Medicine and Health Sciences Commons^™

A Review Of The Neural Basis Underlying The Acoustic Startle Response With A Focus On Recent Developments In Mammals, Alice Zheng, Susanne Schmid

Anatomy and Cell Biology Publications

The startle response consists of whole-body muscle contractions, eye-blink, accelerated heart rate, and freezing in response to a strong, sudden stimulus. It is evolutionarily preserved and can be observed in any animal that can perceive sensory signals, indicating the important protective function of startle. Startle response measurements and its alterations have become a valuable tool for exploring sensorimotor processes and sensory gating, especially in the context of pathologies of psychiatric disorders. The last reviews on the neural substrates underlying acoustic startle were published around 20 years ago. Advancements in methods and techniques have since allowed new insights into acoustic startle …

Developmental Changes In Electrophysiological Properties Of Auditory Cortical Neurons In The Cntnap2 Knockout Rat, Rajkamalpreet S Mann, Brian L Allman, Susanne Schmid

Anatomy and Cell Biology Publications

Disruptions in the CNTNAP2 gene are known to cause language impairments and symptoms associated with autism spectrum disorder (ASD). Importantly, knocking out this gene in rodents results in ASD-like symptoms that include auditory processing deficits. This study used in vitro patch-clamp electrophysiology to examine developmental alterations in auditory cortex pyramidal neurons of Cntnap2^-/- rats, hypothesizing that CNTNAP2 is essential for maintaining intrinsic neuronal properties and synaptic wiring in the developing auditory cortex. Whole cell patch-clamp recordings were conducted in wildtype and Cntnap2^-/- littermates at three postnatal age ranges (P8-12, P18-21, and …

Differences In Startle And Prepulse Inhibition In Contactin-Associated Protein-Like 2 Knock-Out Rats Are Associated With Sex-Specific Alterations In Brainstem Neural Activity, Alice Zheng, Kaela E Scott, Ashley L Schormans, Rajkamalpreet Mann, Brian L Allman, Susanne Schmid

Anatomy and Cell Biology Publications

The contactin-associated protein-like 2 (CNTNAP2) gene encodes for the CASPR2 protein, which plays an essential role in neurodevelopment. Mutations in CNTNAP2 are associated with neurodevelopmental disorders, including autism spectrum disorder and schizophrenia. Rats with a loss of function mutation in the Cntnap2 gene show increased acoustic startle response (ASR) and decreased prepulse inhibition (PPI). The neural basis of this altered auditory processing in Cntnap2 knock-out rats is currently unknown. Auditory brainstem recordings previously revealed no differences between the genotypes. The next step is to investigate brainstem structures outside of the primary auditory pathway that mediate ASR and PPI, which are …

Expression And Localization Of Nrf2/Keap1 Signalling Pathway Genes In Mouse Preimplantation Embryos Exposed To Free Fatty Acids., Grace Dionne, Michele D. Calder, Dean H Betts, Basim Abu Rafea, Andrew J Watson

Obstetrics & Gynaecology Publications

Obese women experience greater incidence of infertility, with reproductive tracts exposing preimplantation embryos to elevated free fatty acids (FFA) such as palmitic acid (PA) and oleic acid (OA). PA treatment impairs mouse preimplantation development in vitro, while OA co-treatment rescues blastocyst development of PA treated embryos. In the present study, we investigated the effects of PA and OA treatment on NRF2/Keap1 localization, and relative antioxidant enzyme (Glutathione peroxidase; Gpx1, Catalase; Cat, Superoxide dismutase; Sod1 and γ-Glutamylcysteine ligase catalytic unit; Gclc) mRNA levels, during in vitro mouse preimplantation embryo development. Female mice were superovulated, mated, and embryos cultured in the presence …

Hyperexcitable And Immature-Like Neuronal Activity In The Auditory Cortex Of Adult Rats Lacking The Language-Linked Cntnap2 Gene., Kaela E Scott, Rajkamalpreet S Mann, Ashley L Schormans, Susanne Schmid, Brian L Allman

