Use of prescription stimulants by normal healthy individuals to enhance cognition is said to be on the rise. Who is using these medications for cognitive enhancement, and how prevalent is this practice? Do prescription stimulants in fact enhance cognition for normal healthy people? We review the epidemiological and cognitive neuroscience literatures in search of answers to these questions. Epidemiological issues addressed include the prevalence of nonmedical stimulant use, user demographics, methods by which users obtain prescription stimulants, and motivations for use. Cognitive neuroscience issues addressed include the effects of prescription stimulants on learning and executive function, as well as the task and individual variables associated with these effects. Little is known about the prevalence of prescription stimulant use for cognitive enhancement outside of student populations. Among college students, estimates of use vary widely but, taken together, suggest that the practice is commonplace. The cognitive effects of stimulants on normal healthy people cannot yet be characterized definitively, despite the volume of research that has been carried out on these issues. Published evidence suggests that declarative memory can be improved by stimulants, with some evidence consistent with enhanced consolidation of memories. Effects on the executive functions of working memory and cognitive control are less reliable but have been found for at least some individuals on some tasks. In closing, we enumerate the many outstanding questions that remain to be addressed by future research and also identify obstacles facing this research.

The highly variable clinical course and the lack of a direct measurement of disease activity have made evaluation of experimental therapies in multiple sclerosis (MS) difficult. Recent studies indicate that clinically silent lesions can be demonstrated by magnetic resonance imaging (MRI) in patients with mild relapsing-remitting MS. Thus, MRI may provide a means for monitoring therapeutic trials in the early phase of MS. We studied 12 patients longitudinally for 12 to 21 months with monthly gadolinium (Gd)-enhanced MRIs. The data have been used to identify the most effective design of a clinical trial using Gd-enhanced lesions as the outcome measure. Frequent (>l/mo) Gd-enhancing lesions were observed in 9 of the 12 patients, indicating that the disease is active even during the early phase of the illness.The frequency of the lesions was not constant; there was marked fluctuation in lesion number from month to month. However, the magnitude of the peak number of lesions and the frequency of the peaks varied among patients. Because of this variability, the most effective use of Gd-enhancing lesions as an outcome measure in a clinical trial was a crossover design with study arms of sufficient duration to allow accurate estimation of lesion frequency. Monitoring Gd-enhancing lesions may be an effective tool to assist in the assessment of experimental therapies in early MS.

Neuroimaging studies have identified brain regions that respond preferentially to specific stimulus categories, including 3 areas that activate maximally during viewing of real-world scenes: The parahippocampal place area (PPA), retrosplenial complex (RSC), and transverse occipital sulcus (TOS). Although these findings suggest the existence of regions specialized for scene processing, this interpretation is challenged by recent reports that activity in scene-preferring regions is modulated by properties of isolated single objects. To understand the mechanisms underlying these object-related responses, we collected functional magnetic resonance imaging data while subjects viewed objects rated along 7 dimensions, shown both in isolation and on a scenic background. Consistent with previous reports, we find that scene-preferring regions are sensitive to multiple object properties; however, results of an item analysis suggested just 2 independent factors--visual size and the landmark suitability of the objects--sufficed to explain most of the response. This object-based modulation was found in PPA and RSC irrespective of the presence or absence of a scenic background, but was only observed in TOS for isolated objects. We hypothesize that scene-preferring regions might process both visual qualities unique to scenes and spatial qualities that can appertain to either scenes or objects.

We found a positive effect of recombinant human nerve growth factor on neuropathic pain and pin sensitivity in HIV-associated sensory neuropathy. rhNGF was safe and well tolerated, but injection site pain was frequent.

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Clinically and immunologically stable HIV-infected children had more frequent behavioral problems and lower developmental and cognitive scores than established childhood norms.

Alendronate increased BMD at both the spine and hip in elderly female residents of long-term care facilities.

Magnetic resonance imaging (MRI) has been a valuable tool to understand the pathophysiology and natural history of multiple sclerosis (MS), and increasing attention is focusing on the use of MRI findings as outcome measures in treatment trials in MS. The recently completed trial of interferon-beta-1b (IFN-beta 1b) demonstrated a decrease in accumulation of diseased tissue on T2-weighted images and a reduction in new lesions on T2-weighted images. To examine the effect of IFN-beta 1b on blood-brain barrier (BBB) breakdown, and to provide additional insights into the usefulness of MRI in the evolution of effectiveness of experimental treatments in MS, we used the contrast-enhanced lesion frequency of 7-month baseline MRIs compared with the enhanced lesion frequency for 6-month treatment period MRIs in 14 relapsing-remitting (RR) MS patients. Longer baselines were also available for analysis in a subset of 8 patients, as these patients had been followed by monthly MRI in a natural history study for up to 4 years prior to the current study. A significant reduction in the total or new enhancing lesion frequency was detected in the patients analyzed as a whole, and 13 of 14 of the patients demonstrated a reduction in enhancing lesion frequency on treatment over the 6 months studied. These findings suggest that IFN-beta has a mechanism of action that at least temporarily inhibits the opening of the BBB in RRMS patients. This trial also illustrates the usefulness of a baseline versus treatment trial design to evaluate the effect of drug therapy in MS.