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Westmark PR, Swietlik TJ, Runde E, Corsiga B, Nissan R, Boeck B, Granger R, Jennings E, Nebbia M, Thauwald A, Lyon G, Maganti RK, Westmark CJ. Adult Inception of Ketogenic Diet Therapy Increases Sleep during the Dark Cycle in C57BL/6J Wild Type and Fragile X Mice. Int J Mol Sci 2024; 25:6679. [PMID: 38928388 PMCID: PMC11203515 DOI: 10.3390/ijms25126679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/10/2024] [Accepted: 06/14/2024] [Indexed: 06/28/2024] Open
Abstract
Sleep problems are a significant phenotype in children with fragile X syndrome. Our prior work assessed sleep-wake cycles in Fmr1KO male mice and wild type (WT) littermate controls in response to ketogenic diet therapy where mice were treated from weaning (postnatal day 18) through study completion (5-6 months of age). A potentially confounding issue with commencing treatment during an active period of growth is the significant reduction in weight gain in response to the ketogenic diet. The aim here was to employ sleep electroencephalography (EEG) to assess sleep-wake cycles in mice in response to the Fmr1 genotype and a ketogenic diet, with treatment starting at postnatal day 95. EEG results were compared with prior sleep outcomes to determine if the later intervention was efficacious, as well as with published rest-activity patterns to determine if actigraphy is a viable surrogate for sleep EEG. The data replicated findings that Fmr1KO mice exhibit sleep-wake patterns similar to wild type littermates during the dark cycle when maintained on a control purified-ingredient diet but revealed a genotype-specific difference during hours 4-6 of the light cycle of the increased wake (decreased sleep and NREM) state in Fmr1KO mice. Treatment with a high-fat, low-carbohydrate ketogenic diet increased the percentage of NREM sleep in both wild type and Fmr1KO mice during the dark cycle. Differences in sleep microstructure (length of wake bouts) supported the altered sleep states in response to ketogenic diet. Commencing ketogenic diet treatment in adulthood resulted in a 15% (WT) and 8.6% (Fmr1KO) decrease in body weight after 28 days of treatment, but not the severe reduction in body weight associated with starting treatment at weaning. We conclude that the lack of evidence for improved sleep during the light cycle (mouse sleep time) in Fmr1KO mice in response to ketogenic diet therapy in two studies suggests that ketogenic diet may not be beneficial in treating sleep problems associated with fragile X and that actigraphy is not a reliable surrogate for sleep EEG in mice.
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Affiliation(s)
- Pamela R. Westmark
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Timothy J. Swietlik
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Ethan Runde
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Brian Corsiga
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Rachel Nissan
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Brynne Boeck
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Ricky Granger
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Erica Jennings
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Maya Nebbia
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Andrew Thauwald
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Greg Lyon
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Rama K. Maganti
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
| | - Cara J. Westmark
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (T.J.S.); (E.R.); (B.C.); (R.N.); (B.B.); (R.G.); (E.J.); (M.N.); (A.T.); (G.L.); (R.K.M.)
- Molecular Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
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Severino L, Kim J, Nam MH, McHugh TJ. From synapses to circuits: What mouse models have taught us about how autism spectrum disorder impacts hippocampal function. Neurosci Biobehav Rev 2024; 158:105559. [PMID: 38246230 DOI: 10.1016/j.neubiorev.2024.105559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 01/23/2024]
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that impacts a variety of cognitive and behavioral domains. While a genetic component of ASD has been well-established, none of the numerous syndromic genes identified in humans accounts for more than 1% of the clinical patients. Due to this large number of target genes, numerous mouse models of the disorder have been generated. However, the focus on distinct brain circuits, behavioral phenotypes and diverse experimental approaches has made it difficult to synthesize the overwhelming number of model animal studies into concrete throughlines that connect the data across levels of investigation. Here we chose to focus on one circuit, the hippocampus, and one hypothesis, a shift in excitatory/inhibitory balance, to examine, from the level of the tripartite synapse up to the level of in vivo circuit activity, the key commonalities across disparate models that can illustrate a path towards a better mechanistic understanding of ASD's impact on hippocampal circuit function.
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Affiliation(s)
- Leandra Severino
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea; Division of Bio-Medical Science & Technology, KIST-School, University of Science and Technology, Seoul, South Korea
| | - Jinhyun Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea; Division of Bio-Medical Science & Technology, KIST-School, University of Science and Technology, Seoul, South Korea
| | - Min-Ho Nam
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea; Division of Bio-Medical Science & Technology, KIST-School, University of Science and Technology, Seoul, South Korea.
| | - Thomas J McHugh
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea; Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako-shi Saitama, Japan.
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Ethridge LE, Pedapati EV, Schmitt LM, Norris JE, Auger E, De Stefano LA, Sweeney JA, Erickson CA. Validating brain activity measures as reliable indicators of individual diagnostic group and genetically mediated sub-group membership Fragile X Syndrome. RESEARCH SQUARE 2024:rs.3.rs-3849272. [PMID: 38313274 PMCID: PMC10836101 DOI: 10.21203/rs.3.rs-3849272/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
Recent failures translating preclinical behavioral treatment effects to positive clinical trial results in humans with Fragile X Syndrome (FXS) support refocusing attention on biological pathways and associated measures, such as electroencephalography (EEG), with strong translational potential and small molecule target engagement. This study utilized guided machine learning to test promising translational EEG measures (resting power and auditory chirp oscillatory variables) in a large heterogeneous sample of individuals with FXS to identify best performing EEG variables for reliably separating individuals with FXS, and genetically-mediated subgroups within FXS, from typically developing controls. Best performing variables included resting relative frontal theta power, all combined whole-head resting power bands, posterior peak alpha frequency (PAF), combined PAF across all measured regions, combined theta, alpha, and gamma power during the chirp, and all combined chirp oscillatory variables. Sub-group analyses best discriminated non-mosaic FXS males via whole-head resting relative power (AUC = .9250), even with data reduced to a 20-channel clinical montage. FXS females were nearly perfectly discriminated by combined theta, alpha, and gamma power during the chirp (AUC = .9522). Results support use of resting and auditory oscillatory tasks to reliably identify neural deficit in FXS, and to identify specific translational targets for genetically-mediated sub-groups, supporting potential points for stratification.