Anatomy and Cell Biology Publications

The contactin-associated protein-like 2 gene, CNTNAP2, is a highly penetrant risk gene thought to play a role in the genetic etiology of language-related disorders, such as autism spectrum disorder and developmental language disorder. Despite its candidacy for influencing language development, few preclinical studies have examined the role of CNTNAP2 in auditory processing. Using in vivo and in vitro electrophysiological recordings in a rat model with translational validity, we report that a loss of the Cntnap2 gene function caused immature-like cortical evoked potentials, delayed multiunit response latencies to acoustic stimuli, impaired temporal processing, and led to a pattern of hyperexcitability in …

No Statistical Learning Advantage In Children Over Adults: Evidence From Behaviour And Neural Entrainment., Christine N Moreau, Marc F. Joanisse, Jerrica Mulgrew, Laura J. Batterink

Brain and Mind Institute Researchers' Publications

Explicit recognition measures of statistical learning (SL) suggest that children and adults have similar linguistic SL abilities. However, explicit tasks recruit additional cognitive processes that are not directly relevant for SL and may thus underestimate children's true SL capacities. In contrast, implicit tasks and neural measures of SL should be less influenced by explicit, higher-level cognitive abilities and thus may be better suited to capturing developmental differences in SL. Here, we assessed SL to six minutes of an artificial language in English-speaking children (n = 56, 24 females, M = 9.98 years) and adults (n = 44; 31 females, M …

Sex-Specific Alterations In Hepatic Cholesterol Metabolism In Low Birth Weight Adult Guinea Pigs., Ousseynou Sarr, Katherine E Mathers, Christina Vanderboor, Kristina Wiggers, Aditya Devgan, Daniel B Hardy, Lin Zhao, Timothy Regnault

Paediatrics Publications

BACKGROUND: Intrauterine growth restriction and low birth weight (LBW) have been widely reported as an independent risk factor for adult hypercholesterolaemia and increased hepatic cholesterol in a sex-specific manner. However, the specific impact of uteroplacental insufficiency (UPI), a leading cause of LBW in developed world, on hepatic cholesterol metabolism in later life, is ill defined and is clinically relevant in understanding later life liver metabolic health trajectories.

METHODS: Hepatic cholesterol, transcriptome, cholesterol homoeostasis regulatory proteins, and antioxidant markers were studied in UPI-induced LBW and normal birth weight (NBW) male and female guinea pigs at 150 days.

RESULTS: Hepatic free and …

In Vivo Magnetic Resonance Spectroscopy Of Hyperpolarized [1-, Lauren M Smith, Conrad B Pitts, Lanette J Friesen-Waldner, Neetin H Prabhu, Katherine E Mathers, Kevin J Sinclair, Trevor P Wade, Timothy Regnault, Charles A Mckenzie

Paediatrics Publications

BACKGROUND: Alterations in glycolysis are central to the increasing incidence of non-alcoholic fatty liver disease (NAFLD), highlighting a need for in vivo, non-invasive technologies to understand the development of hepatic metabolic aberrations.

PURPOSE: To use hyperpolarized magnetic resonance spectroscopy (MRS) and proton density fat fraction (PDFF) magnetic resonance imaging (MRI) techniques to investigate the effects of a chronic, life-long exposure to the Western diet (WD) in an animal model resulting in NAFLD; to investigate the hypothesis that exposure to the WD will result in NAFLD in association with altered pyruvate metabolism.

STUDY TYPE: Prospective.

ANIMAL MODEL: Twenty-eight male guinea pigs …

Effects Of Maternal Obesity And Gestational Diabetes Mellitus On The Placenta: Current Knowledge And Targets For Therapeutic Interventions, Samantha Bedell, Janine Hutson, Barbra De Vrijer, Genevieve Eastabrook

Obstetrics & Gynaecology Publications

Obesity and gestational diabetes mellitus (GDM) are becoming more common among pregnant women worldwide and are individually associated with a number of placenta-mediated obstetric complications, including preeclampsia, macrosomia, intrauterine growth restriction and stillbirth. The placenta serves several functions throughout pregnancy and is the main exchange site for the transfer of nutrients and gas from mother to fetus. In pregnancies complicated by maternal obesity or GDM, the placenta is exposed to environmental changes, such as increased inflammation and oxidative stress, dyslipidemia, and altered hormone levels. These changes can affect placental development and function and lead to abnormal fetal growth and development …

Atrx Deletion In Neurons Leads To Sexually Dimorphic Dysregulation Of Mir-137 And Spatial Learning And Memory Deficits., Renee J. Tamming, Vanessa Dumeaux, Yan Jiang, Sarfraz Shafiq, Luana Langlois, Jacob Ellegood, Lily R. Qiu, Jason P. Lerch, Nathalie G. Bérubé

