1
|
Müller CP. Serotonin and Consciousness-A Reappraisal. Behav Brain Res 2022; 432:113970. [PMID: 35716774 DOI: 10.1016/j.bbr.2022.113970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/01/2022] [Accepted: 06/06/2022] [Indexed: 11/02/2022]
Abstract
The serotonergic system of the brain is a major modulator of behaviour. Here we describe a re-appraisal of its function for consciousness based on anatomical, functional and pharmacological data. For a better understanding, the current model of consciousness is expanded. Two parallel streams of conscious flow are distinguished. A flow of conscious content and an affective consciousness flow. While conscious content flow has its functional equivalent in the activity of higher cortico-cortical and cortico-thalamic networks, affective conscious flow originates in segregated deeper brain structures for single emotions. It is hypothesized that single emotional networks converge on serotonergic and other modulatory transmitter neurons in the brainstem where a bound percept of an affective conscious flow is formed. This is then dispersed to cortical and thalamic networks, where it is time locked with conscious content flow at the level of these networks. Serotonin acts in concert with other modulatory systems of the brain stem with some possible specialization on single emotions. Together, these systems signal a bound percept of affective conscious flow. Dysfunctions in the serotonergic system may not only give rise to behavioural and somatic symptoms, but also essentially affect the coupling of conscious affective flow with conscious content flow, leading to the affect-stained subjective side of mental disorders like anxiety, depression, or schizophrenia. The present model is an attempt to integrate the growing insights into serotonergic system function. However, it is acknowledged, that several key claims are still at a heuristic level that need further empirical support.
Collapse
Affiliation(s)
- Christian P Müller
- Department of Psychiatry and Psychotherapy, University Clinic, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany; Centre for Drug Research, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
| |
Collapse
|
2
|
Biophysical Model: A Promising Method in the Study of the Mechanism of Propofol: A Narrative Review. COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE 2022; 2022:8202869. [PMID: 35619772 PMCID: PMC9129930 DOI: 10.1155/2022/8202869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 04/02/2022] [Accepted: 04/19/2022] [Indexed: 11/17/2022]
Abstract
The physiological and neuroregulatory mechanism of propofol is largely based on very limited knowledge. It is one of the important puzzling issues in anesthesiology and is of great value in both scientific and clinical fields. It is acknowledged that neural networks which are comprised of a number of neural circuits might be involved in the anesthetic mechanism. However, the mechanism of this hypothesis needs to be further elucidated. With the progress of artificial intelligence, it is more likely to solve this problem through using artificial neural networks to perform temporal waveform data analysis and to construct biophysical computational models. This review focuses on current knowledge regarding the anesthetic mechanism of propofol, an intravenous general anesthetic, by constructing biophysical computational models.
Collapse
|
3
|
Kho W, von Haefen C, Paeschke N, Nasser F, Endesfelder S, Sifringer M, González-López A, Lanzke N, Spies CD. Dexmedetomidine Restores Autophagic Flux, Modulates Associated microRNAs and the Cholinergic Anti-inflammatory Pathway upon LPS-Treatment in Rats. J Neuroimmune Pharmacol 2022; 17:261-276. [PMID: 34357471 PMCID: PMC9726767 DOI: 10.1007/s11481-021-10003-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 06/26/2021] [Indexed: 12/29/2022]
Abstract
Infections and perioperative stress can lead to neuroinflammation, which in turn is linked to cognitive impairments such as postoperative delirium or postoperative cognitive dysfunctions. The α2-adrenoceptor agonist dexmedetomidine (DEX) prevents cognitive impairments and has organo-protective and anti-inflammatory properties. Macroautophagy (autophagy) regulates many biological processes, but its role in DEX-mediated anti-inflammation and the underlying mechanism of DEX remains largely unclear. We were interested how a pretreatment with DEX protects against lipopolysaccharide (LPS)-induced inflammation in adult male Wistar rats. We used Western blot and activity assays to study how DEX modulated autophagy- and apoptosis-associated proteins as well as molecules of the cholinergic anti-inflammatory pathway, and qPCR to analyse the expression of autophagy and inflammation-associated microRNAs (miRNA) in the spleen, cortex and hippocampus at different time points (6 h, 24 h, 7 d). We showed that a DEX pretreatment prevents LPS-induced impairments in autophagic flux and attenuates the LPS-induced increase in the apoptosis-associated protein cleaved poly(ADP-ribose)-polymerase (PARP) in the spleen. Both, DEX and LPS altered miRNA expression and molecules of the cholinergic anti-inflammatory pathway in the spleen and brain. While only a certain set of miRNAs was up- and/or downregulated by LPS in each tissue, which was prevented or attenuated by a DEX pretreatment in the spleen and hippocampus, all miRNAs were up- and/or downregulated by DEX itself - independent of whether or not they were altered by LPS. Our results indicate that the organo-protective effect of DEX may be mediated by autophagy, possibly by acting on associated miRNAs, and the cholinergic anti-inflammatory pathway. Preventive effects of DEX on LPS-induced inflammation. DEX restores the LPS-induced impairments in autophagic flux, attenuates PARP cleavage and alters molecules of the cholinergic system in the spleen. Furthermore, DEX alters and prevents LPS-induced miRNA expression changes in the spleen and brain along with LPS.
