1
|
Wang Y, Wang X, Wang L, Zheng L, Meng S, Zhu N, An X, Wang L, Yang J, Zheng C, Ming D. Dynamic prediction of goal location by coordinated representation of prefrontal-hippocampal theta sequences. Curr Biol 2024; 34:1866-1879.e6. [PMID: 38608677 DOI: 10.1016/j.cub.2024.03.032] [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: 10/25/2023] [Revised: 01/20/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024]
Abstract
Prefrontal (PFC) and hippocampal (HPC) sequences of neuronal firing modulated by theta rhythms could represent upcoming choices during spatial memory-guided decision-making. How the PFC-HPC network dynamically coordinates theta sequences to predict specific goal locations and how it is interrupted in memory impairments induced by amyloid beta (Aβ) remain unclear. Here, we detected theta sequences of firing activities of PFC neurons and HPC place cells during goal-directed spatial memory tasks. We found that PFC ensembles exhibited predictive representation of the specific goal location since the starting phase of memory retrieval, earlier than the hippocampus. High predictive accuracy of PFC theta sequences existed during successful memory retrieval and positively correlated with memory performance. Coordinated PFC-HPC sequences showed PFC-dominant prediction of goal locations during successful memory retrieval. Furthermore, we found that theta sequences of both regions still existed under Aβ accumulation, whereas their predictive representation of goal locations was weakened with disrupted spatial representation of HPC place cells and PFC neurons. These findings highlight the essential role of coordinated PFC-HPC sequences in successful memory retrieval of a precise goal location.
Collapse
Affiliation(s)
- Yimeng Wang
- Academy of Medical Engineering and Translational Medicine, Medical College, Tianjin University, Tianjin 300072, China
| | - Xueling Wang
- Academy of Medical Engineering and Translational Medicine, Medical College, Tianjin University, Tianjin 300072, China
| | - Ling Wang
- Academy of Medical Engineering and Translational Medicine, Medical College, Tianjin University, Tianjin 300072, China; Tianjin Key Laboratory of Brain Science and Neuroengineering, Tianjin 300072, China
| | - Li Zheng
- Academy of Medical Engineering and Translational Medicine, Medical College, Tianjin University, Tianjin 300072, China
| | - Shuang Meng
- Academy of Medical Engineering and Translational Medicine, Medical College, Tianjin University, Tianjin 300072, China
| | - Nan Zhu
- Academy of Medical Engineering and Translational Medicine, Medical College, Tianjin University, Tianjin 300072, China
| | - Xingwei An
- Academy of Medical Engineering and Translational Medicine, Medical College, Tianjin University, Tianjin 300072, China; Tianjin Key Laboratory of Brain Science and Neuroengineering, Tianjin 300072, China
| | - Lei Wang
- School of Statistics and Data Science, Nankai University, Tianjin 300071, China.
| | - Jiajia Yang
- Academy of Medical Engineering and Translational Medicine, Medical College, Tianjin University, Tianjin 300072, China; Tianjin Key Laboratory of Brain Science and Neuroengineering, Tianjin 300072, China; Haihe Laboratory of Brain-Computer Interaction and Human-Machine Integration, Tianjin 300072, China.
| | - Chenguang Zheng
- Academy of Medical Engineering and Translational Medicine, Medical College, Tianjin University, Tianjin 300072, China; Tianjin Key Laboratory of Brain Science and Neuroengineering, Tianjin 300072, China; Haihe Laboratory of Brain-Computer Interaction and Human-Machine Integration, Tianjin 300072, China.
| | - Dong Ming
- Academy of Medical Engineering and Translational Medicine, Medical College, Tianjin University, Tianjin 300072, China; Tianjin Key Laboratory of Brain Science and Neuroengineering, Tianjin 300072, China; Haihe Laboratory of Brain-Computer Interaction and Human-Machine Integration, Tianjin 300072, China.
