Importance effects on performance in event-based prospective memory tasks

In the present study we manipulated the importance of performing two event-based prospective memory tasks. In Experiment 1, the event-based task was assumed to rely on relatively automatic processes, whereas in Experiment 2 the event-based task was assumed to rely on a more demanding monitoring process. In contrast to the first experiment, the second experiment showed that importance had a positive effect on prospective memory performance. In addition, the occurrence of an importance effect on prospective memory performance seemed to be mainly due to the features of the prospective memory task itself, and not to the characteristics of the ongoing tasks that only influenced the size of the importance effect. The results suggest that importance instructions may improve prospective memory if the prospective task requires the strategic allocation of attentional monitoring resources.     

The redundant target effect is affected by modality switch costs

When participants have to respond to stimuli of two modalities, faster reaction times are observed for simultaneous, bimodal events than for unimodal events (the redundant target effect [RTE]). This finding has been interpreted as reflecting processing gains for bimodal relative to unimodal stimuli, possibly due to multisensory interactions. In random stimulus sequences, reaction times are slower when the stimulus is preceded by a stimulus of a different modality (modality switch effect [MSE]). Simple reaction time redundant target experiments with auditory-visual, visual-tactile, and auditory-tactile stimulus combinations were run to determine whether the RTE may be partly explained by MSEs because bimodal stimuli do not require a modality switch. In all three modality pairings, significant MSEs and RTEs were observed. However, the RTE was still significant after reaction times were corrected for the MSE, supporting the hypothesis that coactivation occurs independently of modality switch costs.     

Being seaward-handed: a computational model of the acquisition of language-specific spatial references

Empirical findings of cross-linguistic studies reveal three different frames of spatial reference: intrinsic, relative, and absolute. Of special interest are relative and absolute systems because they have antagonistic logical implications concerning the dependence on standpoint and orientation of the speaker/hearer. On the background of these findings it becomes crucial to show how an agent can form such language-specific spatial representations. In this paper, the system Locator is introduced as a model of concept formation in the spatial domain. It is assumed that an agent creates necessary discriminative features in processes of self-organization and selection and cannot just discover or find them in its environment. A number of simulations show that agents successfully create concepts of either a relative system (German) or an absolute system (Marquesan), relying solely on multimodal input (visual and linguistic).

The lay assessment of subclinical depression in daily life

This study examined how laypersons assess subclinical depression in others on the basis of information about their daily lives. For 2 days, 96 participants were tracked with the Electronically Activated Recorder, a naturalistic observation method that samples ambient sounds from participants' momentary environments. Judges rated participants' levels of depression after listening to the sampled ambient sounds. Participants' depressive symptoms were assessed with the Beck Depression Inventory. Overall, judges showed little accuracy at determining participants' levels of depressive symptoms from the ambient sounds. Exploratory analyses, however, revealed that judges were more accurate among moderately and severely depressed participants, presumably because the cues judges used to assess depression (e.g., spending time alone, not socializing, not laughing) discriminated successfully only at high levels of subclinical depression.     

Psychosocial stress enhances time-based prospective memory in healthy young men

Forgetting of intentions (such as to take one's medication) is the most frequent everyday memory failure. No study so far has looked into the possible consequences stress might exert on memory for intentions (i.e., prospective memory). Twenty healthy young male adults were exposed to a psychosocial stress test and a non-stress condition. After a delay of 15 min, a time- and an event-based prospective memory task were administered during the peak of cortisol concentrations. Results show that participants performed significantly better in the time-based memory task after stress in comparison to the non-stress condition. In contrast, there was no stress effect on event-based prospective memory. The results demonstrate that prospective memory might be enhanced when participants are exposed to stress prior to the memory task and that this effect is associated to stress-related glucocorticoid effects.     

