Pre-training to find a hidden platform in the Morris water maze can compensate for a deficit to find a cued platform in a rat model of Parkinson's disease

The bilateral intranigral infusion of 1 micromol 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in adult male Wistar rats caused a specific and partial loss of substantia nigra pars compacta (SNc) dopamine neurons, a partial depletion of striatal dopamine, and a deficit to learn the intra-maze cued version of the Morris water maze. Pre-training the SNc rats in the spatial version of the water maze or simply maintaining the animals on the water maze platform reversed this deficit. This improvement was even observed when the order of the extra-maze cues presented to the rats during pre-training of the spatial version was changed during training of the intra-maze cued version. However, this deficit was not reversed either by maintaining the animals on the platform if the spatial cues were surrounded and covered with a curtain or by swimming sessions in the maze without the escape platform and the curtain. These findings suggest that none of the following elements alone, learned during the spatial task pre-training, could help SNc rats learn the intra-maze cued task: improvement of swimming skills or knowledge of the existence of the escape platform; distance between the platform and the border of the pool; location of a particular extra-maze cue; relations among extra-maze cues. However, the simultaneous presence of the escape platform and extra-maze cues (irrespective of their relational configuration) during the pre-training sessions proved to be necessary for this improving effect to occur.     

Peer-Initiated Motivational Climate and Group Cohesion in Youth Sport

The purpose of the present study was to examine the reciprocal relationship between peer-initiated motivational climate and group cohesion. Measures of peer climate and cohesion were completed across the first half of a competitive season. Controlling for early season perceptions of the dependent variables, hierarchical regression results from 189 participants revealed that early season ego-related climate negatively predicted task cohesion near midseason (p <.01), and task cohesion at early season positively predicted task-related climate at midseason (p <.01). The current study offers preliminary insight into the direction of the relationships between the two constructs in competitive youth sport.     

Going home: the complex effects of reunification on internalizing problems among children in foster care

When children in foster care are reunified with their families of origin they encounter changes that may influence their well-being in both positive and negative ways. We examined the effects of reunification among 218 children in foster care to test an integrative model of the effects of reunification using structural equation modeling. We hypothesized that reunification would exert indirect effects on subsequent child adjustment via changes in adverse life events, perceived social isolation, and mental health service utilization. Results indicated no direct effect of reunification on subsequent internalizing problems, but reunification was related to increased adverse life events that, in turn, were related to elevated symptoms. Second, reunification was negatively associated with mental health service use. Finally, reunification was associated with decreased child perceptions of social isolation. In summary, reunification with biological parents is associated with multiple environmental changes, with most but not all effects indicating negative consequences.     

Horizontal plane head stabilization during locomotor tasks

Frequency characteristics of head stabilization were examined during locomotor tasks in healthy young adults(N = 8) who performed normal walking and 3 walking tasks designed to produce perturbations primarily in the horizontal plane. In the 3 walking tasks, the arms moved in phase with leg movement, with abnormally large amplitude, and at twice the frequency of leg movement. Head-in-space angular velocity was examined at the predominant frequencies of trunk motion. Head movements in space occurred at low frequencies (< 4.0 Hz) in all conditions and at higher frequencies (> 4.0 Hz) when the arms moved at twice the frequency of the legs. Head stabilization strategies were determined from head-on-trunk with respect to trunk frequency profiles derived from angular velocity data. During natural walking at low frequencies (< 3.0 Hz), head-on-trunk movement was less than trunk movement. At frequencies 3.0 Hz or greater, equal and opposite compensatory movement ensured head stability. When arm swing was altered, compensatory movement guaranteed head stability at all frequencies. Head stabilization was successful for frequencies up to 10.0 Hz during locomotor tasks. Maintaining head stability at high frequencies during voluntary tasks suggests that participants used feedforward mechanisms to coordinate head and trunk movements. Maintenance of head stability during dynamic tasks allows optimal conditions for vestibulo-ocular reflex function.     

The Epistemology of the Book of Revelation

Recent developments in Christian philosophy, in particular epistemology, need to be enriched by a study of epistemology in the Bible. This article uncovers the epistemological assumptions of the Book of Revelation (specifically related to spiritual experience, revelation, and eschatological vindication) and points out how they may advance the development of a contemporary Christian epistemology.     

Defining Work Stress in Young People

Stress experienced by young workers can be very different from stress experienced by adults because of differing psychosocial developments. It is important to understand how early workplace experiences shape young workers' subsequent attitudes and behaviors, which may affect their psychological well‐being. This study examined how 18 young workers ages 17–29 perceive work stress. The authors found that young workers view job stress in 3 dimensions: lack of opportunity to learn, poor social interaction, and lack of opportunity to exercise initiative. Young workers also view work demands as challenging tasks and become job crafters to find more satisfaction in routine tasks.     

Evidence for the thalamic targets of the medial hypothalamic defensive system mediating emotional memory to predatory threats

Previous studies from our laboratory have documented that the medial hypothalamic defensive system is critically involved in processing actual and contextual predatory threats, and that the dorsal premammillary nucleus (PMd) represents the hypothalamic site most responsive to predatory threats. Anatomical findings suggest that the PMd is in a position to modulate memory processing through a projecting branch to specific thalamic nuclei, i.e., the nucleus reuniens (RE) and the ventral part of the anteromedial nucleus (AMv). In the present study, we investigated the role of these thalamic targets in both unconditioned (i.e., fear responses to predatory threat) and conditioned (i.e., contextual responses to predator-related cues) defensive behaviors. During cat exposure, all experimental groups exhibited intense defensive responses with the animals spending most of the time in the home cage displaying freezing behavior. However, during exposure to the environment previously associated with a cat, the animals with combined RE + AMv lesions, and to a lesser degree, animals with single AMv unilateral lesions, but not animals with single RE lesions, presented a reduction of contextual conditioned defensive responses. Overall, the present results provide clear evidence suggesting that the PMd’s main thalamic targets (i.e., the nucleus reuniens and the AMv) seem to be critically involved in the emotional memory processing related to predator cues.     

Kant and the transparency of the mind

ABSTRACT

It has become standard to treat Kant’s characterization of pure apperception as involving the claim that questions about what I think are transparent to questions about the world. By contrast, empirical apperception is thought to be non-transparent, since it involves a kind of inner observation of my mental states. I propose a reading that reverses this: pure apperception is non-transparent, because conscious only of itself, whereas empirical apperception is transparent to the world. The reading I offer, unlike the standard one, can accommodate Kant’s claim that the I of pure apperception is the same as the I of empirical apperception.