seconds (ascending series). Preference declined when signals were shortened, but for most subjects this decline was small (descending series). Since discriminable shock-free periods were present in the signaled condition at all signal lengths, these results suggest that safety may not be a sufficient condition for preference to develop for signaled shock.

Acoustic Stimulation↗
PubMed1976

A temporal parameter influencing choice between signalled and unsignalled shock schedules.

The present study investigated whether choice of a signalled variable-time shock schedule over an unsignalled one was influenced by the average intershock interval. Eight rats were given a choice between signalled and unsignalled shock schedules in a series of conditions with average intershock intervals of 510, 270, 150, 90, 60, and 45 sec. Each test condition was preceded by a training-baseline condition, and schedule values were arranged in an ascending (four subjects) or descending (four subjects) order. Choice of the signalled conditions was directly related to the average intershock interval of the variable-time schedule for six of the eight subjects. The per cent of time in the signalled condition was highest when the average intershock interval was 150 sec or longer and lowest when the average intershock interval was 45 sec. The findings were interpreted as being due to changes in the safety features of the signalled schedule, rather than to changes in the average intershock interval per se.

Journal Article↗
PubMed1976

Choice and the dependability of stimuli that predict shock and safety.

This study assessed whether choosing a signalled shock condition over an unsignalled one is controlled by a stimulus that predicts the presence of shock (Experiment I), or by a stimulus that predicts the absence of shock (Experiment II). The dependability of these stimuli as predictors of either the presence or the absence of shock was parametrically varied over a wide range, and subjects (rats) were given an option to change from an unsignalled to a signalled condition. In the first experiment, all shocks were preceded by signals; however, the probability of a signal being followed by shock varied from 1.0 to 0.02. The data obtained indicate that the dependability of the signal as a predictor of shock is unimportant. Rats changed to the signalled condition when the signal was completely dependable (all signals followed by shock) and when the dependability of the signal was systematically degraded. In the second experiment, all signals were followed by shock; however, some shocks were not preceded by a signal. The data show that the dependability of a stimulus predicting the absence of shock is important in that, as dependability decreases, changing to the signalled condition also decreases.

Journal Article↗