Prolonged inactivation of the hippocampus reveals temporally graded retrograde amnesia for unreinforced spatial learning in rats

We investigated whether systems consolidation of spatial memory could be detected in a non-navigational, spatial-learning test that takes advantage of rats’ natural propensity to preferentially investigate an object that was displaced relative to spatial cues more than an object that remained stationary. Previous studies using navigational spatial-learning tests have generally failed to reveal temporally-graded retrograde amnesia, possibly because the hippocampus needs to be intact for the retrieval and/or processing of navigational information during the test. In the present study, the hippocampus of rats was kept inactivated, at two sites along its septo-temporal axis (dorsal and intermediate), for four consecutive days, beginning either 3 h or 5 days after familiarization to two identical objects in an open field. Rats that had their hippocampus inactivated beginning 5 days but not 3 h after familiarization showed evidence that they remembered the previous location of the displaced object. The results suggest that systems consolidation of spatial memories can be detected using a non-navigational test of spatial memory.     

The sound of enemies and friends in the neighborhood

Previous studies (e.g., Pecher, Zeelenberg, & Wagenmakers, 2005) found that semantic classification performance is better for target words with orthographic neighbors that are mostly from the same semantic class (e.g., living) compared to target words with orthographic neighbors that are mostly from the opposite semantic class (e.g., nonliving). In the present study we investigated the contribution of phonology to orthographic neighborhood effects by comparing effects of phonologically congruent orthographic neighbors (book-hook) to phonologically incongruent orthographic neighbors (sand-wand). The prior presentation of a semantically congruent word produced larger effects on subsequent animacy decisions when the previously presented word was a phonologically congruent neighbor than when it was a phonologically incongruent neighbor. In a second experiment, performance differences between target words with versus without semantically congruent orthographic neighbors were larger if the orthographic neighbors were also phonologically congruent. These results support models of visual word recognition that assume an important role for phonology in cascaded access to meaning.     

Convex and Concave,Part I: Images of Emptiness in Women

The American Journal of Psychoanalysis -     

The reliability and validity of the panic disorder self-report: a new diagnostic screening measure of panic disorder

This study examined the Panic Disorder Self-Report (PDSR), a new self-report diagnostic measure of panic disorder based on the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1994). PDSR diagnoses were compared with structured interview diagnoses of individuals with generalized anxiety disorder, social phobia, and panic disorder and nonanxious controls. Receiver operating characteristic analyses revealed that the PDSR showed 100% specificity and 89% sensitivity. The PDSR also demonstrated retest reliability, convergent and discriminant validity, and kappa agreement of .93 with a structured interview. Finally, the PDSR demonstrated clinical validity. Students who were identified as having panic disorder using the PDSR did not have significantly different scores on the Panic Disorder Severity Scale--Self-Report form (P. R. Houck, D. A. Speigel, M. K. Shear, & P. Rucci, 2002) than a panic disordered community sample. However, both groups had significantly higher scores than students identified as not meeting criteria for panic disorder.     

Spatial navigation in complex and radial mazes in APP23 animals and neurotrophin signaling as a biological marker of early impairment

Impairment of hippocampal function precedes frontal and parietal cortex impairment in human Alzheimer's disease (AD). Neurotrophins are critical for behavioral performance and neuronal survival in AD. We used complex and radial mazes to assess spatial orientation and learning in wild-type and B6-Tg(ThylAPP)23Sdz (APP23) animals, a transgenic mouse model of AD. We also assessed brain content of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3). Performance was alike in wild-type and APP23 animals in the radial maze. In contrast, performance in the complex maze was better in wild-type than APP23 animals. Contrary to the wild-type, hippocampal BDNF levels decreased on training in APP23 animals. Hippocampal and frontal cortex NGF levels in APP23 animals correlated with the time to solve the complex maze, but correlated inversely with escape time in wild-type animals. NT-3 levels were alike in wild-type and APP23 animals and were unchanged even after training. Both types of mazes depend on hippocampal integrity to some extent. However, according to the cognitive mapping theory of spatial learning, the complex maze because of the increased complexity of the environment most likely depends more strongly on preserved hippocampal function than the radial maze in the working memory configuration applied here. Greater impairment in complex maze performance than in radial maze performance thus resembles the predominant affliction of the loss of hippocampal function in human AD. NGF and BDNF levels on maze learning are different in wild-type and transgenic animals, indicating that biological markers of AD may be altered on challenge even though equilibrium levels are alike.     

Technical intelligence in animals: the kea model

The ability to act on information flexibly is one of the cornerstones of intelligent behavior. As particularly informative example, tool-oriented behavior has been investigated to determine to which extent nonhuman animals understand means-end relations, object affordances, and have specific motor skills. Even planning with foresight, goal-directed problem solving and immediate causal inference have been a focus of research. However, these cognitive abilities may not be restricted to tool-using animals but may be found also in animals that show high levels of curiosity, object exploration and manipulation, and extractive foraging behavior. The kea, a New Zealand parrot, is a particularly good example. We here review findings from laboratory experiments and field observations of keas revealing surprising cognitive capacities in the physical domain. In an experiment with captive keas, the success rate of individuals that were allowed to observe a trained conspecific was significantly higher than that of naive control subjects due to their acquisition of some functional understanding of the task through observation. In a further experiment using the string-pulling task, a well-probed test for means-end comprehension, we found the keas finding an immediate solution that could not be improved upon in nine further trials. We interpreted their performance as insightful in the sense of being sensitive of the relevant functional properties of the task and thereby producing a new adaptive response without trial-and-error learning. Together, these findings contribute to the ongoing debate on the distribution of higher cognitive skills in the animal kingdom by showing high levels of sensorimotor intelligence in animals that do not use tools. In conclusion, we suggest that the 'Technical intelligence hypothesis' (Byrne, Machiavellian intelligence II: extensions and evaluations, pp 289-211, 1997), which has been proposed to explain the origin of the ape/monkey grade-shift in intelligence by a selection pressure upon an increased efficiency in foraging behavior, should be extended, that is, applied to some birds as well.