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Maroon M, Haddad F, Doornaert E, Allman B, Schmid S. Investigating gene-environment interaction on attention in a double-hit model for Autism Spectrum Disorder. PLoS One 2024; 19:e0299380. [PMID: 38748694 PMCID: PMC11095761 DOI: 10.1371/journal.pone.0299380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 02/08/2024] [Indexed: 05/19/2024] Open
Abstract
Autism Spectrum Disorder (ASD) is a neurodevelopmental behavioral disorder characterized by social, communicative, and motor deficits. There is no single etiological cause for ASD, rather, there are various genetic and environmental factors that increase the risk for ASD. It is thought that some of these factors influence the same underlying neural mechanisms, and that an interplay of both genetic and environmental factors would better explain the pathogenesis of ASD. To better appreciate the influence of genetic-environment interaction on ASD-related behaviours, rats lacking a functional copy of the ASD-linked gene Cntnap2 were exposed to maternal immune activation (MIA) during pregnancy and assessed in adolescence and adulthood. We hypothesized that Cntnap2 deficiency interacts with poly I:C MIA to aggravate ASD-like symptoms in the offspring. In this double-hit model, we assessed attention, a core deficit in ASD due to prefrontal cortical dysfunction. We employed a well-established attentional paradigm known as the 5-choice serial reaction time task (5CSRTT). Cntnap2-/- rats exhibited greater perseverative responses which is indicative of repetitive behaviors. Additionally, rats exposed to poly I:C MIA exhibited premature responses, a marker of impulsivity. The rats exposed to both the genetic and environmental challenge displayed an increase in impulsive activity; however, this response was only elicited in the presence of an auditory distractor. This implies that exacerbated symptomatology in the double-hit model may situation-dependent and not generally expressed.
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Affiliation(s)
- Melvin Maroon
- Neuroscience Graduate Program, The University of Western Ontario, London, ON, Canada
| | - Faraj Haddad
- Neuroscience Graduate Program, The University of Western Ontario, London, ON, Canada
| | - Ella Doornaert
- Neuroscience Graduate Program, The University of Western Ontario, London, ON, Canada
| | - Brian Allman
- Neuroscience Graduate Program, The University of Western Ontario, London, ON, Canada
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada
| | - Susanne Schmid
- Neuroscience Graduate Program, The University of Western Ontario, London, ON, Canada
- Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada
- Psychology, The University of Western Ontario, London, ON, Canada
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2
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Hartmann C, Mahajan A, Borges V, Razenberg L, Thönnes Y, Karnani MM. The Switchmaze: an open-design device for measuring motivation and drive switching in mice. PEER COMMUNITY JOURNAL 2024; 4:pcjournal.416. [PMID: 38827787 PMCID: PMC7616052 DOI: 10.1101/2024.01.31.578188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Animals need to switch between motivated behaviours, like drinking, feeding or social interaction, to meet environmental availability, internal needs and more complex ethological needs such as hiding future actions from competitors. Inflexible, repetitive behaviours are a hallmark of many neuropsychiatric disorders. However, how the brain orchestrates switching between the neural mechanisms controlling motivated behaviours, or drives, is unknown. This is partly due to a lack of appropriate measurement systems. We designed an automated extended home-cage, the Switchmaze, using open-source hardware and software. In this study, we use it to establish a behavioural assay of motivational switching in mice. Individual animals access the Switchmaze from the home-cage and choose between entering one of two chambers containing different goal objects or returning to the home-cage. Motivational switching is measured as a ratio of switching between chambers and continuous exploitation of one chamber. Behavioural transition analysis is used to further dissect altered motivational switching. As proof-of-concept, we show environmental manipulation, and targeted brain manipulation experiments which altered motivational switching without effect on traditional behavioural parameters. Chemogenetic inhibition of the prefrontal-hypothalamic axis increased the rate of motivation switching, highlighting the involvement of this pathway in drive switching. This work demonstrates the utility of open-design in understanding animal behaviour and its neural correlates.
