Human frontal midline theta and its synchronization to gamma during a verbal delayed match to sample task

The involvement of oscillatory activity, especially at theta and gamma frequency, in human working memory has been reported frequently. A salient pattern during working memory is electroencephalographic frontal midline theta activity which has been suggested to reflect monitoring functions in order to deal with a task. In general, theta activity has been credited with integrative functions of distributed activity. In the present study, we focused on electroencephalographic power analyses and cross-frequency phase synchronization in order to test whether frontal midline theta activity is linked to more locally generated gamma oscillations during the performance of a verbal delayed match to sample task. The task consisted of two different conditions where subjects either had to reorganize three consonant letters in alphabetical order (manipulation condition) or where they merely had to retain the three consonant letters (retention condition). Results revealed higher frontal midline theta activity for the manipulation of maintained stimulus material compared to pure retention of stimulus material. Interestingly, power differences between conditions were most pronounced during the second half of the delay period. Cross-frequency phase synchronization between frontal midline theta activity and distributed gamma activity, on the other hand, was predominant during the first half of the delay period and was stronger for manipulation compared to retention. We suggest that coupling of frontal midline theta to gamma activity reflects monitoring functions on the temporal segregation of memory items, whereas higher frontal midline theta power in the second half of the delay period might be associated with rehearsal processes. Rehearsal processes in the manipulation condition are likely more pronounced, because rehearsal of a new letter string in a limited time window requires higher mental effort compared to pure retention where rehearsal processes may already start at the beginning of the delay period.     

Bypassing shame and conversion disorder

We report a case of conversion disorder (partial aphonia) that was successfully treated with speech therapy. During the one year duration of this illness, the patient regained transiently (minutes) her normal speech on a few occasions, independently of concomitant pharmacological interventions. One year after recovery she developed aphonia for the second time, which responded again to speech therapy, although the response rate was slower. Several mechanisms of conversion disorder are reviewed as specifically applied to this case. The possible role of pertinent shame mechanisms in the conversion pathology is discussed.     

Coherence in Epistemology and Belief Revision*

A general theory of coherence is proposed, in which systemic and relational coherence are shown to be interdefinable. When this theory is applied to sets of sentences, it turns out that logical closure obscures the distinctions that are needed for a meaningful analysis of coherence. It is concluded that references to “all beliefs” in coherentist phrases such as “all beliefs support each other” have to be modified so that merely derived beliefs are excluded. Therefore, in order to avoid absurd conclusions, coherentists have to accept a weak version of epistemic priority, that sorts out merely derived beliefs. Furthermore, it is shown that in belief revision theory, coherence cannot be adequately represented by logical closure, but has to be represented separately. *Contribution to “Seven Bridges”     

The language of landmarks: the role of background knowledge in indoor wayfinding

To effectively wayfind through unfamiliar buildings, humans infer their relative position to target locations not only by interpreting geometric layouts, especially length of line of sight, but also by using background knowledge to evaluate landmarks with respect to their probable spatial relation to a target. Questionnaire results revealed that participants have consistent background knowledge about the relative position of target locations. Landmarks were rated significantly differently with respect to their spatial relation to targets. In addition, results from a forced-choice task comparing snapshots of a virtual environment revealed that background knowledge influenced wayfinding decisions. We suggest that landmarks are interpreted semantically with respect to their function and spatial relation to the target location and thereby influence wayfinding decisions. This indicates that background knowledge plays a role in wayfinding.     

Supporting her autonomy: the obligations of guardians and physicians in adolescents' refusals of care

This commentary on "Her Own Decision: Impairment and Authenticity in Adolescence" by Campbell, Derrington, Hester, and Lew adds further consideration of obligations for guardians and physicians of minors who struggle in making serious decisions regarding medical treatment.     

