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Gronlier E, Volle J, Coizet V, Paccard A, Habermacher C, Roche Y, Roucard C, Duveau V, David O. Evoked responses to single pulse electrical stimulation reveal impaired striatal excitability in a rat model of Parkinson's disease. Neurobiol Dis 2023; 185:106266. [PMID: 37604316 PMCID: PMC10480488 DOI: 10.1016/j.nbd.2023.106266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/02/2023] [Accepted: 08/18/2023] [Indexed: 08/23/2023] Open
Abstract
BACKGROUND Sensorimotor beta oscillations are increased in Parkinson's disease (PD) due to the alteration of dopaminergic transmission. This electrophysiological read-out is reported both in patients and in animal models such as the 6-OHDA rat model obtained with unilateral nigral injection of 6-hydroxydopamine (6-OHDA). Current treatments, based on dopaminergic replacement, transiently normalize this pathological beta activity and improve patients' quality of life. OBJECTIVES We wanted to assess in vivo whether the abnormal beta oscillations can be correlated with impaired striatal or cortical excitability of the sensorimotor system and modulated by the pharmacological manipulation of the dopaminergic system. METHODS In the unilateral 6-OHDA rat model and control animals, we used intra-striatal and intra-cortical single-pulse electrical stimulation (SPES) and concurrent local field potentials (LFP) recordings. In the two groups, we quantified basal cortico-striatal excitability from time-resolved spectral analyses of LFP evoked responses induced remotely by intracerebral stimulations. The temporal dependance of cortico-striatal excitability to dopaminergic transmission was further tested using electrophysiological recordings combined with levodopa injection. RESULTS LFP evoked responses after striatal stimulation showed a transient reduction of power in a large time-frequency domain in the 6-OHDA group compared to the sham group. This result was specific to the striatum, as no significant difference was observed in cortical LFP evoked responses between the two groups. This impaired striatal excitability in the 6-OHDA group was observed in the striatum at least during the first 3 months after the initial lesion. In addition, the striatum responses to SPES during a levodopa challenge showed a transient potentiation of the decrease of responsiveness in frequencies below 40 Hz. CONCLUSION The spectral properties of striatal responses to SPES show high sensitivity to dopaminergic transmission in the unilateral 6-OHDA rat model. We thus propose that this approach could be used in preclinical models as a time-resolved biomarker of impaired dopaminergic transmission capable of monitoring progressive neurodegeneration and/or challenges to drug intake.
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Affiliation(s)
- Eloïse Gronlier
- SynapCell SAS, Saint-Ismier, France; Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000 Grenoble, France.
| | | | - Véronique Coizet
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Antoine Paccard
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | | | | | | | | | - Olivier David
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000 Grenoble, France; Aix Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille, France
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Jedynak M, Boyer A, Chanteloup-Forêt B, Bhattacharjee M, Saubat C, Tadel F, Kahane P, David O. Variability of Single Pulse Electrical Stimulation Responses Recorded with Intracranial Electroencephalography in Epileptic Patients. Brain Topogr 2023; 36:119-127. [PMID: 36520342 PMCID: PMC9834344 DOI: 10.1007/s10548-022-00928-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 11/09/2022] [Indexed: 12/23/2022]
Abstract
Cohort studies of brain stimulations performed with stereo-electroencephalographic (SEEG) electrodes in epileptic patients allow to derive large scale functional connectivity. It is known, however, that brain responses to electrical or magnetic stimulation techniques are not always reproducible. Here, we study variability of responses to single pulse SEEG electrical stimulation. We introduce a second-order probability analysis, i.e. we extend estimation of connection probabilities, defined as the proportion of responses trespassing a statistical threshold (determined in terms of Z-score with respect to spontaneous neuronal activity before stimulation) over all responses and derived from a number of individual measurements, to an analysis of pairs of measurements.Data from 445 patients were processed. We found that variability between two equivalent measurements is substantial in particular conditions. For long ( > ~ 90 mm) distances between stimulating and recording sites, and threshold value Z = 3, correlation between measurements drops almost to zero. In general, it remains below 0.5 when the threshold is smaller than Z = 4 or the stimulating current intensity is 1 mA. It grows with an increase of either of these factors. Variability is independent of interictal spiking rates in the stimulating and recording sites.We conclude that responses to SEEG stimulation in the human brain are variable, i.e. in a subject at rest, two stimulation trains performed at the same electrode contacts and with the same protocol can give discrepant results. Our findings highlight an advantage of probabilistic interpretation of such results even in the context of a single individual.
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Affiliation(s)
- Maciej Jedynak
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, 38000, Grenoble, France.
- Aix Marseille Université, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France.
| | - Anthony Boyer
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, 38000, Grenoble, France
- Aix Marseille Université, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | | | - Manik Bhattacharjee
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, 38000, Grenoble, France
- Aix Marseille Université, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Carole Saubat
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, 38000, Grenoble, France
| | - François Tadel
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, 38000, Grenoble, France
- Signal and Image Processing Institute, University of Southern California, Los Angeles, USA
| | - Philippe Kahane
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, 38000, Grenoble, France
- Neurology Department, CHU Grenoble Alpes, Grenoble, France
| | - Olivier David
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, 38000, Grenoble, France
- Aix Marseille Université, Inserm, INS, Institut de Neurosciences des Systèmes, Marseille, France
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