The role of the magnocellular and parvocellular pathways in the attentional blink

The attentional blink refers to the transient impairment in perceiving the 2nd of two targets presented in close temporal proximity in a rapid serial visual presentation (RSVP) stream. The purpose of this study was to examine the effect on human attentional-blink performance of disrupting the function of the magnocellular pathway--a major visual-processing pathway specialized in temporal segregation. The study was motivated by recent theories that relate the attentional blink to the limited temporal resolution of attentional responses, and by a number of poorly understood empirical findings, including the effects on the attentional blink of luminance adaptation and distraction. The attentional blink was assessed for stimuli on a red background (Experiment 1), stimuli on an equiluminant background (Experiment 2), and following flicker or motion adaptation (Experiment 3), three psychophysical manipulations known to disrupt magnocellular function. Contrary to our expectations, the attentional blink was not affected by these manipulations, suggesting no specific relationship between the attentional blink and magnocellular and/or parvocellular processing.     

Hidden profiles and the consensualization of social stereotypes: how information distribution affects stereotype content and sharedness

We examined the impact of the distribution of information regarding social groups on the formation of shared stereotypes within triads in two studies. Three‐person groups discussed which of three groups (A, B, and C) was the most able and the most sociable. In Study 1, some of the information about these three groups was available to all group members (shared) whereas the remainder was distributed among group members (unique). Based on the total profile, there was more evidence of group A being sociable and of group B being able than of A being able and B sociable. In Study 1 (n = 58), sampling was manipulated as ‘representative’ (information in line with the overall differences was shared) or ‘unrepresentative’ (only information contradicting these differences was shared). In a third condition, all items of information were shared. Emerging stereotypes were directly influenced by sampling of information independently of the discussion. As well as this, the discussion consensualized initial stereotypes. In Study 2 (n = 52), sampling was always unrepresentative and we manipulated the labels associated with the target groups in such a way that the stereotype associated with the label was either inconsistent or consistent with the overall differences between the target groups. In the inconsistent condition, participants were more likely to discuss information that violated stereotypical expectations, and to be less influenced by sampling as a result of discussion. Altogether, these findings suggest that information sampling directly affects the consensualization of social stereotypes. Copyright © 2003 John Wiley & Sons, Ltd.     

Communicating Justice: Shari‘a Courts and the Christian Community in Seventeenth- and Eighteenth-Century Ottoman Greece

Using Shari‘a court records from Ottoman Salonica and Karaferye, this paper examines the nature of justice as articulated by the state and judges vis à vis Christians. As arbiters of local and state/local relations, the courts were responsible for defining and promoting the state's desire for social harmony, efficiency, and order at the local level while also overseeing the rights and obligations of local populations vis à vis state and local officials. The paper examines the standards of evidence and legal reasoning employed by judges and the relationship between religious law and state law, particularly in the realm of criminal justice. Furthermore, in a bid to assess Christian familiarity with the workings of the law, the paper explores how and when Christians used the courts and the strategies employed by them in the court setting. Ultimately, the Shari‘a courts provided a public forum for strengthening communal networks and resolving disputes between Christians and between Muslims and Christians.     

Linking Substance Use and Problem Behavior Across Three Generations

This study examined patterns of between-generation continuity in substance use from generation 1 (G1) parents to generation 2 (G2) adolescents and from G2 adult substance use and G1 substance use to generation 3 (G3) problem behavior in childhood. Structural equation modeling of prospective, longitudinal data from 808 participants, their parents, and their children showed low levels of G1 to G2 cross-generational continuity in the general tendency to use drugs. This effect was fully mediated by G2 early adolescent behavior problems. Drug-specific residual effects were observed across generations for cigarette smoking. Once established in adolescence, substance use in G2 showed stability over time. G2 substance use at age 27 significantly predicted G3 problem behavior. G1 substance use also was related to G3 problem behavior indirectly. These findings highlight the importance of interrupting intergenerational cycles of substance use and problem behavior.     

Service Needs of Foster Families with Children who have Disabilities

We examined the service needs of foster families with children who have disabilities. Foster parents in a large Canadian city were asked “What services or supports would be helpful to you?” The responses to this question were edited for clarity and to eliminate redundancies, and sorted into piles of like statements by a group of 15 foster care professionals. Two types of statistical analysis were applied to the sorting of the statements to describe the relationship between statements and their groupings. The major concepts were identified according to the contents of the cluster and a map was constructed to provide a graphic representation of the conceptualization process. The major services and supports identified in this study were: support in the community, financial support, accommodating school system, good relationships with social workers, responsive professionals, information, comprehensive medical care, services for aboriginal children and families, transitional services, and respite.     

