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Jia W, Li C, Chen H, Wang X, Liu Y, Shang W, Wang B, Meng W, Guo Y, Zhu L, Wang D, Zhou D, Zhao B, Wei L. ISRIB ameliorates spatial learning and memory impairment induced by adolescent intermittent ethanol exposure in adult male rats. Neurochem Int 2024; 179:105834. [PMID: 39142353 DOI: 10.1016/j.neuint.2024.105834] [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: 04/29/2024] [Revised: 08/08/2024] [Accepted: 08/11/2024] [Indexed: 08/16/2024]
Abstract
Alcohol exposure in adolescence is considered a major cause of cognitive impairments later in life including spatial learning and memory. Integrated stress response (ISR), a program of conservative translation and transcription, is crucial in synaptic plasticity and memory. Although previous studies have elucidated ISR in different brain areas involved in learning and memory disorders, the impact of ISR on learning and memory following adolescent alcohol exposure remains unclear. Here, we demonstrated that adolescent intermittent ethanol (AIE) exposure caused spatial learning and memory impairment, combined with neuronal damage in the medial prefrontal cortex (mPFC), nucleus accumbens (NAc) and hippocampus (HIP) in adult rats. Moreover, integrated stress response inhibitor (ISRIB) administration not only improved spatial learning and memory impairment and neuronal damage but also inhibited the endoplasmic reticulum stress (ER) and reversed changes in synaptic proteins. These findings suggested that ISRIB ameliorates AIE exposure-induced spatial learning and memory deficits by improving neural morphology and synaptic function through inhibiting ER stress signaling pathway in the mPFC, NAc and HIP in adulthood. Our findings may enhance comprehension of cognitive function and neuronal effects of adolescent ethanol exposure and ISRIB treatment may be an underlying potential option for addressing alcohol-induced learning and memory deficits.
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Affiliation(s)
- Wenge Jia
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Chenchen Li
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Hongyun Chen
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Xinyu Wang
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Yuan Liu
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Wanbing Shang
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Bian Wang
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Wenjing Meng
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Yaxin Guo
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Lijie Zhu
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Dan Wang
- Henan Key Laboratory of Biological Psychiatry, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Danya Zhou
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
| | - Bin Zhao
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China; Henan Key Laboratory of Biological Psychiatry, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, 453003, Henan, China.
| | - Lai Wei
- Xinxiang Key Laboratory of Forensic Toxicology, School of Forensic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China; Henan Key Laboratory of Biological Psychiatry, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, 453003, Henan, China.
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Kloc ML, Holmes GL, Barry JM. Sex differences in cholinergic signaling affect functional outcomes for theta-gamma coordination in hippocampal subcircuits following experimental febrile status epilepticus. Epilepsia 2024; 65:2138-2151. [PMID: 38780490 PMCID: PMC11251858 DOI: 10.1111/epi.18017] [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: 12/11/2023] [Revised: 05/06/2024] [Accepted: 05/06/2024] [Indexed: 05/25/2024]
Abstract
OBJECTIVE Sex determines cognitive outcome in animal models of early life seizure, where males exhibit impaired hippocampal-dependent learning and memory compared with females. The physiological underpinnings of this sex effect are unclear. Cholinergic signaling is essential for the generation of hippocampal oscillations, and supplementation of cholinergic precursors prior to status epilepticus in immature male rats prevents subsequent memory deficits. We hypothesized that there are sex differences in acetylcholine circuits and their response to experimental febrile status epilepticus (eFSE). METHODS eFSE was induced in male and female rat pups. We transversed the hippocampus of postnatal day >60 control (CTL) and eFSE rats with a 64-channel laminar silicon probe to assay cholinergic-dependent theta oscillations under urethane anesthesia. Local field potential properties were compared during (1) baseline sensory stimulation, (2) pharmacological stimulation via acetylcholine reuptake blockade, and (3) sensory stimulation after muscarinic acetylcholine receptor block (atropine). RESULTS In all groups, a baseline tail pinch could elicit theta oscillations via corticohippocampal synaptic input. Following atropine, a tail pinch response could no longer be elicited in CTL male, CTL female, or eFSE female rats. In contrast, induced slow theta power in eFSE males after atropine was not decreased to spontaneous levels. Analysis of oscillation bandwidths revealed sex differences in acetylcholine modulation of theta frequency and slow gamma frequency and power. This study also identified significant effects of both sex and eFSE on baseline theta-gamma comodulation, indicating a loss of coupling in eFSE males and a potential gain of function in eFSE females. SIGNIFICANCE There are differences in cholinergic modulation of theta and gamma signal coordination between male and female rats. These differences may underlie worse cognitive outcomes in males following eFSE. Promoting the efficacy of muscarinic acetylcholine signaling prior to or following early life seizures could elucidate a mechanism for the temporal discoordination of neural signals within and between hippocampus and neocortex and provide a novel therapeutic approach for improving cognitive outcomes.