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Leontiadis LJ, Trompoukis G, Tsotsokou G, Miliou A, Felemegkas P, Papatheodoropoulos C. Rescue of sharp wave-ripples and prevention of network hyperexcitability in the ventral but not the dorsal hippocampus of a rat model of fragile X syndrome. Front Cell Neurosci 2023; 17:1296235. [PMID: 38107412 PMCID: PMC10722241 DOI: 10.3389/fncel.2023.1296235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 11/06/2023] [Indexed: 12/19/2023] Open
Abstract
Fragile X syndrome (FXS) is a genetic neurodevelopmental disorder characterized by intellectual disability and is related to autism. FXS is caused by mutations of the fragile X messenger ribonucleoprotein 1 gene (Fmr1) and is associated with alterations in neuronal network excitability in several brain areas including hippocampus. The loss of fragile X protein affects brain oscillations, however, the effects of FXS on hippocampal sharp wave-ripples (SWRs), an endogenous hippocampal pattern contributing to memory consolidation have not been sufficiently clarified. In addition, it is still not known whether dorsal and ventral hippocampus are similarly affected by FXS. We used a Fmr1 knock-out (KO) rat model of FXS and electrophysiological recordings from the CA1 area of adult rat hippocampal slices to assess spontaneous and evoked neural activity. We find that SWRs and associated multiunit activity are affected in the dorsal but not the ventral KO hippocampus, while complex spike bursts remain normal in both segments of the KO hippocampus. Local network excitability increases in the dorsal KO hippocampus. Furthermore, specifically in the ventral hippocampus of KO rats we found an increased effectiveness of inhibition in suppressing excitation and an upregulation of α1GABAA receptor subtype. These changes in the ventral KO hippocampus are accompanied by a striking reduction in its susceptibility to induced epileptiform activity. We propose that the neuronal network specifically in the ventral segment of the hippocampus is reorganized in adult Fmr1-KO rats by means of balanced changes between excitability and inhibition to ensure normal generation of SWRs and preventing at the same time derailment of the neural activity toward hyperexcitability.
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Westmark PR, Gholston AK, Swietlik TJ, Maganti RK, Westmark CJ. Ketogenic Diet Affects Sleep Architecture in C57BL/6J Wild Type and Fragile X Mice. Int J Mol Sci 2023; 24:14460. [PMID: 37833907 PMCID: PMC10572443 DOI: 10.3390/ijms241914460] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 10/15/2023] Open
Abstract
Nearly half of children with fragile X syndrome experience sleep problems including trouble falling asleep and frequent nighttime awakenings. The goals here were to assess sleep-wake cycles in mice in response to Fmr1 genotype and a dietary intervention that reduces hyperactivity. Electroencephalography (EEG) results were compared with published rest-activity patterns to determine if actigraphy is a viable surrogate for sleep EEG. Specifically, sleep-wake patterns in adult wild type and Fmr1KO littermate mice were recorded after EEG electrode implantation and the recordings manually scored for vigilance states. The data indicated that Fmr1KO mice exhibited sleep-wake patterns similar to wild type littermates when maintained on a control purified ingredient diet. Treatment with a high-fat, low-carbohydrate ketogenic diet increased the percentage of non-rapid eye movement (NREM) sleep in both wild type and Fmr1KO mice during the dark cycle, which corresponded to decreased activity levels. Treatment with a ketogenic diet flattened diurnal sleep periodicity in both wild type and Fmr1KO mice. Differences in several sleep microstructure outcomes (number and length of sleep and wake bouts) supported the altered sleep states in response to a ketogenic diet and were correlated with altered rest-activity cycles. While actigraphy may be a less expensive, reduced labor surrogate for sleep EEG during the dark cycle, daytime resting in mice did not correlate with EEG sleep states.
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Affiliation(s)
- Pamela R. Westmark
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
| | - Aaron K. Gholston
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
- Molecular Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
| | - Timothy J. Swietlik
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
| | - Rama K. Maganti
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
| | - Cara J. Westmark
- Department of Neurology, University of Wisconsin, Madison, WI 53706, USA; (P.R.W.); (A.K.G.); (T.J.S.); (R.K.M.)
- Molecular Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, USA
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6
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Lorents A, Colin ME, Bjerke IE, Nougaret S, Montelisciani L, Diaz M, Verschure P, Vezoli J. Human Brain Project Partnering Projects Meeting: Status Quo and Outlook. eNeuro 2023; 10:ENEURO.0091-23.2023. [PMID: 37669867 PMCID: PMC10481639 DOI: 10.1523/eneuro.0091-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 09/07/2023] Open
Abstract
As the European Flagship Human Brain Project (HBP) ends in September 2023, a meeting dedicated to the Partnering Projects (PPs), a collective of independent research groups that partnered with the HBP, was held on September 4-7, 2022. The purpose of this meeting was to allow these groups to present their results, reflect on their collaboration with the HBP and discuss future interactions with the European Research Infrastructure (RI) EBRAINS that has emerged from the HBP. In this report, we share the tour-de-force that the Partnering Projects that were present in the meeting have made in furthering knowledge concerning various aspects of Brain Research with the HBP. We describe briefly major achievements of the HBP Partnering Projects in terms of a systems-level understanding of the functional architecture of the brain and its possible emulation in artificial systems. We then recapitulate open discussions with EBRAINS representatives about the evolution of EBRAINS as a sustainable Research Infrastructure for the Partnering Projects after the HBP, and also for the wider scientific community.