| |
Collapse
|
2
|
Scott KJ, Speers LJ, Bilkey DK. Utilizing synthetic training data for the supervised classification of rat ultrasonic vocalizations. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2024; 155:306-314. [PMID: 38236810 DOI: 10.1121/10.0024340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 12/14/2023] [Indexed: 01/23/2024]
Abstract
Murine rodents generate ultrasonic vocalizations (USVs) with frequencies that extend to around 120 kHz. These calls are important in social behaviour, and so their analysis can provide insights into the function of vocal communication, and its dysfunction. The manual identification of USVs, and subsequent classification into different subcategories is time consuming. Although machine learning approaches for identification and classification can lead to enormous efficiency gains, the time and effort required to generate training data can be high, and the accuracy of current approaches can be problematic. Here, we compare the detection and classification performance of a trained human against two convolutional neural networks (CNNs), DeepSqueak (DS) and VocalMat (VM), on audio containing rat USVs. Furthermore, we test the effect of inserting synthetic USVs into the training data of the VM CNN as a means of reducing the workload associated with generating a training set. Our results indicate that VM outperformed the DS CNN on measures of call identification, and classification. Additionally, we found that the augmentation of training data with synthetic images resulted in a further improvement in accuracy, such that it was sufficiently close to human performance to allow for the use of this software in laboratory conditions.
Collapse
Affiliation(s)
- K Jack Scott
- Department of Psychology, University of Otago, William James Building, 275 Leith Walk, Dunedin 9016, New Zealand
| | - Lucinda J Speers
- Department of Psychology, University of Otago, William James Building, 275 Leith Walk, Dunedin 9016, New Zealand
- Grenoble Institut des Neurosciences, Inserm, France
| | - David K Bilkey
- Department of Psychology, University of Otago, William James Building, 275 Leith Walk, Dunedin 9016, New Zealand
| |
Collapse
|
3
|
Gillespie B, Panthi S, Sundram S, Hill RA. The impact of maternal immune activation on GABAergic interneuron development: A systematic review of rodent studies and their translational implications. Neurosci Biobehav Rev 2024; 156:105488. [PMID: 38042358 DOI: 10.1016/j.neubiorev.2023.105488] [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: 08/11/2023] [Revised: 11/09/2023] [Accepted: 11/27/2023] [Indexed: 12/04/2023]
Abstract
Mothers exposed to infections during pregnancy disproportionally birth children who develop autism and schizophrenia, disorders associated with altered GABAergic function. The maternal immune activation (MIA) model recapitulates this risk factor, with many studies also reporting disruptions to GABAergic interneuron expression, protein, cellular density and function. However, it is unclear if there are species, sex, age, region, or GABAergic subtype specific vulnerabilities to MIA. Furthermore, to fully comprehend the impact of MIA on the GABAergic system a synthesised account of molecular, cellular, electrophysiological and behavioural findings was required. To this end we conducted a systematic review of GABAergic interneuron changes in the MIA model, focusing on the prefrontal cortex and hippocampus. We reviewed 102 articles that revealed robust changes in a number of GABAergic markers that present as gestationally-specific, region-specific and sometimes sex-specific. Disruptions to GABAergic markers coincided with distinct behavioural phenotypes, including memory, sensorimotor gating, anxiety, and sociability. Findings suggest the MIA model is a valid tool for testing novel therapeutics designed to recover GABAergic function and associated behaviour.
Collapse
Affiliation(s)
- Brendan Gillespie
- Department of Psychiatry, School of Clinical Sciences, Monash University, Clayton, VIC 3168, Australia
| | - Sandesh Panthi
- Department of Psychiatry, School of Clinical Sciences, Monash University, Clayton, VIC 3168, Australia
| | - Suresh Sundram
- Department of Psychiatry, School of Clinical Sciences, Monash University, Clayton, VIC 3168, Australia
| | - Rachel A Hill
- Department of Psychiatry, School of Clinical Sciences, Monash University, Clayton, VIC 3168, Australia.