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Affiliation(s)
- Michelle L Kloc
- Epilepsy Cognition and Development Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, Vermont, USA
| | - Gregory L Holmes
- Epilepsy Cognition and Development Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, Vermont, USA
| | - Jeremy M Barry
- Epilepsy Cognition and Development Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, Vermont, USA
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Shipkov D, Nasretdinov A, Khazipov R, Valeeva G. Synchronous excitation in the superficial and deep layers of the medial entorhinal cortex precedes early sharp waves in the neonatal rat hippocampus. Front Cell Neurosci 2024; 18:1403073. [PMID: 38737704 PMCID: PMC11082381 DOI: 10.3389/fncel.2024.1403073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 04/15/2024] [Indexed: 05/14/2024] Open
Abstract
Early Sharp Waves (eSPWs) are the earliest pattern of network activity in the developing hippocampus of neonatal rodents. eSPWs were originally considered to be an immature prototype of adult SPWs, which are spontaneous top-down hippocampal events that are self-generated in the hippocampal circuitry. However, recent studies have shifted this paradigm to a bottom-up model of eSPW genesis, in which eSPWs are primarily driven by the inputs from the layers 2/3 of the medial entorhinal cortex (MEC). A hallmark of the adult SPWs is the relay of information from the CA1 hippocampus to target structures, including deep layers of the EC. Whether and how deep layers of the MEC are activated during eSPWs in the neonates remains elusive. In this study, we investigated activity in layer 5 of the MEC of neonatal rat pups during eSPWs using silicone probe recordings from the MEC and CA1 hippocampus. We found that neurons in deep and superficial layers of the MEC fire synchronously during MEC sharp potentials, and that neuronal firing in both superficial and deep layers of the MEC precedes the activation of CA1 neurons during eSPWs. Thus, the sequence of activation of CA1 hippocampal neurons and deep EC neurons during sharp waves reverses during development, from a lead of deep EC neurons during eSPWs in neonates to a lead of CA1 neurons during adult SPWs. These findings suggest another important difference in the generative mechanisms and possible functional roles of eSPWs compared to adult SPWs.
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Affiliation(s)
- Dmitrii Shipkov
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Azat Nasretdinov
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Roustem Khazipov
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
- INMED - INSERM, Aix-Marseille University, Marseille, France
| | - Guzel Valeeva
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
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Sevastre-Berghian AC, Ielciu I, Bab T, Olah NK, Neculicioiu VS, Toma VA, Sevastre B, Mocan T, Hanganu D, Bodoki AE, Roman I, Lucaciu RL, Hangan AC, Hașaș AD, Decea RM, Băldea I. Betula pendula Leaf Extract Targets the Interplay between Brain Oxidative Stress, Inflammation, and NFkB Pathways in Amyloid Aβ 1-42-Treated Rats. Antioxidants (Basel) 2023; 12:2110. [PMID: 38136229 PMCID: PMC10740548 DOI: 10.3390/antiox12122110] [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: 10/23/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
Alzheimer's disease (AD) is known as the primary and most common cause of dementia in the middle-aged and elderly population worldwide. Chemical analyses of B. pendula leaf extract (BPE), performed using spectrophotometric and chromatographic methods (LC/MS), revealed high amounts of polyphenol carboxylic acids (gallic, chlorogenic, caffeic, trans-p-coumaric, ferulic, and salicylic acids), as well as flavonoids (apigenin, luteolin, luteolin-7-O-glucoside, naringenin, hyperoside, quercetin, and quercitrin). Four groups of Wistar rats were used in this experiment (n = 7/group): control (untreated), Aβ1-42 (2 μg/rat intracerebroventricular (i.c.v.), Aβ1-42 + BPE (200 mg/Kg b.w.), and DMSO (10 μL/rat). On the first day, one dose of Aβ1-42 was intracerebroventricularly administered to animals in groups 2 and 3. Subsequently, BPE was orally administered for the next 15 days to group 3. On the 16th day, behavioral tests were performed. Biomarkers of brain oxidative stress Malondialdehyde (MDA), (Peroxidase (PRx), Catalase (CAT), and Superoxid dismutase (SOD) and inflammation (cytokines: tumor necrosis factor -α (TNF-α), Interleukin 1β (IL-1β), and cyclooxygenase-2 (COX 2)) in plasma and hippocampus homogenates were assessed. Various protein expressions (Phospho-Tau (Ser404) (pTau Ser 404), Phospho-Tau (Ser396) (pTau Ser 396), synaptophysin, and the Nuclear factor kappa B (NFkB) signaling pathway) were analyzed using Western blot and immunohistochemistry in the hippocampus. The results show that BPE diminished lipid peroxidation and neuroinflammation, modulated specific protein expression, enhanced the antioxidant capacity, and improved spontaneous alternation behavior, suggesting that it has beneficial effects in AD.
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Affiliation(s)
- Alexandra-Cristina Sevastre-Berghian
- Department of Physiology, Faculty of Medicine, “Iuliu Hațieganu” University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania; (A.-C.S.-B.); (T.M.); (R.M.D.); (I.B.)
| | - Irina Ielciu
- Department of Pharmaceutical Botany, Faculty of Pharmacy, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400337 Cluj-Napoca, Romania;
| | - Timea Bab
- PlantExtrakt Ltd., Rădaia, 407059 Cluj-Napoca, Romania; (T.B.); (N.-K.O.)
- Department of Pharmacognosy, Faculty of Pharmacy, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400010 Cluj-Napoca, Romania;
| | - Neli-Kinga Olah
- PlantExtrakt Ltd., Rădaia, 407059 Cluj-Napoca, Romania; (T.B.); (N.-K.O.)
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, “Vasile Goldiş” Western University of Arad, 310025 Arad, Romania
| | - Vlad Sever Neculicioiu
- Department of Microbiology, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania
| | - Vlad Alexandru Toma
- Department of Molecular Biology and Biotechnology, Babes-Bolyai University, 400371 Cluj-Napoca, Romania
| | - Bogdan Sevastre
- Department of Clinical and Paraclinical Sciences, University of Agricultural Sciences and Veterinary Medicine, 400372 Cluj-Napoca, Romania; (B.S.); (A.-D.H.)
| | - Teodora Mocan
- Department of Physiology, Faculty of Medicine, “Iuliu Hațieganu” University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania; (A.-C.S.-B.); (T.M.); (R.M.D.); (I.B.)
