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Bridging the gap between neuroscientific and psychodynamic models in child and adolescent psychiatry. Child Adolesc Psychiatr Clin N Am 2013; 22:1-31. [PMID: 23164125 DOI: 10.1016/j.chc.2012.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This article provides a selective review of the neuroscience and child-psychoanalytic literature, focusing on areas of significant overlap and emphasizing comprehensive theories in developmental neuroscience and child psychoanalysis with testable mechanisms of action. Topics include molecular biology and genetics findings relevant to psychotherapy research, neuroimaging findings relevant to psychotherapy, brain regions of interest for psychotherapy, neurobiologic changes caused by psychotherapy, use of neuroimaging to predict treatment outcome, and schemas as a bridging concept between psychodynamic and cognitive neuroscience models. The combined efforts of neuroscientists and psychodynamic clinicians and theorists are needed to unravel the mechanisms of human mental functioning.
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McOmish CE, Burrows EL, Howard M, Hannan AJ. PLC-beta1 knockout mice as a model of disrupted cortical development and plasticity: behavioral endophenotypes and dysregulation of RGS4 gene expression. Hippocampus 2008; 18:824-34. [PMID: 18493969 DOI: 10.1002/hipo.20443] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The complexity of the genetics underlying schizophrenia is highlighted by the multitude of molecular pathways that have been reported to be disrupted in the disorder including muscarinic, serotonergic, and glutamatergic signaling systems. It is of interest, therefore, that phospholipase C-beta1 (PLC-beta1) acts as a point of convergence for these pathways during cortical development and plasticity. These signaling pathways, furthermore, are susceptible to modulation by RGS4, one of the more promising candidate genes for schizophrenia. PLC-beta1 knockout mice were behaviorally assessed on tests including fear conditioning, elevated plus maze, and the Y maze. In situ hybridization was used to assess RGS4 expression. We found that PLC-beta1 knockout mice display abnormal anxiety profiles on some, but not all measures assessed, including decreased anxiety on the elevated plus maze. We also show memory impairment and a complete absence of acquisition of hippocampal-dependent fear conditioning. Furthermore, at a molecular level, we demonstrate dramatic changes in expression of RGS4 mRNA in selective regions of the PLC-beta1 knockout mouse brain, particularly the CA1 region of the hippocampus. These results validate the utility of the PLC-beta1 knockout mouse as a model of schizophrenia, including molecular and cellular evidence for disrupted cortical maturation and associated behavioral endophenotypes.
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Affiliation(s)
- Caitlin E McOmish
- Howard Florey Institute, University of Melbourne, Parkville, Victoria, Australia.
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Bauman MD, Toscano JE, Babineau BA, Mason WA, Amaral DG. Emergence of stereotypies in juvenile monkeys (Macaca mulatta) with neonatal amygdala or hippocampus lesions. Behav Neurosci 2008; 122:1005-15. [PMID: 18823158 PMCID: PMC2884986 DOI: 10.1037/a0012600] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The emergence of stereotypies was examined in juvenile rhesus monkeys (Macaca mulatta) who, at 2 weeks of postnatal age, received selective bilateral ibotenic acid lesions of the amygdala (N = 8) or hippocampus (N = 8). The lesion groups were compared to age-matched control subjects that received a sham surgical procedure (N = 8). All subjects were maternally reared for the first 6 months and provided access to social groups throughout development. Pronounced stereotypies were not observed in any of the experimental groups during the first year of life. However, between 1 to 2 years of age, both amygdala- and hippocampus-lesioned subjects began to exhibit stereotypies. When observed as juveniles, both amygdala- and hippocampus-lesioned subjects consistently produced more stereotypies than the control subjects in a variety of contexts. More interesting, neonatal lesions of either the amygdala or hippocampus resulted in unique repertoires of repetitive behaviors. Amygdala-lesioned subjects exhibited more self-directed stereotypies and the hippocampus-lesioned subjects displayed more head-twisting. We discuss these results in relation to the neurobiological basis of repetitive stereotypies in neurodevelopmental disorders, such as autism.
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Affiliation(s)
- M D Bauman
- Department of Psychiatry and Behavioral Sciences, Center for Neuroscience, The M.I.N.D. Institute, University of California at Davis, CA 95817, USA.
