An assessment of response, direction and place learning by rats in a water T-maze

Behavioral data suggest that distinguishable orientations may be necessary for place learning even when distal cues define different start points in the room and a unique goal location. We examined whether changes in orientation are also important in place learning and navigation in a water T-maze. In Experiment 1, rats were trained to locate a hidden platform and given a no-platform probe trial after 16 and 64 trials with the maze moved to a new position. Direction and response strategies were more prevalent than a place strategy. In Experiment 2, acquisition of place, response and direction strategies was assessed in a water T-maze that was moved between two locations during training. Rats were impaired on the place task when the maze was translated (moved to the L or R) but were successful when the maze was rotated across trials. These data are consistent with findings from appetitive tasks.     

Complete Extensions in Argumentation Coincide with 3-Valued Stable Models in Logic Programming

In this paper, we prove the correspondence between complete extensions in abstract argumentation and 3-valued stable models in logic programming. This result is in line with earlier work of [6] that identified the correspondence between the grounded extension in abstract argumentation and the well-founded model in logic programming, as well as between the stable extensions in abstract argumentation and the stable models in logic programming.     

Dude looks like a lady: Exploring the malleability of person categorization

Recent research has documented how single facial features can trigger person categorization. Questions remain, however, regarding the automaticity of the reported effects. Using a modified flanker paradigm, the current investigation explored the extent to which hair cues drive sex categorization when faces comprise task‐irrelevant (i.e., unattended) stimuli. In three experiments, participants were required to classify target forenames by gender while ignoring irrelevant flanking faces with and without hair cues. When present, hair cues were either congruent or incongruent with prevailing cultural stereotypes. The results demonstrated the potency of category‐specifying featural cues. First, flanker interference only emerged when critical hair cues were present (Experiment 1). Second, flankers with stereotype‐incongruent hairstyles (e.g., men with long hair) facilitated access to information associated with the opposite sex (Experiment 2), even when the flankers were highly familiar celebrities (Experiment 3). The theoretical implications of these findings are considered. Copyright © 2009 John Wiley & Sons, Ltd.     

Openness to experience, plasticity, and creativity: Exploring lower-order, high-order, and interactive effects

What are creative people like? Openness to experience is important to creativity, but little is known about plasticity, the higher-order factor that subsumes openness. College students (n = 189) completed measures of the Big Five and measures of creative cognition (fluency and quality of divergent thinking), everyday creative behaviors, creative achievement, and self-rated creativity. Latent variable models found broad effects of openness to experience and few effects of the other four domains. At the higher-order level, plasticity predicted higher scores on nearly all of the facets of creativity, and stability had several significant effects. For some creativity measures, plasticity and stability had opposing effects. Tests of latent interactions found no significant effects: plasticity and stability predict creatively independently, not jointly.     

Overt naming fMRI pre- and post-TMS: Two nonfluent aphasia patients, with and without improved naming post-TMS

Two chronic, nonfluent aphasia patients participated in overt naming fMRI scans, pre- and post-a series of repetitive transcranial magnetic stimulation (rTMS) treatments as part of a TMS study to improve naming. Each patient received 10, 1-Hz rTMS treatments to suppress a part of R pars triangularis. P1 was a ‘good responder’ with improved naming and phrase length; P2 was a ‘poor responder’ without improved naming.Pre-TMS (10 years poststroke), P1 had significant activation in R and L sensorimotor cortex, R IFG, and in both L and R SMA during overt naming fMRI (28% pictures named). At 3 mo. post-TMS (42% named), P1 showed continued activation in R and L sensorimotor cortex, R IFG, and in R and L SMA. At 16 mo. post-TMS (58% named), he also showed significant activation in R and L sensorimotor cortex mouth and R IFG. He now showed a significant increase in activation in the L SMA compared to pre-TMS and at 3 mo. post-TMS (p < .02; p < .05, respectively). At 16 mo. there was also greater activation in L than R SMA (p < .08). At 46 mo. post-TMS (42% named), this new LH pattern of activation continued. He improved on the Boston Naming Test from 11 pictures named pre-TMS, to scores ranging from 14 to 18 pictures, post-TMS (2–43 mo. post-TMS). His longest phrase length (Cookie Theft picture) improved from three words pre-TMS, to 5–6 words post-TMS.Pre-TMS (1.5 years poststroke), P2 had significant activation in R IFG (3% pictures named). At 3 and 6 mo. post-TMS, there was no longer significant activation in R IFG, but significant activation was present in R sensorimotor cortex. On all three fMRI scans, P2 had significant activation in both the L and R SMA. There was no new, lasting perilesional LH activation across sessions for this patient. Over time, there was little or no change in his activation. His naming remained only at 1–2 pictures during all three fMRI scans. His BNT score and longest phrase length remained at one word, post-TMS.Lesion site may play a role in each patient’s fMRI activation pattern and response to TMS treatment. P2, the poor responder, had an atypical frontal lesion in the L motor and premotor cortex that extended high, near brain vertex, with deep white matter lesion near L SMA. P2 also had frontal lesion in the posterior middle frontal gyrus, an area important for naming (Duffau et al., 2003); P1 did not. Additionally, P2 had lesion inferior and posterior to Wernicke’s area, in parts of BA 21 and 37, whereas P1 did not.The fMRI data of our patient who had good response following TMS support the notion that restoration of the LH language network is linked in part, to better recovery of naming and phrase length in nonfluent aphasia.     

Degrees of Causation

The primary aim of this paper is to analyze the concept of degrees of causal contribution for actual events and examine the way in which it can be formally defined. This should go some way to filling out a gap in the legal and philosophical literature on causation. By adopting the conception of a cause as a necessary element of a sufficient set (the so-called NESS test) we show that the concept of degrees of causation can be given clear and even empirical meaning. We then apply a game theoretical framework to derive a measure of causal contribution. Our favoured measure turns out to be a generalised version of the normalized Penrose–Banzhaf index of voting power.