| | - Daniela Hanganu
- Department of Pharmacognosy, Faculty of Pharmacy, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400010 Cluj-Napoca, Romania;
| | - Andreea Elena Bodoki
- Department of Inorganic Chemistry, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania; (A.E.B.); (A.C.H.)
| | - Ioana Roman
- Department of Experimental Biology and Biochemistry, Institute of Biological Research, 400015 Cluj-Napoca, Romania;
| | - Roxana Liana Lucaciu
- Department of Pharmaceutical Biochemistry and Clinical Laboratory, Faculty of Pharmacy, “Iuliu Hațieganu” University of Medicine and Pharmacy, 8 Victor Babeș Street, 400000 Cluj-Napoca, Romania;
| | - Adriana Corina Hangan
- Department of Inorganic Chemistry, “Iuliu Haţieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania; (A.E.B.); (A.C.H.)
| | - Alina-Diana Hașaș
- Department of Clinical and Paraclinical Sciences, University of Agricultural Sciences and Veterinary Medicine, 400372 Cluj-Napoca, Romania; (B.S.); (A.-D.H.)
| | - Roxana Maria Decea
- Department of Physiology, Faculty of Medicine, “Iuliu Hațieganu” University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania; (A.-C.S.-B.); (T.M.); (R.M.D.); (I.B.)
| | - Ioana Băldea
- Department of Physiology, Faculty of Medicine, “Iuliu Hațieganu” University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania; (A.-C.S.-B.); (T.M.); (R.M.D.); (I.B.)
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Shao N, Ye T, Xuan W, Zhang M, Chen Q, Liu J, Zhou P, Song H, Cai B. The effects of N 6-methyladenosine RNA methylation on the nervous system. Mol Cell Biochem 2023; 478:2657-2669. [PMID: 36899139 DOI: 10.1007/s11010-023-04691-6] [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: 03/19/2022] [Accepted: 02/24/2023] [Indexed: 03/12/2023]
Abstract
Epitranscriptomics, also known as "RNA epigenetics", is a type of chemical modification that regulates RNA. RNA methylation is a significant discovery after DNA and histone methylation. The dynamic reversible process of m6A involves methyltransferases (writers), m6A binding proteins (readers), as well as demethylases (erasers). We summarized the current research status of m6A RNA methylation in the neural stem cells' growth, synaptic and axonal function, brain development, learning and memory, neurodegenerative diseases, and glioblastoma. This review aims to provide a theoretical basis for studying the mechanism of m6A methylation and finding its potential therapeutic targets in nervous system diseases.
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Affiliation(s)
- Nan Shao
- College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Ting Ye
- College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Weiting Xuan
- Department of Neurosurgery (Rehabilitation), Anhui Hospital of Integrated Chinese and Western Medicine, Hefei, 230031, China
| | - Meng Zhang
- College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Qian Chen
- College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, 230012, China
| | - Juan Liu
- Department of Chinese Internal Medicine, Taihe County People's Hospital, Fuyang, 236699, China
| | - Peng Zhou
- College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, 230012, China.
- Institute of Integrated Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, 230012, China.
- Key Laboratory of Xin'an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei, 230012, China.
- Anhui Province Key Laboratory of Chinese Medicinal Formula, Hefei, 230012, China.
| | - Hang Song
- College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, 230012, China.
- Institute of Integrated Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, 230012, China.
- Key Laboratory of Xin'an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei, 230012, China.
- Anhui Province Key Laboratory of Chinese Medicinal Formula, Hefei, 230012, China.
| | - Biao Cai
- College of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, 230012, China.
- Institute of Integrated Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Hefei, 230012, China.
- Key Laboratory of Xin'an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei, 230012, China.
- Anhui Province Key Laboratory of Chinese Medicinal Formula, Hefei, 230012, China.
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Holmes GL. Commentary on the Paper "Effect of Seizures on the Developing Brain and Cognition". Semin Pediatr Neurol 2023; 47:101080. [PMID: 37919042 DOI: 10.1016/j.spen.2023.101080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/14/2023] [Accepted: 09/05/2023] [Indexed: 11/04/2023]
Abstract
EFFECT OF SEIZURES ON THE DEVELOPING BRAIN AND COGNITION Gregory L. Holmes Seminars in Pediatric Neurology Volume 23, Issue 2, May 2016, Pages 120-126 Epilepsy is a complex disorder, which involves much more than seizures, encompassing a range of associated comorbid health conditions that can have significant health and quality-of-life implications. Of these comorbidities, cognitive impairment is one of the most common and distressing aspects of epilepsy. Clinical studies have demonstrated that refractory seizures, resistant to antiepileptic drugs, occurring early in life have significant adverse effects on cognitive function. Much of what has been learned about the neurobiological underpinnings of cognitive impairment following early-life seizures has come from animal models. While early-life seizures in rodents do not result in cell loss, seizures do result in changes in neurogenesis and synaptogenesis and alteration of excitatory/inhibitory balance, network connectivity and temporal coding. These morphological and physiological changes are accompanied by parallel impairment in cognitive skills. This increased understanding of the pathophysiological basis of seizure-induced cognitive deficits should allow investigators to develop novel targets for therapeutic interventions.
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Affiliation(s)
- Gregory L Holmes
- Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington, VT.