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Affiliation(s)
| | | | - Ingvild Elise Bjerke
- Neural Systems Laboratory, Institute of Basic Medical Sciences, University of Oslo, Oslo 0372, Norway
| | - Simon Nougaret
- Institut de Neurosciences de la Timone, Unité Mixte de Recherche 7289, Aix Marseille Université, Centre National de la Recherche Scientifique, Marseille 13005, France
| | - Luca Montelisciani
- Cognitive and Systems Neuroscience Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam 1098XH, The Netherlands
| | - Marissa Diaz
- Institute for Advanced Simulation (IAS), Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich GmbH, Jülich 52428, Germany
| | - Paul Verschure
- Donders Center for Neuroscience (DCN-FNWI), Radboud University, Nijmegen 6500HD, The Netherlands
| | - Julien Vezoli
- Ernst Strügmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main 60528, Germany
- Institut National de la Santé et de la Recherche Médicale Unité 1208, Stem Cell and Brain Research Institute, Université Claude Bernard Lyon 1, Bron 69500, France
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Klaver LMF, Brinkhof LP, Sikkens T, Casado-Román L, Williams AG, van Mourik-Donga L, Mejías JF, Pennartz CMA, Bosman CA. Spontaneous variations in arousal modulate subsequent visual processing and local field potential dynamics in the ferret during quiet wakefulness. Cereb Cortex 2023; 33:7564-7581. [PMID: 36935096 PMCID: PMC10267643 DOI: 10.1093/cercor/bhad061] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 02/11/2023] [Accepted: 02/14/2023] [Indexed: 03/21/2023] Open
Abstract
Behavioral states affect neuronal responses throughout the cortex and influence visual processing. Quiet wakefulness (QW) is a behavioral state during which subjects are quiescent but awake and connected to the environment. Here, we examined the effects of pre-stimulus arousal variability on post-stimulus neural activity in the primary visual cortex and posterior parietal cortex in awake ferrets, using pupil diameter as an indicator of arousal. We observed that the power of stimuli-induced alpha (8-12 Hz) decreases when the arousal level increases. The peak of alpha power shifts depending on arousal. High arousal increases inter- and intra-areal coherence. Using a simplified model of laminar circuits, we show that this connectivity pattern is compatible with feedback signals targeting infragranular layers in area posterior parietal cortex and supragranular layers in V1. During high arousal, neurons in V1 displayed higher firing rates at their preferred orientations. Broad-spiking cells in V1 are entrained to high-frequency oscillations (>80 Hz), whereas narrow-spiking neurons are phase-locked to low- (12-18 Hz) and high-frequency (>80 Hz) rhythms. These results indicate that the variability and sensitivity of post-stimulus cortical responses and coherence depend on the pre-stimulus behavioral state and account for the neuronal response variability observed during repeated stimulation.
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Affiliation(s)
- Lianne M F Klaver
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Lotte P Brinkhof
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Tom Sikkens
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Lorena Casado-Román
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Alex G Williams
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Laura van Mourik-Donga
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Jorge F Mejías
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Research Priority Program Brain and Cognition, University of Amsterdam, Amsterdam, The Netherlands
| | - Cyriel M A Pennartz
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Research Priority Program Brain and Cognition, University of Amsterdam, Amsterdam, The Netherlands
| | - Conrado A Bosman
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Research Priority Program Brain and Cognition, University of Amsterdam, Amsterdam, The Netherlands
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Cope EC, Wang SH, Waters RC, Gore IR, Vasquez B, Laham BJ, Gould E. Activation of the CA2-ventral CA1 pathway reverses social discrimination dysfunction in Shank3B knockout mice. Nat Commun 2023; 14:1750. [PMID: 36991001 PMCID: PMC10060401 DOI: 10.1038/s41467-023-37248-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 03/07/2023] [Indexed: 03/30/2023] Open
Abstract
Mutation or deletion of the SHANK3 gene, which encodes a synaptic scaffolding protein, is linked to autism spectrum disorder and Phelan-McDermid syndrome, conditions associated with social memory impairments. Shank3B knockout mice also exhibit social memory deficits. The CA2 region of the hippocampus integrates numerous inputs and sends a major output to the ventral CA1 (vCA1). Despite finding few differences in excitatory afferents to the CA2 in Shank3B knockout mice, we found that activation of CA2 neurons as well as the CA2-vCA1 pathway restored social recognition function to wildtype levels. vCA1 neuronal oscillations have been linked to social memory, but we observed no differences in these measures between wildtype and Shank3B knockout mice. However, activation of the CA2 enhanced vCA1 theta power in Shank3B knockout mice, concurrent with behavioral improvements. These findings suggest that stimulating adult circuitry in a mouse model with neurodevelopmental impairments can invoke latent social memory function.
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Affiliation(s)
- Elise C Cope
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, 08544, USA
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Samantha H Wang
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Renée C Waters
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Isha R Gore
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Betsy Vasquez
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Blake J Laham
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Elizabeth Gould
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, 08544, USA.