Collapse
Affiliation(s)
- Widuri Kho
- Department of Anesthesiology and Operative Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Clarissa von Haefen
- Department of Anesthesiology and Operative Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Nadine Paeschke
- Department of Anesthesiology and Operative Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Fatme Nasser
- Department of Anesthesiology and Operative Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Stefanie Endesfelder
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Marco Sifringer
- Department of Anesthesiology and Operative Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Adrián González-López
- Department of Anesthesiology and Operative Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany ,CIBER-Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Nadine Lanzke
- Department of Anesthesiology and Operative Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Claudia D. Spies
- Department of Anesthesiology and Operative Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
4
|
Wang J, Sun P, Liang P. Neuropsychopharmacological effects of midazolam on the human brain. Brain Inform 2020; 7:15. [PMID: 33170396 PMCID: PMC7655878 DOI: 10.1186/s40708-020-00116-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 10/26/2020] [Indexed: 12/17/2022] Open
Abstract
As a commonly used anesthetic agent, midazolam has the properties of water-soluble, rapid onset, and short duration of action. With the rapid development in the field of neuroimaging, numerous studies have investigated how midazolam acts on the human brain to induce the alteration of consciousness. However, the neural bases of midazolam-induced sedation or anesthesia remain beginning to be understood in detail. In this review, we summarize findings from neuroimaging studies that have used midazolam to study altered consciousness at different levels and content. We also compare the results to those of neuroimaging studies using diverse anesthetic agents and describe the common neural correlates of anesthetic-induced alteration of consciousness.
Collapse
Affiliation(s)
- Junkai Wang
- School of Psychology, Capital Normal University, Haidian District, Beijing, 100048, China.,Beijing Key Laboratory of Learning and Cognition, Beijing, China.,Department of Psychology, Tsinghua University, Haidian District, Beijing, 100084, China
| | - Pei Sun
- Department of Psychology, Tsinghua University, Haidian District, Beijing, 100084, China.
| | - Peipeng Liang
- School of Psychology, Capital Normal University, Haidian District, Beijing, 100048, China. .,Beijing Key Laboratory of Learning and Cognition, Beijing, China.
| |
Collapse
|
5
|
Madsen SS, Møller K, Olsen KS, Vestergaard MB, Lindberg U, Larsson HBW, Mårtensson J, Werner MU, Santos SAG, Asghar MS. Neuroplasticity induced by general anaesthesia: study protocol for a randomised cross-over clinical trial exploring the effects of sevoflurane and propofol on the brain - A 3-T magnetic resonance imaging study of healthy volunteers. Trials 2020; 21:805. [PMID: 32962743 PMCID: PMC7506820 DOI: 10.1186/s13063-020-04468-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 05/30/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Although used extensively worldwide, the effects of general anaesthesia on the human brain remain largely elusive. Moreover, general anaesthesia may contribute to serious conditions or adverse events such as postoperative cognitive dysfunction and delirium. To understand the basic mechanisms of general anaesthesia, this project aims to study and compare possible de novo neuroplastic changes induced by two commonly used types of general anaesthesia, i.e. inhalation anaesthesia by sevoflurane and intravenously administered anaesthesia by propofol. In addition, we wish to to explore possible associations between neuroplastic changes, neuropsychological adverse effects and subjective changes in fatigue and well-being. METHODS This is a randomised, participant- and assessor-blinded, cross-over clinical trial. Thirty healthy volunteers (male:female ratio 1:1) will be randomised to general anaesthesia by either sevoflurane or propofol. Multimodal magnetic resonance imaging (MRI) of the brain will be performed before and after general anaesthesia and repeated after 1 and 8 days. Each magnetic resonance imaging session will be accompanied by cognitive testing and questionnaires on fatigue and well-being. After a wash-out period of 4 weeks, the volunteers will receive the other type of anaesthetic (sevoflurane or propofol), followed by the same series of tests. Primary outcomes: changes in T1-weighted 3D anatomy and diffusion tensor imaging. SECONDARY OUTCOMES changes in resting-state functional magnetic resonance imaging, fatigue, well-being, cognitive function, correlations between magnetic resonance imaging findings and the clinical outcomes (questionnaires and cognitive function). Exploratory outcomes: changes in cerebral perfusion and oxygen metabolism, lactate, and response to visual stimuli. DISCUSSION To the best of our knowledge, this is the most extensive and advanced series of studies with head-to-head comparison of two widely used methods for general anaesthesia. Recruitment was initiated in September 2019. TRIAL REGISTRATION Approved by the Research Ethics Committee in the Capital Region of Denmark, ref. H-18028925 (6 September 2018). EudraCT and Danish Medicines Agency: 2018-001252-35 (23 March 2018). www.clinicaltrials.gov , ID: NCT04125121 . Retrospectively registered on 10 October 2019.
Collapse
Affiliation(s)
- Signe Sloth Madsen
- Department of Neuroanaesthesiology, The Neuroscience Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Neuroanaesthesiology, Rigshospitalet Glostrup, University of Copenhagen, Valdemar Hansens Vej 15, 2600 Glostrup, Denmark
| | - Kirsten Møller
- Department of Neuroanaesthesiology, The Neuroscience Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Karsten Skovgaard Olsen
- Department of Neuroanaesthesiology, The Neuroscience Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Mark Bitsch Vestergaard
- Functional Imaging Unit, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Valdemar Hansens Vej 1-23, entrance 5, 2600 Glostrup, Denmark
| | - Ulrich Lindberg
- Functional Imaging Unit, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Valdemar Hansens Vej 1-23, entrance 5, 2600 Glostrup, Denmark
| | - Henrik Bo Wiberg Larsson
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Functional Imaging Unit, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Valdemar Hansens Vej 1-23, entrance 5, 2600 Glostrup, Denmark
| | - Johan Mårtensson
- Faculty of Medicine, Department of Clinical Sciences Lund, Logopedics, Phoniatrics and Audiology, Lund University, 22100 Lund, Sweden
| | - Mads U. Werner
- Multidisciplinary Pain Center, The Neuroscience Center, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Sofia Alexandra Gaspar Santos
- Department of Neuroanaesthesiology, The Neuroscience Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Mohammad Sohail Asghar
- Department of Neuroanaesthesiology, The Neuroscience Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
| |
Collapse
|
6
|
Shalgunov V, van Waarde A, Booij J, Michel MC, Dierckx RAJO, Elsinga PH. Hunting for the high-affinity state of G-protein-coupled receptors with agonist tracers: Theoretical and practical considerations for positron emission tomography imaging. Med Res Rev 2018; 39:1014-1052. [PMID: 30450619 PMCID: PMC6587759 DOI: 10.1002/med.21552] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/02/2018] [Accepted: 10/19/2018] [Indexed: 12/15/2022]
Abstract
The concept of the high‐affinity state postulates that a certain subset of G‐protein‐coupled receptors is primarily responsible for receptor signaling in the living brain. Assessing the abundance of this subset is thus potentially highly relevant for studies concerning the responses of neurotransmission to pharmacological or physiological stimuli and the dysregulation of neurotransmission in neurological or psychiatric disorders. The high‐affinity state is preferentially recognized by agonists in vitro. For this reason, agonist tracers have been developed as tools for the noninvasive imaging of the high‐affinity state with positron emission tomography (PET). This review provides an overview of agonist tracers that have been developed for PET imaging of the brain, and the experimental paradigms that have been developed for the estimation of the relative abundance of receptors configured in the high‐affinity state. Agonist tracers appear to be more sensitive to endogenous neurotransmitter challenge than antagonists, as was originally expected. However, other expectations regarding agonist tracers have not been fulfilled. Potential reasons for difficulties in detecting the high‐affinity state in vivo are discussed.
