Adapting to supernormal auditory localization cues. I. Bias and resolution

Head-related transfer functions (HRTFs) were used to create spatialized stimuli for presentation through earphones. Subjects performed forced-choice, identification tests during which allowed response directions were indicated visually. In each experimental session, subjects were first presented with auditory stimuli in which the stimulus HRTFs corresponded to the allowed response directions. The correspondence between the HRTFs used to generate the stimuli and the directions was then changed so that response directions no longer corresponded to the HRTFs in the natural way. Feedback was used to train subjects as to which spatial cues corresponded to which of the allowed responses. Finally, the normal correspondence between direction and HRTFs was reinstated. This basic experimental paradigm was used to explore the effects of the type of feedback provided, the complexity of the stimulated acoustic scene, the number of allowed response positions, and the magnitude of the HRTF transformation subjects had to learn. Data showed that (1) although subjects may not adapt completely to a new relationship between physical stimuli and direction, response bias decreases substantially with training, and (2) the ability to resolve different HRTFs depends both on the stimuli presented and on the state of adaptation of the subject.     

Should large rats be housed in large cages? An empirical issue.

Examined the suggestion of the Canadian Council on Animal Care (CCAC) that large rats should be kept in cages that are 23 cm high rather than 17.5–28 cm high. Eight large rats were each allowed to choose for 24 hrs between a 16.8-cm-high cage and a 23-cm-high cage. Ss failed to exhibit any preference for the higher cage. It is suggested that before the CCAC mandates commitment of substantial resources for a change in the conditions of laboratory animal maintenance, some objective evidence should be provided that the proposed change improves the well-being of animals. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Virtual reality (VR) for psychotherapy: From the physical to the social environment.

Discusses current and future therapeutic applications of virtual reality (VR). To date, treatments incorporating VR have involved the simulation of physical (as opposed to social) aspects of the environment. Researchers have produced simulations of heights, different kinds of spaces, and the experience of flying, with the goal of improving the delivery of exposure and desensitization for the treatment of phobias. Researchers are only beginning to explore simulation of the social environment. When VR gains the ability to simulate human social interaction, it can be used to assist in treating a wider variety of conditions, including social phobia, fear of intimacy, and sexual aversion. More long range goals are the use of VR for the exploration of childhood memories, overcoming maladaptive thinking, empowerment, increasing empathy, expressing emotions, developing and maintaining boundaries, and promoting marital satisfaction and bonding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Postprandial cholesteryl ester transfer and high density lipoprotein composition in normotriglyceridemic non-insulin-dependent diabetic patients

Altered postprandial HDL metabolism is a possible cause of defective reverse cholesterol transport and increased cardiovascular risk in diabetic patients with a normal fasting lipoprotein profile. Ten normolipidemic, normoponderal non-insulin dependent diabetes mellitus (NIDDM) patients and seven controls received a 980 kcal meal containing 78 g lipids with 100 000 IU vitamin A. Chylomicron clearance was not different, but area under the curve (AUC) for retinyl palmitate in chylimicron-free serum (remnant clearance) was greater in patients (P < 0.02). LCAT activity increased postprandially to the same extent in both groups. In control subjects, cholesteryl ester transfer protein (CETP) activity (CETA) also increased by 20% (P < 0.01 at 6 h) in parallel with a 20% decrease in HDL2-CE (r = -0.55, P = 0.009). In NIDDM patients, on the contrary, CETA which was 35% higher in the fasting state (P < 0.005), decreased postprandially yet HDL2-CE remained unchanged. Postprandial HDL3 of controls were enriched with phospholipid (PL) (30.3 +/- 2.6% at 6 h) with respect to fasting (25.6 +/- 2.5%, P < 0.01) and to NIDDM-HDL3 (25.8 +/- 1.7% at 6 h, P < 0.01). These results show that variation in plasma CETA has little impact on HDL2-CE in NIDDH subjects. They support the concept that, in controls, the combined enrichment of HDL3 with PL, increased LCAT and CETA create the conditions for stimulation of cell cholesterol efflux and CE transfer to apo B lipoproteins. In NIDDM, because of the lesser HDL3 enrichment with PL and of the inverse trend of CETA, these conditions fail to occur, depriving the patients of a potentially efficient mechanism of unesterified cholesterol (UC) clearance, despite their strictly normal preprandial profile.     