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Gredell M, Lu J, Zuo Y. The effect of single-cell knockout of Fragile X Messenger Ribonucleoprotein on synaptic structural plasticity. Front Synaptic Neurosci 2023; 15:1135479. [PMID: 37035256 PMCID: PMC10076639 DOI: 10.3389/fnsyn.2023.1135479] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 03/07/2023] [Indexed: 04/11/2023] Open
Abstract
Fragile X Syndrome (FXS) is the best-known form of inherited intellectual disability caused by the loss-of-function mutation in a single gene. The FMR1 gene mutation abolishes the expression of Fragile X Messenger Ribonucleoprotein (FMRP), which regulates the expression of many synaptic proteins. Cortical pyramidal neurons in postmortem FXS patient brains show abnormally high density and immature morphology of dendritic spines; this phenotype is replicated in the Fmr1 knockout (KO) mouse. While FMRP is well-positioned in the dendrite to regulate synaptic plasticity, intriguing in vitro and in vivo data show that wild type neurons embedded in a network of Fmr1 KO neurons or glia exhibit spine abnormalities just as neurons in Fmr1 global KO mice. This raises the question: does FMRP regulate synaptic morphology and dynamics in a cell-autonomous manner, or do the synaptic phenotypes arise from abnormal pre-synaptic inputs? To address this question, we combined viral and mouse genetic approaches to delete FMRP from a very sparse subset of cortical layer 5 pyramidal neurons (L5 PyrNs) either during early postnatal development or in adulthood. We then followed the structural dynamics of dendritic spines on these Fmr1 KO neurons by in vivo two-photon microscopy. We found that, while L5 PyrNs in adult Fmr1 global KO mice have abnormally high density of thin spines, single-cell Fmr1 KO in adulthood does not affect spine density, morphology, or dynamics. On the contrary, neurons with neonatal FMRP deletion have normal spine density but elevated spine formation at 1 month of age, replicating the phenotype in Fmr1 global KO mice. Interestingly, these neurons exhibit elevated thin spine density, but normal total spine density, by adulthood. Together, our data reveal cell-autonomous FMRP regulation of cortical synaptic dynamics during adolescence, but spine defects in adulthood also implicate non-cell-autonomous factors.
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Affiliation(s)
| | | | - Yi Zuo
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA, United States
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Coupled Dynamics of Stimulus-Evoked Gustatory Cortical and Basolateral Amygdalar Activity. J Neurosci 2023; 43:386-404. [PMID: 36443002 PMCID: PMC9864615 DOI: 10.1523/jneurosci.1412-22.2022] [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: 07/20/2022] [Revised: 11/12/2022] [Accepted: 11/15/2022] [Indexed: 11/29/2022] Open
Abstract
Gustatory cortical (GC) single-neuron taste responses reflect taste quality and palatability in successive epochs. Ensemble analyses reveal epoch-to-epoch firing-rate changes in these responses to be sudden, coherent transitions. Such nonlinear dynamics suggest that GC is part of a recurrent network, producing these dynamics in concert with other structures. Basolateral amygdala (BLA), which is reciprocally connected to GC and central to hedonic processing, is a strong candidate partner for GC, in that BLA taste responses evolve on the same general clock as GC and because inhibition of activity in the BLA→GC pathway degrades the sharpness of GC transitions. These facts motivate, but do not test, our overarching hypothesis that BLA and GC act as a single, comodulated network during taste processing. Here, we provide just this test of simultaneous (BLA and GC) extracellular taste responses in female rats, probing the multiregional dynamics of activity to directly test whether BLA and GC responses contain coupled dynamics. We show that BLA and GC response magnitudes covary across trials and within single responses, and that changes in BLA-GC local field potential phase coherence are epoch specific. Such classic coherence analyses, however, obscure the most salient facet of BLA-GC coupling: sudden transitions in and out of the epoch known to be involved in driving gaping behavior happen near simultaneously in the two regions, despite huge trial-to-trial variability in transition latencies. This novel form of inter-regional coupling, which we show is easily replicated in model networks, suggests collective processing in a distributed neural network.SIGNIFICANCE STATEMENT There has been little investigation into real-time communication between brain regions during taste processing, a fact reflecting the dominant belief that taste circuitry is largely feedforward. Here, we perform an in-depth analysis of real-time interactions between GC and BLA in response to passive taste deliveries, using both conventional coherence metrics and a novel methodology that explicitly considers trial-to-trial variability and fast single-trial dynamics in evoked responses. Our results demonstrate that BLA-GC coherence changes as the taste response unfolds, and that BLA and GC specifically couple for the sudden transition into (and out of) the behaviorally relevant neural response epoch, suggesting (although not proving) that: (1) recurrent interactions subserve the function of the dyad as (2) a putative attractor network.
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11
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Tempio A, Boulksibat A, Bardoni B, Delhaye S. Fragile X Syndrome as an interneuronopathy: a lesson for future studies and treatments. Front Neurosci 2023; 17:1171895. [PMID: 37188005 PMCID: PMC10176609 DOI: 10.3389/fnins.2023.1171895] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/05/2023] [Indexed: 05/17/2023] Open
Abstract
Fragile X Syndrome (FXS) is the most common form of inherited intellectual disability (ID) and a primary genetic cause of autism spectrum disorder (ASD). FXS arises from the silencing of the FMR1 gene causing the lack of translation of its encoded protein, the Fragile X Messenger RibonucleoProtein (FMRP), an RNA-binding protein involved in translational control and in RNA transport along dendrites. Although a large effort during the last 20 years has been made to investigate the cellular roles of FMRP, no effective and specific therapeutic intervention is available to treat FXS. Many studies revealed a role for FMRP in shaping sensory circuits during developmental critical periods to affect proper neurodevelopment. Dendritic spine stability, branching and density abnormalities are part of the developmental delay observed in various FXS brain areas. In particular, cortical neuronal networks in FXS are hyper-responsive and hyperexcitable, making these circuits highly synchronous. Overall, these data suggest that the excitatory/inhibitory (E/I) balance in FXS neuronal circuitry is altered. However, not much is known about how interneuron populations contribute to the unbalanced E/I ratio in FXS even if their abnormal functioning has an impact on the behavioral deficits of patients and animal models affected by neurodevelopmental disorders. We revise here the key literature concerning the role of interneurons in FXS not only with the purpose to better understand the pathophysiology of this disorder, but also to explore new possible therapeutic applications to treat FXS and other forms of ASD or ID. Indeed, for instance, the re-introduction of functional interneurons in the diseased brains has been proposed as a promising therapeutic approach for neurological and psychiatric disorders.