Collapse
Affiliation(s)
- Vladimir Shalgunov
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jan Booij
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Martin C Michel
- Department of Pharmacology, Johannes Gutenberg University, Mainz, Germany
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Department of Nuclear Medicine, Ghent University, University Hospital, Ghent, Belgium
| | - Philip H Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| |
Collapse
|
7
|
Gas Anesthesia Impairs Peripheral Auditory Sensitivity in Barn Owls ( Tyto alba). eNeuro 2018; 5:eN-NWR-0140-18. [PMID: 30713995 PMCID: PMC6354786 DOI: 10.1523/eneuro.0140-18.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 09/28/2018] [Accepted: 10/05/2018] [Indexed: 11/21/2022] Open
Abstract
Auditory nerve single-unit recordings were obtained from two groups of young barn owls (age, between posthatching days 11 and 86) in terminal experiments under two different anesthetic regimes: ketamine (6-11 mg/kg) plus xylazine (∼2 mg/kg); or isoflurane (1-1.5%) in oxygen, delivered via artificial respiration. In a second series of minimally invasive experiments, auditory brainstem responses (ABRs) were recorded in the same four adult barn owls (Tyto alba; age, between 5 and 32 months) under three different anesthetic protocols: ketamine (10 mg/kg) plus xylazine (3 mg/kg), isoflurane (1-1.5%), and sevoflurane (2-3%) in carbogen. Finally, the ABR measurements on adult owls were repeated in terminal experiments including more invasive procedures such as artificial respiration and higher isoflurane dosage. The main finding was a significant deterioration of auditory sensitivity in barn owls under gas anesthesia, at the level of the auditory nerve (i.e., a very peripheral level of the auditory system). The effect was drastic in the young animals that experienced threshold elevations in auditory nerve single-unit responses of ≥20 dB. ABR thresholds assessed repeatedly in experiments on adult owls were also significantly higher under isoflurane and sevoflurane, on average by 7 and 15 dB, compared with ketamine/xylazine. This difference already occurred with minimal dosages and was reversibly enlarged with increased isoflurane concentration. Finally, there was evidence for confounding detrimental effects associated with artificial respiration over many hours, which suggested oxygen toxicity.
Collapse
|
8
|
Walczak M, Błasiak T. Midbrain dopaminergic neuron activity across alternating brain states of urethane anaesthetized rat. Eur J Neurosci 2017; 45:1068-1077. [PMID: 28177164 DOI: 10.1111/ejn.13533] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 01/26/2017] [Accepted: 01/31/2017] [Indexed: 12/23/2022]
Abstract
Midbrain dopaminergic neurons are implicated in the control of motor functions and reward-driven behaviours. The function of this neuronal population is strongly connected with distinct patterns of firing - irregular or bursting, which either maintains basal levels of dopamine (DA) or leads to phasic release, respectively. Heterogeneity of dopaminergic neurons, observed on both structural and functional levels, is also reflected in different responses of DA neurons to changes in global brain states. Preparation of urethane anaesthetized animal is a broadly used model to study brain state dependent activity of neurons. Unfortunately activity of midbrain DA neurons across urethane induced cyclic, spontaneous brain state alternations is poorly described. To fulfil this gap in our knowledge we have performed simultaneous, extracellular recordings of the firing of single putative DA neurons combined with continuous brain state monitoring. We found that during slow wave activity, the firing rate of recorded putative DA neurons was significantly higher compared to firing rates during activated state, both in ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). In the presence of cortical slow waves, putative dopaminergic neurons also intensified bursting activity, but the magnitude of this phenomena differed in respect to the examined region (VTA or SNc). Our results show that activity of DA neurons under urethane anaesthesia is brain-state dependent and emphasize the importance of brain state monitoring during electrophysiological experiments.
