The role of interoception in learned visceral control.

Research concerned with the psychology and physiology of interoceptive processes is reviewed with the purpose of evaluating theoretical formulations of learned visceral control. Basic animal research in interoception provides relevant information; however, much research dealing directly with interoception and learned control is inadequate due either to inappropriate measurement of interoceptive ability or to poor experimental design. The two primary theoretical orientations linking interoception and learned visceral control differ according to the role ascribed to external feedback; the first views feedback as an enhancement of interoceptive cues, the second as an enhancement of exteroceptive cues. These theories are discussed with regard to recent investigations of learned visceral control.     

The role of interoception in learned visceral control

Research concerned with the psychology and physiology of interoceptive processes is reviewed with the purpose of evaluating theoretical formulations of learned visceral control. Basic animal research in interoception provides relevant information; however, much research dealing directly with interoception and learned control is inadequate due either to inappropriate measurement of interoceptive ability or to poor experimental design. The two primary theoretical orientations linking interoception and learned visceral control differ according to the role ascribed to external feedback; the first views feedback as an enhancement of interoceptive cues, the second as an enhancement of exteroceptive cues. These theories are discussed with regard to recent investigations of learned visceral control.     

On the social nature of eyes: The effect of social cues in interaction and individual choice tasks

In an experimental setting, we applied a dual strategy to better understand the effect of pictures of eyes on human behavior. First, we investigated whether the effect of eyes was limited to interaction tasks in which the subjects' decisions influenced the outcomes of other subjects. We expanded the range of tasks to include individual choice tasks in which the subjects' decisions only influenced their own outcomes. Second, we investigated whether pictures of eyes were one of many social cues or were unique in their effect. We compared the effect of pictures of eyes with the effect of a different condition in which we presented the subjects with pictures of other students (peers). Our results suggest that the effect of pictures of eyes is limited to interaction tasks and that eyes should be considered distinct from other social cues, such as reminders of peers. While pictures of eyes uniformly enhanced pro-social behavior in interaction tasks, this was not the case for reminders of peers. Furthermore, the reminders of peers led to more rational behavior in individual choice tasks, whereas the effect of pictures of eyes was limited to situations involving interaction. Combined, these findings are in line with the claim that the effect of pictures of eyes on behavior is caused by a social exchange heuristic that works to enhance mutual cooperative behavior.     

Differential shaping of EEG theta rhythms

Heart rate, EEG, frontal EMG, and forearm EMG were recorded in 20 subjects for 3 baseline, 8 feedback, and 2 postbaseline sessions in order to compare two biofeedback methods of teaching subjects to increase theta EEG activity. Subjects were divided into high- and low-EMG groups. Five high-EMG subjects, and 5 low-EMG subjects then received 8 sessions of strictly theta feedback. The remaining 10 subjects, 5 from the high-EMG group, and 5 from the low-EMG group, received a “graduated” training which involved shaping the target response. This procedure consisted of 4 initial sessions of EMG feedback, followed by a second phase consisting of 4 sessions of theta feedback. Results showed a clear relationship between subjects' baseline frontal EMG levels and the effect of the training methods. Although subjects with high-EMG baseline increased their theta output only with the two-phase training, subjects with low-EMG baseline levels performed better when given theta feedback only. This result shows not only that amounts of theta can be reliably increased, but that training techniques should be adapted to the physiological characteristics of the individual—in this case, baseline levels of frontal EMG levels.     

Adaptive on-line classification for EEG-based brain computer interfaces with AAR parameters and band power estimates.

We present the result of on-line feedback Brain Computer Interface experiments using adaptive and non-adaptive feature extraction methods with an on-line adaptive classifier based on Quadratic Discriminant Analysis. Experiments were performed with 12 na?ve subjects, feedback was provided from the first moment and no training sessions were needed. Experiments run in three different days with each subject. Six of them received feedback with Adaptive Autoregressive parameters and the rest with logarithmic Band Power estimates. The study was done using single trial analysis of each of the sessions and the value of the Error Rate and the Mutual Information of the classification were used to discuss the results. Finally, it was shown that even subjects starting with a low performance were able to control the system in a few hours: and contrary to previous results no differences between AAR and BP estimates were found.     