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Affiliation(s)
- Alessandra Tempio
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
- Alessandra Tempio,
| | - Asma Boulksibat
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Barbara Bardoni
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
- Inserm, Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
- *Correspondence: Barbara Bardoni,
| | - Sébastien Delhaye
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
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12
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Asiminas A, Booker SA, Dando OR, Kozic Z, Arkell D, Inkpen FH, Sumera A, Akyel I, Kind PC, Wood ER. Experience-dependent changes in hippocampal spatial activity and hippocampal circuit function are disrupted in a rat model of Fragile X Syndrome. Mol Autism 2022; 13:49. [PMID: 36536454 PMCID: PMC9764562 DOI: 10.1186/s13229-022-00528-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 12/01/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Fragile X syndrome (FXS) is a common single gene cause of intellectual disability and autism spectrum disorder. Cognitive inflexibility is one of the hallmarks of FXS with affected individuals showing extreme difficulty adapting to novel or complex situations. To explore the neural correlates of this cognitive inflexibility, we used a rat model of FXS (Fmr1-/y). METHODS We recorded from the CA1 in Fmr1-/y and WT littermates over six 10-min exploration sessions in a novel environment-three sessions per day (ITI 10 min). Our recordings yielded 288 and 246 putative pyramidal cells from 7 WT and 7 Fmr1-/y rats, respectively. RESULTS On the first day of exploration of a novel environment, the firing rate and spatial tuning of CA1 pyramidal neurons was similar between wild-type (WT) and Fmr1-/y rats. However, while CA1 pyramidal neurons from WT rats showed experience-dependent changes in firing and spatial tuning between the first and second day of exposure to the environment, these changes were decreased or absent in CA1 neurons of Fmr1-/y rats. These findings were consistent with increased excitability of Fmr1-/y CA1 neurons in ex vivo hippocampal slices, which correlated with reduced synaptic inputs from the medial entorhinal cortex. Lastly, activity patterns of CA1 pyramidal neurons were dis-coordinated with respect to hippocampal oscillatory activity in Fmr1-/y rats. LIMITATIONS It is still unclear how the observed circuit function abnormalities give rise to behavioural deficits in Fmr1-/y rats. Future experiments will focus on this connection as well as the contribution of other neuronal cell types in the hippocampal circuit pathophysiology associated with the loss of FMRP. It would also be interesting to see if hippocampal circuit deficits converge with those seen in other rodent models of intellectual disability. CONCLUSIONS In conclusion, we found that hippocampal place cells from Fmr1-/y rats show similar spatial firing properties as those from WT rats but do not show the same experience-dependent increase in spatial specificity or the experience-dependent changes in network coordination. Our findings offer support to a network-level origin of cognitive deficits in FXS.
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Affiliation(s)
- Antonis Asiminas
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.5254.60000 0001 0674 042XPresent Address: Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Sam A. Booker
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Owen R. Dando
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988UK Dementia Research Institute at the Edinburgh Medical School, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Zrinko Kozic
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Daisy Arkell
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Felicity H. Inkpen
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Anna Sumera
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Irem Akyel
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Peter C. Kind
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK ,Centre for Brain Development and Repair, Bangalore, 560065 India
| | - Emma R. Wood
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK ,Centre for Brain Development and Repair, Bangalore, 560065 India
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13
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Shing N, Walker MC, Chang P. The Role of Aberrant Neural Oscillations in the Hippocampal-Medial Prefrontal Cortex Circuit in Neurodevelopmental and Neurological Disorders. Neurobiol Learn Mem 2022; 195:107683. [PMID: 36174886 DOI: 10.1016/j.nlm.2022.107683] [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: 03/01/2022] [Revised: 09/09/2022] [Accepted: 09/20/2022] [Indexed: 11/30/2022]
Abstract
The hippocampus (HPC) and medial prefrontal cortex (mPFC) have well-established roles in cognition, emotion, and sensory processing. In recent years, interests have shifted towards developing a deeper understanding of the mechanisms underlying interactions between the HPC and mPFC in achieving these functions. Considerable research supports the idea that synchronized activity between the HPC and the mPFC is a general mechanism by which brain functions are regulated. In this review, we summarize current knowledge on the hippocampal-medial prefrontal cortex (HPC-mPFC) circuit in normal brain function with a focus on oscillations and highlight several neurodevelopmental and neurological disorders associated with aberrant HPC-mPFC circuitry. We further discuss oscillatory dynamics across the HPC-mPFC circuit as potentially useful biomarkers to assess interventions for neurodevelopmental and neurological disorders. Finally, advancements in brain stimulation, gene therapy and pharmacotherapy are explored as promising therapies for disorders with aberrant HPC-mPFC circuit dynamics.