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Affiliation(s)
- Clara Hartmann
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Ambika Mahajan
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Vinicius Borges
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Lotte Razenberg
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Yves Thönnes
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Mahesh M Karnani
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
- Institute for Neuroscience and Cardiovascular Research, Centre for Discovery Brain Sciences, University of Edinburgh, 1 George Square, Edinburgh EH8 9JZ, UK
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3
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Fang Q, Frohlich F. Dissection of neuronal circuits underlying sustained attention with the five-choice serial reaction time task. Neurosci Biobehav Rev 2023; 152:105306. [PMID: 37419229 PMCID: PMC10517644 DOI: 10.1016/j.neubiorev.2023.105306] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 06/30/2023] [Accepted: 07/03/2023] [Indexed: 07/09/2023]
Abstract
Attention deficits are common in psychiatric and neurological disorders. The transdiagnostic nature of impaired attention suggests a common set of underlying neural circuits. Yet, there are no circuit-based treatments such as non-invasive brain stimulation currently available due to the lack of sufficiently delineated network targets. Therefore, to better treat attentional deficits, a comprehensive functional dissection of neural circuits underlying attention is imperative. This can be achieved by taking advantage of preclinical animal models and well-designed behavioral assays of attention. The resulting findings in turn can be translated to the development of novel interventions with the goal of advancing them to clinical practice. Here we show that the five-choice serial reaction time task has greatly facilitated the study of the neural circuits underlying attention in a well-controlled setting. We first introduce the task and then focus on its application in preclinical studies on sustained attention, especially in the context of state-of-the-art neuronal perturbations.
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Affiliation(s)
- Qi Fang
- Department of Psychiatry, University of North Carolina, Chapel Hill, NC, USA
| | - Flavio Frohlich
- Department of Psychiatry, University of North Carolina, Chapel Hill, NC, USA; Carolina Center for Neurostimulation, University of North Carolina, Chapel Hill, NC, USA; Neuroscience Center, University of North Carolina, Chapel Hill, NC, USA; Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, USA; Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA; Department of Neurology, University of North Carolina, Chapel Hill, NC, USA.
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4
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d'Isa R, Gerlai R. Designing animal-friendly behavioral tests for neuroscience research: The importance of an ethological approach. Front Behav Neurosci 2023; 16:1090248. [PMID: 36703720 PMCID: PMC9871504 DOI: 10.3389/fnbeh.2022.1090248] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 12/16/2022] [Indexed: 01/12/2023] Open
Affiliation(s)
- Raffaele d'Isa
- Institute of Experimental Neurology (INSPE), Division of Neuroscience (DNS), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Robert Gerlai
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
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5
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Verdier A, Dominique N, Groussard D, Aldanondo A, Bathellier B, Bagur S. Enhanced perceptual task performance without deprivation in mice using medial forebrain bundle stimulation. CELL REPORTS METHODS 2022; 2:100355. [PMID: 36590697 PMCID: PMC9795331 DOI: 10.1016/j.crmeth.2022.100355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 10/04/2022] [Accepted: 11/09/2022] [Indexed: 05/11/2023]
Abstract
Perceptual decision-making tasks are essential to many fields of neuroscience. Current protocols generally reward deprived animals with water. However, balancing animals' deprivation level with their well-being is challenging, and trial number is limited by satiation. Here, we present electrical stimulation of the medial forebrain bundle (MFB) as an alternative that avoids deprivation while yielding stable motivation for thousands of trials. Using licking or lever press as a report, MFB animals learnt auditory discrimination tasks at similar speed to water-deprived mice. Moreover, they more reliably reached higher accuracy in harder tasks, performing up to 4,500 trials per session without loss of motivation. MFB stimulation did not impact the underlying sensory behavior since psychometric parameters and response times are preserved. MFB mice lacked signs of metabolic or behavioral stress compared with water-deprived mice. Overall, MFB stimulation is a highly promising tool for task learning because it enhances task performance while avoiding deprivation.
