In your eyes only: deficits in executive functioning after frontal TMS reflect in eye movements

This study investigated the roles of the right and left dorsolateral prefrontal (rDLPFC, lDLPFC) and the medial frontal cortex (MFC) in executive functioning using a theta burst transcranial magnetic stimulation (TMS) approach. Healthy subjects solved two visual search tasks: a number search task with low cognitive demands, and a number and letter search task with high cognitive demands. To observe how subjects solved the tasks, we assessed their behavior with and without TMS using eye movements when subjects were confronted with specific executive demands. To observe executive functions, we were particularly interested in TMS-induced changes in visual exploration strategies found to be associated with good or bad performance in a control condition without TMS stimulation. TMS left processing time unchanged in both tasks. Inhibition of the rDLPFC resulted in a decrease in anticipatory fixations in the number search task, i.e., a decrease in a good strategy in this low demand task. This was paired with a decrease in stimulus fixations. Together, these results point to a role of the rDLPFC in planning and response selection. Inhibition of the lDLPFC and the MFC resulted in an increase in anticipatory fixations in the number and letter search task, i.e., an increase in the application of a good strategy in this task. We interpret these results as a compensatory strategy to account for TMS-induced deficits in attentional switching when faced with high switching demands. After inhibition of the lDLPFC, an increase in regressive fixations was found in the number and letter search task. In the context of high working memory demands, this strategy appears to support TMS-induced working memory deficits. Combining an experimental TMS approach with the recording of eye movements proved sensitive to discrete decrements of executive functions and allows pinpointing the functional organization of the frontal lobes.

Does World Natural Heritage status trigger sustainable regional development efforts?

Today, there are over 200 World Natural Heritage (WNH) sites. Although the original aim of the World Heritage (WH) Convention was to spark off concerted international efforts to preserve sites of outstanding and universal value, today a multitude of expectations rests on WNH sites in terms of conservation, tourism, management and regional development. This paper identifies the effects of WNH status on sustainable regional development and the driving factors behind these effects. The results are based on a global survey of WNH sites and qualitative interviews with key WNH personnel. The paper shows that WNH status can be an important trigger for sustainable regional development, but its effectiveness depends on a number of intricately interwoven ‘soft’ success factors. Clearer policies and management guidelines, as envisaged by UNESCO, are crucial to achieving a balance between conservation and development.

Disturbed cortico–amygdalar functional connectivity as pathophysiological correlate of working memory deficits in bipolar affective disorder

Patients suffering from bipolar affective disorder show deficits in working memory functions. In a previous functional magnetic resonance imaging study, we observed an abnormal hyperactivity of the amygdala in bipolar patients during articulatory rehearsal in verbal working memory. In the present study, we investigated the dynamic neurofunctional interactions between the right amygdala and the brain systems that underlie verbal working memory in both bipolar patients and healthy controls. In total, 18 euthymic bipolar patients and 18 healthy controls performed a modified version of the Sternberg item-recognition (working memory) task. We used the psychophysiological interaction approach in order to assess functional connectivity between the right amygdala and the brain regions involved in verbal working memory. In healthy subjects, we found significant negative functional interactions between the right amygdala and multiple cortical brain areas involved in verbal working memory. In comparison with the healthy control subjects, bipolar patients exhibited significantly reduced functional interactions of the right amygdala particularly with the right-hemispheric, i.e., ipsilateral, cortical regions supporting verbal working memory. Together with our previous finding of amygdala hyperactivity in bipolar patients during verbal rehearsal, the present results suggest that a disturbed right-hemispheric “cognitive–emotional” interaction between the amygdala and cortical brain regions underlying working memory may be responsible for amygdala hyperactivation and affects verbal working memory (deficits) in bipolar patients.

Unconscious relational encoding depends on hippocampus

Textbooks divide between human memory systems based on consciousness. Hippocampus is thought to support only conscious encoding, while neocortex supports both conscious and unconscious encoding. We tested whether processing modes, not consciousness, divide between memory systems in three neuroimaging experiments with 11 amnesic patients (mean age = 45.55 years, standard deviation = 8.74, range = 23-60) and 11 matched healthy control subjects. Examined processing modes were single item versus relational encoding with only relational encoding hypothesized to depend on hippocampus. Participants encoded and later retrieved either single words or new relations between words. Consciousness of encoding was excluded by subliminal (invisible) word presentation. Amnesic patients and controls performed equally well on the single item task activating prefrontal cortex. But only the controls succeeded on the relational task activating the hippocampus, while amnesic patients failed as a group. Hence, unconscious relational encoding, but not unconscious single item encoding, depended on hippocampus. Yet, three patients performed normally on unconscious relational encoding in spite of amnesia capitalizing on spared hippocampal tissue and connections to language cortex. This pattern of results suggests that processing modes divide between memory systems, while consciousness divides between levels of function within a memory system.