Increase in Syntaxin 1B mRNA in Hippocampal and Cortical Circuits During Spatial Learning Reflects a Mechanism of Trans-synaptic Plasticity Involved in Establishing a Memory Trace

It has long been proposed that the cellular and molecular mechanisms responsible for LTP may well involve the mechanisms that lead to the type of synaptic modification that occurs during learning. However, it is also known that a single memory trace is encoded in spatially distributed networks; implying that alterations of synaptic strength occur at multiple sites along circuits of connected cells. Recent evidence suggests that regulation of the gene encoding syntaxin 1B, a presynaptic protein involved in exocytosis, plays an important role in the mediation of trans-synaptic LTP, a candidate mechanism for the propagation of plasticity in neural circuits during learning. Using in situ hybridization to measure the mRNA levels at different time points after learning a spatial working or reference memory task, we show that expression of the gene encoding this protein in the hippocampal and corticoprefrontal circuits increases linearly with performance at a critical window of learning when rats are reaching between 75% and 100% of their maximal performance. No changes were observed during the early phases of learning or when rats where overtrained. The correlational analysis indicates that coordinated increases in syntaxin 1B expression occurs in hippocampal circuits during working memory and in more widespread hippocampocortical circuits during reference memory. These results suggest that a form of trans-synaptic plasticity mediated in part by regulation of the expression of syntaxin 1B may play an active role in configuring specific spatially distributed circuits during the laying down of memories.     

The effect of asymmetrical sample training on retention functions for hedonic samples in rats

Rats were trained in a symbolic delayed matching-to-sample task to discriminate sample stimuli that consisted of the presence of food or the absence of food. Asymmetrical sample training was provided in which one group was initially trained with only the food sample and the other group was initially trained with only the no-food sample. In addition, within each group half of the rats were trained with an illuminated intertrial interval (ITI) and the remaining rats with a dark ITI. While the retention functions did not differ as a function of which sample was trained first, they did differ as a function of the similarity in the illumination conditions during the ITI and the delay interval. Symmetrical retention functions were obtained when the lighting conditions were similar and slightly asymmetrical retention functions were obtained when the lighting conditions were dissimilar. Probe tests confirmed that features of the no-food sample were attended to and used to generate a memory representation for the no-food sample. The results are not consistent with the hypothesis that asymmetrical sample training encourages coding of the sample introduced initially and default responding to the subsequently introduced sample. Rats generate memory representations for both samples when asymmetrical sample training is given with hedonic samples.     

Partner violence against heterosexual and gay men: Prevalence and correlates

Female victims of intimate partner violence (IPV) have been the focus of a substantial amount of research. However, the subject of male victims of IPV remains a controversial topic, and one which has been comparatively neglected within the literature, despite some findings suggesting that men are victimized by intimate partners at an equivalent, or even higher rate than women. This paper reviews the literature on male victims of IPV, both within opposite and same-gender relationships, focusing on the prevalence and correlates of IPV, as well as exploring the relationship between IPV and ethnicity. According to the literature reviewed, the prevalence of female perpetrated IPV against heterosexual male victims ranges from 0.2% to 93%, homosexual male victimization ranges between 1.8% and 93.7%, and heterosexual female victimization ranges between 1.3% and 86% depending on the type of IPV included, whether the reference period includes the past 12 months, or lifetime experience, and the method used to assess IPV. These data indicate that victimization is as much an issue for men as it is for women. In addition, it appears that men of certain ethnicities may be more at risk than others. Finally, the empirical literature which examines the correlates of male victimization indicates that male victims in heterosexual and gay relationships share many correlates. Unfortunately however, methodological weaknesses in the available literature and a lack of research in some areas restrict the extent to which conclusions can be drawn, and findings generalized. Recommendations for future research are made.     

Exploring the role of primary and supplementary motor areas in simple motor tasks with fNIRS

Studies employing functional magnetic resonance imaging (fMRI) have highlighted a covariation between the amplitude of hemodynamic responses recorded in primary and supplementary motor areas (M1 and SMA) and the duration of a motor task. A subset of these studies have hinted to a possible functional dissociation between processing carried out in these areas, with SMA primarily involved in action preparation, while M1 involved in action execution. This proposed functional dissociation was explored in the present study using a different technique--functional near-infrared spectroscopy--which enabled a finer-grained monitoring of the temporal characteristics of the hemodynamic response compared to fMRI. Here, hemodynamic responses in M1 and SMA were recorded in 7 participants during a right-finger-tapping task of short (1 s) or long (3 s) duration. Hemodynamic responses of larger amplitude were recorded from both contralateral M1 and SMA during long-duration than short-duration tapping. Furthermore, the analysis of the temporal profiles of these responses revealed a more sustained and prolonged activity for long-duration versus short-duration tapping in M1, but not in SMA. Rather than functionally dissociable areas, the present results are more compatible with the hypothesis that M1 and SMA subserve different, though strongly interacting, functional subroutines subtended in motor task preparation and execution.     

‘Murder by Milligrams’: Enhancement Technologies and Therapeutic Zeal in Timothy Findley’s Headhunter”

In his 1993 novel Headhunter, Canadian author Timothy Findley describes the tendency of some medical practitioners to put scientific interests above the therapeutic needs of the individual. As the book's title and name of the main character Dr. Kurtz attest, Findley reflects the colonialist teleology found in Heart of Darkness as an analogue for the therapeutic zeal shown by many of the physicians in Headhunter. In the novel, such zeal is especially problematic when it is combined with so-called enhancement technologies, since enhancement, like colonialism, can be based in the prejudices of the practitioner and/or the dominant society, rather than in the needs of the patient. To counter therapeutic zeal, Findley, like Conrad, proposes an ethics of restraint in which the practitioner's empathy outweighs his or her desire for scientific discovery.