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Arboit A, Ku SP, Krautwald K, Angenstein F. Brief neuronal afterdischarges in the rat hippocampus lead to transient changes in oscillatory activity and to a very long-lasting decline in BOLD signals without inducing a hypoxic state. Neuroimage 2021; 245:118769. [PMID: 34861394 DOI: 10.1016/j.neuroimage.2021.118769] [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: 09/22/2021] [Revised: 11/24/2021] [Accepted: 11/29/2021] [Indexed: 10/19/2022] Open
Abstract
The effects of hippocampal neuronal afterdischarges (nAD) on hemodynamic parameters, such as blood-oxygen-level-dependent (BOLD) signals) and local cerebral blood volume (CBV) changes, as well as neuronal activity and metabolic parameters in the dentate gyrus, was investigated in rats by combining in vivo electrophysiology with functional magnetic resonance imaging (fMRI) or 1H-nuclear magnetic resonance spectroscopy (1H-NMRS). Brief electrical high-frequency pulse-burst stimulation of the right perforant pathway triggered nAD, a seizure-like activity, in the right dentate gyrus with a high incidence, a phenomenon that in turn caused a sustained decrease in BOLD signals for more than 30 min. The decrease was associated with a reduction in CBV but not with signs of hypoxic metabolism. nAD also triggered transient changes mainly in the low gamma frequency band that recovered within 20 min, so that the longer-lasting altered hemodynamics reflected a switch in blood supply rather than transient changes in ongoing neuronal activity. Even in the presence of reduced baseline BOLD signals, neurovascular coupling mechanisms remained intact, making long-lasting vasospasm unlikely. Subsequently generated nAD did not further alter the baseline BOLD signals. Similarly, nAD did not alter baseline BOLD signals when acetaminophen was previously administered, because acetaminophen alone had already caused a similar decrease in baseline BOLD signals as observed after the first nAD. Thus, at least two different blood supply states exist for the hippocampus, one low and one high, with both states allowing similar neuronal activity. Both acetaminophen and nAD switch from the high to the low blood supply state. As a result, the hemodynamic response function to an identical stimulus differed after nAD or acetaminophen, although the triggered neuronal activity was similar.
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Affiliation(s)
- Alberto Arboit
- Functional Neuroimaging Group, Deutsches Zentrum für neurodegenerative Erkrankungen (DZNE), Leipzigerstr, 44, Magdeburg 39118, Germany
| | - Shih-Pi Ku
- Department Functional Architecture of Memory, Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany
| | - Karla Krautwald
- Functional Neuroimaging Group, Deutsches Zentrum für neurodegenerative Erkrankungen (DZNE), Leipzigerstr, 44, Magdeburg 39118, Germany
| | - Frank Angenstein
- Functional Neuroimaging Group, Deutsches Zentrum für neurodegenerative Erkrankungen (DZNE), Leipzigerstr, 44, Magdeburg 39118, Germany; Department Functional Architecture of Memory, Leibniz Institute for Neurobiology (LIN), Magdeburg 39118, Germany; Center for Behavior and Brain Sciences (CBBS), Magdeburg, Germany; Medical Faculty, Otto von Guericke University, Magdeburg 39118, Germany.
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Yokokura M, Takebasashi K, Takao A, Nakaizumi K, Yoshikawa E, Futatsubashi M, Suzuki K, Nakamura K, Yamasue H, Ouchi Y. In vivo imaging of dopamine D1 receptor and activated microglia in attention-deficit/hyperactivity disorder: a positron emission tomography study. Mol Psychiatry 2021; 26:4958-4967. [PMID: 32439845 DOI: 10.1038/s41380-020-0784-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 05/05/2020] [Accepted: 05/11/2020] [Indexed: 02/07/2023]
Abstract
Alterations in the cortical dopamine system and microglial activation have been implicated in the pathophysiology of attention-deficit/hyperactivity disorder (ADHD), one of neurodevelopmental disorders that can be conventionally treated with a dopamine enhancer (methylphenidate) albeit unsatisfactorily. Here, we investigated the contributions of the dopamine D1 receptor (D1R) and activated microglia and their interactions to the clinical severities in ADHD individuals using positron emission tomography (PET). Twenty-four psychotropic-naïve ADHD individuals and 24 age- and sex-matched typically developing (TD) subjects underwent PET measurements with [11C]SCH23390 for the D1R and [11C](R)PK11195 for activated microglia as well as assessments of clinical symptoms and cognitive functions. The ADHD individuals showed decreased D1R in the anterior cingulate cortex (ACC) and increased activated microglia in the dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) compared with the TD subjects. The decreased D1R in the ACC was associated with severe hyperactivity in the participants with ADHD. Microglial activation in the DLPFC were associated with deficits in processing speed and attentional ability, and that in the OFC was correlated with lower processing speed in the ADHD individuals. Furthermore, positive correlations between the D1R and activated microglia in both the DLPFC and the OFC were found to be significantly specific to the ADHD group and not to the TD group. The current findings suggest that microglial activation and the D1R reduction as well as their aberrant interactions underpin the neurophysiological mechanism of ADHD and indicate these biomolecular changes as a novel therapeutic target.