| |
Collapse
|
4
|
Devaraju M, Li A, Ha S, Li M, Shivakumar M, Li H, Nishiguchi EP, Gérardin P, Waldorf KA, Al-Haddad BJS. Beyond TORCH: A narrative review of the impact of antenatal and perinatal infections on the risk of disability. Neurosci Biobehav Rev 2023; 153:105390. [PMID: 37708918 PMCID: PMC10617835 DOI: 10.1016/j.neubiorev.2023.105390] [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: 06/13/2023] [Revised: 09/07/2023] [Accepted: 09/10/2023] [Indexed: 09/16/2023]
Abstract
Infections and inflammation during pregnancy or early life can alter child neurodevelopment and increase the risk for structural brain abnormalities and mental health disorders. There is strong evidence that TORCH infections (i.e., Treponema pallidum, Toxoplasma gondii, rubella virus, cytomegalovirus, herpes virus) alter fetal neurodevelopment across multiple developmental domains and contribute to motor and cognitive disabilities. However, the impact of a broader range of viral and bacterial infections on fetal development and disability is less well understood. We performed a literature review of human studies to identify gaps in the link between maternal infections, inflammation, and several neurodevelopmental domains. We found strong and moderate evidence respectively for a higher risk of motor and cognitive delays and disabilities in offspring exposed to a range of non-TORCH pathogens during fetal life. In contrast, there is little evidence for an increased risk of language and sensory disabilities. While guidelines for TORCH infection prevention during pregnancy are common, further consideration for prevention of non-TORCH infections during pregnancy for fetal neuroprotection may be warranted.
Collapse
Affiliation(s)
- Monica Devaraju
- University of Washington, School of Medicine, 1959 NE Pacific St, Seattle, WA 98195, USA; University of Washington, Department of Obstetrics, 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Amanda Li
- University of Washington, Department of Obstetrics, 1959 NE Pacific St, Seattle, WA 98195, USA; Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, USA
| | - Sandy Ha
- University of Washington, Department of Obstetrics, 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Miranda Li
- University of Washington, School of Medicine, 1959 NE Pacific St, Seattle, WA 98195, USA; University of Washington, Department of Obstetrics, 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Megana Shivakumar
- University of Washington, Department of Obstetrics, 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Hanning Li
- University of Washington, Department of Obstetrics, 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Erika Phelps Nishiguchi
- University of Hawaii, Department of Pediatrics, Division of Community Pediatrics, 1319 Punahou St, Honolulu, HI, USA
| | - Patrick Gérardin
- INSERM CIC1410, Centre Hospitalier Universitaire de la Réunion, Saint Pierre, Réunion, France; Platform for Clinical and Translational Research, Centre Hospitalier Universitaire, Saint Pierre, Réunion, France
| | - Kristina Adams Waldorf
- University of Washington, Department of Obstetrics, 1959 NE Pacific St, Seattle, WA 98195, USA.
| | - Benjamin J S Al-Haddad
- University of Minnesota, Department of Pediatrics, Division of Neonatology, Academic Office Building, 2450 Riverside Ave S AO-401, Minneapolis, MN 55454, USA; Masonic Institute for the Developing Brain, 2025 E River Pkwy, Minneapolis, MN 55414, USA.
| |
Collapse
|
5
|
Munn RGK, Wolff A, Speers LJ, Bilkey DK. Disrupted hippocampal synchrony following maternal immune activation in a rat model. Hippocampus 2023; 33:995-1008. [PMID: 37129454 DOI: 10.1002/hipo.23545] [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: 11/07/2022] [Revised: 03/14/2023] [Accepted: 04/16/2023] [Indexed: 05/03/2023]
Abstract
Maternal immune activation (MIA) is a risk factor for schizophrenia and other neurodevelopmental disorders. MIA in rats models a number of the brain and behavioral changes that are observed in schizophrenia, including impaired memory. Recent studies in the MIA model have shown that the firing of the hippocampal place cells that are involved in memory processes appear relatively normal, but with abnormalities in the temporal ordering of firing. In this study, we re-analyzed data from prior hippocampal electrophysiological recordings of MIA and control animals to determine whether temporal dysfunction was evident. We find that there is a decreased ratio of slow to fast gamma power, resulting from an increase in fast gamma power and a tendency toward reduced slow gamma power in MIA rats. Moreover, we observe a robust reduction in spectral coherence between hippocampal theta and both fast and slow gamma rhythms, as well as changes in the phase of theta at which fast gamma occurs. We also find the phasic organization of place cell phase precession on the theta wave to be abnormal in MIA rats. Lastly, we observe that the local field potential of MIA rats contains more frequent sharp-wave ripple events, and that place cells were more likely to fire spikes during ripples in these animals than control. These findings provide further evidence of desynchrony in MIA animals and may point to circuit-level changes that underlie failures to integrate and encode information in schizophrenia.