Recognition deficits resulting from focussed attention in aphasia

Summary Two nonverbal short-term memory tasks, a Picture Recognition and a Paired Association Task, were performed by matched groups of aphasics and brain-damaged controls (N=52 each). For both tasks the alternatives on the answer forms differed systematically on three dimensions, one of which had been highlighted experimentally for each item before the target picture was indicated. In both tasks aphasics made more errors than braindamaged controls only with respect to those features that had been stressed beforehand; they were less able than controls to take advantage of focussed attention. The number of these errors was correlated with performance in the Token Test, a picture naming and a word comprehension task.There were no differences between the groups in response to variations in the semantic saliency of the discriminating features or in the semantic and phonetic relationship between words denoting the reference stimuli. The lack of interactions might have been due to a strong ceiling effect in both tasks.     

Personality traits in eating-disordered patients with and without self-injurious behaviors

Although there is a high comorbidity of eating disorder and self-injurious behavior (SIB), no systematic research has focused on personality trait differences in patients with and without SIB. In this study, a Dutch adaptation of the NEO-FFI (Costa & McCrae, 1985, 1992) was completed by 178 female, eating-disordered (ED) patients of whom 46.5% showed at least 1 form of SIB (e.g., cutting, burning, hair pulling). A subsample of 41 patients also completed the NEO-PI-R. Compared to patients without SIB, ED patients with SIB scored significantly higher on the Neuroticism scale and significantly lower on the Extraversion scale; on subtraits (facet scores) they appeared to be more anxious, more willing to please and less cheerful, efficient and ambitious. Personality traits were not associated with frequency or form of SIB or subtype of ED (except for impulsiveness). We also did not find a significant interaction effect between ED subtype and presence/absence of SIB.     

Potentiating ballistic limb movements through voluntary production of the stretch-shorten cycle.

The purpose of this study was to examine the effect of learning to produce voluntarily a basic biomechanical mechanism, the stretch-shorten cycle (SSC), on the acceleration of a ballistic arm movement. The task required an elbow flexion at maximal effort performed with the forearm resting upon a horizontal manipulandum. Subjects in three groups received either no augmented feedback, feedback concerning the velocity of the flexion, or a combination of feedback on velocity and feedback related to the rate of stretch of the SSC during 80 training trials. The training trials were preceded by a pretest and followed by a posttest without feedback. Analyses showed that the subjects receiving feedback concerning the SSC exhibited earlier and greater peak angular acceleration than the other groups. These findings provide evidence that acquiring the control of relevant, basic mechanisms like the SSC may be useful in facilitating tasks requiring limb movements of maximal effort.     

European Public Advice on Nanobiotechnology—Four Convergence Seminars

In order to explore public views on nanobiotechnology (NBT), convergence seminars were held in four places in Europe; namely in Visby (Sweden), Sheffield (UK), Lublin (Poland), and Porto (Portugal). A convergence seminar is a new form of public participatory activity that can be used to deal systematically with the uncertainty associated for instance with the development of an emerging technology like nanobiotechnology. In its first phase, the participants are divided into three “scenario groups” that discuss different future scenarios. In the second phase, the participants are regrouped into three “convergence groups”, each of which contains representatives from each of the three groups from the first phase. In the final third phase, all participants meet for a summary discussion. This pilot project had two aims: (1) to develop and assess the new methodology and (2) to gather advice and recommendations from the public that may be useful for future decisions on nanobiotechnology (NBT). Participants emphasized that they wanted the technology to focus on solutions to environmental and medical problems and to meet the needs of developing countries. The need for further public participation and deliberation on NBT issues seemed to be acknowledged by all participants. Many of them also raised equality concerns. Views on the means by which NBT should be steered into socially useful directions were more divided. In particular, different views were expressed on how much regulation of company activities is needed to curb unwanted developments. The participants’ responses in a questionnaire indicate that the methodology of the convergence seminars was successful for decision-making under uncertainty. In particular, the participants stated that their advice was influenced both by access to different possible future developments and by the points of view of their co-participants, which is what the method is specifically intended to achieve.