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Affiliation(s)
- Antonin Verdier
- Institut de l’Audition, Institut Pasteur, Université de Paris, INSERM, 75012 Paris, France
| | - Noémi Dominique
- Institut Pasteur, Université Paris Cité, DT, Animalerie Centrale, 75724 Paris, France
| | - Déborah Groussard
- Institut Pasteur, Université Paris Cité, DT, Animalerie Centrale, 75724 Paris, France
| | - Anna Aldanondo
- Institut de l’Audition, Institut Pasteur, Université de Paris, INSERM, 75012 Paris, France
| | - Brice Bathellier
- Institut de l’Audition, Institut Pasteur, Université de Paris, INSERM, 75012 Paris, France
| | - Sophie Bagur
- Institut de l’Audition, Institut Pasteur, Université de Paris, INSERM, 75012 Paris, France
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Negrón-Moreno PN, Diep DT, Guoynes CD, Sidorov MS. Dissociating motor impairment from five-choice serial reaction time task performance in a mouse model of Angelman syndrome. Front Behav Neurosci 2022; 16:968159. [PMID: 36212189 PMCID: PMC9539753 DOI: 10.3389/fnbeh.2022.968159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 09/05/2022] [Indexed: 12/02/2022] Open
Abstract
Angelman syndrome (AS) is a single-gene neurodevelopmental disorder associated with cognitive and motor impairment, seizures, lack of speech, and disrupted sleep. AS is caused by loss-of-function mutations in the UBE3A gene, and approaches to reinstate functional UBE3A are currently in clinical trials in children. Behavioral testing in a mouse model of AS (Ube3a m-/p+ ) represents an important tool to assess the effectiveness of current and future treatments preclinically. Existing behavioral tests effectively model motor impairments, but not cognitive impairments, in Ube3a m-/p+ mice. Here we tested the hypothesis that the 5-choice serial reaction time task (5CSRTT) can be used to assess cognitive behaviors in Ube3a m-/p+ mice. Ube3a m-/p+ mice had more omissions during 5CSRTT training than wild-type littermate controls, but also showed impaired motor function including open field hypoactivity and delays in eating pellet rewards. Motor impairments thus presented an important confound for interpreting this group difference in omissions. We report that despite hypoactivity during habituation, Ube3a m-/p+ mice had normal response latencies to retrieve rewards during 5CSRTT training. We also accounted for delays in eating pellet rewards by assessing omissions solely on trials where eating delays would not impact results. Thus, the increase in omissions in Ube3a m-/p+ mice is likely not caused by concurrent motor impairments. This work underscores the importance of considering how known motor impairments in Ube3a m-/p+ mice may affect behavioral performance in other domains. Our results also provide guidance on how to design a 5CSRTT protocol that is best suited for future studies in Ube3a mutants.
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Affiliation(s)
- Paola N. Negrón-Moreno
- University of Puerto Rico-Cayey, Cayey, PR, United States
- Department of Cell Biology and Physiology, Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - David T. Diep
- University of Maryland, College Park, College Park, MD, United States
- Center for Neuroscience Research, Children’s National Medical Center, Washington, DC, United States
| | - Caleigh D. Guoynes
- Center for Neuroscience Research, Children’s National Medical Center, Washington, DC, United States
| | - Michael S. Sidorov
- Department of Cell Biology and Physiology, Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Center for Neuroscience Research, Children’s National Medical Center, Washington, DC, United States
- Departments of Pediatrics and Pharmacology and Physiology, The George Washington University School of Medicine and Health Sciences, Washington, DC, United States
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Probing the Skin–Brain Axis: New Vistas Using Mouse Models. Int J Mol Sci 2022; 23:ijms23137484. [PMID: 35806489 PMCID: PMC9267936 DOI: 10.3390/ijms23137484] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 12/10/2022] Open
Abstract
Inflammatory diseases of the skin, including atopic dermatitis and psoriasis, have gained increasing attention with rising incidences in developed countries over the past decades. While bodily properties, such as immunological responses of the skin, have been described in some detail, interactions with the brain via different routes are less well studied. The suggested routes of the skin–brain axis comprise the immune system, HPA axis, and the peripheral and central nervous system, including microglia responses and structural changes. They provide starting points to investigate the molecular mechanisms of neuropsychiatric comorbidities in AD and psoriasis. To this end, mouse models exist for AD and psoriasis that could be tested for relevant behavioral entities. In this review, we provide an overview of the current mouse models and assays. By combining an extensive behavioral characterization and state-of-the-art genetic interventions with the investigation of underlying molecular pathways, insights into the mechanisms of the skin–brain axis in inflammatory cutaneous diseases are examined, which will spark further research in humans and drive the development of novel therapeutic strategies.
