scholarly journals CLoSES: A platform for closed-loop intracranial stimulation in humans

NeuroImage ◽  
2020 ◽  
Vol 223 ◽  
pp. 117314
Author(s):  
Rina Zelmann ◽  
Angelique C. Paulk ◽  
Ishita Basu ◽  
Anish Sarma ◽  
Ali Yousefi ◽  
...  
Keyword(s):  
Closed Loop ◽  
Intracranial Stimulation

scholarly journals CLoSES: A platform for closed-loop intracranial stimulation in humans

2020 ◽  
Author(s):  
Rina Zelmann ◽  
Angelique C. Paulk ◽  
Ishita Basu ◽  
Anish Sarma ◽  
Ali Yousefi ◽  
...  
Keyword(s):  
Real Time ◽  
Closed Loop ◽  
Therapeutic Modality ◽  
Patient Specific ◽  
Cognitive State ◽  
Intracranial Stimulation ◽  
Decision Algorithm ◽  
Depth Electrodes ◽  
Neuropsychiatric Diseases ◽  
Epilepsy Monitoring

AbstractTargeted interrogation of brain networks through invasive brain stimulation has become an increasingly important research tool as well as a therapeutic modality. The majority of work with this emerging capability has been focused on open-loop approaches. Closed-loop techniques, however, could improve neuromodulatory therapies and research investigations by optimizing stimulation approaches using neurally informed, personalized targets. Specifically, closed-loop direct electrical stimulation tests in humans performed during semi-chronic electrode implantation in patients with refractory epilepsy could help deepen our understanding of basic research questions as well as the mechanisms and treatment solutions for many neuropsychiatric diseases.However, implementing closed-loop systems is challenging. In particular, during intracranial epilepsy monitoring, electrodes are implanted exclusively for clinical reasons. Thus, detection and stimulation sites must be participant- and task-specific. In addition, the system must run in parallel with clinical systems, integrate seamlessly with existing setups, and ensure safety features. A robust, yet flexible platform is required to perform different tests in a single participant and to comply with clinical settings.In order to investigate closed-loop stimulation for research and therapeutic use, we developed a Closed-Loop System for Electrical Stimulation (CLoSES) that computes neural features which are then used in a decision algorithm to trigger stimulation in near real-time. To summarize CLoSES, intracranial EEG signals are acquired, band-pass filtered, and local and network features are continuously computed. If target features are detected (e.g. above a preset threshold for certain duration), stimulation is triggered. An added benefit is the flexibility of CLoSES. Not only could the system trigger stimulation while detecting real-time neural features, but we incorporated a pipeline wherein we used an encoder/decoder model to estimate a hidden cognitive state from the neural features. Other features include randomly timed stimulation, which percentage of biomarker detections produce stimulation, and safety refractory periods.CLoSES has been successfully used in twelve patients with implanted depth electrodes in the epilepsy monitoring unit during cognitive tasks, spindle detection during sleep, and epileptic activity detection. CLoSES provides a flexible platform to implement a variety of closed-loop experimental paradigms in humans. We anticipate that probing neural dynamics and interaction between brain states and stimulation responses with CLoSES will lead to novel insights into the mechanism of normal and pathological brain activity, the discovery and evaluation of potential electrographic biomarkers of neurological and psychiatric disorders, and the development and testing of patient-specific stimulation targets and control signals before implanting a therapeutic device.

scholarly journals Closed-loop intracranial stimulation alters movement timing in humans

2018 ◽  
Vol 11 (4) ◽  
pp. 886-895 ◽  
Author(s):  
Bartlett D. Moore ◽  
Adam R. Aron ◽  
Nitin Tandon
Keyword(s):  
Closed Loop ◽  
Intracranial Stimulation ◽  
Movement Timing

Intestinal Bacteriology of Closed Loop, Strangulated Obstruction in Dogs.

1961 ◽  
Vol 41 (3) ◽  
pp. 245-250 ◽  
Author(s):  
George H. Bornside ◽  
Isidore Cohn
Keyword(s):  
Closed Loop

The Impact of Visual Feedback Type on the Mastery of Visuo-Motor Transformations

2012 ◽  
Vol 220 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Sandra Sülzenbrück
Keyword(s):  
Empirical Research ◽  
Visual Feedback ◽  
Closed Loop ◽  
Motor Planning ◽  
Visual Input ◽  
Closed Loop Control ◽  
Loop Control ◽  
Feedback Type ◽  
Effective Use ◽  
The Impact

For the effective use of modern tools, the inherent visuo-motor transformation needs to be mastered. The successful adjustment to and learning of these transformations crucially depends on practice conditions, particularly on the type of visual feedback during practice. Here, a review about empirical research exploring the influence of continuous and terminal visual feedback during practice on the mastery of visuo-motor transformations is provided. Two studies investigating the impact of the type of visual feedback on either direction-dependent visuo-motor gains or the complex visuo-motor transformation of a virtual two-sided lever are presented in more detail. The findings of these studies indicate that the continuous availability of visual feedback supports performance when closed-loop control is possible, but impairs performance when visual input is no longer available. Different approaches to explain these performance differences due to the type of visual feedback during practice are considered. For example, these differences could reflect a process of re-optimization of motor planning in a novel environment or represent effects of the specificity of practice. Furthermore, differences in the allocation of attention during movements with terminal and continuous visual feedback could account for the observed differences.

Generalized full/partial closed loop transmit diversity algorithm for WCDMA

2003 ◽  
Vol 14 (5) ◽  
pp. 471-477
Author(s):  
Dejan M. Novakovic ◽  
Markku J. Juntti ◽  
Miroslav L. Dukic
Keyword(s):  
Closed Loop ◽  
Transmit Diversity
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