Motion tracking modulates capacity allocation of visual working memory

Previous studies on visual working memory (VWM) have primarily investigated memory for an array presented for a single moment. Here, we examined VWM for two arrays separated by a 1,100-msec interval. We focused on the allocation of VWM capacity to the two arrays as a function of dynamic events inserted between them. During the interval, irrelevant dots moved to form three types of motion: (1) coherent (apparent) motion that connected Arrays 1 and 2, (2) jumpy motion, or (3) coherent motion with two disconnected segments. Results showed that VWM for Array 2’s locations was better than for Array 1’s, especially when the arrays were connected by coherent motion. We suggest that coherent motion between two temporally disparate arrays connects the arrays into a single visual event VWM is then biased toward remembering the more recent state of the event.     

Microstimulation reveals opposing influences of prelimbic and infralimbic cortex on the expression of conditioned fear

Recent studies using lesion, infusion, and unit-recording techniques suggest that the infralimbic (IL) subregion of medial prefrontal cortex (mPFC) is necessary for the inhibition of conditioned fear following extinction. Brief microstimulation of IL paired with conditioned tones, designed to mimic neuronal tone responses, reduces the expression of conditioned fear to the tone. In the present study we used microstimulation to investigate the role of additional mPFC subregions: the prelimbic (PL), dorsal anterior cingulate (ACd), and medial precentral (PrCm) cortices in the expression and extinction of conditioned fear. These are tone-responsive areas that have been implicated in both acquisition and extinction of conditioned fear. In contrast to IL, microstimulation of PL increased the expression of conditioned fear and prevented extinction. Microstimulation of ACd and PrCm had no effect. Under low-footshock conditions (to avoid ceiling levels of freezing), microstimulation of PL and IL had opposite effects, respectively increasing and decreasing freezing to the conditioned tone. We suggest that PL excites amygdala output and IL inhibits amygdala output, providing a mechanism for bidirectional modulation of fear expression.     

Developmental study of multiple memory stages in the cuttlefish, Sepia officinalis

The inhibition of predatory behavior observed during the "prawn-in-the-tube" procedure has been extensively used in studies of cuttlefish learning. The present study examines the effect of age on the conditioning of this response in the cuttlefish, Sepia officinalis. Data show that a significant increase in acquisition performance occurs between 15 and 21 days of age. The retention curves in 8- and 15-day-old cuttlefish show a monotonic memory process, presumably reflecting the presence of only short-term memory. In 21-day-old cuttlefish, there are two distinct processes which could be a labile short-term memory, and a subsequent intermediate memory. These mnesic systems seem to become more effective over the course of post-embryonic development. Moreover, the retention curves obtained in the oldest cuttlefish (30- and 90-day-old) bear a close resemblance to that observed in adults. These behavioral findings will allow further work on the cellular and molecular mechanisms of learning and memory in the cuttlefish.     

An immunochemical approach to model and long-term suppression of depressive and anxiety behavior

The inhibitor of monoaminooxydase isatin and the ligand of B-receptors cholecystokinin-4 play a significant role in the suppression and induction of depressive and anxiety states. We induced the formation of auto-antibodies to these compounds against their conjugates with antigen-carrier by immunization of white rats. The result was long-term (more than 2 months) stimulation of depressive and anxiety behavior after immunization to isatin and, in contrast, the suppression of such behavior after immunization to cholecystokinin. The perspective of immunochemical approach to long-term correction of behavior is discussed.     

Ethics, biotechnology, and global health: the development of vaccines in transgenic plants

As compared with conventional vaccine production systems, plant-made vaccines (PMVs) are said to enjoy a range of advantages including cost of production and ease of storage for distribution in developing countries. In this article, we introduce the science of PMV production, and address ethical issues associated with development and clinical testing of PMVs within three interrelated domains: PMVs as transgenic plants; PMVs as clinical research materials; and PMVs as agents of global health. We present three conclusions: first, while many of the ethical issues raised by PMVs are familiar, PMVs add a new dimension to old issues, and raise some novel issues for ethicists and policy-makers; secondly, it is premature to promise broad applicability of PMVs across the developing world without having demonstrated their feasibility; thirdly, in particular, proponents of PMVs as a solution to global health problems must, as a condition of the ethical conduct of their research, define the commercial feasibility of PMVs for distribution in the developing world.     

