An auditory localization model based on high-frequency spectral cues

We present in this paper a connectionist model that extracts interaural intensity differences (IID) from head-related transfer functions (HRTF) in the form of spectral cues to localize broadband high-frequency auditory stimuli, in both azimuth and elevation. A novel discriminative matching measure (DMM) is defined and optimized to characterize matching this IID spectrum. The optimal DMM approach and a novel backpropagation-based fuzzy model of localization are shown to be capable of localizing sources in azimuth, using only spectral IID cues. The fuzzy neural network model is extended to include localization in elevation. The use of training data with additive noise provides robustness to input errors. Outputs are modeled as two-dimensional Gaussians that act as membership functions for the fuzzy sets of sound locations. Error back-propagation is used to train the network to correlate input patterns and the desired output patterns. The fuzzy outputs are used to estimate the location of the source by detecting Gaussians using the max-energy paradigm. The proposed model shows that HRTF-based spectral IID patterns can provide sufficient information for extracting localization cues using a connectionist paradigm. Successful recognition in the presence of additive noise in the inputs indicates that the computational framework of this model is robust to errors made in estimating the IID patterns. The localization errors for such noisy patterns at various elevations and azimuths are compared and found to be within limits of localization blurs observed in humans.     

Self-protective organization in children with conversion and somatoform disorders

Objective

Two centuries of clinical observations have suggested that conversion symptoms are associated with strong emotions or situations that threaten the individual's physical or psychological integrity. This study tested the hypothesis that childhood conversion reactions reflect the motor-sensory components of two distinct emotional responses (one inhibitory, one excitatory) that develop as adaptations to recurring threats within intimate relationships.

Method

Emotional responses to interpersonal threats were assessed in 28 children with conversion disorders using Dynamic-Maturational-Model (DMM) assessments of attachment. Attachment strategies (the inhibitory, Type A; the balanced, Type B; and the excitatory, Type C) provide information about (1) the child's behavioural (motor-sensory) organization in the face of interpersonal threats, and (2) the information processing that underpins this behavioural organization.

Results

Twelve children (43%) used an inhibitory attachment strategy. Twelve (43%) used an excitatory attachment strategy. A smaller group (14%) alternated between inhibitory and excitatory strategies, their conversion symptoms reflecting the latter.

Discussion

These data suggest that conversion reactions are not a single clinical entity and reflect the motor-sensory components of two distinct human emotional responses to threat. This distinction may help to account for the broad range of conversion symptoms seen in clinical practice, both those that involve loss of function and can be explained by a central inhibition hypothesis and those that involve positive symptoms and secondary gain.     

Local intra-articular injection of rapamycin inhibits NLRP3 activity and prevents osteoarthritis in mouse DMM models

Abstract

This study investigated the influence of autophagy on the expression of Collagen type II and light chain 3 (LC-3) in the articular cartilage of osteoarthritis (OA) models. The expression of OA associated biomarkers namely Matrix metalloproteinase (MMP-13), NOD-, LRR- and pyrin domain-containing 3 (NLRP3) induced by destabilizing the medial meniscus operation (DMM) were also investigated. A total of 60 C57BL/6 mice were divided into (1) control; (2) DMM2; (3) DMM8; (4) rapamycin 2?weeks; and (5) rapamycin 8?weeks groups. Saffranin O-Fast green staining, histomorphometry and immunohistochemical methods were used for analysis. In the DMM group, the expression of the OA biomarkers MMP-13, NLRP3 significantly increased, whilst Collagen II and LC-3B levels were significantly lower than other experimental groups. We hypothesized that NLRP3 inhibits autophagy activation and delays disease progression.     

The neurotoxicity of radiosensitizing drugs: a biochemical assessment of desmethylmisonidazole (DMM) in the rat

This study evaluates a major metabolite of misonidazole, desmethylmisonidazole, for its potential to induce peripheral nerve damage using the lysosomal enzyme correlates of neuropathological change, namely beta-glucuronidase and beta-galactosidase. The results showed that desmethylmisonidazole like misonidazole had a similar potential for inducing peripheral nerve damage as measured biochemically, but the dosing regimen had to be maintained for 10 consecutive days as opposed to the 7 days required for misonidazole.