Paediatrics Publications

ATRX gene mutations have been identified in syndromic and non-syndromic intellectual disabilities in humans. ATRX is known to maintain genomic stability in neuroprogenitor cells, but its function in differentiated neurons and memory processes remains largely unresolved. Here, we show that the deletion of neuronal Atrx in mice leads to distinct hippocampal structural defects, fewer presynaptic vesicles, and an enlarged postsynaptic area at CA1 apical dendrite-axon junctions. We identify male-specific impairments in long-term contextual memory and in synaptic gene expression, linked to altered miR-137 levels. We show that ATRX directly binds to the miR-137 locus and that the enrichment of the …

Effects Of A Postnatal Atrx Conditional Knockout In Neurons On Autism-Like Behaviours In Male And Female Mice., Nicole Martin-Kenny, Nathalie G Bérubé

Paediatrics Publications

BACKGROUND: Alpha-thalassemia/mental retardation, X-linked, or ATRX, is an autism susceptibility gene that encodes a chromatin remodeler. Mutations of ATRX result in the ATR-X intellectual disability syndrome and have been identified in autism spectrum disorder (ASD) patients. The mechanisms by which ATRX mutations lead to autism and autistic-like behaviours are not yet known. To address this question, we generated mice with postnatal Atrx inactivation in excitatory neurons of the forebrain and performed a battery of behavioural assays that assess autistic-like behaviours.

METHODS: Male and female mice with a postnatal conditional ablation of ATRX were generated using the Cre/lox system under the …

Evidence Of Increased Hypoxia Signaling In Fetal Liver From Maternal Nutrient Restriction In Mice., Bethany N Radford, Victor K M Han

Paediatrics Publications

BACKGROUND: Intrauterine growth restriction (IUGR) is a pregnancy condition where fetal growth is reduced, and offspring from IUGR pregnancies are at increased risk for type II diabetes as adults. The liver is susceptible to fetal undernutrition experienced by IUGR infants and animal models of growth restriction. This study aimed to examine hepatic expression changes in a maternal nutrient restriction (MNR) mouse model of IUGR to understand fetal adaptations that influence adult metabolism.

METHODS: Liver samples of male offspring from MNR (70% of ad libitum starting at E6.5) or control pregnancies were obtained at E18.5 and differential expression was assessed by …

Insights Image For "Evidence Of Increased Hypoxia Signalling In Fetal Liver From Maternal Nutrient Restriction In Mice"., Bethany N Radford, Victor K M Han

Paediatrics Publications

No abstract provided.

What We Can Learn From A Genetic Rodent Model About Autism., Dorit Möhrle, Marta Fernández, Olga Peñagarikano, Andreas Frick, Brian Allman, Susanne Schmid

Anatomy and Cell Biology Publications

Autism spectrum disorders (ASD) are complex neurodevelopmental disorders that are caused by genetic and/or environmental impacts, often probably by the interaction of both. They are characterised by deficits in social communication and interaction and by restricted and repetitive behaviours and interests from early childhood on, causing significant impairment. While it is clear that no animal model captures the full complexity of ASD in humans, genetic models are extremely useful for studying specific symptoms associated with ASD and the underlying cellular and molecular mechanisms. In this review we summarize the behavioral paradigms used in rodents to model ASD symptoms as they …

A Consensus Guide To Capturing The Ability To Inhibit Actions And Impulsive Behaviors In The Stop-Signal Task., Frederick Verbruggen, Adam R Aron, Guido Ph Band, Christian Beste, Patrick G Bissett, Adam T Brockett, Joshua W Brown, Samuel R Chamberlain, Christopher D Chambers, Hans Colonius, Lorenza S Colzato, Brian D Corneil, James P Coxon, Annie Dupuis, Dawn M Eagle, Hugh Garavan, Ian Greenhouse, Andrew Heathcote, René J Huster, Sara Jahfari, J Leon Kenemans, Inge Leunissen, Chiang-Shan R Li, Gordon D Logan, Dora Matzke, Sharon Morein-Zamir, Aditya Murthy, Martin Paré, Russell A Poldrack, K Richard Ridderinkhof, Trevor W Robbins, Matthew Roesch, Katya Rubia, Russell J Schachar, Jeffrey D Schall, Ann-Kathrin Stock, Nicole C Swann, Katharine N Thakkar, Maurits W Van Der Molen, Luc Vermeylen, Matthijs Vink, Jan R Wessel, Robert Whelan, Bram B Zandbelt, C Nico Boehler