Speaking clearly for the hard of hearing IV: Further studies of the role of speaking rate

The contribution of reduced speaking rate to the intelligibility of "clear" speech (Picheny, Durlach, & Braida, 1985) was evaluated by adjusting the durations of speech segments (a) via nonuniform signal time-scaling, (b) by deleting and inserting pauses, and (c) by eliciting materials from a professional speaker at a wide range of speaking rates. Key words in clearly spoken nonsense sentences were substantially more intelligible than those spoken conversationally (15 points) when presented in quiet for listeners with sensorineural impairments and when presented in a noise background to listeners with normal hearing. Repeated presentation of conversational materials also improved scores (6 points). However, degradations introduced by segment-by-segment time-scaling rendered this time-scaling technique problematic as a means of converting speaking styles. Scores for key words excised from these materials and presented in isolation generally exhibited the same trends as in sentence contexts. Manipulation of pause structure reduced scores both when additional pauses were introduced into conversational sentences and when pauses were deleted from clear sentences. Key-word scores for materials produced by a professional talker were inversely correlated with speaking rate, but conversational rate scores did not approach those of clear speech for other talkers. In all experiments, listeners with normal hearing exposed to flat-spectrum background noise performed similarly to listeners with hearing loss.     

The effects of static and adaptive performance feedback in game-based training

Training in virtual environments (VEs) has the potential to establish mental models and task mastery while providing a safe environment in which to practice. Performance feedback is known to contribute to this learning; however, the most effective ways to provide feedback in VEs have not been established. The present study examined the effects of differing feedback content, focusing on adaptive feedback. Participants learned search procedures during multiple missions in a VE. A control group received only a performance score after each mission. Two groups additionally received either detailed or general feedback after each mission, while two other groups received feedback that adapted based on their performance (either detailed-to-general, or general-to-detailed). Groups that received detailed feedback from the start of training had faster performance improvement than all other groups; however, all feedback groups showed improved performance and by the fourth mission performed at levels above the control group. Results suggest that detailed feedback early in the training cycle is the most beneficial for the fastest learning of new task skills in VEs.     

Polarized Raman microspectroscopy can reveal structural changes of peritumoral dermis in basal cell carcinoma

Polarized Raman microspectroscopy can provide precious information regarding the orientation and ordering of the molecules in a sample without staining or particular preparation. This technique is used for the first time on a human skin section to probe the molecular modifications of the surrounding dermis in superficial basal cell carcinoma. Spectra using polarized and conventional Raman microspectroscopies were recorded on dermis bordering either the tumor or healthy epidermis. Band areas and spectral decomposition on selected vibrations were computed. Significant differences in dermal collagen vibration bands are detected using both polarized and conventional micro-spectroscopies, but the spectral changes between tumor and healthy tissues are enhanced using polarized Raman microspectroscopy. The analysis of these spectral differences highlights structural modifications of the triple helix of collagen. We see polarized Raman microspectroscopy as a potential tool that could be implemented for clinical analyses to guide clinicians and surgeons in the treatment of aggressive skin cancers. The information obtainable could also help better elucidate the molecular mechanisms induced in basal cell carcinoma development.     

Virtual reality (VR) and psychotherapy: opportunities and challenges

Virtual reality technology is now being used to provide exposure and desensitization for a number of phobic conditions. In this paper, we first review these current applications and discuss the work needed to refine and expand these applications to phobias. We then comment briefly on some preliminary applications of VR technology to mental-health problems outside the domain of phobias. Finally, we consider ways in which VR might be used to further enhance psychotherapy and assist in the treatment of a wide variety of disorders. Various possible interventions are discussed, along with the technological developments needed to make them possible.