Collapse
Affiliation(s)
- Magdalena Walczak
- Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, Gronostajowa 9, 30-387, Krakow, Poland
| | - Tomasz Błasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, Gronostajowa 9, 30-387, Krakow, Poland
| |
Collapse
|
9
|
Doyle WI, Meeks JP. Heterogeneous effects of norepinephrine on spontaneous and stimulus-driven activity in the male accessory olfactory bulb. J Neurophysiol 2017; 117:1342-1351. [PMID: 28053247 DOI: 10.1152/jn.00871.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/09/2016] [Accepted: 01/03/2017] [Indexed: 11/22/2022] Open
Abstract
Norepinephrine (NE) release has been linked to experience-dependent plasticity in many model systems and brain regions. Among these is the rodent accessory olfactory system (AOS), which is crucial for detecting and processing socially relevant environmental cues. The accessory olfactory bulb (AOB), the first site of chemosensory information processing in the AOS, receives dense centrifugal innervation by noradrenergic fibers originating in the locus coeruleus. Although NE release has been linked to behavioral plasticity through its actions in the AOB, the impacts of noradrenergic modulation on AOB information processing have not been thoroughly studied. We made extracellular single-unit recordings of AOB principal neurons in ex vivo preparations of the early AOS taken from adult male mice. We analyzed the impacts of bath-applied NE (10 μM) on spontaneous and stimulus-driven activity. In the presence of NE, we observed overall suppression of stimulus-driven neuronal activity with limited impact on spontaneous activity. NE-associated response suppression in the AOB came in two forms: one that was strong and immediate (21%) and one other that involved gradual, stimulus-dependent monotonic response suppression (47%). NE-associated changes in spontaneous activity were more modest, with an overall increase in spontaneous spike frequency observed in 25% of neurons. Neurons with increased spontaneous activity demonstrated a net decrease in chemosensory discriminability. These results reveal that noradrenergic signaling in the AOB causes cell-specific changes in chemosensory tuning, even among similar projection neurons.NEW & NOTEWORTHY Norepinephrine (NE) is released throughout the brain in many behavioral contexts, but its impacts on information processing are not well understood. We studied the impact of NE on chemosensory tuning in the mouse accessory olfactory bulb (AOB). Electrophysiological recordings from AOB neurons in ex vivo preparations revealed that NE, on balance, inhibited mitral cell responses to chemosensory cues. However, NE's effects were heterogeneous, indicating that NE signaling reshapes AOB output in a cell- and stimulus-specific manner.
Collapse
Affiliation(s)
- Wayne I Doyle
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Julian P Meeks
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas
| |
Collapse
|
10
|
Lissek T, Obenhaus HA, Ditzel DAW, Nagai T, Miyawaki A, Sprengel R, Hasan MT. General Anesthetic Conditions Induce Network Synchrony and Disrupt Sensory Processing in the Cortex. Front Cell Neurosci 2016; 10:64. [PMID: 27147963 PMCID: PMC4830828 DOI: 10.3389/fncel.2016.00064] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 02/29/2016] [Indexed: 12/19/2022] Open
Abstract
General anesthetics are commonly used in animal models to study how sensory signals are represented in the brain. Here, we used two-photon (2P) calcium activity imaging with cellular resolution to investigate how neuronal activity in layer 2/3 of the mouse barrel cortex is modified under the influence of different concentrations of chemically distinct general anesthetics. Our results show that a high isoflurane dose induces synchrony in local neuronal networks and these cortical activity patterns closely resemble those observed in EEG recordings under deep anesthesia. Moreover, ketamine and urethane also induced similar activity patterns. While investigating the effects of deep isoflurane anesthesia on whisker and auditory evoked responses in the barrel cortex, we found that dedicated spatial regions for sensory signal processing become disrupted. We propose that our isoflurane-2P imaging paradigm can serve as an attractive model system to dissect cellular and molecular mechanisms that induce the anesthetic state, and it might also provide important insight into sleep-like brain states and consciousness.
Collapse
Affiliation(s)
- Thomas Lissek
- Department of Molecular Neurobiology, Max Planck Institute for Medical ResearchHeidelberg, Germany; Department of Neurobiology, Interdisciplinary Center for Neurosciences, University of HeidelbergHeidelberg, Germany
| | - Horst A Obenhaus
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research Heidelberg, Germany
| | - Désirée A W Ditzel
- Department of Molecular Neurobiology, Max Planck Institute for Medical ResearchHeidelberg, Germany; Max Planck Research Group at the Institute for Anatomy and Cell Biology, Heidelberg UniversityHeidelberg, Germany
| | - Takeharu Nagai
- Laboratory for Nanosystems Physiology, Hokkaido University Hokkaido, Japan
| | - Atsushi Miyawaki
- RIKEN-Brain Science Institute, Laboratory for Cell Function Dynamics Saitama, Japan
| | - Rolf Sprengel
- Department of Molecular Neurobiology, Max Planck Institute for Medical ResearchHeidelberg, Germany; Max Planck Research Group at the Institute for Anatomy and Cell Biology, Heidelberg UniversityHeidelberg, Germany
| | - Mazahir T Hasan
- Department of Molecular Neurobiology, Max Planck Institute for Medical ResearchHeidelberg, Germany; Molecular Neurobiology, Neurocure Cluster of Excellence, Charite-UniversitätsmedizinBerlin, Germany
| |
Collapse
|
11
|
Kufahl PR, Peartree NA, Heintzelman KL, Chung M, Neisewander JL. Region-specific effects of isoflurane anesthesia on Fos immunoreactivity in response to intravenous cocaine challenge in rats with a history of repeated cocaine administration. Brain Res 2015; 1594:256-66. [PMID: 25451087 PMCID: PMC4805112 DOI: 10.1016/j.brainres.2014.10.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 10/14/2014] [Accepted: 10/15/2014] [Indexed: 12/29/2022]
Abstract
We have previously shown that acute intravenous (i.v.) administration of cocaine increases Fos immunoreactivity in rats under isoflurane anesthesia. Given that Fos expression is a marker of neural activation, the results suggested that isoflurane is appropriate for imaging cocaine effects under anesthesia. However, most imaging research in this area utilizes subjects with a history of repeated cocaine exposure and this drug history may interact with anesthetic use differently from acute cocaine exposure. Thus, this study further examined Fos expression under isoflurane in rats with a history of repeated i.v. cocaine administration. Rats received daily injections of either saline or cocaine (2mg/kg, i.v.) across 7 consecutive days, followed by 5 days of no drug exposure. On the test day, rats were either nonanesthetized or anesthetized under isoflurane and were given an acute challenge of cocaine (2mg/kg, i.v.). Additional saline-exposed controls received a saline challenge. Ninety min after the drug challenge, the rats were perfused under isoflurane anesthesia and their brains were processed for Fos protein immunohistochemistry. We found that challenge injections of cocaine following a regimen of repeated cocaine exposure resulted in Fos expression in the prefrontal cortex and striatum roughly equivalent to that found in rats who had received the cocaine challenge after a history of vehicle injections. Additionally, isoflurane anesthesia resulted in a heterogeneous attenuation of cocaine-induced Fos expression, with the most robust effect in the orbital cortex but no effect in the nucleus accumbens core (NAcC). These results indicate that cocaine-induced Fos is preserved in the NAcC under isoflurane, suggesting that isoflurane can be used in imaging studies involving cocaine effects in this region.