The role of behavioral conditioning in the cardiovascular adjustment to exercise

The purpose of this study was to determine if normal subjects could be trained to attenuate their cardiovascular responses while exercising on a bicycle ergometer. Ten young, untrained subjects exercised on a bicycle ergometer for five sessions. Half of the group was asked to slow their heart rate while exercising with heart rate feedback during exercise. Their average heart rate increase was 20% less than that of the control subjects, who exercised without feedback. The control subjects subsequently also received feedback during exercise and they were able to attenuate their heart rate responses comparably. Systolic blood pressure was not affected by feedback training. Changes in rate-pressure product paralleled changes in heart rate. These data show that autonomically mediated adjustments to exercise can be brought under experimental control through the use of appropriate behavioral techniques.     

Biofeedback training in frontalis muscle relaxation and enhancement of belief in personal control

The hypothesis that biofeedback training in frontalis muscle relaxation increases beliefs in internal (personal) locus of control was tested. Subjects were divided into two groups (internals and externals) based on Mirels' (1970) factor analyzedpersonal control subscale of Rotter's (1966) I-E Scale. Internal and external subjects were assigned randomly to one of three conditions: biofeedback (BF), false feedback (FF), or no feedback (NF). All subjects were measured on frontalis electromyographic (EMG) activity. Training consisted of three sessions spaced 1 week apart. Each session was comprised of a 5-minute baseline (nonfeedback) trial followed by a 20-minute experimental session. After each experimental session, subjects completed a questionnaire which assessed the extent to which they attributed their EMG performance to personal and environmental sources. After three sessions, subjects were posttested on the I-E Scale. Results indicated that subjects receiving BF reduced their EMG activity more than did subjects in either the FF or NF conditions, and this effect was maintained across all three sessions. Subjects who received BF shifted toward internal personal locus of control from pre- to posttesting, whereas no such change was found for either FF or NF subjects. Also, the relationship between BF training and change in personal locus of control was mediated by subjects attributing their EMG reduction more to personal effort than to properties of the task. Results are discussed in terms of the importance of contingent feedback as a determinant of cognitions of control.     

Effects on Automatic Attention Due to Exposure to Pictures of Emotional Faces while Performing Chinese Word Judgment Tasks

Two experiments were conducted to investigate the automatic processing of emotional facial expressions while performing low or high demand cognitive tasks under unattended conditions. In Experiment 1, 35 subjects performed low (judging the structure of Chinese words) and high (judging the tone of Chinese words) cognitive load tasks while exposed to unattended pictures of fearful, neutral, or happy faces. The results revealed that the reaction time was slower and the performance accuracy was higher while performing the low cognitive load task than while performing the high cognitive load task. Exposure to fearful faces resulted in significantly longer reaction times and lower accuracy than exposure to neutral faces on the low cognitive load task. In Experiment 2, 26 subjects performed the same word judgment tasks and their brain event-related potentials (ERPs) were measured for a period of 800 ms after the onset of the task stimulus. The amplitudes of the early component of ERP around 176 ms (P2) elicited by unattended fearful faces over frontal-central-parietal recording sites was significantly larger than those elicited by unattended neutral faces while performing the word structure judgment task. Together, the findings of the two experiments indicated that unattended fearful faces captured significantly more attention resources than unattended neutral faces on a low cognitive load task, but not on a high cognitive load task. It was concluded that fearful faces could automatically capture attention if residues of attention resources were available under the unattended condition.     

Blood glucose discrimination training in insulin-dependent diabetes mellitus (IDDM) patients

Self-management of insulin-dependent diabetes mellitus (IDDM) is dependent on a negative feedback loop of blood glucose (BG) fluctuations, which in turn directs treatment decisions to maintain normal BG. Although this feedback is typically accomplished by self-monitoring of blood glucose (SMBG), SMBG has limitations, and patients often rely on what their BG "feels" like. Two studies were performed to evaluate whether patients could learn to more accurately "feel"/discriminate their BG on the basis of internal cues or internal plus external BG cues. In Study I, BG Awareness Training significantly improved pre- to posttreatment BG estimation accuracy, relative to a control group. Study II replicated BG Awareness Training efficacy in improving BG estimation accuracy. Improvement in estimation accuracy was related only to initial accuracy; those who were initially less accurate improved the most. This improvement was represented in a 31% reduction in dangerous BG estimation errors and a 9% increase in accurate estimates. Resulting estimations were, however, still significantly less accurate than SMBG at the end of training.     