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Gutiérrez-Menéndez A, Méndez M, Arias JL. Learning and metabolic brain differences between juvenile male and female rats in the execution of different training regimes of a spatial memory task. Physiol Behav 2023; 267:114203. [PMID: 37086830 DOI: 10.1016/j.physbeh.2023.114203] [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: 02/14/2023] [Revised: 04/17/2023] [Accepted: 04/19/2023] [Indexed: 04/24/2023]
Abstract
Spatial memory is responsible for encoding spatial information to form a path, storing this mental representation, and evaluating and recovering spatial configurations to find a target location in the environment. It is mainly supported by the hippocampus and its interaction with other structures, such as the prefrontal cortex, and emerges in rodents around postnatal day (PND) 20. Sex differences in spatial tasks have been found in adults, with a supposedly better performance in males. However, few studies have examined sex differences in orientation throughout postnatal development. This study aimed to analyse the performance of juvenile (PND 23) male (n=18) and female (n=21) Wistar rats in a spatial reference memory task in the Morris water maze (MWM) with two different training regimes in the acquisition phase, and their subjacent metabolic brain activity. Based on sex, subjects were assigned to two different groups: one that performed four learning trials per day (n=9 males and n=8 females) and the other that was submitted to two trials per day (n=9 males and n=13 females). After the behavioural protocols, metabolic activity was evaluated using cytochrome c oxidase histochemistry. Results showed no metabolic brain or behavioural differences in the four-trial protocol performance, in which both sexes reached the learning criterion on the fourth day. By contrast, the two-trial protocol revealed an advantage for females, who reached the learning criterion on day four, whereas males needed more training and succeeded on day six. The female group showed lower metabolic activity than the male group in the cingulate and prelimbic cortex. These results suggest a faster consolidation process in the female group than the male group. Further research is needed to understand sex differences in spatial memory at early stages.
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Affiliation(s)
- Alba Gutiérrez-Menéndez
- Laboratory of Neuroscience, Department of Psychology, University of Oviedo, Plaza Feijóo, s/n, E-33003, Oviedo, Spain; Instituto de Neurociencias del Principado de Asturias (INEUROPA), Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain.
| | - Marta Méndez
- Laboratory of Neuroscience, Department of Psychology, University of Oviedo, Plaza Feijóo, s/n, E-33003, Oviedo, Spain; Instituto de Neurociencias del Principado de Asturias (INEUROPA), Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Jorge L Arias
- Laboratory of Neuroscience, Department of Psychology, University of Oviedo, Plaza Feijóo, s/n, E-33003, Oviedo, Spain; Instituto de Neurociencias del Principado de Asturias (INEUROPA), Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
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8
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Velasquez F, Dickson C, Kloc ML, Schneur CA, Barry JM, Holmes GL. Optogenetic modulation of hippocampal oscillations ameliorates spatial cognition and hippocampal dysrhythmia following early-life seizures. Neurobiol Dis 2023; 178:106021. [PMID: 36720444 DOI: 10.1016/j.nbd.2023.106021] [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: 09/14/2022] [Revised: 01/22/2023] [Accepted: 01/24/2023] [Indexed: 01/30/2023] Open
Abstract
There is increasing human and animal evidence that brain oscillations play a critical role in the development of spatial cognition. In rat pups, disruption of hippocampal rhythms via optogenetic stimulation during the critical period for memory development impairs spatial cognition. Early-life seizures are associated with long-term deficits in spatial cognition and aberrant hippocampal oscillatory activity. Here we asked whether modulation of hippocampal rhythms following early-life seizures can reverse or improve hippocampal connectivity and spatial cognition. We used optogenetic stimulation of the medial septum to induce physiological 7 Hz theta oscillations in the hippocampus during the critical period of spatial cognition following early-life seizures. Optogenetic stimulation of the medial septum in control and rats subjected to early-life seizures resulted in precisely regulated frequency-matched hippocampal oscillations. Rat pups receiving active blue light stimulation performed better than the rats receiving inert yellow light in a test of spatial cognition. The improvement in spatial cognition in these rats was associated with a faster theta frequency and higher theta power, coherence and phase locking value in the hippocampus than rats with early-life seizures receiving inert yellow light. These findings indicate that following early life seizures, modification of hippocampal rhythms may be a potential novel therapeutic modality.
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Affiliation(s)
- Francisco Velasquez
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Conor Dickson
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Michelle L Kloc
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Carmel A Schneur
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Jeremy M Barry
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Gregory L Holmes
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA.
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Tukker JJ, Beed P, Brecht M, Kempter R, Moser EI, Schmitz D. Microcircuits for spatial coding in the medial entorhinal cortex. Physiol Rev 2022; 102:653-688. [PMID: 34254836 PMCID: PMC8759973 DOI: 10.1152/physrev.00042.2020] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The hippocampal formation is critically involved in learning and memory and contains a large proportion of neurons encoding aspects of the organism's spatial surroundings. In the medial entorhinal cortex (MEC), this includes grid cells with their distinctive hexagonal firing fields as well as a host of other functionally defined cell types including head direction cells, speed cells, border cells, and object-vector cells. Such spatial coding emerges from the processing of external inputs by local microcircuits. However, it remains unclear exactly how local microcircuits and their dynamics within the MEC contribute to spatial discharge patterns. In this review we focus on recent investigations of intrinsic MEC connectivity, which have started to describe and quantify both excitatory and inhibitory wiring in the superficial layers of the MEC. Although the picture is far from complete, it appears that these layers contain robust recurrent connectivity that could sustain the attractor dynamics posited to underlie grid pattern formation. These findings pave the way to a deeper understanding of the mechanisms underlying spatial navigation and memory.
