Habituation of the proleg withdrawal reflex in Manduca sexta does not involve changes in motoneuron properties or depression at the sensorimotor synapse

Larvae of the hawkmoth, Manduca sexta, exhibit a defensive proleg withdrawal reflex in which deflection of mechanosensory hairs on the proleg tip (the planta) evokes retraction of the proleg. A previous behavioral study showed that this reflex habituates in response to repeated planta hair deflection and exhibits several other defining features of habituation. In a semi-intact preparation consisting of a proleg and its associated segmental ganglion, repeated deflection of a planta hair or electrical stimulation of its sensory neuron causes a neural correlate of habituation, manifested as a decrease in the number of action potentials evoked in the proleg motor nerve. Monosynaptic connections from planta hair sensory neurons to the principal planta retractor motoneuron exhibit several forms of activity-dependent plasticity. In the present study we recorded intracellularly from this motoneuron during repetitive electrical stimulation of a planta hair sensory neuron. The number of action potentials evoked in the motoneuron decreased significantly, representing a neural correlate of habituation. The motoneuron's resting membrane potential, input resistance. and spike threshold measured before and after repetitive stimulation did not differ between the stimulated group and a control group. Furthermore, the amplitude of the monosynaptic excitatory postsynaptic potential, as well as the magnitude of paired-pulse facilitation, evoked in the motoneuron by the sensory neuron did not change after repetitive stimulation. These results suggest that depression at the sensorimotor synapse does not contribute to reflex habituation. Rather, other mechanisms in the ganglion of the stimulated segment, such as changes in polysynaptic reflex pathways, appear to be responsible.     

Which cheek to turn? The effect of gender and emotional expressivity on posing behavior

Nicholls et al. (1999, Proc. Royal Soc. B, 266, 1517-1522) demonstrated that models turn their left or right cheeks when expressing or concealing emotion, respectively. This study examined whether emotionally expressive individuals are more likely to turn their left cheek when posing for a photograph than less emotionally expressive individuals. One hundred twenty-four normal participants completed an Emotional Expressivity Scale (EES) and posed for a photograph. Females had a higher EES than males and there was a trend for left cheek posers to have a higher EES than right cheek posers. Females were more likely to turn their left cheek than were males. Results support our argument that emotionally expressive individuals turn their left cheek when posing. The higher incidence of leftward poses in females than males may reflect the higher EES for females. These results support the proposition that the leftward bias in painted portraits is related to a desire to capture the emotive qualities of the left side of the face.     

Use of the Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood: Revised Edition (DC:0–3R) with Canadian Infants and Young Children Prenatally Exposed to Substances

The current study examined the mental health diagnostic profiles of infants and young children prenatally exposed to substances using the Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood, Revised (DC:0–3R) diagnostic system. Participants were 46 biological mother–infant dyads who were engaged in a clinical program for mothers with substance‐use problems and their young children (aged 10–41 months). Diagnostic information was reported for each of the five axes listed in the DC:0–3R diagnostic system based on file reviews. In addition, the children's socioemotional and adaptive behaviors were assessed using the Child Behavior Checklist, Infant–Toddler Social Emotional Assessment, the Social‐Emotional Scale, and the Adaptive Behavior Assessment System (2nd ed.). In this sample of young children with prenatal substance exposure, a broad range of socioemotional symptoms were evident, with almost one third of the children meeting criteria for at least one Axis I mental health diagnosis. In addition, the majority of dyads demonstrated features of a disordered relationship. Children in more problematic relationships demonstrated higher levels of socioemotional and adaptive functioning difficulties and were more likely to have an Axis I diagnosis than were children in adapted relationships. The importance of early intervention efforts aimed at infants with prenatal substance exposure and their biological mothers is highlighted, with a particular focus on enhancing the quality of the mother–child relationship.     

Cultural Stereotypes and the Self: A Closer Examination of Implicit Self-Stereotyping

Recent research and theory on implicit self-stereotyping suggests that individuals nonconsciously incorporate stereotypes about their social groups into the self-concept; however, evidence as to whether this holds true for negative stereotypes remains limited. Using a subliminal priming measure, the current research found that women (Experiment 1) and White Americans (Experiment 2) implicitly associated the self with in-group stereotypic traits but not out-group stereotypic traits. Of importance, both groups implicitly self-stereotyped on negative in-group traits to a similar extent as they did on positive in-group traits. Moreover, exploratory analysis showed that the degree to which White Americans associated positive, but not negative, in-group stereotypes with the self was related to higher self-esteem. Implications of implicit self-stereotyping on self-esteem and stereotype-consistent behavior are discussed.     