Video Preference Assessment and Behavioral Management of Single-Caged Japanese Macaques (Macaca fuscata) by Movie Presentation

Movie presentation can act as an enrichment technique for nonhuman primates, who also show preferences for certain contents. This study investigated the video preferences and effects of movies on behavioral abnormalities in single-caged Japanese macaques. When movie rewards were provided for subjects' touch responses, the subjects maintained the touch responses during 40 2-hr sessions. Although repeated presentation of 1 stimulus set decreased the subject's touch response, changing the stimulus set led to recovery of this response. The subjects showed clear preferences, consistent across 2 different stimulus sets, for movies showing humans or animation (61.1% of total duration). Subjects consistently played movies both with and without their preferred content. The availability of a variety of contents might be important for attracting subjects' interest. The frequency with which monkeys engaged in abnormal behaviors decreased in the experimental (20.9%) and the postexperimental (25.6%) periods compared with the preexperimental period (33.5%). Movie presentations could keep attracting the interest of single-caged monkeys in their visual environment, ameliorating their behavioral abnormalities for some time. In summary, social experience during infancy might influence Japanese macaques' movie preferences.     

Variations in digital temperature during frontal EMG biofeedback training in normal subjects

During frontal EMG biofeedback training, the relationship between frontal EMG and digital skin temperature was investigated in two experiments, which varied the number of baseline and feedback sessions. The results of Experiment 1 suggested a "general relaxation effect," where digital temperature increased as frontal EMG decreased, especially for subjects with initially low hand temperature. Experiment 2 extended the number of baseline and feedback sessions and qualified the results of Experiment 1. EMG and digital temperature did not simultaneously converge toward general relaxation over the extended baseline or feedback sessions in Experiment 2. Furthermore, when the feedback signal was introduced, digital temperature dropped quickly but recovered to baseline levels within three feedback sessions; this drop in digital temperature was interpreted within the context of attentional demands of the biofeedback task. The results appeared consistent with the view that frontal biofeedback training teaches a discriminative skill of lower frontal EMG, and that this skill does not readily generalize to digital skin temperature.     

Racial Differences in Selection of Ideal Body Size by Adolescent Females

Cultural differences may partially account for the fact that more black women than white women are overweight in the United States. This study measured perceptions of ideal body size among 93 black and 80 white females, 14–17 years old, who were randomly selected from three public high schools in a southeastern state. The subjects' height and weight were measured along with their estimates of their mother's body size, weight control attitudes, and demographic variables . Blacks preferred a significantly larger body sue than whites when asked to select ideal body size (p=0.045). Subjects who estimated their mother's size to be larger, also selected a larger ideal body size (p=.047). Those who perceived themselves as too fat were more likely to skip meals to help control their weight, compared with those who perceived themselves as normal or too thin (p=.003). Approximately 30% of the sample was overweight or obese. There were not significant racial differences in weight or BMI . These results suggest that overweight is more acceptable among black females than among white females and may help explain why more black females are obese .     

Interoceptive "satiety" signals produced by leptin and CCK

The present studies assessed the extent to which the adiposity signal leptin and the brain-gut hormone cholecystokinin (CCK), administered alone or in combination, give rise to interoceptive sensory cues like those that are produced by a low (1h) level of food deprivation. Rats were trained with cues arising from 1 to 24-h food deprivation as discriminative stimuli. For one group, 24-h food deprivation predicted the delivery of sucrose pellets, whereas 1-h food deprivation did not. Another group received the reversed deprivation level-sucrose contingency. After asymptotic performance was achieved, the effects of leptin and CCK on food intake and on discrimination performance were tested under 24-h food deprivation. In Experiment 1a, leptin administered into the third cerebroventricle (i3vt) at 3.5 or 7.0 microg doses had little effect, compared to saline on food intake or discriminative responding. In Experiment 1b, leptin (7.0 microg, i3vt) combined with CCK-8 (2 microg/kg, i.p.) reduced food intake significantly, but the findings indicated that CCK-8 alone produces interoceptive discriminative cues more like those produced by 1- than 24-h food deprivation. Experiment 2a tested rats with i.p. leptin (0.3 and 0.5mg/kg). Although neither dose suppressed intake, the 0.3mg/kg dose produced interoceptive cues like 1-h food deprivation. Experiment 2b tested two doses of CCK-8 (2 and 4 mg/kg, i.p.) and found significant intake suppression and generalization of discrimination with both doses of CCK-8. These findings suggest a role for both leptin and CCK in the production of sensory consequences that correspond to "satiety".     