Collapse
Affiliation(s)
- Robert G K Munn
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Amy Wolff
- Department of Neuroscience and Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota, USA
| | - Lucinda J Speers
- Department of Psychology, University of Otago, Dunedin, New Zealand
| | - David K Bilkey
- Department of Psychology, University of Otago, Dunedin, New Zealand
| |
Collapse
|
6
|
Speers LJ, Chin P, Bilkey DK. No evidence that acute clozapine administration alters CA1 phase precession in rats. Brain Res 2023; 1814:148446. [PMID: 37301424 DOI: 10.1016/j.brainres.2023.148446] [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: 07/27/2022] [Revised: 05/25/2023] [Accepted: 06/04/2023] [Indexed: 06/12/2023]
Abstract
Hippocampal phase precession, wherein there is a systematic shift in the phase of neural firing against the underlying theta activity, is proposed to play an important role in the sequencing of information in memory. Previous research shows that the starting phase of precession is more variable in rats following maternal immune activation (MIA), a known risk factor for schizophrenia. Since starting phase variability has the potential to disorganize the construction of sequences of information, we tested whether the atypical antipsychotic clozapine, which ameliorates some cognitive deficits in schizophrenia, alters this aspect of phase precession. Either saline or clozapine (5 mg/kg) was administered to rats and then CA1 place cell activity was recorded from the CA1 region of the hippocampus as the animals ran around a rectangular track for food reward. When compared to saline trials, acute administration of clozapine did not affect any place cell properties, including those related to phase precession, in either control or MIA animals. Clozapine did, however, produce a reduction in locomotion speed, indicating that its presence had some effect on behaviour. These results help to constrain explanations of phase precession mechanisms and their potential role in sequence learning deficits.
Collapse
Affiliation(s)
| | - Phoebe Chin
- Psychology Dept., Otago Univ., Dunedin, New Zealand
| | | |
Collapse
|
7
|
Parra-Barrero E, Vijayabaskaran S, Seabrook E, Wiskott L, Cheng S. A map of spatial navigation for neuroscience. Neurosci Biobehav Rev 2023; 152:105200. [PMID: 37178943 DOI: 10.1016/j.neubiorev.2023.105200] [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: 01/25/2023] [Revised: 04/13/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023]
Abstract
Spatial navigation has received much attention from neuroscientists, leading to the identification of key brain areas and the discovery of numerous spatially selective cells. Despite this progress, our understanding of how the pieces fit together to drive behavior is generally lacking. We argue that this is partly caused by insufficient communication between behavioral and neuroscientific researchers. This has led the latter to under-appreciate the relevance and complexity of spatial behavior, and to focus too narrowly on characterizing neural representations of space-disconnected from the computations these representations are meant to enable. We therefore propose a taxonomy of navigation processes in mammals that can serve as a common framework for structuring and facilitating interdisciplinary research in the field. Using the taxonomy as a guide, we review behavioral and neural studies of spatial navigation. In doing so, we validate the taxonomy and showcase its usefulness in identifying potential issues with common experimental approaches, designing experiments that adequately target particular behaviors, correctly interpreting neural activity, and pointing to new avenues of research.
