Development of a fully automated system for delivering odors in an MRI environment

We describe the development and evaluation of a computer-controlled system for delivering odors in a magnetic resonance imaging (MRI) environment. The system allows a timely presentation of different odors in synchrony with MRI sequences and participant’s inspiration phase. The rise/fall time of odor deliverance has been optimized to generate prompt and strong stimulations. Equipped with a user-friendly programming interface, the system can be used reliably in a wide range of experimental paradigms. We have paid particular attention to developing a portable system that is relatively easy, rapid, and inexpensive to replicate. The equipment has been tested in a 3-Tesla MRI in a boxcar paradigm, in which stimulation conditions alternated with rest periods (no stimulation). The experiment demonstrated the good functioning of the device and its efficiency in producing the expected activation in the olfactory cortex; it also revealed some methodological and technical aspects to be improved.     

Public events and flashbulb memories in Parkinson's disease

Public events and Flashbulb memories were investigated in 12 non-demented patients with Parkinson's disease (PD) and 12 controls. Knowledge of public events and flashbulbs memories were assessed using a Famous Events Test (EVE 30). Contributions of semantic, episodic, as well as executive functioning and anterograde memory were examined. Results primarily showed that the performances of patients with PD were lower than these of controls in 4 tasks: free recall, specific questions, dating events and date recognition. They also had difficulties in finding the temporal order of 8 events. In contrast, the PD group benefited from events recognition themselves to the same extent as the controls. Secondly, the recall of flashbulb memories (FBM) was lower in the PD group than in the controls. Finally, correlations appeared in PD between the detailed recall of the events with the "recall" abilities of the MATTIS scale, possibly reflect an impairment in rebuilding memories. A positive correlation is also observed with the initiation score of the MATTIS (executive component), suggesting that the difficulties of rebuilding can be related to a dysfunction in accessing information because of a certain degree of frontal amnesia.     

The basolateral amygdala is necessary for learning but not relearning extinction of context conditioned fear

Extinction of conditioned fear involves new learning that inhibits but does not eliminate the original fear memory. This inhibitory learning is thought to require activation of NMDA receptors (NMDAr) within the basolateral amygdala (BLA). However, once extinction has been learned, the role played by the BLA during subsequent extinction procedures remains unknown. The present study examined the role of neuronal activity and NMDAr activation in rats receiving their first or second extinction of context fear. We found that BLA infusion of DL-APV, a competitive antagonist of NMDAr, depressed fear responses at both the first and second extinction. It impaired learning extinction but spared and even facilitated relearning extinction. BLA infusion of muscimol, a GABA(A) agonist, produced a similar outcome, suggesting that DL-APV not only blocked NMDAr-dependent plasticity but also disrupted neuronal activity. In contrast, infusion of ifenprodil, a more selective antagonist of NMDAr containing the NR2B subunit, did not depress fear responses but impaired short- and long-term inhibition of fear at both the first and second extinction. Therefore, we suggest that relearning extinction normally requires NMDAr containing the NR2B subunit in the BLA. However, simultaneous blockade of these receptors and neuronal activity in the BLA results in compensatory learning that is able to promote long-term re-extinction. These data are consistent with a current model that attributes fear extinction to interactions between several neural substrates, including the amygdala and the medial prefrontal cortex.     

An evaluation of psychophysical models of auditory change perception

In many psychophysical experiments, the participant's task is to detect small changes along a given stimulus dimension or to identify the direction (e.g., upward vs. downward) of such changes. The results of these experiments are traditionally analyzed with a constant-variance Gaussian (CVG) model or a high-threshold (HT) model. Here, the authors demonstrate that for changes along three basic sound dimensions (frequency, intensity, and amplitude-modulation rate), such models cannot account for the observed relationship between detection thresholds and direction-identification thresholds. It is shown that two alternative models can account for this relationship. One of them is based on the idea of sensory quanta; the other assumes that small changes are detected on the basis of Poisson processes with low means. The predictions of these two models are then compared against receiver operating characteristics (ROCs) for the detection of changes in sound intensity. It is concluded that human listeners' perception of small and unidimensional acoustic changes is better described by a discrete-state Poisson model than by the more commonly used CVG model or by the less favored HT and quantum models.     