Eye Exercises Enhance Accuracy and Letter Recognition,but Not Reaction Time,in a Modified Rapid Serial Visual Presentation Task

Eye exercises have been prescribed to resolve a multitude of eye-related problems. However, studies on the efficacy of eye exercises are lacking, mainly due to the absence of simple assessment tools in the clinic. Because similar regions of the brain are responsible for eye movements and visual attention, we used a modified rapid serial visual presentation (RSVP) to assess any measurable effect of short-term eye exercise in improvements within these domains. In the present study, twenty subjects were equally divided into control and experimental groups, each of which performed a pre-training RSVP assessment where target letters, to which subjects were asked to respond to by pressing a spacebar, were serially and rapidly presented. Response time to target letters, accuracy of correctly responding to target letters, and correct identification of target letters in each of 12 sessions was measured. The experimental group then performed active eye exercises, while the control group performed a task that minimized eye movements for 18.5 minutes. A final post-training RSVP assessment was performed by both groups and response time, accuracy, and letter identification were compared between and within subject groups both pre- and post-training. Subjects who performed eye exercises were more accurate in responding to target letters separated by one distractor and in letter identification in the post-training RSVP assessment, while latency of responses were unchanged between and within groups. This suggests that eye exercises may prove useful in enhancing cognitive performance on tasks related to attention and memory over a very brief course of training, and RSVP may be a useful measure of this efficacy. Further research is needed on eye exercises to determine whether they are an effective treatment for patients with cognitive and eye-related disorders.     

Blood glucose discrimination training in patients with type II diabetes

This study was designed to determine whether patients with Type II diabetes could be taught to discriminate blood glucose after experiencing a variety of blood glucose levels and receiving feedback on the accuracy of their estimates. Thirty-six subjects (18 on oral agents and 18 on insulin) were randomly assigned to one of two feedback conditions: (1) current feedback, which received accurate information regarding their blood glucose levels, (2) noncurrent feedback, which received blood glucose levels from the preceding session. Subjects were exposed to a wide range of blood glucose values in six training sessions by ingesting drinks with three different caloric loads. In pre/post comparisons using several indices of accuracy, both groups showed significant improvement in estimating blood glucose levels. However, feedback on current blood glucose levels did not produce greater improvement than noncurrent. Accuracy was unrelated to the degree to which subjects reported associating internal sensations to their estimates. Failure to find differences between the two feedback conditions may have been due to the noncurrent feedback group's receiving fairly accurate information, to the difficulty of the discrimination task, and to the limited number of training trials.     

Does the Integration of Haptic and Visual Cues Reduce the Effect of a Biased Visual Reference Frame on the Subjective Head Orientation?

Background

The selection of appropriate frames of reference (FOR) is a key factor in the elaboration of spatial perception and the production of robust interaction with our environment. The extent to which we perceive the head axis orientation (subjective head orientation, SHO) with both accuracy and precision likely contributes to the efficiency of these spatial interactions. A first goal of this study was to investigate the relative contribution of both the visual and egocentric FOR (centre-of-mass) in the SHO processing. A second goal was to investigate humans'' ability to process SHO in various sensory response modalities (visual, haptic and visuo-haptic), and the way they modify the reliance to either the visual or egocentric FORs. A third goal was to question whether subjects combined visual and haptic cues optimally to increase SHO certainty and to decrease the FORs disruption effect.

Methodology/Principal Findings

Thirteen subjects were asked to indicate their SHO while the visual and/or egocentric FORs were deviated. Four results emerged from our study. First, visual rod settings to SHO were altered by the tilted visual frame but not by the egocentric FOR alteration, whereas no haptic settings alteration was observed whether due to the egocentric FOR alteration or the tilted visual frame. These results are modulated by individual analysis. Second, visual and egocentric FOR dependency appear to be negatively correlated. Third, the response modality enrichment appears to improve SHO. Fourth, several combination rules of the visuo-haptic cues such as the Maximum Likelihood Estimation (MLE), Winner-Take-All (WTA) or Unweighted Mean (UWM) rule seem to account for SHO improvements. However, the UWM rule seems to best account for the improvement of visuo-haptic estimates, especially in situations with high FOR incongruence. Finally, the data also indicated that FOR reliance resulted from the application of UWM rule. This was observed more particularly, in the visual dependent subject. Conclusions: Taken together, these findings emphasize the importance of identifying individual spatial FOR preferences to assess the efficiency of our interaction with the environment whilst performing spatial tasks.     