Collapse
Affiliation(s)
- Peter R Kufahl
- Department of Psychology, Arizona State University, Tempe, AZ 85287-1104, United States.
| | - Natalie A Peartree
- Department of Psychology, Arizona State University, Tempe, AZ 85287-1104, United States
| | - Krista L Heintzelman
- Department of Psychology, Arizona State University, Tempe, AZ 85287-1104, United States
| | - Maggie Chung
- Department of Psychology, Arizona State University, Tempe, AZ 85287-1104, United States
| | - Janet L Neisewander
- School of Life Sciences, Arizona State University, PO Box 874501, Tempe, AZ 85287-4501, United States
| |
Collapse
|
12
|
Mozafari H, Asadi Fakhr A, Salehi I, Moghimbigi A. The ability of bispectral-guided management compared to routine monitoring for reflecting awareness rate in patients undergoing abdominal surgery. IRANIAN RED CRESCENT MEDICAL JOURNAL 2014; 16:e13584. [PMID: 25593710 PMCID: PMC4270681 DOI: 10.5812/ircmj.13584] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 02/14/2014] [Accepted: 03/11/2014] [Indexed: 11/25/2022]
Abstract
Background: Awareness during general anesthesia in different types of surgery is an important described adverse event. Bispectral (BIS) monitoring is one of the recent techniques proposed to monitor the depth of anesthesia. Objectives: The present study tested the hypothesis that the awareness rate and changes in hemodynamic parameters within anesthesia would be lower in patients allocated to BIS-guided management than those allocated to routine monitoring. Materials and Methods In total, 333 adult patients with the American Society of Anesthesiologists (ASA) physical status I-III, aged between 18 and 65 years scheduled for elective abdominal surgery under general anesthesia were included in this randomized double-blind placebo controlled trial. Patients were randomly allocated to BIS monitoring (n = 163) or routine monitoring (n = 170). BIS values and hemodynamic parameters including systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and SPO2 were marked before induction (control value), after intubation and laryngoscopy, at intubation, after incision, and also during the operation every 15 minutes until extubation. Results: The overall incidence of awareness in the BIS and routine monitoring groups were 5.5% and 4.1%, which was not significantly different. There were no significant differences in hemodynamic indices including SBP, DBP, HR, and SPO2 before induction of anesthesia between the two groups. These between-group differences in the studied indices remained insignificant at different time points after anesthesia induction as well as post ICU hospitalization. Furthermore, the trend of changes in hemodynamic parameters was comparable in the two groups. Conclusions: BIS-guided management may not be superior to routine monitoring protocols to prevent awareness as well as hemodynamic changes during general anesthesia in patients undergoing abdominal surgeries.
Collapse
Affiliation(s)
- Hamedeh Mozafari
- Department of Anesthesiology, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, IR Iran
| | - Amir Asadi Fakhr
- Department of Anesthesiology, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, IR Iran
- Corresponding Author: Amir Asadi Fakhr, Department of Anesthesiology, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, IR Iran. Tel: +98-9183159883, E-mail: .
| | - Iraj Salehi
- Department of Anesthesiology, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, IR Iran
| | - Abbas Moghimbigi
- Modeling of Non Communicable Diseases Research Center, Department of Epidemiology and Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, IR Iran
| |
Collapse
|
13
|
Anesthetic effects of propofol in the healthy human brain: functional imaging evidence. J Anesth 2014; 29:279-88. [PMID: 25056258 DOI: 10.1007/s00540-014-1889-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 07/07/2014] [Indexed: 01/18/2023]
Abstract
Functional imaging methods, including positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), have become important tools for studying how anesthetic drugs act in the human brain to induce the state of general anesthesia. Recent imaging studies using fMRI and PET techniques have demonstrated the regional effects of propofol on the brain. However, the pharmacological mechanism of the action of propofol in the intact human central nervous system is unclear. To explore the possible action targets of propofol in the human brain, a systematic review of the literature was performed. The literature search was performed with limiting factors of "propofol," "functional imaging," "positron emission tomography", and "functional magnetic resonance imaging" from 1966 to July 2013 (using Medline, EMBASE, CINAHL and hand searches of references). Studies meeting the inclusion criteria were reviewed and critiqued for the purpose of this literature research. Eighteen researches meeting the inclusion criteria were reviewed in terms of the appropriateness of valuation technique. In the unconscious state, propofol sharply reduces the regional glucose metabolism rate (rGMR) and regional cerebral blood flow (rCBF) in all brain regions, particularly in the thalamus. However, GMR, such as in the occipital, temporal, and frontal lobes, was obviously decreased at a sedative dosage of propofol, whereas, changes in the thalamus were not obvious. Using fMRI, several studies observed a decrease of connectivity of the thalamus versus an increase of connectivity within the pons of the brainstem during propofol-induced mild sedation. During deep sedation, propofol preserves cortical sensory reactivity, the specific thalamocortical network is moderately affected, whereas the nonspecific thalamocortical network is severely suppressed. In contrast, several recent fMRI studies are consistent on the systemic decreased effects of propofol in the frontoparietal network. Accumulating evidence suggest that propofol-induced unconsciousness is associated with a global metabolic and vascular depression in the human brain and especially with a significant reduction in the thalamocortical network and the frontoparietal network.