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Affiliation(s)
- John J Tukker
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany
| | - Prateep Beed
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humbold-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Brecht
- Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Berlin, Germany
- Neurocure Cluster of Excellence, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Einstein Center for Neurosciences Berlin, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Richard Kempter
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany
- Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Berlin, Germany
- Einstein Center for Neurosciences Berlin, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Edvard I Moser
- Einstein Center for Neurosciences Berlin, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Dietmar Schmitz
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humbold-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
- Neurocure Cluster of Excellence, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Einstein Center for Neurosciences Berlin, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
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10
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Abstract
The investigation of the topographic organization of spatially coding cell types in the medial entorhinal cortex (MEC) has so far been held back by the lack of appropriate tools that enable the precise recording of both the anatomical location and activity of large populations of cells while animals forage in open environments. In this study, we use the newest generation of head-mounted, miniaturized two-photon microscopes to image grid, head-direction, border, as well as object-vector cells in MEC and neighboring parasubiculum within the same animals. The majority of cell types were intermingled, but grid and object-vector cells exhibited little overlap. The results have implications for network models of spatial coding. The medial entorhinal cortex (MEC) creates a map of local space, based on the firing patterns of grid, head-direction (HD), border, and object-vector (OV) cells. How these cell types are organized anatomically is debated. In-depth analysis of this question requires collection of precise anatomical and activity data across large populations of neurons during unrestrained behavior, which neither electrophysiological nor previous imaging methods fully afford. Here, we examined the topographic arrangement of spatially modulated neurons in the superficial layers of MEC and adjacent parasubiculum using miniaturized, portable two-photon microscopes, which allow mice to roam freely in open fields. Grid cells exhibited low levels of co-occurrence with OV cells and clustered anatomically, while border, HD, and OV cells tended to intermingle. These data suggest that grid cell networks might be largely distinct from those of border, HD, and OV cells and that grid cells exhibit strong coupling among themselves but weaker links to other cell types.
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11
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Keith RE, Ogoe RH, Dumas TC. Behind the scenes: Are latent memories supported by calcium independent plasticity? Hippocampus 2022; 32:73-88. [PMID: 33905147 PMCID: PMC8548406 DOI: 10.1002/hipo.23332] [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: 11/11/2020] [Revised: 04/08/2021] [Accepted: 04/11/2021] [Indexed: 02/03/2023]
Abstract
N-methyl-D-aspartate receptors (NMDARs) can be considered to be the de facto "plasticity" receptors in the brain due to their central role in the activity-dependent modification of neuronal morphology and synaptic transmission. Since the 1980s, research on NMDARs has focused on the second messenger properties of calcium and the downstream signaling pathways that mediate alterations in neural form and function. Recently, NMDARs were shown to drive activity-dependent synaptic plasticity without calcium influx. How this "nonionotropic" plasticity occurs in vitro is becoming clearer, but research on its involvement in behavior and cognition is in its infancy. There is a partial overlap in the downstream signaling molecules that are involved in ionotropic and nonionotropic NMDAR-dependent plasticity. Given this, and prior studies of the cognitive impacts of ionotropic NMDAR plasticity, a preliminary model explaining how NMDAR nonionotropic plasticity affects learning and memory can be established. We hypothesize that nonionotropic NMDAR plasticity takes part in latent memory encoding in immature rodents through nonassociative depression of synaptic efficacy, and possibly shrinking of dendritic spines. Further, the late postnatal alteration in NMDAR composition in the hippocampus appears to reduce nonionotropic signaling and remove a restriction on memory retrieval. This framework substantially alters the canonical model of NMDAR involvement in spatial cognition and hippocampal maturation and provides novel and exciting inroads for future studies.
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Affiliation(s)
- Rachel E. Keith
- Interdisciplinary Program in Neuroscience, College of Science, George Mason University, Fairfax, Virginia
| | - Richard H. Ogoe
- Department of Psychology, College of Humanities and Social Sciences, George Mason University, Fairfax, Virginia
| | - Theodore C. Dumas
- Interdisciplinary Program in Neuroscience, College of Science, George Mason University, Fairfax, Virginia,Department of Psychology, College of Humanities and Social Sciences, George Mason University, Fairfax, Virginia
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12
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Abrous DN, Koehl M, Lemoine M. A Baldwin interpretation of adult hippocampal neurogenesis: from functional relevance to physiopathology. Mol Psychiatry 2022; 27:383-402. [PMID: 34103674 PMCID: PMC8960398 DOI: 10.1038/s41380-021-01172-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 05/03/2021] [Accepted: 05/12/2021] [Indexed: 02/05/2023]
Abstract
Hippocampal adult neurogenesis has been associated to many cognitive, emotional, and behavioral functions and dysfunctions, and its status as a selected effect or an "appendix of the brain" has been debated. In this review, we propose to understand hippocampal neurogenesis as the process underlying the "Baldwin effect", a particular situation in evolution where fitness does not rely on the natural selection of genetic traits, but on "ontogenetic adaptation" to a changing environment. This supports the view that a strong distinction between developmental and adult hippocampal neurogenesis is made. We propose that their functions are the constitution and the lifelong adaptation, respectively, of a basic repertoire of cognitive and emotional behaviors. This lifelong adaptation occurs through new forms of binding, i.e., association or dissociation of more basic elements. This distinction further suggests that a difference is made between developmental vulnerability (or resilience), stemming from dysfunctional (or highly functional) developmental hippocampal neurogenesis, and adult vulnerability (or resilience), stemming from dysfunctional (or highly functional) adult hippocampal neurogenesis. According to this hypothesis, developmental and adult vulnerability are distinct risk factors for various mental disorders in adults. This framework suggests new avenues for research on hippocampal neurogenesis and its implication in mental disorders.
