Mental models and the suppositional account of conditionals

The mental model theory of conditional reasoning presented by P. N. Johnson-Laird and R. M. J. Byrne (2002) has recently been the subject of criticisms (e.g., J. St. B. T. Evans, D. E. Over, & S. J. Handley, 2005). The authors argue that the theoretical conflict can be resolved by differentiating 2 kinds of reasoning, reasoning about possibilities given the truth of assertions and reasoning about the truth of assertions given possibilities. The standard mental model theory accounts for the former kind of reasoning but does not adequately account for the latter, contrary to the suppositional approach favored by J. St. B. T. Evans et al. (2005). The authors thus propose a modified mental model theory of conditionals that reconciles the 2 theoretical approaches. It is demonstrated that this theory is able to explain the key findings that have been opposed to the standard theory by J. St. B. T. Evans et al. and makes new predictions that are empirically verified.     

The NO-cGMP-PKG signaling pathway regulates synaptic plasticity and fear memory consolidation in the lateral amygdala via activation of ERK/MAP kinase

Recent studies have shown that nitric oxide (NO) signaling plays a crucial role in memory consolidation of Pavlovian fear conditioning and in synaptic plasticity in the lateral amygdala (LA). In the present experiments, we examined the role of the cGMP-dependent protein kinase (PKG), a downstream effector of NO, in fear memory consolidation and long-term potentiation (LTP) at thalamic and cortical input pathways to the LA. In behavioral experiments, rats given intra-LA infusions of either the PKG inhibitor Rp-8-Br-PET-cGMPS or the PKG activator 8-Br-cGMP exhibited dose-dependent impairments or enhancements of fear memory consolidation, respectively. In slice electrophysiology experiments, bath application of Rp-8-Br-PET-cGMPS or the guanylyl cyclase inhibitor LY83583 impaired LTP at thalamic, but not cortical inputs to the LA, while bath application of 8-Br-cGMP or the guanylyl cyclase activator YC-1 resulted in enhanced LTP at thalamic inputs to the LA. Interestingly, YC-1-induced enhancement of LTP in the LA was reversed by concurrent application of the MEK inhibitor U0126, suggesting that the NO-cGMP-PKG signaling pathway may promote synaptic plasticity and fear memory formation in the LA, in part by activating the ERK/MAPK signaling cascade. As a test of this hypothesis, we next showed that rats given intra-LA infusion of the PKG inhibitor Rp-8-Br-PET-cGMPS or the PKG activator 8-Br-cGMP exhibit impaired or enhanced activation, respectively, of ERK/MAPK in the LA after fear conditioning. Collectively, our findings suggest that an NO-cGMP-PKG-dependent form of synaptic plasticity at thalamic input synapses to the LA may underlie memory consolidation of Pavlovian fear conditioning, in part, via activation of the ERK/MAPK signaling cascade.     

Le risque médico-judiciaire des infections nosocomiales

These last years in France, the term ‘nosocomial infection’ has been replaced by ‘health-care associated infection’, which has a much broader definition. In all cases, the plausibility of the association between infection and the care provided deserved to be rigorously analyzed. To qualify an infection as nosocomial, the expert witness must at the judge's request determine that infection actually occurred within the health facility and is linked to health care. French Public Health Code as well the most recent jurisprudence give currently a rather close definition of nosocomial infection. The principle of faultness liability in the field of nosocomial infection has been enshrined in the law of March 4^th 2002, the most severe situations (death; permanent functional deficit > 25 percent) being compensated by ONIAM, the French national office of compensation for nosocomial infection.     

Stream segregation of narrow-band noise bursts

Normally hearing adults heard rapid alternations of a pair of band-limited noise bursts that had flat spectra (in terms of equal-loudness weighting of components) and sharp band edges. The bursts differed in center frequency (CF), but were matched on overall intensity, on bandwidth (BW) on a logfrequency scale, and (roughly) on pitch strength. Listeners judged the ease with which the sequence could be held together perceptually in a single auditory stream (vs. forming separate high and low streams). Involuntary segregation was examined as a function of the following measures of frequency separation of the alternating noise bands: (1) the closest band edges, (2) the most remote band edges, (3) the CFs of the bands on a logarithmic scale, and (4) the BWs. Segregation was best predicted from the separation of the two CFs on a log-frequency scale (very strong effect). Increasing the BWs of the two alternating bursts (the same size, in log frequency, for both bands) also led to greater segregation (very weak effect).     

Involvement of amygdala in inhibitory control over aggression in the rat: A synopsis

An experimentally produced hyperreactivity facilitates initiation of mouse-killing in rats that did not previously develop any stable inhibition of interspecific aggression. Destruction of the corticomedial amygdala or interruption of the stria terminalis interferes with the development of such an inhibition on the basis of “social” influences, whereas lateral amygdaloid lesions have no effect on mouse-killing.     

Ignorance,Knowledge, and Two Epistemic Intuitions

Philosophia - One of the most venerable and enduring intuitions in epistemology concerns the relationship between true belief and knowledge. Famously articulated by Socrates, it holds that true...     

Visual Attention in Real-World Conversation: Gaze Patterns Are Modulated by Communication and Group Size

Gaze behavior both initiates and maintains conversations, playing a crucial role in real-world collaboration. Hitherto, most findings on social attention stem from research using pictures of faces in the laboratory, however, attention operates differently in the real world. Thus, we know little of how gaze behavior operates in naturalistic interactions. To bridge this gap, we applied mobile eye-tracking to investigate the gaze patterns present in naturalistic conversations. Specifically, we examined gaze behavior of participants in a group of two or five, either sitting together in silence, or engaging in a conversation, in which they took turns either listening or speaking to each other. Results show that participants looked more frequently towards others when the group was communicating compared to when remaining silent, and that they looked at others more frequently when listening compared to when speaking. Furthermore, being part of a dyad led to more social attention being afforded during conversation compared to the group situation, regardless of whether subjects were listening or speaking. Meanwhile, when sitting in silence subjects showed less social gazing in a dyad than in a group of five. Our results provide qualitative and quantitative insights into the patterns of visual attention during dynamic naturalistic conversations.