Blood glucose discrimination training in patients with Type II diabetes

This study was designed to determine whether patients with Type II diabetes could be taught to discriminate blood glucose after experiencing a variety of blood glucose levels and receiving feedback on the accuracy of their estimates. Thirty-six subjects (18 on oral agents and 18 on insulin) were randomly assigned to one of two feedback conditions: (1) current feedback, which received accurate information regarding their blood glucose levels, (2) noncurrent feedback, which received blood glucose levels from the preceding session. Subjects were exposed to a wide range of blood glucose values in six training sessions by ingesting drinks with three different caloric loads. In pre/post comparisons using several indices of accuracy, both groups showed significant improvement in estimating blood glucose levels. However, feedback on current blood glucose levels did not produce greater improvement than noncurrent. Accuracy was unrelated to the degree to which subjects reported associating internal sensations to their estimates. Failure to find differences between the two feedback conditions may have been due to the noncurrent feedback group's receiving fairly accurate information, to the difficulty of the discrimination task, and to the limited number of training trials.The authors thank Marsha D. Marcus, Ph.D., for her contributions to this study.     

Internal and External Cues of Meal Cessation: The French Paradox Redux?

Objective: Our objective was to investigate whether people who use internal cues of satiation when eating a meal are likely to weigh less than people who instead rely on external cues. In addition to exploring the role that internal and external cues play in meal cessation, this study raises an overlooked explanation of the French paradox. Research Methods and Procedures: A demographically‐matched student sample of 133 Parisians and 145 Chicagoans completed a brief survey on meal cessation that asked the extent to which they agreed with statements associated with internal cessation cues and statements with external cessation cues. Their answers to these were compared across BMI levels and across countries. Results: Normal‐weight people indicated that they were more likely to be influenced by internal cues of meal cessation (p = 0.043), while overweight people indicated that they were more influenced by external cues (p = 0.005). Similarly, while the French were influenced by internal cues of meal cessation (p < 0.001), Americans were more influenced by external cues (p < 0.001). Discussion: This research revisits Schachter's externality hypothesis and suggests that one's over‐reliance on external cues may prove useful in offering a partial explanation of why BMI might vary across people and potentially across cultures. Relying on internal cues for meal cessation, rather than on external cues, may improve eating patterns over the long term.     

Variations in digital temperature during frontal EMG biofeedback training in normal subjects

During frontal EMG biofeedback training, the relationship between frontal EMG and digital skin temperature was investigated in two experiments, which varied the number of baseline and feedback sessions. The results of Experiment 1 suggested a general relaxation effect, where digital temperature increased as frontal EMG decreased, especially for subjects with initially low hand temperature. Experiment 2 extended the number of baseline and feedback sessions and qualified the results of Experiment 1. EMG and digital temperature did not simultaneously converge toward general relaxation over the extended baseline or feedback sessions in Experiment 2. Furthermore, when the feedback signal was introduced, digital temperature dropped quickly but recovered to baseline levels within three feedback sessions; this drop in digital temperature was interpreted within the context of attentional demands of the biofeedback task. The results appeared consistent with the view that frontal biofeedback training teaches a discriminative skill of lower frontal EMG, and that this skill does not readily generalize to digital skin temperature.This research was supported by Grant 2 S06RR08038-17 funded by the National Institutes of Mental Health.     

Illusionary pattern detection in habitual gamblers

Does problem gambling arise from an illusion that patterns exist where there are none? Our prior research suggested that “hot hand,” a tendency to perceive illusory streaks in sequences, may be a human universal, tied to an evolutionary history of foraging for clumpy resources. Like other evolved propensities, this tendency might be expressed more stongly in some people than others, leading them to see luck where others see only chance. If the desire to gamble is enhanced by illusory pattern detection, such individual differences could be predictive of gambling risk. While previous research has suggested a potential link between cognitive strategies and propensity to gamble, no prior study has directly measured gamblers' cognitive strategies using behavioral choice tasks, and linked them to risk taking or gambling propensities. Using a computerized sequential decision-making paradigm that directly measured subjects' predictions of sequences, we found evidence that subjects who have a greater tendency to gamble also have a higher tendency to perceive illusionary patterns, as measured by their preferences for a random slot machine over a negatively autocorrelated one. Casino gamblers played the random slot machine significantly more often even though a training phase and a history of outcomes were provided. Additionally, we found a marginally significant group difference between gamblers and matched community members in their slot-machine choice proportions. Performance on our behavioral choice task correlated with subjects' risk attitudes toward gambling and their frequency of play, as well as the selection of choice strategies in gambling activities.