Short and long-term motor skill learning in an accelerated rotarod training paradigm

Rodent models of motor skill learning include skilled forelimb reaching and acrobatic locomotor paradigms. This study characterizes motor skill learning in the accelerated rotarod task. Thirty Long-Evans rats (300-400 g) were trained on an accelerated rotarod (1cm/s(2)) over eight consecutive sessions (=days, 20 trials each). Improvement in rotarod velocities mastered before falling off the rod was observed within and between sessions (plateau after five sessions). Intrasession improvement was incompletely retained at the beginning of the next day's session. Over several training sessions, intrasession improvement diminished, suggesting a ceiling effect. After 1 week of pause, the rotarod skill was retained. Locomotor exercise in a running wheel for 30 min before the first rotarod session did not affect intrasession improvement. Running-wheel exposure for 6 days did not diminish the rate of rotarod skill learning (steepness of the learning curve) but improved overall performance (upward shift of curve). Video analysis of gait on the rotarod showed that rats developed a motor strategy by modifying their gait patterns during training. The data demonstrate that rotarod improvement is not the result of enhanced general locomotor ability or fitness, which are trained in the running wheel, but requires a change in the motor strategy to master the task. Accelerated rotarod training can be regarded a valid paradigm for motor skill learning over short (intrasession, minutes) and long time frames (intersession, days).     

Developmental changes in facial expressions of emotions in the strange situation during the second year of life

Infants' expressions of discrete emotions were coded during the more stressful episodes (4 through 8) of the Strange Situation at 13 and 18 months. The data showed a significant decrease in full-face expressions (more complex configurations of movements) and a significant increase in component expressions (simpler and more constrained patterns of movements). The authors interpreted this trend as a developmental change toward more regulated and less intense emotions. Consistent with this view, the aggregate index of infants' full-face negative emotion expressions, interpreted as reflecting relatively unregulated intense emotions, correlated significantly with maternal ratings of difficult temperament. The authors discuss alternative interpretations of the findings in terms of changes in reactivity/arousability and the emerging capacity for self-regulation.     

Influence of neighborhood size and exposure duration on visual-word recognition: evidence with the yes/no and the go/no-go lexical decision tasks

We present two experiments in which we measured lexical decision latencies and errors to words with few or many orthographic neighbors (ie., Coltheart's N). The main goal of the study was to examine whether or not the neighborhood size effect in a lexical decision task could be affected by the exposure duration of the stimulus item (unlimited vs. limited time exposure, 150 msec plus a backward mask) and the type of decision involved in the task (yes/no vs. go/no-go lexical decision tasks). In the yes/no task, the results showed a facilitative neighborhood size effect for low frequency that did not interact with exposure duration (Experiment 1). In contrast, in the go/no-go task (in this task, participants are instructed to respond as quickly as they can when a word is presented and not to respond if a nonword is presented), the neighborhood size effect for low-frequency words (and for nonwords) was greater under limited viewing time (Experiment 2). In addition, the word frequency effect was greater in the go/no-go task than in the yes/no task, replicating Hino and Lupker (1998, 2000). The results were interpreted in terms of the interaction of decision and lexical factors in visual-word recognition.     

Lesion of the ventral periaqueductal gray reduces conditioned fear but does not change freezing induced by stimulation of the dorsal periaqueductal gray

Previously-reported evidence showed that freezing to a context previously associated with footshock is impaired by lesion of the ventral periaqueductal gray (vPAG). It has also been shown that stepwise increase in the intensity of the electrical stimulation of the dorsal periaqueductal gray (dPAG) produces alertness, then freezing, and finally escape. These aversive responses are mimicked by microinjections of GABA receptor antagonists, such as bicuculline, or blockers of the glutamic acid decarboxylase (GAD), such as semicarbazide, into the dPAG. In this work, we examined whether the expression of these defensive responses could be the result of activation of ventral portion of the periaqueductal gray. Sham- or vPAG electrolytic–lesioned rats were implanted with an electrode in the dPAG for the determination of the thresholds of freezing and escape responses. The vPAG electrolytic lesions were behaviorally verified through a context-conditioned fear paradigm. Results indicated that lesion of the vPAG disrupted conditioned freezing response to contextual cues associated with footshocks but did not change the dPAG electrical stimulation for freezing and escape responses. In a second experiment, lesion of the vPAG also did not change the amount of freezing and escape behavior produced by microinjections of semicarbazide into the dPAG. These findings indicate that freezing and escape defensive responses induced by dPAG stimulation do not depend on the integrity of the vPAG. A discussion on different neural circuitries that might underlie different inhibitory and active defensive behavioral patterns that animals display during threatening situations is presented.     

Children as carers: the impact of parental illness and disability on children's caring roles

The nature and extent of young caring in the UK continue to be a feature of a growing number of research programmes motivated by a children and carers' rights philosophy. However, the context in which young caring occurs as a result of parental ill-health or disability can only be fully understood by examining the findings and implications of medical research into parental impairment, and the social movements that have served to re-define the concept of 'disability' in society. This paper examines the arguments put forward by medical researchers, by those proposing a social model of disability and by those who have specifically investigated the conditions and experiences of young carers. It argues that children's caring roles within families where there is parental illness or disability need to be understood not only as a reflection of the nature of the medical condition itself, but as a consequence of complex family, social and economic processes. A 'whole family' approach is proposed, where the needs of children and parents are respected and responded to.     

Neurocognitive Performance in Alcoholics: Is Polysubstance Abuse Important?

The neurocognitive effects of alcohol have been frequently examined. Studies reveal a wide array of cognitive deficits. Attempts to develop a parsimonious model for these effects have been difficult because of the intra- and intersubject variability. Complicating the development of a model of cognitive deficits in substance abusers is the common practice of polysubstance abuse. The use of theoretical models that focus on the underlying cognitive processes offers flexibility while maintaining sufficient theoretical precision. This article briefly reviews the literature on neurocognitive changes associated with substance abuse as well as the various theoretical models that have been studied. It also provides an overview of recovery of function. Its primary objective is to evaluate cognitive function among alcoholic subtypes, defined by patterns of other drug use. This analysis suggests there are significant differences in neurocognitive function among these subtypes.     

Drop the Small Talk When Establishing Baseline Behaviour in Interviews

The present experiment investigated the behavioural patterns of interviewees when comparing their baseline behaviour, prior to the interview, with their behaviour during the investigative interview. Similar to what has been advised in the police literature, the truthful baseline behaviour was established prior to the interview through non‐threatening questions. The investigative part of the interview then followed in which the interviewee was aware that they would be assessed on whether they were lying. During the investigative part, interviewees either discussed the job that they had (truth tellers, n = 128) or pretended to have (liars, n = 115). Findings revealed that both liars and truth tellers' behavioural patterns differed between the baseline behaviour and the investigative part of the interview. The findings suggest small talk should not be used as a baseline comparison with the investigative part of the interview when determining if the interviewee is being deceitful. An alternative way of using a baseline lie detection method, the comparable truth method, is discussed. Copyright © 2014 John Wiley & Sons, Ltd.