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Affiliation(s)
- Nathanael Shing
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, WC1N 3BG, UK; Department of Medicine, University of Central Lancashire, Preston, PR17BH, UK
| | - Matthew C Walker
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Pishan Chang
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, WC1E 6BT.
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14
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Alemany-González M, Vilademunt M, Gener T, Puig MV. Postnatal environmental enrichment enhances memory through distinct neural mechanisms in healthy and trisomic female mice. Neurobiol Dis 2022; 173:105841. [PMID: 35988873 DOI: 10.1016/j.nbd.2022.105841] [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: 06/09/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 10/15/2022] Open
Abstract
Stimulating lifestyles have powerful effects on cognitive abilities, especially when they are experienced early in life. Cognitive therapies are widely used to improve cognitive impairment due to intellectual disability, aging, and neurodegeneration, however the underlying neural mechanisms are poorly understood. We investigated the neural correlates of memory amelioration produced by postnatal environmental enrichment (EE) in diploid mice and the Ts65Dn mouse model of Down syndrome (trisomy 21). We recorded neural activities in brain structures key for memory processing, the hippocampus and the prefrontal cortex, during rest, sleep and memory performance in mice reared in non-enriched or enriched environments. Enriched wild-type animals exhibited enhanced neural synchrony in the hippocampus across different brain states (increased gamma oscillations, theta-gamma coupling, sleep ripples). Trisomic females showed increased theta and gamma rhythms in the hippocampus and prefrontal cortex across different brain states along with enlarged ripples and disrupted circuit gamma signals that were associated with memory deficits. These pathological activities were attenuated in their trisomic EE-reared peers. Our results suggest distinct neural mechanisms for the generation and rescue of healthy and pathological brain synchrony, respectively, by EE and put forward hippocampal-prefrontal hypersynchrony and miscommunication as major targets underlying the beneficial effects of EE in intellectual disability.
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Affiliation(s)
- Maria Alemany-González
- Integrative Pharmacology and Systems Neuroscience, Hospital del Mar Medical Research Institute, Barcelona Biomedical Research Park, 08003 Barcelona, Spain
| | - Marta Vilademunt
- Integrative Pharmacology and Systems Neuroscience, Hospital del Mar Medical Research Institute, Barcelona Biomedical Research Park, 08003 Barcelona, Spain
| | - Thomas Gener
- Integrative Pharmacology and Systems Neuroscience, Hospital del Mar Medical Research Institute, Barcelona Biomedical Research Park, 08003 Barcelona, Spain; Catalan Institute of Nanoscience and Nanotechnology (ICN2), the Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain; Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - M Victoria Puig
- Integrative Pharmacology and Systems Neuroscience, Hospital del Mar Medical Research Institute, Barcelona Biomedical Research Park, 08003 Barcelona, Spain; Catalan Institute of Nanoscience and Nanotechnology (ICN2), the Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain; Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
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15
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Kenny A, Wright D, Stanfield AC. EEG as a translational biomarker and outcome measure in fragile X syndrome. Transl Psychiatry 2022; 12:34. [PMID: 35075104 PMCID: PMC8786970 DOI: 10.1038/s41398-022-01796-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 12/01/2021] [Accepted: 01/12/2022] [Indexed: 01/08/2023] Open
Abstract
Targeted treatments for fragile X syndrome (FXS) have frequently failed to show efficacy in clinical testing, despite success at the preclinical stages. This has highlighted the need for more effective translational outcome measures. EEG differences observed in FXS, including exaggerated N1 ERP amplitudes, increased resting gamma power and reduced gamma phase-locking in the sensory cortices, have been suggested as potential biomarkers of the syndrome. These abnormalities are thought to reflect cortical hyper excitability resulting from an excitatory (glutamate) and inhibitory (GABAergic) imbalance in FXS, which has been the target of several pharmaceutical remediation studies. EEG differences observed in humans also show similarities to those seen in laboratory models of FXS, which may allow for greater translational equivalence and better predict clinical success of putative therapeutics. There is some evidence from clinical trials showing that treatment related changes in EEG may be associated with clinical improvements, but these require replication and extension to other medications. Although the use of EEG characteristics as biomarkers is still in the early phases, and further research is needed to establish its utility in clinical trials, the current research is promising and signals the emergence of an effective translational biomarker.
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Affiliation(s)
- Aisling Kenny
- Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, EH10 5HF, Edinburgh, UK.
| | - Damien Wright
- grid.4305.20000 0004 1936 7988Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, EH10 5HF Edinburgh, UK
| | - Andrew C. Stanfield
- grid.4305.20000 0004 1936 7988Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, EH10 5HF Edinburgh, UK
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16
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Bach S, Shovlin S, Moriarty M, Bardoni B, Tropea D. Rett Syndrome and Fragile X Syndrome: Different Etiology With Common Molecular Dysfunctions. Front Cell Neurosci 2021; 15:764761. [PMID: 34867203 PMCID: PMC8640214 DOI: 10.3389/fncel.2021.764761] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/27/2021] [Indexed: 01/04/2023] Open
Abstract
Rett syndrome (RTT) and Fragile X syndrome (FXS) are two monogenetic neurodevelopmental disorders with complex clinical presentations. RTT is caused by mutations in the Methyl-CpG binding protein 2 gene (MECP2) altering the function of its protein product MeCP2. MeCP2 modulates gene expression by binding methylated CpG dinucleotides, and by interacting with transcription factors. FXS is caused by the silencing of the FMR1 gene encoding the Fragile X Mental Retardation Protein (FMRP), a RNA binding protein involved in multiple steps of RNA metabolism, and modulating the translation of thousands of proteins including a large set of synaptic proteins. Despite differences in genetic etiology, there are overlapping features in RTT and FXS, possibly due to interactions between MeCP2 and FMRP, and to the regulation of pathways resulting in dysregulation of common molecular signaling. Furthermore, basic physiological mechanisms are regulated by these proteins and might concur to the pathophysiology of both syndromes. Considering that RTT and FXS are disorders affecting brain development, and that most of the common targets of MeCP2 and FMRP are involved in brain activity, we discuss the mechanisms of synaptic function and plasticity altered in RTT and FXS, and we consider the similarities and the differences between these two disorders.