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Vincent KF, Zhang ER, Kato R, Cho A, Moody OA, Solt K. Return of the Righting Reflex Does Not Portend Recovery of Cognitive Function in Anesthetized Rats. Front Syst Neurosci 2021; 15:762096. [PMID: 34867222 PMCID: PMC8637163 DOI: 10.3389/fnsys.2021.762096] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/28/2021] [Indexed: 11/18/2022] Open
Abstract
As the number of individuals undergoing general anesthesia rises globally, it becomes increasingly important to understand how consciousness and cognition are restored after anesthesia. In rodents, levels of consciousness are traditionally captured by physiological responses such as the return of righting reflex (RORR). However, tracking the recovery of cognitive function is comparatively difficult. Here we use an operant conditioning task, the 5-choice serial reaction time task (5-CSRTT), to measure sustained attention, working memory, and inhibitory control in male and female rats as they recover from the effects of several different clinical anesthetics. In the 5-CSRTT, rats learn to attend to a five-windowed touchscreen for the presentation of a stimulus. Rats are rewarded with food pellets for selecting the correct window within the time limit. During each session we tracked both the proportion of correct (accuracy) and missed (omissions) responses over time. Cognitive recovery trajectories were assessed after isoflurane (2% for 1 h), sevoflurane (3% for 20 min), propofol (10 mg/kg I.V. bolus), ketamine (50 mg/kg I.V. infusion over 10 min), and dexmedetomidine (20 and 35 μg/kg I.V. infusions over 10 min) for up to 3 h following RORR. Rats were classified as having recovered accuracy performance when four of their last five responses were correct, and as having recovered low omission performance when they missed one or fewer of their last five trials. Following isoflurane, sevoflurane, and propofol anesthesia, the majority (63-88%) of rats recovered both accuracy and low omission performance within an hour of RORR. Following ketamine, accuracy performance recovers within 2 h in most (63%) rats, but low omission performance recovers in only a minority (32%) of rats within 3 h. Finally, following either high or low doses of dexmedetomidine, few rats (25-32%) recover accuracy performance, and even fewer (0-13%) recover low omission performance within 3 h. Regardless of the anesthetic, RORR latency is not correlated with 5-CSRTT performance, which suggests that recovery of neurocognitive function cannot be inferred from changes in levels of consciousness. These results demonstrate how operant conditioning tasks can be used to assess real-time recovery of neurocognitive function following different anesthetic regimens.
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Affiliation(s)
- Kathleen F. Vincent
- Anesthesia, Critical Care, and Pain Medicine, Massachusetts’s General Hospital, Boston, MA, United States,Harvard Medical School, Boston, MA, United States
| | - Edlyn R. Zhang
- Anesthesia, Critical Care, and Pain Medicine, Massachusetts’s General Hospital, Boston, MA, United States
| | - Risako Kato
- Anesthesia, Critical Care, and Pain Medicine, Massachusetts’s General Hospital, Boston, MA, United States,Harvard Medical School, Boston, MA, United States
| | - Angel Cho
- Touro College of Osteopathic Medicine, New York, NY, United States
| | - Olivia A. Moody
- Anesthesia, Critical Care, and Pain Medicine, Massachusetts’s General Hospital, Boston, MA, United States,Harvard Medical School, Boston, MA, United States
| | - Ken Solt
- Anesthesia, Critical Care, and Pain Medicine, Massachusetts’s General Hospital, Boston, MA, United States,Harvard Medical School, Boston, MA, United States,*Correspondence: Ken Solt,
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9
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Strachan EL, Mac White-Begg D, Crean J, Reynolds AL, Kennedy BN, O’Sullivan NC. The Role of Mitochondria in Optic Atrophy With Autosomal Inheritance. Front Neurosci 2021; 15:784987. [PMID: 34867178 PMCID: PMC8634724 DOI: 10.3389/fnins.2021.784987] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 10/22/2021] [Indexed: 11/13/2022] Open
Abstract
Optic atrophy (OA) with autosomal inheritance is a form of optic neuropathy characterized by the progressive and irreversible loss of vision. In some cases, this is accompanied by additional, typically neurological, extra-ocular symptoms. Underlying the loss of vision is the specific degeneration of the retinal ganglion cells (RGCs) which form the optic nerve. Whilst autosomal OA is genetically heterogenous, all currently identified causative genes appear to be associated with mitochondrial organization and function. However, it is unclear why RGCs are particularly vulnerable to mitochondrial aberration. Despite the relatively high prevalence of this disorder, there are currently no approved treatments. Combined with the lack of knowledge concerning the mechanisms through which aberrant mitochondrial function leads to RGC death, there remains a clear need for further research to identify the underlying mechanisms and develop treatments for this condition. This review summarizes the genes known to be causative of autosomal OA and the mitochondrial dysfunction caused by pathogenic mutations. Furthermore, we discuss the suitability of available in vivo models for autosomal OA with regards to both treatment development and furthering the understanding of autosomal OA pathology.