Brain and Mind Institute Researchers' Publications

Response inhibition is essential for navigating everyday life. Its derailment is considered integral to numerous neurological and psychiatric disorders, and more generally, to a wide range of behavioral and health problems. Response-inhibition efficiency furthermore correlates with treatment outcome in some of these conditions. The stop-signal task is an essential tool to determine how quickly response inhibition is implemented. Despite its apparent simplicity, there are many features (ranging from task design to data analysis) that vary across studies in ways that can easily compromise the validity of the obtained results. Our goal is to facilitate a more accurate use of the …

Ctcf Governs The Identity And Migration Of Mge-Derived Cortical Interneurons., Adrienne Elbert, Daniel Vogt, Ashley Watson, Michael Levy, Yan Jiang, Emilie Brûlé, Megan E Rowland, John Rubenstein, Nathalie G Bérubé

Paediatrics Publications

The CCCTC-binding factor (CTCF) is a central regulator of chromatin topology recently linked to neurodevelopmental disorders such as intellectual disability, autism, and schizophrenia. The aim of this study was to identify novel roles of CTCF in the developing mouse brain. We provide evidence that CTCF is required for the expression of the LIM homeodomain factor LHX6 involved in fate determination of cortical interneurons (CINs) that originate in the medial ganglionic eminence (MGE). Conditional

The Loss Of Atrx Increases Susceptibility To Pancreatic Injury And Oncogenic Kras In Female But Not Male Mice., Claire C Young, Ryan M Baker, Christopher J Howlett, Todd Hryciw, Joshua E Herman, Douglas Higgs, Richard Gibbons, Howard Crawford, Arthur Brown, Christopher L Pin

Paediatrics Publications

Background

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in North America, accounting for >30,000 deaths annually. Although somatic activating mutations in KRAS appear in 97% of PDAC patients, additional factors are required to initiate PDAC. Because mutations in genes encoding chromatin remodelling proteins have been implicated in KRAS-mediated PDAC, we investigated whether loss of chromatin remodeler ɑ-thalassemia, mental-retardation, X-linked (ATRX) affects oncogenic KRAS’s ability to promote PDAC. ATRX affects DNA replication, repair, and gene expression and is implicated in other cancers including glioblastomas and pancreatic neuroendocrine tumors. The hypothesis was that deletion of Atrx …

App21 Transgenic Rats Develop Age-Dependent Cognitive Impairment And Microglia Accumulation Within White Matter Tracts., Nina Weishaupt, Qingfan Liu, Sheojung Shin, Ramandeep Singh, Yuksel Agca, Cansu Agca, Vladimir Hachinski, Shawn Narain Whitehead

Paediatrics Publications

Background

Most of the animal models commonly used for preclinical research into Alzheimer's disease (AD) largely fail to address the pathophysiology, including the impact of known risk factors, of the widely diagnosed sporadic form of the disease. Here, we use a transgenic rat (APP21) that does not develop AD-like pathology spontaneously with age, but does develop pathology following vascular stress. To further the potential of this novel rat model as a much-needed pre-clinical animal model of sporadic AD, we characterize APP21 transgenic rats behaviorally and histologically up to 19 months of age.

Methods

The open field test was used as …

N-Glycosylation Regulates Pannexin 2 Localization But Is Not Required For Interacting With Pannexin 1., Rafael E Sanchez-Pupo, Danielle Johnston, Silvia Penuela

Anatomy and Cell Biology Publications

Pannexins (Panx1, 2, 3) are channel-forming glycoproteins expressed in mammalian tissues. We previously reported that N-glycosylation acts as a regulator of the localization and intermixing of Panx1 and Panx3, but its effects on Panx2 are currently unknown. Panx1 and Panx2 intermixing can regulate channel properties, and both pannexins have been implicated in neuronal cell death after ischemia. Our objectives were to validate the predicted N-glycosylation site of Panx2 and to study the effects of Panx2 glycosylation on localization and its capacity to interact with Panx1. We used site-directed mutagenesis, enzymatic de-glycosylation, cell-surface biotinylation, co-immunoprecipitation, and confocal microscopy. Our results showed …