Collapse
|
14
|
Li Z, Liu X, Zhang Y, Shi J, Zhang Y, Xie P, Yu T. Connection changes in somatosensory cortex induced by different doses of propofol. PLoS One 2014; 9:e87829. [PMID: 24516566 PMCID: PMC3917837 DOI: 10.1371/journal.pone.0087829] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/01/2014] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The mechanism by which general anesthetics, widely used in clinical practice for over 160 years, effects on sensory responsiveness has been unclear until now. In the present study, the authors sought to explore the effect of different doses of propofol on somatosensory cortex by whisker stimulation in rats. METHODS In a fixed cage, rats were anesthetized with propofol 80 mg/kg intraperitoneally and then cathetered tail vein with 23-gauge metal needle connected with a pump. Two holes (2 mm diameter) were drilled and recording electrodes implantated in the primary somatosensory cortex barrel field (S1BF) and secondary somatosensory cortex (S2). The extracellular (20 rats) and intracellular (8 rats) recordings were used to test the neuron activity in both cortices at different doses of propofol (20, 40 and 80 mg/kg/h) through tail vein by pump. Meantime, vibrissal, olfactory, corneal responses (VOCR, sedation), and tail-pinch response (TRP, analgesia) were tested every 10 min during the doses of propofol 20, 40 and 80 mg/kg/h. RESULTS VOCR and TRP were depressed by propofol in a dose-dependent manner. The amplitude by whisker stimulation in S1BF was stronger and the peak latency was shorter compared with that of in S2. The response latency of S1BF and S2 was increased by raising infusion rate of propofol with the response latency in S2 being longer than that in S1BF at the same doses of propofol. The cross-correlation between S1BF and S2 decreased as the propofol infusion rate increased. The input resistance was higher by increasing infusion rate of propofol. CONCLUSION The sedation and analgesia effects of propofol were dose-dependent. Both the connectivity and instinctive oscillation between S1BF and S2 were proportionally modulated by the different doses of propofol.
Collapse
Affiliation(s)
- Zhaoduan Li
- Department of Anesthesiology, Zunyi Medical College, Zunyi, Guizhou, People's Republic of China
| | - Xingkui Liu
- Department of Anesthesiology, Zunyi Medical College, Zunyi, Guizhou, People's Republic of China
| | - Yi Zhang
- Department of Anesthesiology, Zunyi Medical College, Zunyi, Guizhou, People's Republic of China
| | - Jinshan Shi
- Department of Anesthesiology, Zunyi Medical College, Zunyi, Guizhou, People's Republic of China
| | - Yu Zhang
- Department of Anesthesiology, Zunyi Medical College, Zunyi, Guizhou, People's Republic of China
| | - Peng Xie
- Department of Anesthesiology, Zunyi Medical College, Zunyi, Guizhou, People's Republic of China
| | - Tian Yu
- Department of Anesthesiology, Zunyi Medical College, Zunyi, Guizhou, People's Republic of China
- * E-mail:
| |
Collapse
|
15
|
Neuropsychiatric Conditions Associated With Anesthesia Exposure. PSYCHOSOMATICS 2014; 55:21-8. [DOI: 10.1016/j.psym.2013.06.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 06/25/2013] [Accepted: 06/26/2013] [Indexed: 02/07/2023]
|
16
|
Fouillen L, Petruzziello F, Veit J, Bhattacharyya A, Kretz R, Rainer G, Zhang X. Neuropeptide alterations in the tree shrew hypothalamus during volatile anesthesia. J Proteomics 2012; 80:311-9. [PMID: 23228960 DOI: 10.1016/j.jprot.2012.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/15/2012] [Accepted: 11/04/2012] [Indexed: 12/25/2022]
Abstract
Neuropeptides are critical signaling molecules, involved in the regulation of diverse physiological processes including energy metabolism, pain perception and brain cognitive state. Prolonged general anesthesia has an impact on many of these processes, but the regulation of peptides by general anesthetics is poorly understood. In this study, we present an in-depth characterization of the hypothalamic neuropeptides of the tree shrew during volatile isoflurane/nitrous oxide anesthesia administered accompanying a neurosurgical procedure. Using a predicted-peptide database and hybrid spectral analysis, we first identified 85 peptides from the tree shrew hypothalamus. Differential analysis was then performed between control and experimental group animals. The levels of 12 hypothalamic peptides were up-regulated following prolonged general anesthesia. Our study revealed for the first time that several neuropeptides, including alpha-neoendorphin and somatostatin-14, were altered during general anesthesia. Our study broadens the scope for the involvement of neuropeptides in volatile anesthesia regulation, opening the possibility for investigating the associated regulatory mechanisms.