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Affiliation(s)
- Djoher Nora Abrous
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, Neurogenesis and Pathophysiology group, F-33000, Bordeaux, France.
| | - Muriel Koehl
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, Neurogenesis and Pathophysiology group, F-33000 Bordeaux, France
| | - Maël Lemoine
- grid.412041.20000 0001 2106 639XUniversity Bordeaux, CNRS, ImmunoConcEpT, UMR 5164, Bordeaux, France
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13
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Kloc ML, Marchand DH, Holmes GL, Pressman RD, Barry JM. Cognitive impairment following experimental febrile seizures is determined by sex and seizure duration. Epilepsy Behav 2022; 126:108430. [PMID: 34902661 PMCID: PMC8748413 DOI: 10.1016/j.yebeh.2021.108430] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/22/2021] [Accepted: 11/05/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND Febrile seizures are the most common type of seizures in children. While in most children the outcome is favorable, children with febrile status epilepticus may exhibit modest cognitive impairment. Whether children with other forms of complex febrile seizure, such as repetitive febrile seizures within the same illness are at risk of cognitive deficits is not known. In this study, we used a well-established model of experimental febrile seizures in rat pups to compare the effects of febrile status epilepticus and recurrent febrile seizures on subsequent spatial cognition and anxiety. METHODS Male and female rat pups were subjected to hyperthermic seizures at postnatal day 10 and were divided into groups of rats with continuous seizures for ≥40 min or recurrent febrile seizures. They were then tested as adults in the active avoidance and spatial accuracy tests to assess spatial learning and memory and the elevated plus maze to measure anxiety. RESULTS Febrile status epilepticus rats demonstrated impaired spatial cognition in active avoidance and spatial accuracy and exhibited reduced anxiety-like behavior in the elevated plus maze. Rats with recurrent febrile seizures did not differ significantly from the controls on any measures. There were also significant sex-related differences with females with FSE performing far better than males with FSE in active avoidance but demonstrating a navigational learning impairment relative to CTL females in spatial accuracy. However, once learned, females with FSE performed the spatial accuracy task as well as CTL females. CONCLUSION There is a duration-dependent effect of febrile seizures on subsequent cognitive and behavioral outcomes. Febrile status epilepticus resulted in spatial cognitive deficits and reduced anxiety-related behaviors whereas rats with recurrent febrile seizures did not differ from controls. Sex had a remarkable effect on spatial cognitive outcome where males with FSE fared worse than females with FSE. The results demonstrate that sex should be considered as a biological variable in studies evaluating the effects of seizures on the developing brain.
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14
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Kloc ML, Daglian JM, Holmes GL, Baram TZ, Barry JM. Recurrent febrile seizures alter intrahippocampal temporal coordination but do not cause spatial learning impairments. Epilepsia 2021; 62:3117-3130. [PMID: 34562024 DOI: 10.1111/epi.17082] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/13/2021] [Accepted: 09/13/2021] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Febrile seizures (FSs) are the most common form of seizures in children. Single short FSs are benign, but FSs lasting longer than 30 min, termed febrile status epilepticus, may result in neurological sequelae. However, there is little information about an intermediary condition, brief recurrent FSs (RFSs). The goal of this study was to determine the role of RFSs on spatial learning and memory and the properties of spontaneous hippocampal signals. METHODS A hippocampus-dependent active avoidance task was used to assess spatial learning and memory in adult rats that underwent experimental RFSs (eRFSs) in early life compared with their littermate controls. Following completion of the task, we utilized high-density laminar probes to measure spontaneous hippocampal CA1 circuit activity under urethane anesthesia, which allowed for the simultaneous recording of input regions in CA1 associated with both CA3 and entorhinal cortex. RESULTS RFSs did not result in deficits in the active avoidance spatial test, a hippocampus-dependent test of spatial learning and memory. However, in vivo high-density laminar electrode recordings from eRFS rats had significantly altered power and frequency expression of theta and gamma bandwidths as well as signaling efficacy along the CA1 somatodendritic axis. Thus, although eRFS modified CA1 neuronal input/output dynamics, these alterations were not sufficient to impair active avoidance spatial behavior. SIGNIFICANCE These findings indicate that although eRFSs do not result in spatial cognitive deficits in the active avoidance task, recurrent seizures do alter the brain and result in longstanding changes in the temporal organization of the hippocampus.
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Affiliation(s)
- Michelle L Kloc
- Department of Neurological Sciences, Epilepsy Development and Cognition Group, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - Jennifer M Daglian
- Department of Pediatrics, University California, Irvine, Irvine, California, USA
| | - Gregory L Holmes
- Department of Neurological Sciences, Epilepsy Development and Cognition Group, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - Tallie Z Baram
- Department of Pediatrics, University California, Irvine, Irvine, California, USA.,Department of Anatomy/Neurobiology, University California, Irvine, Irvine, California, USA.,Department of Neurology, University California, Irvine, Irvine, California, USA
| | - Jeremy M Barry
- Department of Neurological Sciences, Epilepsy Development and Cognition Group, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
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15
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Almulla AYH, Mogulkoc R, Baltaci AK, Dasdelen D. Learning, Neurogenesis, and Effects of Flavonoids on Learning. Mini Rev Med Chem 2021; 22:355-364. [PMID: 34238155 DOI: 10.2174/1389557521666210707120719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/09/2021] [Accepted: 04/19/2021] [Indexed: 11/22/2022]
Abstract
Learning and memory are two of our mind's most magical abilities. Different brain regions have roles in processing and storing different types of memories. The hippocampus is the part of the brain responsible for receiving information and storing it in the neocortex. One of the most impressive characteristics of the hippocampus is its capacity for neurogenesis, which is a process in which new neurons are produced and then transformed into mature neurons and finally integrated into neural circuits. The neurogenesis process in the hippocampus, an example of neuroplasticity in the adult brain, is believed to aid hippocampal-dependent learning and memory. New neurons are constantly produced in the hippocampus and integrated into the pre-existing neuronal network; this allows old memories already stored in the neocortex to be removed from the hippocampus and replaced with new ones. Factors affecting neurogenesis in the hippocampus may also affect hippocampal-dependent learning and memory. The flavonoids can particularly exert powerful actions in mammalian cognition and improve hippocampal-dependent learning and memory by positively affecting hippocampal neurogenesis.