Serotonergic dysfunction: Brain imaging and behavioral correlates

Identification of gene-environment and gene-gene interactions has become increasingly important in understanding psychiatric disorders. Dysfunction of central serotonergic neurotransmission has been implicated in alcoholism, depression, and anxiety. We review the literature on nonhuman primates that assesses the interaction between the genetic constitution of the regulatory region of the serotonin transporter (5-HTT) and environmental factors. Prospective studies in nonhuman primates that underwent social stress found a reduction of the serotonin turnover rate among carriers of one or two short alleles in a functional polymorphism of the 5-HTT promoter. In these primates, brain imaging studies showed a relative increase in the availability of raphe serotonin transporters. A low serotonin turnover rate and a high availability of serotonin transporters were associated with reduced response to excessive alcohol intake, anxiety, and impulsive aggression. Animal experiments point to a relationship between serotonergic dysfunction, negative mood states, and excessive alcohol intake, which may in part be mediated by reduced alcohol-induced sedation.     

Consensus conference on environmental values in radiation protection: a report on building consensus among experts

During the fall of 2001 (October 22–25), The Norwegian Radiation Protection Authority (NRPA) and the Agricultural University of Norway arranged a consensus conference on the protection of the environment against ionising radiation. The motive for the conference was the need to study the ethical and philosophical basis for protection of nature in its own right. The conference was funded by Nordic Nuclear Safety Research (NKS), in cooperation with the International Union of Radioecology (IUR). The National Committee for Research Ethics in Science and Technology (NENT) was hired as facilitators for the consensus process. This paper will give a brief outline of the aims and method of the conference, distinguishing these from other kinds of consensus conferences. The paper ends with some general reflections on the appropriateness of seeking consensus on ethics-related issues among experts.     

Activation of the cannabinoid receptor type 1 decreases glutamatergic and GABAergic synaptic transmission in the lateral amygdala of the mouse

The endogenous cannabinoid system has been shown recently to play a crucial role in the extinction of aversive memories. As the amygdala is presumably involved in this process, we investigated the effects of the cannabinoid receptor agonist WIN 55,212-2 (WIN-2) on synaptic transmission in the lateral amygdala (LA) of wild-type and cannabinoid receptor type 1 (CB1)-deficient mice. Extracellular field potential recordings and patch-clamp experiments were performed in an in vitro slice preparation. We found that WIN-2 reduces basal synaptic transmission and pharmacologically isolated AMPA receptor- and GABA_A receptor-mediated postsynaptic currents in wild-type, but not in CB1-deficient mice. These results indicate that, in the LA, cannabinoids modulate both excitatory and inhibitory synaptic transmission via CB1. WIN-2-induced changes of paired-pulse ratio and of spontaneous and miniature postsynaptic currents suggest a presynaptic site of action. Inhibition of G_i/o proteins and blockade of voltage-dependent and G protein-gated inwardly rectifying K⁺ channels inhibited WIN-2 action on basal synaptic transmission. In contrast, modulation of the adenylyl cyclase-protein kinase A pathway, and blockade of presynaptic N- and P/Q- or of postsynaptic L- and R/T-type voltage-gated Ca²⁺ channels did not affect WIN-2 effects. Our results indicate that the mechanisms underlying cannabinoid action in the LA partly resemble those observed in the nucleus accumbens and differ from those described for the hippocampus.     

Early modulation of visual perception by emotional arousal: Evidence from steady-state visual evoked brain potentials

Allocation of processing resources to emotional picture stimuli was examined using steady-state visual evoked brain potentials (ssVEPs). Participants viewed a set of 60 colored affective pictures from the International Affective Picture System, presented in a flickering mode at 10 Hz in order to elicit ssVEPs. Phase and amplitude of the 10-Hz ssVEP were examined for six picture categories: threat and mutilation (unpleasant), families and erotica (pleasant), and household objects and persons (neutral). Self-reported affective arousal and hedonic valence of the picture stimuli were assessed by means of subjective ratings. Viewing affectively arousing (unpleasant and pleasant) pictures was associated with enhanced ssVEP amplitude at parieto-occipital recording sites, as compared with neutral stimuli. Phase information suggested increased coactivation of right occipitotemporal and frontotemporal sources during processing of affectively arousing stimuli. These findings are consistent with reentrant modulation of early visual processing by distributed networks including subcortical and neocortical structures according to a stimulus's motivational relevance.