Modified Origins Of Cortical Projections To The Superior Colliculus In The Deaf: Dispersion Of Auditory Efferents., Blake E Butler, Julia K Sunstrum, Stephen G Lomber

Brain and Mind Institute Researchers' Publications

Following the loss of a sensory modality, such as deafness or blindness, crossmodal plasticity is commonly identified in regions of the cerebrum that normally process the deprived modality. It has been hypothesized that significant changes in the patterns of cortical afferent and efferent projections may underlie these functional crossmodal changes. However, studies of thalamocortical and corticocortical connections have refuted this hypothesis, instead revealing a profound resilience of cortical afferent projections following deafness and blindness. This report is the first study of cortical outputs following sensory deprivation, characterizing cortical projections to the superior colliculus in mature cats (

Cortical And Thalamic Connectivity To The Second Auditory Cortex Of The Cat Is Resilient To The Onset Of Deafness., Blake E Butler, Alexandra De La Rua, Taylor Ward-Able, Stephen G Lomber

Brain and Mind Institute Researchers' Publications

It has been well established that following sensory loss, cortical areas that would normally be involved in perceiving stimuli in the absent modality are recruited to subserve the remaining senses. Despite this compensatory functional reorganization, there is little evidence to date for any substantial change in the patterns of anatomical connectivity between sensory cortices. However, while many auditory areas are contracted in the deaf, the second auditory cortex (A2) of the cat undergoes a volumetric expansion following hearing loss, suggesting this cortical area may demonstrate a region-specific pattern of structural reorganization. To address this hypothesis, and to complement existing literature …

Identification Of A Novel Synaptic Protein, Tmtc3, Involved In Periventricular Nodular Heterotopia With Intellectual Disability And Epilepsy, Sali M K Farhan, Kevin C J Nixon, Michelle Everest, Tara N Edwards, Shirley Long, Dmitri Segal, Maria J Knip, Heleen H Arts, Rana Chakrabarti, Jian Wang, John F Robinson, Donald Lee, Seyed M Mirsattari, C Anthony Rupar, Victoria M Siu, Forge Canada Consortium, Michael O Poulter, Robert A Hegele, Jamie M Kramer

Paediatrics Publications

Defects in neuronal migration cause brain malformations, which are associated with intellectual disability (ID) and epilepsy. Using exome sequencing, we identified compound heterozygous variants (p.Arg71His and p. Leu729ThrfsTer6) in TMTC3, encoding transmembrane and tetratricopeptide repeat containing 3, in four siblings with nocturnal seizures and ID. Three of the four siblings have periventricular nodular heterotopia (PVNH), a common brain malformation caused by failure of neurons to migrate from the ventricular zone to the cortex. Expression analysis using patient-derived cells confirmed reduced TMTC3 transcript levels and loss of the TMTC3 protein compared to parental and control cells. As TMTC3 function is currently …

Disruption Of Hippocampal Multisynaptic Networks By General Anesthetics., Min-Ching Kuo, L Stan Leung

Physiology and Pharmacology Publications

BACKGROUND: Previous studies showed that synaptic transmission is affected by general anesthetics, but an anesthetic dose response in freely moving animals has not been done. The hippocampus provides a neural network for the evaluation of isoflurane and pentobarbital on multisynaptic transmission that is relevant to memory function.

METHODS: Male Long-Evans rats were implanted with multichannel and single electrodes in the hippocampus. Spontaneous local field potentials and evoked field potentials were recorded in freely behaving rats before (baseline) and after various doses of isoflurane (0.25 to 1.5%) and sodium pentobarbital (10 mg/kg intraperitoneal).

