Effects of multiple exposures to D-cycloserine on extinction of conditioned fear in rats

Previous research has shown that an acute, post-training injection of D-cycloserine (DCS) facilitates extinction of conditioned fear in rats; however, the effects of multiple exposures to DCS in this situation are not known. In Experiment 1, rats were conditioned (light-shock pairings) and 24 h later given six extinction (light-alone) trials followed by an injection of DCS (15 mg/kg) or saline. The next day, all rats were tested for light-elicited freezing. In Experiment 2, the effect of DCS on extinction was tested in the same manner, except that rats were pre-exposed to DCS (0, 1, or 5 injections) just prior to conditioning. In Experiment 3, rats received five pre-exposures of DCS but conditioning occurred either 2 or 28 days after the last pre-exposure. The results showed that DCS facilitated extinction of conditioned freezing to the light CS when no drug pre-exposure had occurred, but pre-exposure to DCS just prior to conditioning disrupted the facilitation of extinction effect. When 28 days were interposed between pre-exposure and conditioning, the facilitatory effects of DCS on extinction were restored. These findings suggest that DCS has significant clinical value but that behavioral desensitization may occur with multiple exposures; however, desensitization is not permanent and is reduced by the passage of time.     

The "minimal self" in psychopathology: re-examining the self-disorders in the schizophrenia spectrum

The notion of minimal, basic, pre-reflective or core self is currently debated in the philosophy of mind, cognitive sciences and developmental psychology. However, it is not clear which experiential features such a self is believed to possess. Studying the schizophrenic experience may help exploring the following aspects of the minimal self: the notion of perspective and first person perspective, the 'mineness' of the phenomenal field, the questions of transparency, embodiment of point of view, and the issues of agency and ownership, considered as different and less fundamental than the feeling of mineness. Two clinical vignettes of patients with the diagnosis of schizophrenia will be presented: the first one, illustrating early illness stages, and the second case, of chronic schizophrenia, symptomatically marked by persistent hallucinations. Through their analysis, we will discuss the experiential dimensions of minimal self.     

What can self-disorders in schizophrenia tell us about the nature of subjectivity? A psychopathological investigation

The purpose of this article is to show how schizophrenia, understood as a distortion of the most intimate structures of subjectivity, illustrates the nature of subjectivity as such, while at the same time how philosophical considerations may help to understand schizophrenia. More precisely, schizophrenic experiences of self-alienation seem to reflect a congealing or concretization of a form of differentiation or potential alterity implicit in the dynamic nature of subjectivity. In other words, we propose that the structure of subjectivity includes potential divisions and fissures that condition the experiences of radical self-alienation seen in schizophrenia. In order to elucidate how this alterity emerges within the self in schizophrenia and in order to consider its conditions of possibility we examine the disorders of the self as described in phenomenological psychopathology. We especially use the work of the Japanese psychiatrists Mari Nagai, her teacher Bin Kimura, and the French psychiatrist Henry Ey, supplemented with clinical material from our own research. Finally, we shed light on the development of the psychotic symptoms such as hallucinations and delusions, which are understood as the expressions of a radical alterization (i.e., becoming other) of the self.     

Women and Natural Hierarchy in Aristotle

In this paper, I examine the frame of reference in Aristotle's Politics within which he makes claims about women and their place in his conception of politics.     

A logic for describing, not verifying, software

An important perquisite for verification of the correctness of software is the ability to write mathematically precise documents that can be read by practitioners and advanced users. Without such documents, we won't know what properties we should verify. Tabular expressions, in which predicate expressions may appear, have been found useful for this purpose. We frequently use partial functions in our tabular documentation. Conventional interpretations of expressions that describe predicates are not appropriate for our application because they do not deal with partial functions. Experience with this documentation has led us to choose a logic in which predicates are total but functions remain partial. We have found that this particular interpretation results in simpler expressions and is easily understood by practitioners.     

Extinction of conditioned odor potentiation of startle

Several recent studies with rats (Sprague-Dawley strain) have documented that an odor previously paired with shock potentiates the acoustic startle response, a phenomenon referred to as conditioned odor potentiation of startle (OPS). A surprising finding in these studies was that OPS did not extinguish even though the odor was present throughout the 25-min test session. Therefore, the present study more fully examined extinction of OPS. The results of Experiment 1, which employed both within-subject and between-group comparisons, showed that extinction of OPS occurred in adult rats only after several days of testing. Experiment 2 used the between-group procedure and found similar results with 23-day-old rats, the youngest age that exhibits the OPS effect. Experiment 2 also showed that giving rats 15 odor-shock pairings at 16 days of age, an age where they acquire the odor-shock association but cannot express it via OPS, does not increase subsequent resistance to extinction following odor-shock pairings at 23 days of age. Taken together, the results of this study show that (1) although OPS is somewhat resistant to extinction, it does extinguish with repeated tests and (2) suggests that there are no age differences in the rate of extinction of OPS.