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Affiliation(s)
- Masamichi Yokokura
- Department of Psychiatry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Kiyokazu Takebasashi
- Department of Psychiatry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | | | - Kyoko Nakaizumi
- Department of Psychiatry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Etsuji Yoshikawa
- Central Research Laboratory, Hamamatsu Photonics K.K, Hamamatsu, Japan
| | - Masami Futatsubashi
- Global Strategic Challenge Center, Hamamatsu Photonics K.K, Hamamatsu, Japan.,Hamamatsu PET Imaging Center, Hamamatsu Medical Photonics Foundation, Hamamatsu, Japan
| | - Katsuaki Suzuki
- Department of Biofunctional Imaging, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | | | - Hidenori Yamasue
- Department of Psychiatry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Yasuomi Ouchi
- Department of Biofunctional Imaging, Hamamatsu University School of Medicine, Hamamatsu, Japan.
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Schicknick H, Henschke JU, Budinger E, Ohl FW, Gundelfinger ED, Tischmeyer W. β-adrenergic modulation of discrimination learning and memory in the auditory cortex. Eur J Neurosci 2019; 50:3141-3163. [PMID: 31162753 PMCID: PMC6900137 DOI: 10.1111/ejn.14480] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 05/27/2019] [Accepted: 05/31/2019] [Indexed: 01/11/2023]
Abstract
Despite vast literature on catecholaminergic neuromodulation of auditory cortex functioning in general, knowledge about its role for long‐term memory formation is scarce. Our previous pharmacological studies on cortex‐dependent frequency‐modulated tone‐sweep discrimination learning of Mongolian gerbils showed that auditory‐cortical D1/5‐dopamine receptor activity facilitates memory consolidation and anterograde memory formation. Considering overlapping functions of D1/5‐dopamine receptors and β‐adrenoceptors, we hypothesised a role of β‐adrenergic signalling in the auditory cortex for sweep discrimination learning and memory. Supporting this hypothesis, the β1/2‐adrenoceptor antagonist propranolol bilaterally applied to the gerbil auditory cortex after task acquisition prevented the discrimination increment that was normally monitored 1 day later. The increment in the total number of hurdle crossings performed in response to the sweeps per se was normal. Propranolol infusion after the seventh training session suppressed the previously established sweep discrimination. The suppressive effect required antagonist injection in a narrow post‐session time window. When applied to the auditory cortex 1 day before initial conditioning, β1‐adrenoceptor‐antagonising and β1‐adrenoceptor‐stimulating agents retarded and facilitated, respectively, sweep discrimination learning, whereas β2‐selective drugs were ineffective. In contrast, single‐sweep detection learning was normal after propranolol infusion. By immunohistochemistry, β1‐ and β2‐adrenoceptors were identified on the neuropil and somata of pyramidal and non‐pyramidal neurons of the gerbil auditory cortex. The present findings suggest that β‐adrenergic signalling in the auditory cortex has task‐related importance for discrimination learning of complex sounds: as previously shown for D1/5‐dopamine receptor signalling, β‐adrenoceptor activity supports long‐term memory consolidation and reconsolidation; additionally, tonic input through β1‐adrenoceptors may control mechanisms permissive for memory acquisition.
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Affiliation(s)
- Horst Schicknick
- Special Lab Molecular Biological Techniques, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Julia U Henschke
- Department Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Institute of Cognitive Neurology and Dementia Research, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Eike Budinger
- Department Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Frank W Ohl
- Department Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany.,Institute of Biology, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Eckart D Gundelfinger
- Center for Behavioral Brain Sciences, Magdeburg, Germany.,Department Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Molecular Neurobiology, Medical Faculty, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Wolfgang Tischmeyer
- Special Lab Molecular Biological Techniques, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
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Krautwald K, Mahnke L, Angenstein F. Electrical Stimulation of the Lateral Entorhinal Cortex Causes a Frequency-Specific BOLD Response Pattern in the Rat Brain. Front Neurosci 2019; 13:539. [PMID: 31191231 PMCID: PMC6547013 DOI: 10.3389/fnins.2019.00539] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 05/09/2019] [Indexed: 11/13/2022] Open
Abstract
Although deep brain stimulation of the entorhinal cortex has recently shown promise in the treatment of early forms of cognitive decline, the underlying neurophysiological processes remain elusive. Therefore, the lateral entorhinal cortex (LEC) was stimulated with trains of continuous 5 Hz and 20 Hz pulses or with bursts of 100 Hz pulses to visualize activated neuronal networks, i.e., neuronal responses in the dentate gyrus and BOLD responses in the entire brain were simultaneously recorded. Electrical stimulation of the LEC caused a wide spread pattern of BOLD responses. Dependent on the stimulation frequency, BOLD responses were only triggered in the amygdala, infralimbic, prelimbic, and dorsal peduncular cortex (5 Hz), or in the nucleus accumbens, piriform cortex, dorsal medial prefrontal cortex, hippocampus (20 Hz), and contralateral entorhinal cortex (100 Hz). In general, LEC stimulation caused stronger BOLD responses in frontal cortex regions than in the hippocampus. Identical stimulation of the perforant pathway, a fiber bundle projecting from the entorhinal cortex to the dentate gyrus, hippocampus proper, and subiculum, mainly elicited significant BOLD responses in the hippocampus but rarely in frontal cortex regions. Consequently, BOLD responses in frontal cortex regions are mediated by direct projections from the LEC rather than via signal propagation through the hippocampus. Thus, the beneficial effects of deep brain stimulation of the entorhinal cortex on cognitive skills might depend more on an altered prefrontal cortex than hippocampal function.
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Affiliation(s)
- Karla Krautwald
- Functional Neuroimaging Group, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Magdeburg, Germany
| | - Liv Mahnke
- Department Functional Architecture of Memory, Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany
| | - Frank Angenstein
- Functional Neuroimaging Group, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Magdeburg, Germany.,Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Medical Faculty, Otto von Guericke University Magdeburg, Magdeburg, Germany
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