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Affiliation(s)
| | - Rasim Mogulkoc
- Selcuk University, Medical School Department of Physiology, 42075, Konya, Turkey
| | | | - Dervis Dasdelen
- Selcuk University, Medical School Department of Physiology, 42075, Konya, Turkey
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16
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Cassel JC, Ferraris M, Quilichini P, Cholvin T, Boch L, Stephan A, Pereira de Vasconcelos A. The reuniens and rhomboid nuclei of the thalamus: A crossroads for cognition-relevant information processing? Neurosci Biobehav Rev 2021; 126:338-360. [PMID: 33766671 DOI: 10.1016/j.neubiorev.2021.03.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 03/17/2021] [Accepted: 03/17/2021] [Indexed: 01/29/2023]
Abstract
Over the past twenty years, the reuniens and rhomboid (ReRh) nuclei, which constitute the ventral midline thalamus, have received constantly growing attention. Since our first review article about the functional contributions of ReRh nuclei (Cassel et al., 2013), numerous (>80) important papers have extended anatomical knowledge, including at a developmental level, introduced new and very original electrophysiological insights on ReRh functions, and brought novel results on cognitive and non-cognitive implications of the ReRh. The current review will cover these recent articles, more on Re than on Rh, and their contribution will be approached according to their affiliation with work before 2013. These neuroanatomical, electrophysiological or behavioral findings appear coherent and point to the ReRh nuclei as two major components of a multistructural system supporting numerous cognitive (and non-cognitive) functions. They gate the flow of information, perhaps especially from the medial prefrontal cortex to the hippocampus and back, and coordinate activity and processing across these two (and possibly other) brain regions of major cognitive relevance.
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Affiliation(s)
- Jean-Christophe Cassel
- Laboratoire de Neurosciences Cognitives et Adaptatives, Université de Strasbourg, F-67000 Strasbourg, France; LNCA, UMR 7364 - CNRS, F-67000 Strasbourg, France.
| | - Maëva Ferraris
- Aix Marseille Université, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Pascale Quilichini
- Aix Marseille Université, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Thibault Cholvin
- Institute for Physiology I, University Clinics Freiburg, 79104 Freiburg, Germany
| | - Laurine Boch
- Laboratoire de Neurosciences Cognitives et Adaptatives, Université de Strasbourg, F-67000 Strasbourg, France; LNCA, UMR 7364 - CNRS, F-67000 Strasbourg, France
| | - Aline Stephan
- Laboratoire de Neurosciences Cognitives et Adaptatives, Université de Strasbourg, F-67000 Strasbourg, France; LNCA, UMR 7364 - CNRS, F-67000 Strasbourg, France
| | - Anne Pereira de Vasconcelos
- Laboratoire de Neurosciences Cognitives et Adaptatives, Université de Strasbourg, F-67000 Strasbourg, France; LNCA, UMR 7364 - CNRS, F-67000 Strasbourg, France
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17
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Gursky ZH, Klintsova AY. Changes in Representation of Thalamic Projection Neurons within Prefrontal-Thalamic-Hippocampal Circuitry in a Rat Model of Third Trimester Binge Drinking. Brain Sci 2021; 11:323. [PMID: 33806485 PMCID: PMC8001051 DOI: 10.3390/brainsci11030323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/26/2021] [Accepted: 02/27/2021] [Indexed: 01/02/2023] Open
Abstract
Alcohol exposure (AE) during the third trimester of pregnancy-a period known as the brain growth spurt (BGS)-could result in a diagnosis of a fetal alcohol spectrum disorder (FASD), a hallmark of which is impaired executive functioning (EF). Coordinated activity between prefrontal cortex and hippocampus is necessary for EF and thalamic nucleus reuniens (Re), which is required for prefrontal-hippocampal coordination, is damaged following high-dose AE during the BGS. The current experiment utilized high-dose AE (5.25 g/kg/day) during the BGS (i.e., postnatal days 4-9) of Long-Evans rat pups. AE reduces the number of neurons in Re into adulthood and selectively alters the proportion of Re neurons that simultaneously innervate both medial prefrontal cortex (mPFC) and ventral hippocampus (vHPC). The AE-induced change unique to Re→(mPFC + vHPC) projection neurons (neuron populations that innervate either mPFC or vHPC individually were unchanged) is not mediated by reduction in neuron number. These data are the first to examine mPFC-Re-HPC circuit connectivity in a rodent model of FASD, and suggest that both short-term AE-induced neuron loss and long-term changes in thalamic connectivity may be two distinct (but synergistic) mechanisms by which developmental AE can alter mPFC-Re-vHPC circuitry and impair EF throughout the lifespan.