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Affiliation(s)
- Elin L. Strachan
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Delphi Mac White-Begg
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - John Crean
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- UCD Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Alison L. Reynolds
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Breandán N. Kennedy
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Niamh C. O’Sullivan
- UCD Conway Institute, University College Dublin, Dublin, Ireland
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
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Hegedüs P, Velencei A, Belval CHD, Heckenast J, Hangya B. Training protocol for probabilistic Pavlovian conditioning in mice using an open-source head-fixed setup. STAR Protoc 2021; 2:100795. [PMID: 34522902 PMCID: PMC8424585 DOI: 10.1016/j.xpro.2021.100795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
High throughput, temporally controlled, reproducible quantitative behavioral assays are important for understanding the neural mechanisms underlying behavior. Here, we provide a step-by-step training protocol for a probabilistic Pavlovian conditioning task, where two auditory cues predict probabilistic outcomes with different contingencies. This protocol allows us to study the differential behavioral and neuronal correlates of expected and surprising outcomes. It has been tested in combination with chronic in vivo electrophysiological recordings and optogenetic manipulations in ChAT-Cre and PV-Cre mouse lines. For complete details on the use and execution of this protocol, please refer to Hegedüs et al. (2021). We provide a training protocol for a probabilistic Pavlovian conditioning task in mice Two auditory cues predict probabilistic outcomes with different contingencies Possible to combine with chronic in vivo electrophysiology and optogenetics Ideal for testing behavioral and neural correlates of expected and surprising outcomes
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Affiliation(s)
- Panna Hegedüs
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary.,János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Anna Velencei
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Claire-Hélène de Belval
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary.,Interdisciplinary Masters' in Life Sciences, Ecole Normale Supérieure, Paris, France
| | - Julia Heckenast
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Hangya
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
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Localizing Microemboli within the Rodent Brain through Block-Face Imaging and Atlas Registration. eNeuro 2021; 8:ENEURO.0216-21.2021. [PMID: 34272259 PMCID: PMC8342264 DOI: 10.1523/eneuro.0216-21.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/27/2021] [Accepted: 07/07/2021] [Indexed: 12/01/2022] Open
Abstract
Brain microinfarcts are prevalent in humans, however because of the inherent difficulty of identifying and localizing individual microinfarcts, brain-wide quantification is impractical. In mice, microinfarcts have been created by surgically introducing microemboli into the brain, but a major limitation of this model is the absence of automated methods to identify and localize individual occlusions. We present a novel and semi-automated workflow to identify the anatomic location of fluorescent emboli (microspheres) within the mouse brain through histologic processing and atlas registration. By incorporating vibratome block-face imaging with the QuickNII brain registration tool, we show that the anatomic location of microspheres can be accurately registered to brain structures within the Allen mouse brain (AMB) atlas (e.g., somatomotor areas, hippocampal region, visual areas, etc.). Compared with registering images of slide mounted sections to the AMB atlas, microsphere location was more accurately determined when block-face images were used. As a proof of principle, using this workflow we compared the distribution of microspheres within the brains of mice that were either perfused or immersion fixed. No significant effect of perfusion on total microsphere number or location was detected. In general, microspheres were distributed brain-wide, with the largest density found in the thalamus. In sum, our block-face imaging workflow enables efficient characterization of the widespread distribution of fluorescent microemboli, facilitating future investigation into the impact of microinfarct load and location on brain health.
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