How conscious experience and working memory interact

Active components of classical working memory are conscious, but traditional theory does not account for this fact. Global Workspace theory suggests that consciousness is needed to recruit unconscious specialized networks that carry out detailed working memory functions. The IDA model provides a fine-grained analysis of this process, specifically of two classical working-memory tasks, verbal rehearsal and the utilization of a visual image. In the process, new light is shed on the interactions between conscious and unconscious aspects of working memory.     

The neural basis of the Weber-Fechner law: a logarithmic mental number line

The recent discovery of number neurons allows for a dissection of the neuronal implementation of number representation. In a recent article, Nieder and Miller demonstrate a neural correlate of Weber's law, and thus resolve a classical debate in psychophysics: the mental number line seems to be logarithmic rather than linear.     

Electrophysiological correlates of anterior cingulate function in a go/no-go task: Effects of response conflict and trial type frequency

Neuroimaging and computational modeling studies have led to the suggestion that response conflict monitoring by the anterior cingulate cortex plays a key role in cognitive control. For example, response conflict is high when a response must be withheld (no-go) in contexts in which there is a prepotent tendency to make an overt (go) response. An event-related brain potential (ERP) component, the N2, is more pronounced on no-go than on go trials and was previously thought to reflect the need to inhibit the go response. However, the N2 may instead reflect the high degree of response conflict on no-go trials. If so, an N2 should also be apparent when subjects make a go response in conditions in which nogo events are more common. To test this hypothesis, we collected high-density ERP data from subjects performing a go/no-go task, in which the relative frequency of go versus no-go stimuli was varied. Consistent with our hypothesis, an N2 was apparent on both go and no-go trials and showed the properties expected of an ERP measure of conflict detection on correct trials: (1) It was enhanced for low-frequency stimuli, irrespective of whether these stimuli were associated with generating or suppressing a response, and (2) it was localized to the anterior cingulate cortex. This suggests that previous conceptions of the no-go N2 as indexing response inhibition may be in need of revision. Instead, the results are consistent with the view that the N2 in go/no-go tasks reflects conflict arising from competition between the execution and the inhibition of a single response.     

Efficacy of telephone-administered cognitive behaviour therapy for obsessive-compulsive spectrum disorders: case studies

Cognitive behaviour therapy is effective for obsessive-compulsive disorder and for obsessive-compulsive spectrum disorders such as trichotillomania. Unfortunately, many people with these disorders, especially those living in rural areas, have limited access to treatment. Telephone-administered cognitive behaviour therapy may help address this problem. In a recent study of telephone treatment for obsessive-compulsive disorder, we found that such treatment was often effective (42% in remission at post-treatment, and 47% in remission at 12-week follow-up). This article presents 2 case reports of the same treatment, applied to obsessive-compulsive spectrum disorders (trichotillomania and compulsive skin picking). Treatment was associated with symptom reduction for both participants, although one subsequently relapsed. Possible reasons for relapse are discussed. The findings encourage further studies to identify the characteristics of people most likely to benefit from telephone treatment for spectrum disorders.     

The clinical effectiveness of cognitive behaviour therapy for chronic insomnia: implementation and evaluation of a sleep clinic in general medical practice

Chronic insomnia is a very common clinical condition which may respond well to non-pharmacological treatment. Indeed, the literature supports the efficacy of cognitive behaviour therapy (CBT). However, there has been no substantial study of clinical effectiveness. Since insomniacs typically present in general medical practice this is a crucial gap in the outcome research. This study, therefore, specifically investigated the clinical effectiveness of CBT delivered by Health Visitors (primary care nurses) trained as therapists. One hundred and thirty-nine insomniacs (mean age 51 yr) were randomised to CBT or Self-Monitoring Control (SMC) in a controlled trial. CBT comprised six group sessions (n=4 to 6 patients). After the controlled phase, SMC patients entered deferred treatment (CBT-DEF), allowing both treatment replication and long-term outcome to be investigated for a sizeable, treated sample. Repeated measures ANOVAs demonstrated superiority of CBT over SMC in substantially reducing sleep latency and wakefulness during the night. CBT-DEF replicated similar effects and maintained improvement was observed in both groups one year later. Furthermore, total sleep increased significantly during follow-up and 84% of patients initially using hypnotics remained drug-free. Results suggest that CBT administered by Health Visitors offers a clinically effective treatment for insomnia.