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Apud JA, Weinberger DR. Treatment of cognitive deficits associated with schizophrenia: potential role of catechol-O-methyltransferase inhibitors. CNS Drugs 2007; 21:535-57. [PMID: 17579498 DOI: 10.2165/00023210-200721070-00002] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
In the last two decades, understanding of the dynamics of dopamine function in the prefrontal cortex and its role in prefrontal cortex physiology has opened up new avenues for therapeutic interventions in conditions in which prefrontal cortex function is compromised. Neuropsychological and imaging studies of prefrontal information processing have confirmed specific cognitive and neurophysiological abnormalities in individuals with schizophrenia. Because such findings are also observed in the healthy siblings of patients with schizophrenia, they may represent intermediate phenotypes related to schizophrenia susceptibility genes.Catechol-O-methyltransferase (COMT) represents an important candidate as a susceptibility gene for cognitive dysfunction in schizophrenia because of the unique role this enzyme plays in regulating prefrontal dopaminergic function. A functional COMT polymorphism (Val158Met) predicts performance in tasks of prefrontal executive function and the neurophysiological response measured with electroencephalography and functional magnetic resonance imaging in tasks assessing working memory. In fact, individuals with the Val/Val genotype, which encodes for the high-activity enzyme resulting in lower dopamine concentrations in the prefrontal cortex, perform less well and are less efficient physiologically than Met/Met individuals. These findings raise the possibility of new pharmacological interventions for the treatment of prefrontal cortex dysfunction and of predicting outcome based on COMT genotype. One strategy consists of the use of CNS-penetrant COMT inhibitors such as tolcapone. A second strategy is to increase extracellular dopamine concentrations in the frontal cortex by blocking the noradrenaline (norepinephrine) reuptake system, a secondary mechanism responsible for the disposal of dopamine from synaptic clefts in the prefrontal cortex. A third possibility involves the use of modafinil, a drug with an unclear mechanism of action but with positive effects on working memory in rodents. The potential of these drugs to improve executive cognitive function by selectively increasing dopamine load in the frontal cortex but not in subcortical territories, and the possibility that response to them may be modified by a COMT polymorphism, provides a novel genotype-based targeted pharmacological approach without abuse potential for the treatment of cognitive disorder in schizophrenia and in other conditions involving prefrontal cortex dysfunction.
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Affiliation(s)
- José A Apud
- Clinical Brain Disorders Branch, Genes, Cognition and Psychosis Program, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
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Le Pen G, Kew J, Alberati D, Borroni E, Heitz MP, Moreau JL. Prepulse inhibition deficits of the startle reflex in neonatal ventral hippocampal-lesioned rats: reversal by glycine and a glycine transporter inhibitor. Biol Psychiatry 2003; 54:1162-70. [PMID: 14643083 DOI: 10.1016/s0006-3223(03)00374-3] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Neonatal ventral hippocampal (NVH) lesions in rats induce behavioral abnormalities at adulthood thought to simulate some aspects of the positive, negative, and cognitive deficits classically observed in schizophrenic patients. Such lesions induce a postpubertal emergence of prepulse inhibition (PPI) deficits of the startle reflex reminiscent of the sensorimotor gating deficits observed in a majority of schizophrenic patients. To study the potential involvement of the glycinergic neurotransmission in such deficits, we investigated the capacity of glycine (an obligatory N-methyl-D-aspartate [NMDA] receptor co-agonist) and ORG 24598 (a selective glycine transporter 1 inhibitor) to reverse NVH lesion-induced PPI deficits in rats. METHODS Ibotenic acid was injected bilaterally into the ventral hippocampus of 7-day-old pups. Prepulse inhibition of the startle reflex was measured at adulthood. RESULTS Glycine (.8 and 1.6 g/kg IP) and ORG 24598 (10 mg/kg IP) fully and partially reversed lesion-induced PPI deficits, respectively. CONCLUSIONS These findings confirm that an impaired glutamatergic neurotransmission may be responsible for PPI deficits exhibited by NVH-lesioned rats and support the hypoglutamatergic hypothesis of schizophrenia. They also suggest that drugs acting either directly at the NMDA receptor glycine site or indirectly on the glycine transporter 1 could offer promising targets for the development of novel therapies for schizophrenia.