Preference for negative emotions

This research demonstrates that preference for emotions sometimes cannot be equated with a positive-negative valence dimension. Participants were asked to make choices between pairs of affect-inducing options opposite in valence but equal in activation. The results showed that in absence of contextual cues or situational constraints, choices followed a pleasure-maximizing principle. However, when information was provided about a context cueing appropriateness of certain emotions over others, a preference reversal was observed so that negative emotions were preferred over positive emotions. These results are discussed in relation to current theories of pleasure-maximizing choice and behavior.     

Cross-validating the Berlin Affective Word List

We introduce the Berlin Affective Word List (BAWL) in order to provide researchers with a German database containing both emotional valence and imageability ratings for more than 2,200 German words. The BAWL was cross-validated using a forced choice valence decision task in which two distinct valence categories (negative or positive) had to be assigned to a highly controlled selection of 360 words according to varying emotional content (negative, neutral, or positive). The reaction time (RT) results corroborated the valence categories: Words that had been rated as “neutral” in the norms yielded maximum RTs. The BAWL is intended to help researchers create stimulus materials for a wide range of experiments dealing with the emotional processing of words.     

Manipulating inattentional blindness within and across sensory modalities

People often fail to consciously perceive visual events that are outside the focus of attention, a phenomenon referred to as inattentional blindness or IB (i.e., Mack & Rock, 1998). Here, we investigated IB for words within and across sensory modalities (visually and auditorily) in order to assess whether dividing attention across different senses has the same consequences as dividing attention within an individual sensory modality. Participants were asked to monitor a rapid stream of pictures or sounds presented concurrently with task-irrelevant words (spoken or written). A word recognition test was used to measure the processing for unattended words compared to word recognition levels after explicitly monitoring the word stream. We were able to produce high levels of IB for visually and auditorily presented words under unimodal conditions (Experiment 1) as well as under crossmodal conditions (Experiment 2). A further manipulation revealed, however, that IB is less prevalent when attention is divided across modalities than within the same modality (Experiment 3). These findings are explained in terms of the attentional load hypothesis and suggest that, contrary to some claims, attention resources are to a certain extent shared across sensory modalities.     

The hoarding dimension of OCD: psychological comorbidity and the five-factor personality model

Although hoarding has been associated with several psychological disorders, it is most frequently linked to obsessive-compulsive disorder (OCD). The present study assessed hoarding obsessions and compulsions in 204 individuals with OCD, and evaluated how hoarding was related to obsessive-compulsive symptom severity, psychological comorbidity, and personality as measured by the five-factor model. Results indicated that hoarding in OCD is a dimensional variable that is positively associated with dysphoria, total number of lifetime Axis I disorders, and lifetime histories of bipolar I, PTSD, and body dysmorphic disorder. Hoarding was negatively correlated with the NEO-Personality Inventory-Revised (NEO-PI-R) factor of Conscientiousness and positively associated with the NEO-PI-R factor of Neuroticism. When all personality and psychopathology variables were entered into a regression equation, dysphoria, bipolar II disorder, Conscientiousness, age, and Extraversion emerged as significant predictors of hoarding severity. Recommendations are made for clinicians and for future research.     

Development of the false-memory illusion

The counterintuitive developmental trend in the Deese-Roediger-McDermott (DRM) illusion (that false-memory responses increase with age) was investigated in learning-disabled and nondisabled children from the 6- to 14-year-old age range. Fuzzy-trace theory predicts that because there are qualitative differences in how younger versus older children and disabled versus nondisabled children connect meaning information across the words on DRM lists, certain key effects that are observed in adult studies will be absent in young children and in learning-disabled children. Data on 6 such adult effects (list strength, recall inflation, delayed inflation, delayed stability, thematic intrusion, and true-false dissociation) were used to investigate this hypothesis, and the resulting data were consistent with prediction.