Sleep deprivation impairs object recognition in mice

Many studies in animals and humans suggest that sleep facilitates learning, memory consolidation, and retrieval. Moreover, sleep deprivation (SD) incurred after learning, impaired memory in humans, mice, rats, and hamsters. We investigated the importance of sleep and its timing in an object recognition task in OF1 mice subjected to 6h SD either immediately after the acquisition phase (0-6 SD) or 6h later (7-12 SD), and in corresponding undisturbed controls. Motor activity was continuously recorded with infrared sensors. All groups explored two familiar, previously encountered objects to a similar extent, both at the end of the acquisition phase and 24h later during the test phase, indicating intact familiarity detection. During the test phase 0-6 SD mice failed to discriminate between the single novel and the two familiar objects. In contrast, the 7-12 SD group and the two control groups explored the novel object significantly longer than the two familiar objects. Plasma corticosterone levels determined after SD did not differ from time-matched undisturbed controls, but were significantly below the level measured after learning alone. ACTH did not differ between the groups. Therefore, it is unlikely that stress contributed to the memory impairment. We conclude that the loss of sleep and the activities the mice engaged in during the SD, impaired recognition memory retrieval, when they occurred immediately after acquisition. The delayed SD enabled memory consolidation during the 6h when the mice were allowed to sleep, and had no detrimental effect on memory. Neither SD schedule impaired object familiarity processing, suggesting that only specific cognitive abilities were sensitive to the intervention. Sleep may either actively promote memory formation, or alternatively, sleep may provide optimal conditions of non-interference for consolidation.     

Reinforcement value and substitutability of sucrose and wheel running: implications for activity anorexia

Choice between sucrose and wheel-running reinforcement was assessed in two experiments. In the first experiment, ten male Wistar rats were exposed to concurrent VI 30 s VI 30 s schedules of wheel-running and sucrose reinforcement. Sucrose concentration varied across concentrations of 2.5, 7.5, and 12.5%. As concentration increased, more behavior was allocated to sucrose and more reinforcements were obtained from that alternative. Allocation of behavior to wheel running decreased, but obtained wheel-running reinforcement did not change. Overall, the results suggested that food-deprived rats were sensitive to qualitative changes in food supply (sucrose concentration) while continuing to defend a level of physical activity (wheel running). In the second study, 15 female Long Evans rats were exposed to concurrent variable ratio schedules of sucrose and wheel-running, wheel-running and wheel-running, and sucrose and sucrose reinforcement. For each pair of reinforcers, substitutability was assessed by the effect of income-compensated price changes on consumption of the two reinforcers. Results showed that, as expected, sucrose substituted for sucrose and wheel running substituted for wheel running. Wheel running, however, did not substitute for sucrose; but sucrose partially substituted for wheel running. We address the implications of the interrelationships of sucrose and wheel running for an understanding of activity anorexia.     

The Social Ecological Model and Physical Activity in African American Women

Little is known about the social and contextual correlates (e.g., social norms, environment, social networks, and organizational support) influencing the adoption and maintenance of regular physical activity among minority and underserved populations. The purpose of this review was to apply the social ecological model to better understand physical activity among African American women. A review of the literature pertaining to correlates of physical activity among African American women was conducted and applied to a social ecological perspective. Understanding and addressing social and contextual correlates of physical activity behavior among African American women are necessary to establish comprehensive programs, particularly within community settings. The social ecological model provides a strong theoretical basis to guide physical activity intervention in this population.     

Psychophysiology of prospective memory

Prospective memory involves the self-initiated retrieval of an intention upon an appropriate retrieval cue. Cue identification can be considered as an orienting reaction and may thus trigger a psychophysiological response. Here we present two experiments in which skin conductance responses (SCRs) elicited by prospective memory cues were compared to SCRs elicited by aversive stimuli to test whether a single prospective memory cue triggers a similar SCR as an aversive stimulus. In Experiment 2 we also assessed whether cue specificity had a differential influence on prospective memory performance and on SCRs. We found that detecting a single prospective memory cue is as likely to elicit a SCR as an aversive stimulus. Missed prospective memory cues also elicited SCRs. On a behavioural level, specific intentions led to better prospective memory performance. However, on a psychophysiological level specificity had no influence. More generally, the results indicate reliable SCRs for prospective memory cues and point to psychophysiological measures as valuable approach, which offers a new way to study one-off prospective memory tasks. Moreover, the findings are consistent with a theory that posits multiple prospective memory retrieval stages.     

Experiences of activity and causality in schizophrenia: When predictive deficits lead to a retrospective over-binding

In this paper I discuss an intriguing and relatively little studied symptomatic expression of schizophrenia known as experiences of activity in which patients form the delusion that they can control some external events by the sole means of their mind. I argue that experiences of activity result from patients being prone to aberrantly infer causal relations between unrelated events in a retrospective way owing to widespread predictive deficits. Moreover, I suggest that such deficits may, in addition, lead to an aberrant intentional binding effect i.e., the subjective compression of the temporal interval between an intentional action and its external effects (Haggard et al., 2002a, Haggard et al., 2002b). In particular, it might be that patient’s thoughts are bound to the external events they aimed to control producing, arguably, a temporal contiguity between these two components. Such temporal contiguity would reinforce or sustain the (causal) feeling that the patient mind is directly causally efficient.     

How Does Religion Promote Forgiveness? Linking Beliefs,Orientations, and Practices

Scholars have long observed that religion and forgiveness are generally positively linked, but it is unclear why this is the case. This article proposes and tests potential mechanisms by which religion promotes forgiveness. Using data from the 1998 General Social Survey, I find that holding a collaborative orientation toward God, subscribing to a pervasive role of religion, and believing God forgives are primary factors promoting one's propensity to forgive both oneself and others. These factors have varying influence on interpersonal forgiveness compared to self‐forgiveness and further illuminate the differences between the two processes. My findings demonstrate the importance of analyzing a person's religious beliefs and orientations directly, in addition to examining other dimensions of religion, such as affiliation, frequency of religious activity, and official religious teachings.     

Analysis of the Vocal Profiles of Male Seduction: From Exhibition to Self-Disclosure

The authors analyzed the suprasegmental (temporary) vocal profiles of 19 young men (not married) during their seductive interaction with 19 young women (not married) whom they had not known previously. The aim of the research was to verify the specificity, the sequential temporal stream, and the efficacy of the acoustical features of the seducer's voice during seductive interaction. In an ecological laboratory situation, the male participants were asked to meet their female partners. Participant-by-participant analysis showed that the male seductive voice is characterized by strong variations during the course of the seductive sequence. At the beginning of the sequence it had a higher pitch and an elevated intensity, as well as a faster rate of articulation than it did during normal speech (the exhibition voice). In the following phases it became gradually lower, weaker, and warmer (the self-disclosure voice). The modulation and variability of the vocal profiles during the seductive interaction were significantly stressed in the 9 successful seducers (those who succeeded in arranging a subsequent meeting with the partner), compared with the 10 unsuccessful seducers. The results have been interpreted as an ability to perform an effective local management of seductive communication.