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Daenen EWPM, Wolterink G, Van Der Heyden JA, Kruse CG, Van Ree JM. Neonatal lesions in the amygdala or ventral hippocampus disrupt prepulse inhibition of the acoustic startle response; implications for an animal model of neurodevelopmental disorders like schizophrenia. Eur Neuropsychopharmacol 2003; 13:187-97. [PMID: 12729945 DOI: 10.1016/s0924-977x(03)00007-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Prepulse inhibition of the acoustic startle response is a behavioural tool applied to assess sensorimotor gating processes in humans and rats. Schizophrenic patients show deficits in prepulse inhibition of the acoustic startle response. The animal model of neurodevelopmental disorders such as schizophrenia, as purported in earlier reports and the present study, is based on the assumption that damage to brain structures early in life (on day 7) disrupts brain maturation of structures connected to the damaged areas, measurable by behavioural changes, whereas similar damage later in life (on day 21) does not result in these behavioural changes. Locomotor activity, the acoustic startle response and its prepulse inhibition were investigated in adult rats lesioned in the amygdala or ventral hippocampus on day 7 or 21 of life. The acoustic startle response was increased in animals lesioned in the amygdala on day 7 or 21 of life, but not in animals lesioned in the ventral hippocampus. Prepulse inhibition was impaired and locomotor activity enhanced in animals lesioned in the amygdala or ventral hippocampus on day 7, but not in animals lesioned in these structures on day 21 of life. The results on the acoustic startle response are suggestive of amygdaloid influences on modulation of the acoustic startle response. The effects of early postnatal lesions on prepulse inhibition and locomotor activity are in support of the animal model of neurodevelopmental disorders like schizophrenia.
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Affiliation(s)
- Elisabeth W P M Daenen
- Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Department of Pharmacology and Anatomy, P.O. Box 85060, 3508 AB Utrecht, The Netherlands
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Vyssotski AL, Dell'Omo G, Poletaeva II, Vyssotsk DL, Minichiello L, Klein R, Wolfer DP, Lipp HP. Long-term monitoring of hippocampus-dependent behavior in naturalistic settings: mutant mice lacking neurotrophin receptor TrkB in the forebrain show spatial learning but impaired behavioral flexibility. Hippocampus 2002; 12:27-38. [PMID: 11918285 DOI: 10.1002/hipo.10002] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Previous behavioral studies (Minichiello et al., Neuron 1999;24:401-414) showed that mice deficient for the TrkB receptor in the forebrain were unable to learn a swimming navigation task with an invisible platform and were severely impaired in finding a visible platform in the same setup. Likewise, additional behavioral deficits suggested a malfunction of the hippocampus and proximally connected forebrain structures. In order to discriminate whether the behavioral impairment was caused either by deficits in spatial memory and learning, or alternatively by loss of behavioral flexibility, 8 trkB mutant, 13 wild-type, and 22 heterozygous mice were implanted with transponders and released for 21 days into a large outdoor pen (10 x 10 m). The enclosure contained 2 shelters and 8 computer-controlled feeder boxes, delivering food portions for every mouse only during their first visit. Every third day, mice received food ad libitum inside the shelters. All mice learned to patrol the boxes correctly within a few days. However, significant differences emerged during those days with free food available. Wild-type mice remained inside the shelters, while all homozygous mutants continued to patrol the boxes in their habitual way, the heterozygous mutants showing intermediate scores. These and previous data suggest that one of the natural functions of the mouse hippocampus is to comediate behavioral flexibility, and that TrkB receptors might play an essential role in maintaining the neuronal short-term plasticity necessary for this capacity.
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Affiliation(s)
- Alexei L Vyssotski
- Division of Neuroanatomy and Behavior and Neuroscience Center, Institute of Anatomy, University of Zürich, Switzerland
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Daenen EW, Van der Heyden JA, Kruse CG, Wolterink G, Van Ree JM. Adaptation and habituation to an open field and responses to various stressful events in animals with neonatal lesions in the amygdala or ventral hippocampus. Brain Res 2001; 918:153-65. [PMID: 11684053 DOI: 10.1016/s0006-8993(01)02987-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A rat model of neurodevelopmental psychopathological disorders, designed to determine neurodevelopmental deficits following damage to the brain early in life, was used to investigate behavioural changes in adaptation and habituation to an open field and responses to different kinds of stressful events. Animals with bilateral ibotenic acid lesions in the amygdala or ventral hippocampus on day 7 or 21 of life were compared to sham-operated animals. According to the model it was assumed that behavioural changes in animals lesioned on day 7, but not in animals lesioned on day 21 of life, were caused by maldevelopment of one or more structures connected to the damaged area. Animals lesioned in the amygdala or ventral hippocampus on day 7, but not animals lesioned in these structures on day 21 of life, displayed decreased (within-session) adaptation and (between-session) habituation to the open field and a decrease in immobility in the forced swim test, whereas only animals lesioned in the amygdala displayed enhanced general activity. These results were indicative of neurodevelopmental deficits. No changes in stress-induced hyperthermia were found, while animals lesioned in the amygdala both on day 7 or 21 of life exhibited decreased conditioned ultrasonic vocalizations. These latter results suggest that the amygdala is implicated in the conditioned stress-induced response. The contribution of the present findings to the animal model of neurodevelopmental disorders like schizophrenia and possible brain structures and neurotransmitter systems involved in the neurodevelopmental deficits are discussed.