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Affiliation(s)
- Snow Bach
- School of Mathematical Sciences, Dublin City University, Dublin, Ireland.,Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity College Dublin, Trinity Translational Medicine Institute, St James's Hospital, Dublin, Ireland
| | - Stephen Shovlin
- Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity College Dublin, Trinity Translational Medicine Institute, St James's Hospital, Dublin, Ireland
| | | | - Barbara Bardoni
- Inserm, CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology, Université Côte d'Azur, Valbonne, France
| | - Daniela Tropea
- Neuropsychiatric Genetics, Department of Psychiatry, School of Medicine, Trinity College Dublin, Trinity Translational Medicine Institute, St James's Hospital, Dublin, Ireland.,Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland.,FutureNeuro, The SFI Research Centre for Chronic and Rare Neurological Diseases, Dublin, Ireland
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17
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Tok S, Ahnaou A, Drinkenburg W. Functional Neurophysiological Biomarkers of Early-Stage Alzheimer's Disease: A Perspective of Network Hyperexcitability in Disease Progression. J Alzheimers Dis 2021; 88:809-836. [PMID: 34420957 PMCID: PMC9484128 DOI: 10.3233/jad-210397] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Network hyperexcitability (NH) has recently been suggested as a potential neurophysiological indicator of Alzheimer’s disease (AD), as new, more accurate biomarkers of AD are sought. NH has generated interest as a potential indicator of certain stages in the disease trajectory and even as a disease mechanism by which network dysfunction could be modulated. NH has been demonstrated in several animal models of AD pathology and multiple lines of evidence point to the existence of NH in patients with AD, strongly supporting the physiological and clinical relevance of this readout. Several hypotheses have been put forward to explain the prevalence of NH in animal models through neurophysiological, biochemical, and imaging techniques. However, some of these hypotheses have been built on animal models with limitations and caveats that may have derived NH through other mechanisms or mechanisms without translational validity to sporadic AD patients, potentially leading to an erroneous conclusion of the underlying cause of NH occurring in patients with AD. In this review, we discuss the substantiation for NH in animal models of AD pathology and in human patients, as well as some of the hypotheses considering recently developed animal models that challenge existing hypotheses and mechanisms of NH. In addition, we provide a preclinical perspective on how the development of animal models incorporating AD-specific NH could provide physiologically relevant translational experimental data that may potentially aid the discovery and development of novel therapies for AD.
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Affiliation(s)
- Sean Tok
- Department of Neuroscience, Janssen Research & Development, Janssen Pharmaceutica NV, Beerse, Belgium.,Groningen Institute for Evolutionary Life Sciences, Faculty of Science and Engineering, University of Groningen, The Netherlands
| | - Abdallah Ahnaou
- Department of Neuroscience, Janssen Research & Development, Janssen Pharmaceutica NV, Beerse, Belgium
| | - Wilhelmus Drinkenburg
- Department of Neuroscience, Janssen Research & Development, Janssen Pharmaceutica NV, Beerse, Belgium.,Groningen Institute for Evolutionary Life Sciences, Faculty of Science and Engineering, University of Groningen, The Netherlands
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18
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Smith E, Pedapati E, Liu R, Schmitt L, Dominick K, Shaffer R, Sweeney J, Erickson C. Sex differences in resting EEG power in Fragile X Syndrome. J Psychiatr Res 2021; 138:89-95. [PMID: 33836434 PMCID: PMC8192450 DOI: 10.1016/j.jpsychires.2021.03.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/10/2021] [Accepted: 03/24/2021] [Indexed: 12/21/2022]
Abstract
Electrophysiological alterations may represent a neural substrate of impaired neurocognitive processes and other phenotypic features in Fragile X Syndrome (FXS). However, the role of biological sex in electroencephalography (EEG) patterns that differentiate FXS from typical development has not been determined. This limits use of EEG in both the search for biomarkers of impairment in FXS as well as application of those markers to enhance our understanding of underlying neural mechanisms to speed treatment discovery. We investigated topographical relative EEG power in participants at rest in a sample of males and females with FXS and in age- and sex-matched typically developing controls (TDC) using a cluster-based analysis. While alterations in theta and low beta power were similar across males and females in FXS, relative power varied by sex in the alpha, upper beta, gamma, and epsilon frequency bands. Follow up analyses showed that Individual Alpha Peak Frequency (IAPF), a continuous variable that may capture atypicalities across the theta and alpha ranges in neurodevelopmental disorders, also varied by sex. Finally, performance on an auditory filtering task correlated with theta power in males, but not females with FXS. The impact of biological sex on resting state EEG power differences in FXS is discussed as it relates to potential GABAergic and glutamatergic etiologies of neurocognitive deficits in FXS.
