Differential involvement of NMDA and AMPA receptors within the nucleus accumbens in consolidation of information necessary for place navigation and guidance strategy of mice

Recent evidence now points to a role of glutamate transmission within the nucleus accumbens (Nacc) in spatial learning and memory. Unfortunately, the role of the distinct classes of glutamate receptors within this structure in mediating the different steps of the memorization process is not clear. The aim of this study therefore was to further investigate this issue, trying to assess the involvement of the two classes of glutamate receptors within the Nacc in consolidation of spatial information using an associative spatial task, the water maze. For this purpose, focal injections of the NMDA antagonist, AP-5, and of the AMPA antagonist, DNQX, have been performed immediately after the training phase, and mice have been tested for retention 24 h later. Two different versions of the water-maze task have been used: In the place version, animals could learn the position of the platform using visual distal cues, and in the cue version, the location of the platform was indicated by a single proximal cue. The results demonstrated that posttraining NMDA receptor blockade affects mice response in the place but not in the cue water-maze task. On the contrary, AMPA receptor blockade induced no effect in either version of the task. These data confirm a functional dissociation between glutamate receptors located in the Nacc in modulating spatial memory consolidation and indicate that they are specifically involved in consolidation of information necessary to acquire a place but not to a guidance strategy.     

EEG decoding of semantic category reveals distributed representations for single concepts

Achieving a clearer picture of categorial distinctions in the brain is essential for our understanding of the conceptual lexicon, but much more fine-grained investigations are required in order for this evidence to contribute to lexical research. Here we present a collection of advanced data-mining techniques that allows the category of individual concepts to be decoded from single trials of EEG data. Neural activity was recorded while participants silently named images of mammals and tools, and category could be detected in single trials with an accuracy well above chance, both when considering data from single participants, and when group-training across participants. By aggregating across all trials, single concepts could be correctly assigned to their category with an accuracy of 98%. The pattern of classifications made by the algorithm confirmed that the neural patterns identified are due to conceptual category, and not any of a series of processing-related confounds. The time intervals, frequency bands and scalp locations that proved most informative for prediction permit physiological interpretation: the widespread activation shortly after appearance of the stimulus (from 100 ms) is consistent both with accounts of multi-pass processing, and distributed representations of categories. These methods provide an alternative to fMRI for fine-grained, large-scale investigations of the conceptual lexicon.     

Paradoxical frames and creative sparks: Enhancing individual creativity through conflict and integration

Across industries, organizations operate in increasingly complex and uncertain environments. To succeed in such environments, organizations require their members to think creatively and integrate conflicting demands. We propose that the adoption of paradoxical frames—mental templates that encourage individuals to recognize and embrace contradictions—increases creativity. In four laboratory studies using different creativity tasks and different manipulations for eliciting paradoxical frames, participants who adopted paradoxical frames were more creative than their counterparts who did not. Our results suggest that the positive influence of paradoxical frames on creativity is due to the paradoxical relationship between task elements and not merely to their joint activation. This paradoxical relationship creates a sense of conflict in individuals and enhances their ability to integrate contradictions, which in turn increases creativity.     

Use of Anticipatory Cues to Reduce Dependence on Physical Prompts by an Adolescent with Multiple Disabilities

Anticipatory cues (vibratory stimulation activated through remote control) were used in this study to help an adolescent with multiple disabilities to reduce his dependence on the caregiver's physical prompts. The results show that anticipatory cues were effective in helping the adolescent perform practical daily responses independently of physical prompts. Towards the end of the study, the adolescent could also perform increasingly independently of the anticipatory cues. Implications of the findings are discussed.     

Persons with acquired brain injury and multiple disabilities access stimulation independently through microswitch-based technology

The possibility of enabling two adults with acquired brain injury and profound multiple disabilities to use microswitch-based technology to attain preferred environmental stimuli on their own was assessed. Each of the participants was provided with two microswitches that could be activated by right and left head-turning or head-bending responses. The microswitches were introduced sequentially according to a multiple probe design across microswitches (responses) and allowed access to different sets of auditory or visual stimuli. Eventually, the two microswitches were made available simultaneously. Sessions lasted 5 min. Each participant learned to use the two microswitches successfully and maintained consistent levels of responding when they were simultaneously available. During this phase, both participants showed large within-session variations in their right and left response frequencies, with one of them showing an overall prevalence of the left-side response. The importance of assistive technology within programs for persons with acquired brain injury and multiple disabilities is discussed.     

Attentional distractor interference may be diminished by concurrent working memory load in normal participants and traumatic brain injury patients

A reduction in congruency effects under working memory (WM) load has been previously described using different attentional paradigms (e.g.,  and ). One hypothesis is that different types of WM load have different effects on attentional selection, depending on whether a specific memory load demands resources in common with target or distractor processing. In particular, if information in WM is related to the distractors in the selective attention task, there is a reduction in distraction (Kim et al., 2005). However, although previous results seem to point to a decrease in interference under high WM load conditions (Kim et al., 2005), the lack of a neutral baseline for the congruency effects makes it difficult to differentiate between a decrease in interference or in facilitation. In the present work we included neutral trials in the task introduced by Kim et al. (2005) and tested normal participants and traumatic brain injury patients. Results support a reduction in the processing of distractors under WM load, at least for incongruent trials in both groups. Theoretical as well as applied implications are discussed.