RESULTS: Monosynaptic population excitatory postsynaptic potentials at the …

Mutations In Keops-Complex Genes Cause Nephrotic Syndrome With Primary Microcephaly, Daniela A Braun, Jia Rao, Geraldine Mollet, David Schapiro, Marie-Claire Daugeron, Weizhen Tan, Olivier Gribouval, Olivia Boyer, Patrick Revy, Tilman Jobst-Schwan, Johanna Magdalena Schmidt, Jennifer A Lawson, Denny Schanze, Shazia Ashraf, Jeremy F P Ullmann, Charlotte A Hoogstraten, Nathalie Boddaert, Bruno Collinet, Gaëlle Martin, Dominique Liger, Svjetlana Lovric, Monica Furlano, I Chiara Guerrera, Oraly Sanchez-Ferras, Jennifer F Hu, Anne-Claire Boschat, Sylvia Sanquer, Björn Menten, Sarah Vergult, Nina De Rocker, Merlin Airik, Tobias Hermle, Shirlee Shril, Eugen Widmeier, Heon Yung Gee, Won-Il Choi, Carolin E Sadowski, Werner L Pabst, Jillian K Warejko, Ankana Daga, Tamara Basta, Verena Matejas, Karin Scharmann, Sandra D Kienast, Babak Behnam, Brendan Beeson, Amber Begtrup, Malcolm Bruce, Gaik-Siew Ch'ng, Shuan-Pei Lin, Jui-Hsing Chang, Chao-Huei Chen, Megan T Cho, Patrick M Gaffney, Patrick E Gipson, Chyong-Hsin Hsu, Jameela A Kari, Yu-Yuan Ke, Cathy Kiraly-Borri, Wai-Ming Lai, Emmanuelle Lemyre, Rebecca Okashah Littlejohn, Amira Masri, Mastaneh Moghtaderi, Kazuyuki Nakamura, Fatih Ozaltin, Marleen Praet, Chitra Prasad, Agnieszka Prytula, Elizabeth R Roeder, Patrick Rump, Rhonda E Schnur, Takashi Shiihara, Manish D Sinha, Neveen A Soliman, Kenza Soulami, David A Sweetser, Wen-Hui Tsai, Jeng-Daw Tsai, Rezan Topaloglu, Udo Vester, David H Viskochil, Nithiwat Vatanavicharn, Jessica L Waxler, Klaas J Wierenga, Matthias T F Wolf, Sik-Nin Wong, Sebastian A Leidel, Gessica Truglio, Peter C Dedon, Annapurna Poduri, Shrikant Mane, Richard P Lifton, Maxime Bouchard, Peter Kannu, David Chitayat, Daniella Magen, Bert Callewaert, Herman Van Tilbeurgh, Martin Zenker, Corinne Antignac, Friedhelm Hildebrandt

Paediatrics Publications

Galloway-Mowat syndrome (GAMOS) is an autosomal-recessive disease characterized by the combination of early-onset nephrotic syndrome (SRNS) and microcephaly with brain anomalies. Here we identified recessive mutations in OSGEP, TP53RK, TPRKB, and LAGE3, genes encoding the four subunits of the KEOPS complex, in 37 individuals from 32 families with GAMOS. CRISPR-Cas9 knockout in zebrafish and mice recapitulated the human phenotype of primary microcephaly and resulted in early lethality. Knockdown of OSGEP, TP53RK, or TPRKB inhibited cell proliferation, which human mutations did not rescue. Furthermore, knockdown of these genes impaired protein translation, caused endoplasmic reticulum stress, activated DNA-damage-response signaling, and ultimately induced …

Activating Transcription Factor 3 Promotes Loss Of The Acinar Cell Phenotype In Response To Cerulein-Induced Pancreatitis In Mice, Elena N Fazio, Claire C Young, Jelena Toma, Michael Levy, Kurt R Berger, Charis L Johnson, Rashid Mehmood, Patrick Swan, Alphonse Chu, Sean P Cregan, F Jeffrey Dilworth, Christopher J Howlett, Christopher L Pin

Paediatrics Publications

Pancreatitis is a debilitating disease of the exocrine pancreas that, under chronic conditions, is a major susceptibility factor for pancreatic ductal adenocarcinoma (PDAC). Although down-regulation of genes that promote the mature acinar cell fate is required to reduce injury associated with pancreatitis, the factors that promote this repression are unknown. Activating transcription factor 3 (ATF3) is a key mediator of the unfolded protein response, a pathway rapidly activated during pancreatic insult. Using chromatin immunoprecipitation followed by next-generation sequencing, we show that ATF3 is bound to the transcriptional regulatory regions of >30% of differentially expressed genes during the initiation of pancreatitis. …

Sensory Processing In Autism Spectrum Disorders And Fragile X Syndrome-From The Clinic To Animal Models., D Sinclair, B Oranje, K A Razak, S J Siegel, S Schmid