Sexually transmitted infections in HIV-infected people in Switzerland: cross-sectional study.

Sexually transmitted infections (STI) in HIV-infected people are of increasing concern. We estimated STI prevalence and sexual healthcare seeking behaviour in 224 sexually active HIV-infected people, including men who have sex with men (MSM, n = 112), heterosexual men (n = 65) and women (n = 47). Laboratory-diagnosed bacterial STI were more common in MSM (Chlamydia trachomatis 10.7%; 95% CI 6.2, 18.0%, lymphogranuloma venereum 0.9%; 95% CI 0.1, 6.2%, Neisseria gonorrhoeae 2.7%; 95% CI 0.9, 8.0%, syphilis seroconversion 5.4%; 95% CI 2.0, 11.3%) than heterosexual men (gonorrhoea 1.5%; 95% CI 0.2, 10.3%) or women (no acute infections). Combined rates of laboratory-diagnosed and self-reported bacterial STI in the year before the study were: MSM (27.7%; 95% CI 21.1, 36.7%); heterosexual men (1.5%; 95% CI 0.2, 10.3%); and women (6.4%; 95% CI 2.1, 21.0%). Antibodies to hepatitis C virus were least common in MSM. Antibodies to herpes simplex type 2 virus were least common in heterosexual men. Most MSM, but not heterosexual men or women, agreed that STI testing should be offered every year. In this study, combined rates of bacterial STI in MSM were high; a regular assessment of sexual health would allow those at risk of STI to be offered testing, treatment and partner management.

Detecting Analogies Unconsciously

Analogies may arise from the conscious detection of similarities between a present and a past situation. In this functional magnetic resonance imaging study, we tested whether young volunteers would detect analogies unconsciously between a current supraliminal (visible) and a past subliminal (invisible) situation. The subliminal encoding of the past situation precludes awareness of analogy detection in the current situation. First, participants encoded subliminal pairs of unrelated words in either one or nine encoding trials. Later, they judged the semantic fit of supraliminally presented new words that either retained a previously encoded semantic relation (“analog”) or not (“broken analog”). Words in analogs versus broken analogs were judged closer semantically, which indicates unconscious analogy detection. Hippocampal activity associated with subliminal encoding correlated with the behavioral measure of unconscious analogy detection. Analogs versus broken analogs were processed with reduced prefrontal but enhanced medial temporal activity. We conclude that analogous episodes can be detected even unconsciously drawing on the episodic memory network.

Word encoding during sleep is suggested by correlations between word-evoked up-states and post-sleep semantic priming

To test whether humans can encode words during sleep we played everyday words to men while they were napping and assessed priming from sleep played words following waking. Words were presented during non rapid eye movement (NREM) sleep. Priming was assessed using a semantic and a perceptual priming test. These tests measured differences in the proces sing of words that had been or had not been played during sleep. Synonyms to sleep played words were the targets in the semantic priming test that tapped the meaning of sleep played words. All men responded to sleep played words by producing up states in their electroencephalogram. Up states are NREM sleep specific phases of briefly increased neuronal excitability. The word evoked up states might have promoted word processing during sleep. Yet, the mean performance in the priming tests administered following sleep was at chance level, which suggests that participants as a group failed to show priming following sleep. However, performance in the two priming tests was positively correlated to each other and to the magnitude of the word evoked up states. Hence, the larger a participant’s word evoked up states, the larger his perceptual and semantic priming. Those participants who scored high on all variables must have encoded words during sleep. We conclude that some humans are able to encode words during sleep, but more research is needed to pin down the factors that modulate this ability.

Chameleons everywhere

We report the case of an HIV-infected man returning from Thailand with secondary syphilis with general symptoms, hepatitis and a pulmonary mass lesion. A cerebrospinal fluid examination showed no signs of neurosyphilis. Two months after successful treatment with benzathine penicillin he presented with a mass lesion in the brain suspected to be a glioma or glioblastoma, which turned out to be a syphilitic gumma. Syphilis remains a great imitator in clinical medicine. Syphilitic brain gummata can develop within a few months.