Long-term Effects of Subliminal Priming on Academic Performance

This research examines the temporal range of subliminal priming effects on complex behavior. In Experiments 1 and 2, participants were subliminally primed with words either related or unrelated to intelligence before completing a practice exam, administered 1 to 4 days before an actual course midterm. Results revealed that the intelligence primes increased performance on the midterm compared to neutral primes. Experiment 1 demonstrated that being told that the priming task was designed to help exam performance moderated the effect of the intelligence primes. In Experiment 2, practice test performance mediated the effect of the primes on midterm performance. These experiments demonstrated that subliminal priming may have long-term effects on real-world behavior, and demonstrates one means by which long-term priming effects may occur.     

The erosion of CVD diamond by diamond particles

This paper describes the damage features generated by the high-velocity impact of diamond particles on diamond produced by chemical vapour deposition (CVD). Two types of diamond grit - angular and cubo-octahedral - were used to impact the surface of the diamond target at a mean impact velocity of 268?m?s^?1. The main damage features were elastic-plastic radial and lateral cracks. Distorted Hertzian ring cracks were also seen on samples impacted with cubo-octahedral diamond grit. This indicates that, in contrast to previous experiments by the authors using silica sand erodent, Hertzian damage can be generated at this velocity when the mechanical properties of the erodent and target are comparable. Fragmentation of the diamond grit occurred on impact; however, the extent of the degradation was much reduced compared with the silica sand erodent.     

The influence of emotional cues on prospective memory: a systematic review with meta-analyses

ABSTRACT

Remembering to perform a behaviour in the future, prospective memory, is essential to ensuring that people fulfil their intentions. Prospective memory involves committing to memory a cue to action (encoding), and later recognising and acting upon the cue in the environment (retrieval). Prospective memory performance is believed to be influenced by the emotionality of the cues, however the literature is fragmented and inconsistent. We conducted a systematic search to synthesise research on the influence of emotion on prospective memory. Sixty-seven effect sizes were extracted from 17 articles and hypothesised effects tested using three meta-analyses. Overall, prospective memory was enhanced when positively-valenced rather than neutral cues were presented (d?=?0.32). In contrast, negatively-valenced cues did not enhance prospective memory overall (d?=?0.07), but this effect was moderated by the timing of the emotional manipulation. Prospective memory performance was improved when negatively-valenced cues were presented during both encoding and retrieval (d?=?0.40), but undermined when presented only during encoding (d?=??0.25). Moderating effects were also found for cue-focality and whether studies controlled for the arousal level of the cues. The principal finding is that positively-valenced cues improve prospective memory performance and that timing of the manipulation can moderate emotional effects on prospective memory. We offer a new agenda for future empirical work and theorising in this area.     

Binding actions and scenes in visual long-term memory

How does visual long-term memory store representations of different entities (e.g., objects, actions, and scenes) that are present in the same visual event? Are the different entities stored as an integrated representation in memory, or are they stored separately? To address this question, we asked observers to view a large number of events; in each event, an action was performed within a scene. Afterward, the participants were shown pairs of action–scene sets and indicated which of the two they had seen. When the task required recognizing the individual actions and scenes, performance was high (80 %). Conversely, when the task required remembering which actions had occurred within which scenes, performance was significantly lower (59 %). We observed this dissociation between memory for individual entities and memory for entity bindings across multiple testing conditions and presentation durations. These experiments indicate that visual long-term memory stores information about actions and information about scenes separately from one another, even when an action and scene were observed together in the same visual event. These findings also highlight an important limitation of human memory: Situations that require remembering actions and scenes as integrated events (e.g., eyewitness testimony) may be particularly vulnerable to memory errors.     

Sexuality and Teen Television: Emerging Adults Respond to Representations of Queer Identity on Glee

Academic scholarship on teen television programs indicates that images of queer sexualities can strongly impact the identities of emerging adults. Yet what is missing from this body of scholarship is an in-depth examination of how these representations are incorporated into the identity projects of the emerging adults who watch these shows. This study fills this gap by examining qualitative interviews with emerging adults who watch Glee. The participants consistently and overwhelmingly identified Glee as representing “progressive” emerging adult sexuality. Within that, three key themes emerged. First, identifying with Glee is a gendered practice. Second, Glee fandom aligns with an affinity for musical theater, which is traditionally considered a mirror for gay culture. Finally, while viewers recognized queer narrative content, it did not produce a broader acceptance of non-heterosexual identities. Viewers normalized their own (real, straight) identities in relation to the (fake, queer) identities shown in the narrative.