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Affiliation(s)
| | - Anna Y. Klintsova
- Department of Psychological & Brain Sciences, University of Delaware, Newark, DE 19716, USA;
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18
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Kloc ML, Velasquez F, Niedecker RW, Barry JM, Holmes GL. Disruption of hippocampal rhythms via optogenetic stimulation during the critical period for memory development impairs spatial cognition. Brain Stimul 2020; 13:1535-1547. [PMID: 32871261 DOI: 10.1016/j.brs.2020.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/14/2020] [Accepted: 08/18/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Hippocampal oscillations play a critical role in the ontogeny of allocentric memory in rodents. During the critical period for memory development, hippocampal theta is the driving force behind the temporal coordination of neuronal ensembles underpinning spatial memory. While known that hippocampal oscillations are necessary for normal spatial cognition, whether disrupted hippocampal oscillatory activity during the critical period impairs long-term spatial memory is unknown. Here we investigated whether disruption of normal hippocampal rhythms during the critical period have enduring effects on allocentric memory in rodents. OBJECTIVE/HYPOTHESIS We hypothesized that disruption of hippocampal oscillations via artificial regulation of the medial septum during the critical period for memory development results in long-standing deficits in spatial cognition. METHODS After demonstrating that pan-neuronal medial septum (MS) optogenetic stimulation (465 nm activated) regulated hippocampal oscillations in weanling rats we used a random pattern of stimulation frequencies to disrupt hippocampal theta rhythms for either 1Hr or 5hr a day between postnatal (P) days 21-25. Non-stimulated and yellow light-stimulated (590 nm) rats served as controls. At P50-60 all rats were tested for spatial cognition in the active avoidance task. Rats were then sacrificed, and the MS and hippocampus assessed for cell loss. Power spectrum density of the MS and hippocampus, coherences and voltage correlations between MS and hippocampus were evaluated at baseline for a range of stimulation frequencies from 0.5 to 110 Hz and during disruptive hippocampal stimulation. Unpaired t-tests and ANOVA were used to compare oscillatory parameters, behavior and cell density in all animals. RESULTS Non-selective optogenetic stimulation of the MS in P21 rats resulted in precise regulation of hippocampal oscillations with 1:1 entrainment between stimulation frequency (0.5-110 Hz) and hippocampal local field potentials. Across bandwidths MS stimulation increased power, coherence and voltage correlation at all frequencies whereas the disruptive stimulation increased power and reduced coherence and voltage correlations with most statistical measures highly significant (p < 0.001, following correction for false detection). Rats receiving disruptive hippocampal stimulation during the critical period for memory development for either 1Hr or 5hr had marked impairment in spatial learning as measured in active avoidance test compared to non-stimulated or yellow light-control rats (p < 0.001). No cell loss was measured between the blue-stimulated and non-stimulated or yellow light-stimulated controls in either the MS or hippocampus. CONCLUSION The results demonstrated that robust regulation of hippocampal oscillations can be achieved with non-selective optogenetic stimulation of the MS in rat pups. A disruptive hippocampal stimulation protocol, which markedly increases power and reduces coherence and voltage correlations between the MS and hippocampus during the critical period of memory development, results in long-standing spatial cognitive deficits. This spatial cognitive impairment is not a result of optogenetic stimulation-induced cell loss.
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Affiliation(s)
- Michelle L Kloc
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Francisco Velasquez
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Rhys W Niedecker
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Jeremy M Barry
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Gregory L Holmes
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA.
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19
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A Unique Mouse Model of Early Life Exercise Enables Hippocampal Memory and Synaptic Plasticity. Sci Rep 2020; 10:9174. [PMID: 32513972 PMCID: PMC7280304 DOI: 10.1038/s41598-020-66116-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/13/2020] [Indexed: 12/25/2022] Open
Abstract
Physical exercise is a powerful modulator of learning and memory. Mechanisms underlying the cognitive benefits of exercise are well documented in adult rodents. Exercise studies targeting postnatal periods of hippocampal maturation (specifically targeting periods of synaptic reorganization and plasticity) are lacking. We characterize a model of early-life exercise (ELE) in male and female mice designed with the goal of identifying critical periods by which exercise may have a lasting impact on hippocampal memory and synaptic plasticity. Mice freely accessed a running wheel during three postnatal periods: the 4th postnatal week (juvenile ELE, P21–27), 6th postnatal week (adolescent ELE, P35–41), or 4th-6th postnatal weeks (juvenile-adolescent ELE, P21–41). All exercise groups increased their running distances during ELE. When exposed to a subthreshold learning stimulus, juv ELE and juv-adol ELE formed lasting long-term memory for an object location memory task, whereas sedentary and adol ELE mice did not. Electrophysiological experiments revealed enhanced long-term potentiation in hippocampal CA1 in the juvenile-adolescent ELE group. I/O curves were also significantly modulated in all mice that underwent ELE. Our results suggest that early-life exercise, specifically during the 4th postnatal week, can enable hippocampal memory, synaptic plasticity, and alter hippocampal excitability when occurring during postnatal periods of hippocampal maturation.
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20
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Short AK, Baram TZ. Early-life adversity and neurological disease: age-old questions and novel answers. Nat Rev Neurol 2019; 15:657-669. [PMID: 31530940 PMCID: PMC7261498 DOI: 10.1038/s41582-019-0246-5] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2019] [Indexed: 12/24/2022]
Abstract
Neurological illnesses, including cognitive impairment, memory decline and dementia, affect over 50 million people worldwide, imposing a substantial burden on individuals and society. These disorders arise from a combination of genetic, environmental and experiential factors, with the latter two factors having the greatest impact during sensitive periods in development. In this Review, we focus on the contribution of adverse early-life experiences to aberrant brain maturation, which might underlie vulnerability to cognitive brain disorders. Specifically, we draw on recent robust discoveries from diverse disciplines, encompassing human studies and experimental models. These discoveries suggest that early-life adversity, especially in the perinatal period, influences the maturation of brain circuits involved in cognition. Importantly, new findings suggest that fragmented and unpredictable environmental and parental signals comprise a novel potent type of adversity, which contributes to subsequent vulnerabilities to cognitive illnesses via mechanisms involving disordered maturation of brain 'wiring'.
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Affiliation(s)
- Annabel K Short
- Departments of Anatomy and Neruobiology, University of California-Irvine, Irvine, CA, USA
- Departments of Pediatrics, University of California-Irvine, Irvine, CA, USA
| | - Tallie Z Baram
- Departments of Anatomy and Neruobiology, University of California-Irvine, Irvine, CA, USA.
- Departments of Pediatrics, University of California-Irvine, Irvine, CA, USA.
- Departments of Neurology, University of California-Irvine, Irvine, CA, USA.
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