Using synchronized brain rhythms to bias memory-guided decisions.

Functional interactions between the prefrontal cortex and hippocampus, as revealed by strong oscillatory synchronization in the theta (6-11 Hz) frequency range, correlate with memory-guided decision-making. However, the degree to which this form of long-range synchronization influences memory-guided choice remains unclear. We developed a brain machine interface that initiated task trials based on the magnitude of prefrontal hippocampal theta synchronization, then measured choice outcomes. Trials initiated based on strong prefrontal-hippocampal theta synchrony were more likely to be correct compared to control trials on both working memory-dependent and -independent tasks. Prefrontal-thalamic neural interactions increased with prefrontal-hippocampal synchrony and optogenetic activation of the ventral midline thalamus primarily entrained prefrontal theta rhythms, but dynamically modulated synchrony. Together, our results show that prefrontal-hippocampal theta synchronization leads to a higher probability of a correct choice and strengthens prefrontal-thalamic dialogue. Our findings reveal new insights into the neural circuit dynamics underlying memory-guided choices and highlight a promising technique to potentiate cognitive processes or behavior via brain machine interfacing.

Expanded distribution of an investigational drug in parallel with ongoing controlled clinical trials: the didanosine model.

The purpose of the didanosine Expanded Access Program was to provide a needed antiretroviral agent to individuals who were unable to tolerate other therapy for human immunodeficiency virus infection or in whom such therapy was failing. The logistics of establishing this program are described, and the results of on-site auditing that confirmed the validity of the data obtained through this program are presented.

An evaluation of the susceptibility patterns of gram-negative organisms isolated in cancer centres with aminoglycoside usage.

This study in 12 cancer treatment centres across the United States was designed to evaluate the potential for increased resistance to amikacin with unrestricted use. An initial 3-month baseline period during which the use of amikacin was restricted and that of tobramycin and gentamicin unrestricted was followed by a period of at least 12 months when amikacin was the primary aminoglycoside. Resistance of Gram-negative bacilli to these aminoglycosides from hospitalized patients was monitored and compared for the two periods. Amikacin usage increased from a mean of 20.1% to a mean of 83.9% of aminoglycoside patient-days. A reduction in the use of tobramycin and gentamicin were observed with means of 66.1 and 10%, and 13.9 and 6.1%, respectively for the two periods. Resistance to amikacin was 0.85% at baseline and 1.3% at end-point which was not clinically significant (P = 0.614). Baseline resistance was 6.5 and 7.6%, while final resistance was 2.6 and 4.8%, respectively for tobramycin (P = 0.001) and gentamicin (P = 0.052).