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Objective. A major challenge in designing closed-loop brain-computer interfaces is finding optimal stimulation patterns as a function of ongoing neural activity for different subjects and different objectives. Traditional approaches, such as those currently used for deep brain stimulation, have largely followed a manual trial-and-error strategy to search for effective open-loop stimulation parameters, a strategy that is inefficient and does not generalize to closed-loop activity-dependent stimulation. Approach. To achieve goal-directed closed-loop neurostimulation, we propose the use of brain co-processors, devices which exploit artificial intelligence to shape neural activity and bridge injured neural circuits for targeted repair and restoration of function. Here we investigate a specific type of co-processor called a 'neural co-processor' which uses artificial neural networks and deep learning to learn optimal closed-loop stimulation policies. The co-processor adapts the stimulation policy as the biological circuit itself adapts to the stimulation, achieving a form of brain-device co-adaptation. Here we use simulations to lay the groundwork for future in vivo tests of neural co-processors. We leverage a previously published cortical model of grasping, to which we applied various forms of simulated lesions. We used our simulations to develop the critical learning algorithms and study adaptations to non-stationarity in preparation for future in vivo tests. Main results. Our simulations show the ability of a neural co-processor to learn a stimulation policy using a supervised learning approach, and to adapt that policy as the underlying brain and sensors change. Our co-processor successfully co-adapted with the simulated brain to accomplish the reach-and-grasp task after a variety of lesions were applied, achieving recovery towards healthy function in the range 75%-90%. Significance. Our results provide the first proof-of-concept demonstration, using computer simulations, of a neural co-processor for adaptive activity-dependent closed-loop neurostimulation for optimizing a rehabilitation goal after injury. While a significant gap remains between simulations and in vivo applications, our results provide insights on how such co-processors may eventually be developed for learning complex adaptive stimulation policies for a variety of neural rehabilitation and neuroprosthetic applications., (Creative Commons Attribution license.)

Background: Heel prick is a frequent painful procedure in newborns. A lancet or a 26-gauge needle is used for a heel prick in India., Objective: To compare the pain caused by heel prick with a lancet or a 26-gauge needle in newborns admitted in the neonatal intensive care unit (NICU) using the preterm infant pain profile (PIPP)., Methods: This randomized controlled trial was conducted over 2 months in a Level III NICU with a sample size of 40 subjects (20 in each group), which was required for the study to have a power of 80% with an alpha error of 0.05. Hemodynamically stable newborns on at least those on partial oral feeds undergoing heel prick for routine glucose monitoring were randomized into two groups within 48 h of NICU admission after informed parental consent: heel prick with a lancet or with a 26-gauge needle using computer-generated random numbers. Two milliliters of expressed breast milk was given 2 min before the heel prick. Pain before, during and after (1 and 5 min) was assessed using the PIPP score. The primary outcome measure was the PIPP score. The secondary outcome measures were the duration of audible cry and the number of pricks needed for an adequate sample. Statistical analysis was done using the Mann Whitney U test and Friedman's test on SPSS v.21. A p value of < 0.05 was significant., Results: There were 40 neonates, 24 males and 16 females included in the study with a median age of 7 days. The mean birth weight was 2441 g (SD: 699) at a mean gestation of 34.4 weeks (SD: 3.2). The median PIPP scores at 0-30 s after heel prick were 7.05 ± 3.57 with a lancet vs. 9.35 ± 3.68 a needle (p = 0.052). There was a significantly lower duration of audible cry with use of lancet (10.5 ± 18.5 s vs. 75.2 ± 12.0 s with needle; p = 0.03). All heel pricks resulted in adequate sampling., Conclusion: Heel prick with a lancet causes less crying than a 26-gauge needle, though the PIPP scores are not significantly different., (© The Author [2017]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com)