Collapse
Affiliation(s)
- Eloy Parra-Barrero
- Institute for Neural Computation, Faculty of Computer Science, Ruhr University Bochum, Bochum, Germany; International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Sandhiya Vijayabaskaran
- Institute for Neural Computation, Faculty of Computer Science, Ruhr University Bochum, Bochum, Germany
| | - Eddie Seabrook
- Institute for Neural Computation, Faculty of Computer Science, Ruhr University Bochum, Bochum, Germany
| | - Laurenz Wiskott
- Institute for Neural Computation, Faculty of Computer Science, Ruhr University Bochum, Bochum, Germany; International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Sen Cheng
- Institute for Neural Computation, Faculty of Computer Science, Ruhr University Bochum, Bochum, Germany; International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany.
| |
Collapse
|
8
|
Speers LJ, Sissons DJ, Cleland L, Bilkey DK. Hippocampal phase precession is preserved under ketamine, but the range of precession across a theta cycle is reduced. J Psychopharmacol 2023; 37:809-821. [PMID: 37515458 PMCID: PMC10399102 DOI: 10.1177/02698811231187339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
BACKGROUND Hippocampal phase precession, which depends on the precise spike timing of place cells relative to local theta oscillations, has been proposed to underlie sequential memory. N-methyl-D-asparate (NMDA) receptor antagonists such as ketamine disrupt memory and also reproduce several schizophrenia-like symptoms, including spatial memory impairments and disorganized cognition. It is possible that these impairments result from disruptions to phase precession. AIMS/METHODS We used an ABA design to test whether an acute, subanesthetic dose (7.5 mg/kg) of ketamine disrupted phase precession in CA1 of male rats as they navigated around a rectangular track for a food reward. RESULTS/OUTCOMES Ketamine did not affect the ability of CA1 place cells to precess despite changes to place cell firing rates, local field potential properties and locomotor speed. However, ketamine reduced the range of phase precession that occurred across a theta cycle. CONCLUSION Phase precession is largely robust to acute NMDA receptor antagonism by ketamine, but the reduced range of precession could have important implications for learning and memory.
Collapse
Affiliation(s)
| | - Daena J Sissons
- Psychology Department, Otago University Dunedin, New Zealand
- Psychology Department, University of Canterbury, Christchurch, New Zealand
| | - Lana Cleland
- Psychology Department, Otago University Dunedin, New Zealand
- Department Psychological Medicine, Otago University, Christchurch, New Zealand
- Department Population Health, Otago University, Christchurch, New Zealand
| | - David K Bilkey
- Psychology Department, Otago University Dunedin, New Zealand
| |
Collapse
|
9
|
Speers LJ, Bilkey DK. Maladaptive explore/exploit trade-offs in schizophrenia. Trends Neurosci 2023; 46:341-354. [PMID: 36878821 DOI: 10.1016/j.tins.2023.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/30/2023] [Accepted: 02/08/2023] [Indexed: 03/07/2023]
Abstract
Schizophrenia is a complex disorder that remains poorly understood, particularly at the systems level. In this opinion article we argue that the explore/exploit trade-off concept provides a holistic and ecologically valid framework to resolve some of the apparent paradoxes that have emerged within schizophrenia research. We review recent evidence suggesting that fundamental explore/exploit behaviors may be maladaptive in schizophrenia during physical, visual, and cognitive foraging. We also describe how theories from the broader optimal foraging literature, such as the marginal value theorem (MVT), could provide valuable insight into how aberrant processing of reward, context, and cost/effort evaluations interact to produce maladaptive responses.
Collapse
Affiliation(s)
- Lucinda J Speers
- Department of Psychology, University of Otago, Dunedin 9016, New Zealand
| | - David K Bilkey
- Department of Psychology, University of Otago, Dunedin 9016, New Zealand.