Visual discrimination by heifers (Bos taurus) of their own species

Species discrimination has been described in several taxa but rarely in domestic animals. In contrast to wild species, domestic species present a great phenotypic variety. This study investigated whether 10 Prim'Holstein heifers (Bos taurus) could discriminate images of cows from images of other domestic animals. The experiment was based on simultaneous discrimination. Responses were obtained through instrumental conditioning using a food reward. In Experiment 1, the reward was associated with a cow face and, in the reversal learning task, with faces of other domestic species. The results showed that in both tasks, cows were able to reach the criterion in few sessions. Therefore, despite great phenotypic variety (a cognitive challenge) cows were able to visually discriminate their own species from other domestic species.     

Rapid reacquisition of fear to a completely extinguished context is replaced by transient impairment with additional extinction training

A series of experiments studied reacquisition of fear reactions to a completely extinguished context. Reacquisition was rapid when reconditioning occurred as soon as the fear reactions were completely extinguished, showing that the original conditioning was intact. However, when reconditioning occurred after massive extinction training, fear reactions were depressed but then recovered across a long retention interval. This recovery was due to reconditioning and was similar to that produced by conditioning a massively preexposed context. These results show that massive extinction converts a potentially dangerous context into one that is merely familiar.     

Situational consistency in behavioral patterns of aggressive boys: Methodological considerations on observational measures

The issue of situational consistency is of great interest for early intervention with aggressive boys, but efforts to show behavior stability across settings have been unsuccessful to date, due principally to methodological problems. It is argued here that a more appropriate matching of response form, interaction partner, and situations should increase the situation consistency of observed behavior. The results support this proposition in that, more crosssetting behavior consistency was found in the pairing of situations where aggressive boys (age 6–7 years) were interacting with an adult female (mother/child versus baby-sitter/child) than in the pairing of situations where the boys were interacting with an adult male (mother/child versus father/child) or with the teacher in a nondyadic situation (classroom). The implications of using an extreme group are also discussed.This research program was funded by Le Conseil Québécois de la Recherche Sociale, the Quebec Government's FCAR research program, the Social Sciences and Humanities Research Council of Canada, the Canadian Ministry of Employment and Immigration, and the University of Montreal FDR program.     

Organizational Competencies: A Valid Approach for the Future?

This paper attempts to integrate concepts of organizational competency across a number of levels of analysis. It provides grounded evidence on existing application and practice, and synthesizes research and development in the area of organizationally derived management competencies. Consideration is given to the underlying theoretical assumptions and definitional issues raised by existing practice. The paper highlights the range of human resource strategies or programmes used to integrate activity and implement strategic changes, and examines the shift in thinking about the importance and nature of management competency. Organization-specific approaches are reviewed and the benefits analysed. A critical review of attempts at integration suggests that application of competency-based approaches within organizations has fallen behind advances in strategic human resource management and that there is a need to shift application towards more future–oriented and strategic contexts. Weaknesses associated with existing approaches to management competency are analysed as is the issue of validity. Finally, the implications of considering competencies as an organizational level resource for human resource strategy are discussed.     

The efficiency of skilled performance

The observed ease or effort of performance has traditionally been considered an integral part of any definition of skill (e.g., Guthrie, 1935). Empirical investigations of skill learning and performance have, however, largely ignored the effort or efficiency with which the movement is performed. This situation has arisen despite the fact that in many skills, particularly athletic endurance events or industrial work tasks, efficiency of performance may be essential to the goal of the task. This paper focuses on the energy demand of various skills and its relationship to issues of learning, performance, and individual differences in preferred rhythm. It is shown that across a variety of tasks the individual's freely chosen work-rate is the most efficient. The significance of preferred rhythm to theoretical perspectives on rhythmic activity is discussed.