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Affiliation(s)
- Elizabeth Smith
- Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA,Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Elizabeth G. Smith, corresponding author Cincinnati Children’s Hospital, 3333 Burnet Avenue, MLC 7039 Cincinnati, OH 45229 , (513) 517-1383
| | - Ernest Pedapati
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Department of Psychiatry, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Rui Liu
- Department of Psychiatry, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Lauren Schmitt
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Division of Developmental and Behavioral Pediatrics, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Kelli Dominick
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Department of Psychiatry, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Rebecca Shaffer
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Division of Developmental and Behavioral Pediatrics, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - John Sweeney
- Department of Psychiatry, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Craig Erickson
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, 3230 Eden Avenue, Cincinnati, OH 45267, USA,Department of Psychiatry, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
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19
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Albeely AM, Williams OOF, Perreault ML. GSK-3β Disrupts Neuronal Oscillatory Function to Inhibit Learning and Memory in Male Rats. Cell Mol Neurobiol 2021; 42:1341-1353. [PMID: 33392916 DOI: 10.1007/s10571-020-01020-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 11/27/2020] [Indexed: 12/25/2022]
Abstract
Alterations in glycogen synthase kinase-3β (GSK-3β) activity have been implicated in disorders of cognitive impairment, including Alzheimer's disease and schizophrenia. Cognitive dysfunction is also characterized by the dysregulation of neuronal oscillatory activity, macroscopic electrical rhythms in brain that are critical to systems communication. A direct functional relationship between GSK-3β and neuronal oscillations has not been elucidated. Therefore, in the present study, using an adeno-associated viral vector containing a persistently active mutant form of GSK-3β, GSK-3β(S9A), the impact of elevated kinase activity in prefrontal cortex (PFC) or ventral hippocampus (vHIP) of rats on neuronal oscillatory activity was evaluated. GSK-3β(S9A)-induced changes in learning and memory were also assessed and the phosphorylation status of tau protein, a substrate of GSK-3β, examined. It was demonstrated that increasing GSK-3β(S9A) activity in either the PFC or vHIP had similar effects on neuronal oscillatory activity, enhancing theta and/or gamma spectral power in one or both regions. Increasing PFC GSK-3β(S9A) activity additionally suppressed high gamma PFC-vHIP coherence. These changes were accompanied by deficits in recognition memory, spatial learning, and/or reversal learning. Elevated pathogenic tau phosphorylation was also evident in regions where GSK-3β(S9A) activity was upregulated. The neurophysiological and learning and memory deficits induced by GSK-3β(S9A) suggest that aberrant GSK-3β signalling may not only play an early role in cognitive decline in Alzheimer's disease but may also have a more central involvement in disorders of cognitive dysfunction through the regulation of neurophysiological network function.
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Affiliation(s)
- Abdalla M Albeely
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, ON, N1G 2W1, Canada.,Collaborative Neuroscience Program, University of Guelph, 50 Stone Rd. E, Guelph, ON, Canada
| | - Olivia O F Williams
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, ON, N1G 2W1, Canada
| | - Melissa L Perreault
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd. E, Guelph, ON, N1G 2W1, Canada. .,Collaborative Neuroscience Program, University of Guelph, 50 Stone Rd. E, Guelph, ON, Canada.
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Impaired Reliability and Precision of Spiking in Adults But Not Juveniles in a Mouse Model of Fragile X Syndrome. eNeuro 2019; 6:ENEURO.0217-19.2019. [PMID: 31685673 PMCID: PMC6917895 DOI: 10.1523/eneuro.0217-19.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 10/02/2019] [Accepted: 10/04/2019] [Indexed: 12/26/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common source of intellectual disability and autism. Extensive studies have been performed on the network and behavioral correlates of the syndrome, but our knowledge about intrinsic conductance changes is still limited. In this study, we show a differential effect of FMRP knockout in different subsections of hippocampus using whole-cell patch clamp in mouse hippocampal slices. We observed no significant change in spike numbers in the CA1 region of hippocampus, but a significant increase in CA3, in juvenile mice. However, in adult mice we see a reduction in spike number in the CA1 with no significant difference in CA3. In addition, we see increased variability in spike numbers in CA1 cells following a variety of steady and modulated current step protocols. This effect emerges in adult mice (8 weeks) but not juvenile mice (4 weeks). This increased spiking variability was correlated with reduced spike number and with elevated AHP. The increased AHP arose from elevated SK currents (small conductance calcium-activated potassium channels), but other currents involved in medium AHP, such as Ih and M, were not significantly different. We obtained a partial rescue of the cellular variability phenotype when we blocked SK current using the specific blocker apamin. Our observations provide a single-cell correlate of the network observations of response variability and loss of synchronization, and suggest that the elevation of SK currents in FXS may provide a partial mechanistic explanation for this difference.
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Cardin JA. Inhibitory Interneurons Regulate Temporal Precision and Correlations in Cortical Circuits. Trends Neurosci 2018; 41:689-700. [PMID: 30274604 PMCID: PMC6173199 DOI: 10.1016/j.tins.2018.07.015] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 07/24/2018] [Accepted: 07/31/2018] [Indexed: 01/16/2023]
Abstract
GABAergic interneurons, which are highly diverse, have long been thought to contribute to the timing of neural activity as well as to the generation and shaping of brain rhythms. GABAergic activity is crucial not only for entrainment of oscillatory activity across a neural population, but also for precise regulation of the timing of action potentials and the suppression of slow-timescale correlations. The diversity of inhibition provides the potential for flexible regulation of patterned activity, but also poses a challenge to identifying the elements of excitatory-inhibitory interactions underlying network engagement. This review highlights the key roles of inhibitory interneurons in spike correlations and brain rhythms, describes several scales on which GABAergic inhibition regulates timing in neural networks, and identifies potential consequences of inhibitory dysfunction.
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Affiliation(s)
- Jessica A Cardin
- Department of Neuroscience, Yale University, New Haven, CT 06520, USA; Kavli Institute for Neuroscience, Yale University, New Haven, CT 06520, USA.
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