Dissociation between extension of the sensitive period for avian vocal learning and dendritic spine loss in the song nucleus lMAN

Several instances of early learning coincide with significant rearrangements of neural connections in regions contributing to these behaviors. In fact developmentally restricted learning may be constrained temporally by the opportunity for experience to selectively maintain appropriate synapses amidst the elimination of exuberant connections. Consistent with this notion, during the normal sensitive period for vocal learning in zebra finches (Taenopygia guttata), there is a decline in the density of dendritic spines within a region essential for song development, the lateral magnocellular nucleus of the anterior nidopallium (lMAN). Moreover, in birds isolated from conspecific song shortly after hatching, both the closure of the sensitive period for vocal learning and the pruning of spines from lMAN neurons is delayed. Here, we employed a more subtle form of deprivation to delay the close of the sensitive period for song learning, and found that late song learning occurred without obvious alterations in the pruning of dendritic spines on lMAN neurons. At posthatch day (PHD) 65 (beyond the end of the normal sensitive period for song memorization in zebra finches), birds isolated from song beginning on PHD30 did not differ from normally reared birds in measures of dendritic spine density on Golgi-Cox stained lMAN neurons. Moreover, tutor exposure from PHD65 to 90 did not increase spine elimination in these isolates (who memorized new song material) relative to controls (who did not). Thus, we conclude that the extent of normally occurring lMAN spine loss is not sufficient to account for the timing of the sensitive period for zebra finch song learning.     

View dependence in scene recognition after active learning

Human spatial encoding of three-dimensional navigable space was studied, using a virtual environment simulation. This allowed subjects to become familiar with a realistic scene by making simulated rotational and translational movements during training. Subsequent tests determined whether subjects could generalize their recognition ability by identifying novel-perspective views and topographic floor plans of the scene. Results from picture recognition tests showed that familiar direction views were most easily recognized, although significant generalization to novel views was observed. Topographic floor plans were also easily identified. In further experiments, novel-view performance diminished when active training was replaced by passive viewing of static images of the scene. However, the ability to make self-initiated movements, as opposed to watching dynamic movie sequences, had no effect on performance. These results suggest that representation of navigable space is view dependent and highlight the importance of spatial-temporal continuity during learning.     

Comparing view sensitivity in shape discrimination with shape sensitivity in view discrimination

In three picture-picture matching experiments, the effects of a view change on our ability to detect a shape change (Experiments 1 and 2) were contrasted with the effects of a shape change on our ability to detect a view change (Experiment 3). In each experiment, both view changes and shape changes influenced performance. However, shape changes had more influence than did view changes in the shape change detection task Conversely, view changes were more influential when the task was to detect view changes. Thus, the participants could often discriminate between the effects of shape changes and the effects of view changes. The disruptive effect of task-irrelevant changes (view changes in the first two experiments; shape changes in the final experiment) does not support Stankiewicz's (2002) claim that information about viewpoint and about shape can be estimated independently by human observers. However, the greater effect of variation in the task-relevant than in the task-irrelevant dimension indicates that the observers were moderately successful at disregarding irrelevant changes.     

Die Therapeutenrotation

For seven years, the so-called “rotation of therapists”, has been a central part of OLITA, the outpatient longterm intensive therapy for alcoholics. Thus far, the participation of several equally responsible therapists in the treatment of a patient has rarely been seen as a defined therapeutic approach. The present work discusses whether the “rotation of therapists” has any essential influence on the success of OLITA. It considers both, potential advantages and disadvantages for patients and therapists and tries to identify conditions under which this approach appears to promote therapeutic interactions. Following an overview of the present knowledge regarding the therapeutic interaction in addiction therapy, a method is described which may be seen as the precedent of the “rotation of therapists”, the multiple psychotherapy. Finally, the practical procedure in OLITA is outlined as well as its theoretical background. New areas of application for the “rotation of therapists” are discussed.     

Virtual reality for the psychophysiological assessment of phobic fear: responses during virtual tunnel driving

An overall assessment of phobic fear requires not only a verbal self-report of fear but also an assessment of behavioral and physiological responses. Virtual reality can be used to simulate realistic (phobic) situations and therefore should be useful for inducing emotions in a controlled, standardized way. Verbal and physiological fear reactions were examined in 15 highly tunnel-fearful and 15 matched control participants in 3 virtual driving scenarios: an open environment, a partially open tunnel (gallery), and a closed tunnel. Highly tunnel-fearful participants were characterized by elevated fear responses specifically during tunnel drives as reflected in verbal fear ratings, heart rate reactions, and startle responses. Heart rate and fear ratings differentiated highly tunnel-fearful from control participants with an accuracy of 88% and 93%, respectively. Results indicate that virtual environments are valuable tools for the assessment of fear reactions and should be used in future experimental research.