Brain and Mind Institute Researchers' Publications

Brains are constantly flooded with sensory information that needs to be filtered at the pre-attentional level and integrated into endogenous activity in order to allow for detection of salient information and an appropriate behavioral response. People with Autism Spectrum Disorder (ASD) or Fragile X Syndrome (FXS) are often over- or under-reactive to stimulation, leading to a wide range of behavioral symptoms. This altered sensitivity may be caused by disrupted sensory processing, signal integration and/or gating, and is often being neglected. Here, we review translational experimental approaches that are used to investigate sensory processing in humans with ASD and FXS, and …

Bk Channels Mediate Synaptic Plasticity Underlying Habituation In Rats., Tariq Zaman, Cleusa De Oliveira, Mahabba Smoka, Chakravarthi Narla, Michael O Poulter, Susanne Schmid

Brain and Mind Institute Researchers' Publications

Habituation is a basic form of implicit learning and represents a sensory filter that is disrupted in autism, schizophrenia, and several other mental disorders. Despite extensive research in the past decades on habituation of startle and other escape responses, the underlying neural mechanisms are still not fully understood. There is evidence from previous studies indicating that BK channels might play a critical role in habituation. We here used a wide array of approaches to test this hypothesis. We show that BK channel activation and subsequent phosphorylation of these channels are essential for synaptic depression presumably underlying startle habituation in rats, …

Mosaic Expression Of Atrx In The Mouse Central Nervous System Causes Memory Deficits, Renee J Tamming, Jennifer R Siu, Yan Jiang, Marco A M Prado, Frank Beier, Nathalie G Bérubé

Paediatrics Publications

The rapid modulation of chromatin organization is thought to play a crucial role in cognitive processes such as memory consolidation. This is supported in part by the dysregulation of many chromatin-remodelling proteins in neurodevelopmental and psychiatric disorders. A key example is ATRX, an X-linked gene commonly mutated in individuals with syndromic and nonsyndromic intellectual disability. The consequences of Atrx inactivation for learning and memory have been difficult to evaluate because of the early lethality of hemizygous-null animals. In this study, we evaluated the outcome of brain-specific Atrx deletion in heterozygous female mice. These mice exhibit a mosaic pattern of ATRX …

Adolescent Cannabinoid Exposure Induces A Persistent Sub-Cortical Hyper-Dopaminergic State And Associated Molecular Adaptations In The Prefrontal Cortex., Justine Renard, Laura G Rosen, Michael Loureiro, Cleusa De Oliveira, Susanne Schmid, Walter J Rushlow, Steven R Laviolette

Brain and Mind Institute Researchers' Publications

Considerable evidence suggests that adolescent exposure to delta-9-tetrahydrocanabinol (THC), the psychoactive component in marijuana, increases the risk of developing schizophrenia-related symptoms in early adulthood. In the present study, we used a combination of behavioral and molecular analyses with in vivo neuronal electrophysiology to compare the long-term effects of adolescent versus adulthood THC exposure in rats. We report that adolescent, but not adult, THC exposure induces long-term neuropsychiatric-like phenotypes similar to those observed in clinical populations. Thus, adolescent THC exposure induced behavioral abnormalities resembling positive and negative schizophrenia-related endophenotypes and a state of neuronal hyperactivity in the mesocorticolimbic dopamine (DA) pathway. …

Hippocampal Neurogenesis And Volume In Migrating And Wintering Semipalmated Sandpipers (Calidris Pusilla)., Nara Gyzely De Morais Magalhães, Cristovam Guerreiro Diniz, Daniel Guerreiro Diniz, Ediely Pereira Henrique, Patrick Douglas Corrêa Pereira, Isis Ananda Matos Moraes, Mauro André Damasceno De Melo, David Francis Sherry, Cristovam Wanderley Picanço Diniz

Brain and Mind Institute Researchers' Publications

Long distance migratory birds find their way by sensing and integrating information from a large number of cues in their environment. These cues are essential to navigate over thousands of kilometers and reach the same breeding, stopover, and wintering sites every year. The semipalmated sandpiper (Calidris pusilla) is a long-distance migrant that breeds in the arctic tundra of Canada and Alaska and winters on the northeast coast of South America. Its fall migration includes a 5,300-kilometer nonstop flight over the Atlantic Ocean. The avian hippocampus has been proposed to play a central role in the integration of multisensory spatial information …