Collapse
Affiliation(s)
- Laetitia Fouillen
- Visual Cognition Laboratory, Department of Medicine, University of Fribourg, Chemin du Musée 5, Fribourg, CH-1700, Switzerland
| | | | | | | | | | | | | |
Collapse
|
17
|
Pesavento MJ, Pinto DJ. Network and neuronal membrane properties in hybrid networks reciprocally regulate selectivity to rapid thalamocortical inputs. J Neurophysiol 2012; 108:2452-72. [PMID: 22896716 DOI: 10.1152/jn.00914.2011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Rapidly changing environments require rapid processing from sensory inputs. Varying deflection velocities of a rodent's primary facial vibrissa cause varying temporal neuronal activity profiles within the ventral posteromedial thalamic nucleus. Local neuron populations in a single somatosensory layer 4 barrel transform sparsely coded input into a spike count based on the input's temporal profile. We investigate this transformation by creating a barrel-like hybrid network with whole cell recordings of in vitro neurons from a cortical slice preparation, embedding the biological neuron in the simulated network by presenting virtual synaptic conductances via a conductance clamp. Utilizing the hybrid network, we examine the reciprocal network properties (local excitatory and inhibitory synaptic convergence) and neuronal membrane properties (input resistance) by altering the barrel population response to diverse thalamic input. In the presence of local network input, neurons are more selective to thalamic input timing; this arises from strong feedforward inhibition. Strongly inhibitory (damping) network regimes are more selective to timing and less selective to the magnitude of input but require stronger initial input. Input selectivity relies heavily on the different membrane properties of excitatory and inhibitory neurons. When inhibitory and excitatory neurons had identical membrane properties, the sensitivity of in vitro neurons to temporal vs. magnitude features of input was substantially reduced. Increasing the mean leak conductance of the inhibitory cells decreased the network's temporal sensitivity, whereas increasing excitatory leak conductance enhanced magnitude sensitivity. Local network synapses are essential in shaping thalamic input, and differing membrane properties of functional classes reciprocally modulate this effect.
Collapse
Affiliation(s)
- Michael J Pesavento
- Department of Neurobiology and Anatomy, University of Rochester School of Medicine, Rochester, New York 14642, USA.
| | | |
Collapse
|
18
|
High resolution 3T fMRI in anesthetized monkeys. J Neurosci Methods 2012; 205:86-95. [PMID: 22230769 DOI: 10.1016/j.jneumeth.2011.12.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 12/23/2011] [Accepted: 12/23/2011] [Indexed: 11/24/2022]
Abstract
Although there are numerous 3T MRI research devices all over the world, only a few functional studies at 3T have been done in anesthetized monkeys. In the past, anesthetized preparations were reported to be misleading when exploring cortical brain regions outside the primary sensory areas. Nonetheless, a great improvement has been achieved in the limited effect of anesthetic agents on the reactivity of the brain. Here, we re-address the feasibility and potential applications of the brain oxygen level dependent (BOLD) fMRI signal in Macaca mulatta monkeys that have been lightly anesthetized with sevoflurane and curarized. The monkeys were studied with commercially available coils and sequences using a 3T clinical magnet. We obtained sagittal T1 scout images, gray matter double inversion recovery, standard gradient echo sequences and gradient echo functional imaging sequences. Given that fMRI signals are most readily identified in the cerebral cortices, we optimized Echo Planar Imaging sequences to reproduce significant changes in the BOLD signal subsequent to a visual stimulation paradigm. Our results provide a satisfactory signal to noise ratio with a limited standard deviation range, when compared with studies on alert macaques. We suggest that the 3T magnet remains a valuable tool to analyze neural pathways in the macaque brain under light anesthesia and report the use of spatially resolved fMRI in higher visual areas of anesthetized monkeys. This methodology avoids the need for time-consuming training of awake monkeys, is stable over many hours, provides reproducible data and could be applied successfully to future functional studies.
Collapse
|
19
|
HICHIRI K, SHIRAI O, KANO K. Influence of Inhalation Anesthetics on Ion Transport across a Planar Bilayer Lipid Membrane. ANAL SCI 2012; 28:45-9. [DOI: 10.2116/analsci.28.45] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Kei HICHIRI
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University
| | - Osamu SHIRAI
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University
| | - Kenji KANO
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University
| |
Collapse
|
20
|
Müller CP, Pum ME, Amato D, Schüttler J, Huston JP, De Souza Silva MA. The in vivo neurochemistry of the brain during general anesthesia. J Neurochem 2011; 119:419-46. [DOI: 10.1111/j.1471-4159.2011.07445.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
21
|
Smoliga JM, Vang O, Baur JA. Challenges of translating basic research into therapeutics: resveratrol as an example. J Gerontol A Biol Sci Med Sci 2011; 67:158-67. [PMID: 21746739 DOI: 10.1093/gerona/glr062] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Basic science literature abounds with molecules that promise to ameliorate almost any disease, from curing cancer to slowing the aging process itself. However, most of these compounds will never even be evaluated in humans, let alone proven effective. Here, we use resveratrol as an example to highlight the enormous difficulties in understanding pharmacokinetics, determining side effects, and, ultimately, establishing mechanisms of action for a natural compound. Despite extensive interest and effort, and continuing promising results from basic science groups, very little is known even today about the effects of resveratrol in humans. Part of the problem is the unattractiveness of natural compounds to large, well-funded companies that could run clinical trials because developing their own molecules affords much greater protection for their intellectual property. In fact, selling unpatentable material motivates smaller nutraceutical companies to complicate the scientific problem even more--each creates its own proprietary blend, making it extremely difficult to compare their data with those of other companies, or of academic labs using pure compounds. But even beyond these problems lies a deeper one; resveratrol, and almost every natural compound, is likely to have many clinically relevant targets with different dose-response profiles, tissue distributions, and modifiers. Tackling this type of problem efficiently, and even beginning to address the spectrum of other molecules with claimed benefits, is likely to require the development of new paradigms and approaches. Examples include better molecular modeling to predict interactions, large-scale screens for toxic or other common effects, affinity-based methods to identify drug-interacting proteins, and better synthesis of existing data, including legislation to promote the release of trial results, and tracking of voluntary supplement usage. The evidence for benefits of resveratrol in humans remains too sparse to be conclusive; yet, the limited data that are available, combined with a growing list of animal studies, provide a strong justification for further study.