| |
Collapse
|
10
|
Speers LJ, Schmidt R, Bilkey DK. Aberrant Phase Precession of Lateral Septal Cells in a Maternal Immune Activation Model of Schizophrenia Risk May Disrupt the Integration of Location with Reward. J Neurosci 2022; 42:4187-4201. [PMID: 35396329 PMCID: PMC9121831 DOI: 10.1523/jneurosci.0039-22.2022] [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: 12/22/2021] [Revised: 03/16/2022] [Accepted: 04/03/2022] [Indexed: 11/21/2022] Open
Abstract
Spatial memory and reward processing are known to be disrupted in schizophrenia. Since the lateral septum (LS) may play an important role in the integration of location and reward, we examined the effect of maternal immune activation (MIA), a known schizophrenia risk factor, on spatial representation in the rat LS. In support of a previous study, we found that spatial location is represented as a phase code in the rostral LS of adult male rats, so that LS cell spiking shifts systematically against the phase of the hippocampal, theta-frequency, local field potential as an animal moves along a track toward a reward (phase precession). Whereas shallow precession slopes were observed in control group cells, they were steeper in the MIA animals, such that firing frequently precessed across several theta cycles as the animal moved along the length of the apparatus, with subsequent ambiguity in the phase representation of location. Furthermore, an analysis of the phase trajectories of the control group cells revealed that the population tended to converge toward a common firing phase as the animal approached the reward location. This suggested that phase coding in these cells might signal both reward location and the distance to reward. By comparison, the degree of phase convergence in the MIA-group cells was weak, and the region of peak convergence was distal to the reward location. These findings suggest that a schizophrenia risk factor disrupts the phase-based encoding of location-reward relationships in the LS, potentially smearing reward representations across space.SIGNIFICANCE STATEMENT It is unclear how spatial or contextual information generated by hippocampal cells is converted to a code that can be used to signal reward location in regions, such as the VTA. Here we provide evidence that the firing phase of cells in the lateral septum, a region that links the two areas, may code reward location in the firing phase of cells. This phase coding is disrupted in a maternal immune activation model of schizophrenia risk such that representations of reward may be smeared across space in maternal immune activation animals. This could potentially underlie erroneous reward processing and misattribution of salience in schizophrenia.
Collapse
Affiliation(s)
- Lucinda J Speers
- Psychology Department, Otago University, Dunedin 9054, New Zealand
| | - Robert Schmidt
- Psychology Department, University of Sheffield, Sheffield, United Kingdom
| | - David K Bilkey
- Psychology Department, Otago University, Dunedin 9054, New Zealand
| |
Collapse
|
11
|
Speers LJ, Bilkey DK. Disorganization of Oscillatory Activity in Animal Models of Schizophrenia. Front Neural Circuits 2021; 15:741767. [PMID: 34675780 PMCID: PMC8523827 DOI: 10.3389/fncir.2021.741767] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 09/16/2021] [Indexed: 01/02/2023] Open
Abstract
Schizophrenia is a chronic, debilitating disorder with diverse symptomatology, including disorganized cognition and behavior. Despite considerable research effort, we have only a limited understanding of the underlying brain dysfunction. In this article, we review the potential role of oscillatory circuits in the disorder with a particular focus on the hippocampus, a region that encodes sequential information across time and space, as well as the frontal cortex. Several mechanistic explanations of schizophrenia propose that a loss of oscillatory synchrony between and within these brain regions may underlie some of the symptoms of the disorder. We describe how these oscillations are affected in several animal models of schizophrenia, including models of genetic risk, maternal immune activation (MIA) models, and models of NMDA receptor hypofunction. We then critically discuss the evidence for disorganized oscillatory activity in these models, with a focus on gamma, sharp wave ripple, and theta activity, including the role of cross-frequency coupling as a synchronizing mechanism. Finally, we focus on phase precession, which is an oscillatory phenomenon whereby individual hippocampal place cells systematically advance their firing phase against the background theta oscillation. Phase precession is important because it allows sequential experience to be compressed into a single 120 ms theta cycle (known as a 'theta sequence'). This time window is appropriate for the induction of synaptic plasticity. We describe how disruption of phase precession could disorganize sequential processing, and thereby disrupt the ordered storage of information. A similar dysfunction in schizophrenia may contribute to cognitive symptoms, including deficits in episodic memory, working memory, and future planning.
Collapse
Affiliation(s)
| | - David K. Bilkey
- Department of Psychology, Otago University, Dunedin, New Zealand
| |
Collapse
|