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Colombi I, Nieus T, Massimini M, Chiappalone M. Spontaneous and Perturbational Complexity in Cortical Cultures. Brain Sci 2021; 11:1453. [PMID: 34827452 PMCID: PMC8615728 DOI: 10.3390/brainsci11111453] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/27/2021] [Accepted: 10/27/2021] [Indexed: 12/18/2022] Open
Abstract
Dissociated cortical neurons in vitro display spontaneously synchronized, low-frequency firing patterns, which can resemble the slow wave oscillations characterizing sleep in vivo. Experiments in humans, rodents, and cortical slices have shown that awakening or the administration of activating neuromodulators decrease slow waves, while increasing the spatio-temporal complexity of responses to perturbations. In this study, we attempted to replicate those findings using in vitro cortical cultures coupled with micro-electrode arrays and chemically treated with carbachol (CCh), to modulate sleep-like activity and suppress slow oscillations. We adapted metrics such as neural complexity (NC) and the perturbational complexity index (PCI), typically employed in animal and human brain studies, to quantify complexity in simplified, unstructured networks, both during resting state and in response to electrical stimulation. After CCh administration, we found a decrease in the amplitude of the initial response and a marked enhancement of the complexity during spontaneous activity. Crucially, unlike in cortical slices and intact brains, PCI in cortical cultures displayed only a moderate increase. This dissociation suggests that PCI, a measure of the complexity of causal interactions, requires more than activating neuromodulation and that additional factors, such as an appropriate circuit architecture, may be necessary. Exploring more structured in vitro networks, characterized by the presence of strong lateral connections, recurrent excitation, and feedback loops, may thus help to identify the features that are more relevant to support causal complexity.
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Affiliation(s)
- Ilaria Colombi
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia, 16163 Genova, Italy;
| | - Thierry Nieus
- Department of Biomedical and Clinical Sciences “L. Sacco”, University of Milan, 20157 Milan, Italy; (T.N.); (M.M.)
| | - Marcello Massimini
- Department of Biomedical and Clinical Sciences “L. Sacco”, University of Milan, 20157 Milan, Italy; (T.N.); (M.M.)
- IRCCS, Fondazione Don Carlo Gnocchi, 20148 Milan, Italy
| | - Michela Chiappalone
- Department of Informatics, Bioengineering, Robotics and System Engineering, 16145 Genova, Italy
- Rehab Technologies Lab., Istituto Italiano di Tecnologia, 16163 Genova, Italy
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Edhi MM, Heijmans L, Vanent KN, Bloye K, Baanante A, Jeong KS, Leung J, Zhu C, Esteller R, Saab CY. Time-dynamic pulse modulation of spinal cord stimulation reduces mechanical hypersensitivity and spontaneous pain in rats. Sci Rep 2020; 10:20358. [PMID: 33230202 PMCID: PMC7683561 DOI: 10.1038/s41598-020-77212-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 10/30/2020] [Indexed: 12/22/2022] Open
Abstract
Enhancing the efficacy of spinal cord stimulation (SCS) is needed to alleviate the burden of chronic pain and dependence on opioids. Present SCS therapies are characterized by the delivery of constant stimulation in the form of trains of tonic pulses (TPs). We tested the hypothesis that modulated SCS using novel time-dynamic pulses (TDPs) leads to improved analgesia and compared the effects of SCS using conventional TPs and a collection of TDPs in a rat model of neuropathic pain according to a longitudinal, double-blind, and crossover design. We tested the effects of the following SCS patterns on paw withdrawal threshold and resting state EEG theta power as a biomarker of spontaneous pain: Tonic (conventional), amplitude modulation, pulse width modulation, sinusoidal rate modulation, and stochastic rate modulation. Results demonstrated that under the parameter settings tested in this study, all tested patterns except pulse width modulation, significantly reversed mechanical hypersensitivity, with stochastic rate modulation achieving the highest efficacy, followed by the sinusoidal rate modulation. The anti-nociceptive effects of sinusoidal rate modulation on EEG outlasted SCS duration on the behavioral and EEG levels. These results suggest that TDP modulation may improve clinical outcomes by reducing pain intensity and possibly improving the sensory experience.
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Affiliation(s)
- Muhammad M Edhi
- Department of Neurosurgery, Rhode Island Hospital, 593 Eddy St., Providence, RI, 02903, USA.,Department of Biomedical Engineering, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Lonne Heijmans
- Department of Neurosurgery, Rhode Island Hospital, 593 Eddy St., Providence, RI, 02903, USA.,Department of Translational Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Kevin N Vanent
- Department of Neurosurgery, Rhode Island Hospital, 593 Eddy St., Providence, RI, 02903, USA
| | - Kiernan Bloye
- Department of Neurosurgery, Rhode Island Hospital, 593 Eddy St., Providence, RI, 02903, USA
| | - Amanda Baanante
- Department of Neurosurgery, Rhode Island Hospital, 593 Eddy St., Providence, RI, 02903, USA
| | - Ki-Soo Jeong
- Department of Neurosurgery, Rhode Island Hospital, 593 Eddy St., Providence, RI, 02903, USA.,Department of Biomedical Engineering, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Jason Leung
- Department of Neurosurgery, Rhode Island Hospital, 593 Eddy St., Providence, RI, 02903, USA.,Department of Biomedical Engineering, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Changfang Zhu
- Boston Scientific Neuromodulation, Valencia, CA, 91355, USA
| | | | - Carl Y Saab
- Department of Neurosurgery, Rhode Island Hospital, 593 Eddy St., Providence, RI, 02903, USA. .,Department of Neuroscience, Brown University, Providence, RI, 02903, USA. .,Carney Institute for Brain Science, Brown University, Providence, RI, 02912, USA. .,Department of Biomedical Engineering, Cleveland Clinic, Cleveland, OH, 44195, USA. .,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106, USA.
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