Collapse
Affiliation(s)
- James M Smoliga
- Department of Health and Physical Education, Human Physiology Laboratory, Marywood University, Scranton, Pennsylvania, USA
| | | | | |
Collapse
|
22
|
Zhang H, Wang W, Zhao Z, Ge Y, Zhang J, Yu D, Chai W, Wu S, Xu L. The Action Sites of Propofol in the Normal Human Brain Revealed by Functional Magnetic Resonance Imaging. Anat Rec (Hoboken) 2010. [DOI: 10.1002/ar.21289] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|
23
|
Hoogendam JM, Ramakers GMJ, Di Lazzaro V. Physiology of repetitive transcranial magnetic stimulation of the human brain. Brain Stimul 2009; 3:95-118. [PMID: 20633438 DOI: 10.1016/j.brs.2009.10.005] [Citation(s) in RCA: 454] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 10/19/2009] [Accepted: 10/28/2009] [Indexed: 02/07/2023] Open
Abstract
During the last two decades, transcranial magnetic stimulation (TMS) has rapidly become a valuable method to investigate noninvasively the human brain. In addition, repetitive TMS (rTMS) is able to induce changes in brain activity that last after stimulation. Therefore, rTMS has therapeutic potential in patients with neurologic and psychiatric disorders. It is, however, unclear by which mechanism rTMS induces these lasting effects on the brain. The effects of rTMS are often described as LTD- or LTP-like, because the duration of these alterations seems to implicate changes in synaptic plasticity. In this review we therefore discuss, based on rTMS experiments and knowledge about synaptic plasticity, whether the physiologic basis of rTMS-effects relates to changes in synaptic plasticity. We present seven lines of evidence that strongly suggest a link between the aftereffects induced by rTMS and the induction of synaptic plasticity. It is, nevertheless, important to realize that at present it is impossible to demonstrate a direct link between rTMS on the one hand and synaptic plasticity on the other. Therefore, we provide suggestions for future, innovating research, aiming to investigate both the local effects of rTMS on the synapse and the effects of rTMS on other, more global levels of brain organization. Only in that way can the aftereffects of rTMS on the brain be completely understood.
Collapse
Affiliation(s)
- Janna Marie Hoogendam
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, The Netherlands.
| | | | | |
Collapse
|
24
|
An ex vivo preparation of the intact mouse vomeronasal organ and accessory olfactory bulb. J Neurosci Methods 2008; 177:440-7. [PMID: 19073215 DOI: 10.1016/j.jneumeth.2008.11.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2008] [Revised: 10/31/2008] [Accepted: 11/04/2008] [Indexed: 11/29/2022]
Abstract
The accessory olfactory system (AOS) in mammals detects and processes information from liquid-phase environmental odorants, including pheromones. The AOS carries out tasks such as individual recognition, learning, and decision-making with relatively few stages of neural processing; it thus represents an attractive system for investigating the neural circuits that carry out these functions. Progress in understanding the AOS has long been impeded by its relative inaccessibility to standard physiological approaches. In this report, we detail a novel dissection and tissue perfusion strategy that improves access to the accessory olfactory bulb (AOB) while maintaining afferent connections from sensory neurons in the vomeronasal organ (VNO). Mitral cells demonstrated spontaneous and evoked firing patterns consistent with recent in vivo reports. We assayed cell degradation in the AOB tissue using Fluoro-Jade C and found that the VNO and AOB glomerular, external plexiform, and mitral cell layers showed minimal signs of degeneration for up to 6h. Whereas histology indicated some degeneration in the deep inhibitory granule cell layer over time, electrophysiological assays demonstrated intact inhibitory function on mitral cells. Pharmacological blockade of GABA(A) receptors with 3microM SR95531 (gabazine) resulted in increased evoked mitral cell activity. Furthermore, mitral cells displayed suppression of responses to preferred urine stimuli when preferred and non-preferred stimuli were mixed, an effect thought to involve functional laterally connected inhibition. These results demonstrate the utility of whole mount ex vivo preparations for studying sensory processing in the AOS, and suggest that similar strategies may improve experimental access to other difficult-to-study neural circuits.
Collapse
|
25
|
Population based models of cortical drug response: insights from anaesthesia. Cogn Neurodyn 2008; 2:283-96. [PMID: 19003456 PMCID: PMC2585619 DOI: 10.1007/s11571-008-9063-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 08/28/2008] [Accepted: 08/28/2008] [Indexed: 11/21/2022] Open
Abstract
A great explanatory gap lies between the molecular pharmacology of psychoactive agents and the neurophysiological changes they induce, as recorded by neuroimaging modalities. Causally relating the cellular actions of psychoactive compounds to their influence on population activity is experimentally challenging. Recent developments in the dynamical modelling of neural tissue have attempted to span this explanatory gap between microscopic targets and their macroscopic neurophysiological effects via a range of biologically plausible dynamical models of cortical tissue. Such theoretical models allow exploration of neural dynamics, in particular their modification by drug action. The ability to theoretically bridge scales is due to a biologically plausible averaging of cortical tissue properties. In the resulting macroscopic neural field, individual neurons need not be explicitly represented (as in neural networks). The following paper aims to provide a non-technical introduction to the mean field population modelling of drug action and its recent successes in modelling anaesthesia.
Collapse
|
26
|
Hewapathirane DS, Dunfield D, Yen W, Chen S, Haas K. In vivo imaging of seizure activity in a novel developmental seizure model. Exp Neurol 2008; 211:480-8. [DOI: 10.1016/j.expneurol.2008.02.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2007] [Revised: 02/06/2008] [Accepted: 02/16/2008] [Indexed: 10/22/2022]
|