Reduced right hemisphere activation in severely abused violent offenders during a working memory task: An fMRI study

This study uses functional magnetic resonance imaging (fMRI) to address two important gaps in our knowledge of brain functioning and violence: (1) What are the brain correlates of adults in the community who have suffered severe physical abuse early in life and who go on to perpetrate serious violence in adulthood? (2) What characterizes those who experience severe physical abuse but who refrain from serious violence? Four groups of participants recruited from the community (controls, severe physical child abuse only, serious violence only, and severely abused, seriously violent offenders) underwent fMRI while performing a visual/verbal working memory task. Violent offenders who had suffered severe child abuse show reduced right hemisphere functioning, particularly in the right temporal cortex. Abused individuals who refrain from serious violence showed relatively lower left, but higher right, activation of the superior temporal gyrus. Abused individuals, irrespective of violence status, showed reduced cortical activation during the working memory task, especially in the left hemisphere. Brain deficits were independent of IQ, history of head injury, task performance, cognitive strategy, and mental activity during the control task. Findings constitute the first fMRI study of brain dysfunction in violent offenders, and indicate that initial right hemisphere dysfunction, when combined with the effects of severe early physical abuse, predisposes to serious violence but that relatively good right hemisphere functioning protects against violence in physically abused children. Aggr. Behav. 27:111–129, 2001. © 2001 Wiley‐Liss, Inc.     

发展性阅读障碍视听时间整合缺陷可能的机制：视听时间再校准能力受损

发展性阅读障碍的本质一直是研究者争论的焦点。大量研究发现,阅读障碍者具有视听时间整合缺陷。然而,这些研究仅考察了阅读障碍者视听时间整合加工的整体表现,也就是平均水平的表现,却对整合加工的变化过程缺乏探讨。视听时间再校准反映了视听时间整合的动态加工过程,对内部时间表征与感觉输入之间差异的再校准困难则会导致多感觉整合受损,而阅读障碍者的再校准相关能力存在缺陷。因此,视听时间再校准能力受损可能是发展性阅读障碍视听时间整合缺陷的根本原因。未来的研究需要进一步考察发展性阅读障碍者视听时间再校准能力的具体表现,以及这些表现背后的认知神经机制。     

Sequential effects of interval duration on fixed-interval performance

The bar pressing of rats was reinforced on a multiple fixed-interval schedule. The schedule intervals were 1 and 5 min long, and the sequence was such that intervals of either duration were equally likely to be followed by intervals of the same or of the other duration. Rates were higher during 1-min and after 5-min intervals. Best fit equations for cumulative responses during the 5-min intervals produced very similar exponents regardless of preceding duration. It was concluded that preceding duration may have affected the subjects' performances through direct effects on temporal discrimination.     

Optimal temporal differentiation

In order to illuminate a light signaling a correct response, adult humans had to space their button presses according to a range of time requirements. In some conditions, the spacing needed only to exceed a minimum duration; in others, it had to fall between lower and upper bounds. Mean interresponse times always exceeded the lower limit, and decreased the more stringent were the upper bounds. Variability of interresponse times increased with larger lower bounds, but was unaffected by the size of the upper bound. Feedback about the direction of errors in conditions involving both upper and lower bounds did not affect the means, but it did reduce variability. Predictions were derived from optimality theory, based on the assumption that the critical factor was minimization of the time between correct responses. Without upper bounds, the theory overestimated the mean interresponse times by about 10%; with upper bounds, the theoretical predictions corresponded closely to the actual data. The results did not appear to reflect a scalar timing process. Optimality theory, in contrast to Weber's law, correctly predicted the variety of curves relating sensitivity to duration requirements.     

Temporal discrimination and a free-operant psychophysical procedure.

Pigeons were presented a series of keylight time periods (separated by blackouts) during which two response keys were lit, one by blue light and the other either by orange or green. Blue-key responses changed the color on the other key. Orange-key responses sometimes produced food during the first half of a time period; green-key responses sometimes produced food during the second half. In three experiments, the probability of a green-key response increased as a function of elapsed time. Experiment 1 compared performance when the duration of the keylight periods was varied across a wide range. Discrimination of performance was similar across the range of durations. Experiment 2 varied both relative reinforcement rate and the local reinforcement rate for orange-key and green-key responses. These manipulations produced changes in response bias but not discrimination sensitivity. Experiment 3 varied the local temporal placement of reinforcers within time periods and demonstrated that choice behavior was affected by differential reinforcement at different points during the time periods. The results were consistent with previous research on duration discrimination that used psychophysical trials procedures.     

Pure timing in temporal differentiation

Temporal control appears to depend on whether the critical durations are those of stimuli or those of responses. Stimulus timing (temporal discrimination) supports Weber's law, whereas response timing (temporal differentiation) indicates decreasing relative sensitivity with longer time intervals. The two types of procedure also yield different conclusions in scaling experiments designed to study the functional midpoint of two or more durations (temporal bisection procedures). In addition, the fractional-exponent power relation between emitted and required duration usually found with animals in differentiation experiments conflicts with deductions from formal analyses. The experiment reported here derived from considering differentiation arrangements as schedules of reinforcement. When analyzed from this perspective, the procedures are tandem schedules involving a required pause followed by a response, and it is the pause alone that involves temporal control. A choice procedure separated timing from responding, and enabled observations of pause timing in isolation. Pure temporal control in differentiation consisted of linear overestimation of the standard duration, and Weber's law described sensitivity. These results indicate that the two problems, the fractional-exponent power relations and the apparently different nature of sensitivity in differentiation and discrimination, disappear when temporal control is observed alone in differentiation.     

The hope of the future: The experience of pregnancy influences women’s implicit space–time mappings

It has long been observed that speakers employ spatial concepts “front” and “back” to talk about temporal concepts “past” and “future.” However, the direction of space-time mappings varies across cultures. According to Temporal Focus Hypothesis (TFH), people’s implicit associations between space and time are conditioned by their temporal focus. Here we tested whether pregnancy can affect Chinese women’s temporal focus and thereby influence their space-time mappings. One of the most striking characteristics of pregnant women noted by previous research is their future-oriented thought. Based on this, we predicted that pregnant women should be more future-focused. Consistent with this prediction, the results demonstrated that pregnant women tended to be more future-focused than non-pregnant women and demonstrated a greater tendency to conceptualize the future as in front of them, supporting the TFH. The current research offers a new perspective that culture-external factors such as pregnancy can also influence people’s spatialization of time.     

Understanding supplement use: an application of temporal self-regulation theory

Vitamin and mineral supplement use is increasing worldwide. As evidence of the effects of these practices are equivocal at best, it is important to determine why individuals engage in vitamin and mineral supplement use through the application of a theoretical framework. The aim of this study was to employ temporal self-regulation theory (TST) to establish the determinants of supplement use. A cross-sectional design was used with a sample of 121 individuals who consume vitamins or minerals as dietary supplements. Hierarchical regression analyses were conducted to determine the influence of intention, habit, self-control, and the interaction between intention and habit and self-control on the frequency of supplement use. The model accounted for a significant proportion of variance in behaviour (R² = .44) with intention and habit significantly related to supplement use. Self-control moderated the relationship between intention and behaviour indicating that intention was not related to behaviour when self-control was low. The TST model offers a satisfactory account of supplement use and provides avenues for interventions aimed at increasing safe and beneficial supplement use and decreasing potentially harmful supplement use.