A neuro-cognitive visual system for object recognition based on testing of interactive attentional top-down hypotheses

We propose an extension of a systemic model for object recognition formulated by Rybak et al (1998 Vision Research 38 2387-2400) which is based on the functional organisation of the visual systems in primate brains. In contrast to the learning and recognition scheme of Rybak et al we do not assume a behavioural paradigm, i.e. a visuomotor programmed scanpath that determines the sequence of foveation on the different parts of the object. As in the basis architecture of Rybak et al, the system modules are separated into 'what'-like subsystems corresponding to the ventral occipito-inferotemporal visual path and 'where'-like complexes analogous to the dorsal occipito-parietal visual path. The 'what' system analyses local features in the actual foveation as in Rybak et al. But, in our case, the 'where' memory, instead of programming a behavioural scanpath, scores the spatial relationship between successive fixation and the spatial relationship between the associated main edges. The recognition is based on the identification of parts and their spatial relationship. This gives the learning and recognition mechanisms more flexibility in the sense that, for recognising an object, several different fixation sequences may be accepted.     

The SCL-90-R as a screening instrument for severe personality disturbance among outpatients with mood and anxiety disorders

Our objective was to examine whether the SCL-90-R, a widely used self-report measure of distress and psychopathology, could screen for personality disorders in general and for severe personality disturbance (SPD) in particular, at the time when patients seek treatment for a state (mood or anxiety) disorder. The SCL-90-R was administered to 112 consecutive outpatients with various mood and anxiety disorders. The personality severity index (PSI) score, defined as the mean value of the scores on the SCL-90-R subscales of interpersonal sensitivity, hostility, and paranoid ideation, was compared with the current symptom index (CSI) score, defined as the mean value of the scores on the remaining six SCL-90-R subscales. A positive screen was considered if PSI > CSI. SPD was defined as the presence of any DSM-III-R Cluster A and/or Cluster B personality disorder. The accuracy of the screen was verified by means of the Structured Clinical Interview for DSM-III-R Personality Disorders. The sensitivity of the PSI > CSI criterion to screen for SPD was 89.4%, while its sensitivity to screen for any DSM-III-R personality disorder was 72.9%. The SCL-90-R subscales that contributed the most to the screening discriminability of this SCL-90-R-derived screening measure were hostility, paranoid ideation, somatization, and obsessive-compulsive behavior. The SCL-90-R may be used to screen for SPD in routine work with outpatients with mood and anxiety disorders, but the results of the screening need to be verified because of the possibility of false negatives and false positives, although that possibility is apparently low. These findings may have important prognostic and treatment implications.     

Development of object permanence in food-storing magpies (Pica pica)

The development of object permanence was investigated in black-billed magpies (Pica pica), a food-storing passerine bird. The authors tested the hypothesis that food-storing development should be correlated with object-permanence development and that specific stages of object permanence should be achieved before magpies become independent. As predicted, Piagetian Stages 4 and 5 were reached before independence was achieved, and the ability to represent a fully hidden object (Piagetian Stage 4) emerged by the age when magpies begin to retrieve food. Contrary to psittacine birds and humans, but as in dogs and cats, no "A-not-B error" occurred. Although magpies also mastered 5 of 6 invisible displacement tasks, evidence of Piagetian Stage 6 competence was ambiguous.