Bidirectional deep brain stimulation (DBS) platforms have enabled a surge in hours of recordings in naturalistic environments, allowing further insight into neurological and psychiatric disease states. However, high amplitude, high frequency stimulation generates artifacts that contaminate neural signals and hinder our ability to interpret the data. This is especially true in psychiatric disorders, for which high amplitude stimulation is commonly applied to deep brain structures where the native neural activity is miniscule in comparison. Here, we characterized artifact sources in recordings (...) from a bidirectional DBS platform, the Medtronic Summit RC + S, with the goal of optimizing recording configurations to improve signal to noise ratio (SNR). Data were collected from three subjects in a clinical trial of DBS for obsessive-compulsive disorder. Stimulation was provided bilaterally to the ventral capsule/ventral striatum (VC/VS) using two independent implantable neurostimulators. We first manipulated DBS amplitude within safe limits (2–5.3 mA) to characterize the impact of stimulation artifacts on neural recordings. We found that high amplitude stimulation produces slew overflow, defined as exceeding the rate of change that the analog to digital converter can accurately measure. Overflow led to expanded spectral distortion of the stimulation artifact, with a six fold increase in the bandwidth of the 150.6 Hz stimulation artifact from 147–153 to 140–180 Hz. By increasing sense blank values during high amplitude stimulation, we reduced overflow by as much as 30% and improved artifact distortion, reducing the bandwidth from 140–180 Hz artifact to 147–153 Hz. We also identified artifacts that shifted in frequency through modulation of telemetry parameters. We found that telemetry ratio changes led to predictable shifts in the center-frequencies of the associated artifacts, allowing us to proactively shift the artifacts outside of our frequency range of interest. Overall, the artifact characterization methods and results described here enable increased data interpretability and unconstrained biomarker exploration using data collected from bidirectional DBS devices. (shrink)

The author discusses the contribution of humanities teaching in medical education. Five "qualities of mind" specifically engendered by the humanistic disciplines are isolated, delineated, and illustrated: critical abilities, flexibility of perspective, nondogmatism, discernment of values, and empathy and self-knowledge. Keywords: humanities, humanities and medicine, medical education CiteULike Connotea Del.icio.us What's this?

The author of this comment suggests that some of the important points made by Dr Adrian Rogers are vitiated by a tendency to contrast the worst of modern medical practice with an over-idealised view of the past. The state of medical ethics today, the author suggests, is more hopeful than Dr Rogers allows.

L'article est une critique de l'analyse faite par Richard Robinson du livre IV de la République de Platon. Ces pages de Platon offrent une analyse de la faiblesse de la volonté en termes d'un conflit entre les parties de l'âme. Robinson rejette l'analyse faite par Platon de la faiblesse de la volonté du fait que son principe de base selon lequel la même [chose] ne fait ni ne souffre des choses opposées est invalide. La critique de Robinson dépend en grand (...) partie de la conception du principe de non-contradiction en cours au temps où il écrivait et qui se trouve en forme résumée dans les écrits du logicien polonais Jan Łukasiewicz. En conséquence, l'auteur critique la compréhension du principe de non-contradiction par le logicien polonais; il applique ensuite cette critique à ce que Robinson dit au sujet de Platon. Sa conclusion est que Robinson non a raison d'insister que la logique n'a rien à faire avec la psychologie et que, donc, sa critique de Platon est inconclusive. (shrink)