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Affiliation(s)
- E W Daenen
- Division of Pharmacology and Anatomy, University Medical Center Utrecht, Rudolf Magnus Institute for Neurosciences, P.O. Box 85060, 3508 AB Utrecht, The Netherlands
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Broersen LM. Attentional processes and learning and memory in rats: the prefrontal cortex and hippocampus compared. PROGRESS IN BRAIN RESEARCH 2001; 126:79-94. [PMID: 11105641 DOI: 10.1016/s0079-6123(00)26008-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- L M Broersen
- Netherlands Institute for Brain Research, Amsterdam, The Netherlands.
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Minichiello L, Korte M, Wolfer D, Kühn R, Unsicker K, Cestari V, Rossi-Arnaud C, Lipp HP, Bonhoeffer T, Klein R. Essential role for TrkB receptors in hippocampus-mediated learning. Neuron 1999; 24:401-14. [PMID: 10571233 DOI: 10.1016/s0896-6273(00)80853-3] [Citation(s) in RCA: 619] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) and its receptor TrkB regulate both short-term synaptic functions and long-term potentiation (LTP) of brain synapses, raising the possibility that BDNF/TrkB may be involved in cognitive functions. We have generated conditionally gene targeted mice in which the knockout of the trkB gene is restricted to the forebrain and occurs only during postnatal development. Adult mutant mice show increasingly impaired learning behavior or inappropriate coping responses when facing complex and/or stressful learning paradigms but succeed in simple passive avoidance learning. Homozygous mutants show impaired LTP at CA1 hippocampal synapses. Interestingly, heterozygotes show a partial but substantial reduction of LTP but appear behaviorally normal. Thus, CA1 LTP may need to be reduced below a certain threshold before behavioral defects become apparent.
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Affiliation(s)
- L Minichiello
- European Molecular Biology Laboratory, Heidelberg, Germany
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11
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Abstract
Transmitters that are primarily or secondarily involved in the pathogenesis of schizophrenia have been extensively studied for many years. This review will focus on the transmitter systems that are known to be directly or indirectly involved in the mode of action of the novel atypical antipsychotics and clozapine, i.e. the dopaminergic, serotonergic and glutamatergic systems. The consequences of transmitter dysfunction for perception and for the ability of the individual to adapt to a constantly changing environment are discussed, and a hypothesis that can explain how a primary cortical defect will progressively involve secondary transmitter dysfunction and spontaneous dopaminergic sensitization is proposed. According to the suggested hypothesis for the pathogenesis of development of schizophrenic symptoms, pharmacological treatment strategies should focus on flexible as opposed to rigid modulation of sensorimotor gating. The hypothetical effects of serotonergic and dopaminergic interactions on sensorimotor gating are illustrated, and the implications of the broader receptor profile of atypical antipsychotics for the reduced capacity to induce extrapyramidal side-effects and the supposedly superior effect on cognitive dysfunction and negative symptoms are discussed.
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Affiliation(s)
- B Y Glenthøj
- Department of Psychiatry, University Hospital Bispebjerg, Copenhagen, Denmark
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Baca SM, Lipska BK, Egan MF, Bachus SE, Ferguson JN, Hyde TM. Effects of prefrontal cortical lesions on neuropeptide and dopamine receptor gene expression in the striatum-accumbens complex. Brain Res 1998; 797:55-64. [PMID: 9630515 DOI: 10.1016/s0006-8993(98)00343-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the rat, neurochemical, behavioral, and anatomical investigations suggest that medial prefrontal cortical input modulates the activity of the basal ganglia. To understand how prefrontal dysfunction might alter striatal-accumbens function, in situ hybridization histochemistry with S35-labeled oligonucleotide probes was used to assess changes in striatal-accumbens gene expression following bilateral excitotoxic ibotenic acid (IA) lesions of the rat medial prefrontal cortex. Quantitative densitometry was used to measure changes in mRNA levels for preproenkephalin A (ENK), D1 dopamine receptor, protachykinin (SubP), glutamic acid decarboxylase (GAD65), and D2 dopamine receptor. No differences were found between sham and lesion groups for ENK, D1, SubP, or GAD65 mRNA levels in the striatum or nucleus accumbens (NAC). D2 receptor mRNA levels were, however, significantly higher in the dorsomedial striatum and in the core area of the NAC of the lesioned rats. Although the functional significance of increased D2 mRNA is unclear, these findings demonstrate that glutamate mPFC projections modulate gene expression in relatively regionally-localized subcortical neuronal populations.
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Affiliation(s)
- S M Baca
- Clinical Brain Disorders Branch, Intramural Research Program, National Institute of Mental Health, Neuroscience Center, St. Elizabeths Hospital, Washington, DC 20032, USA
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Handa RJ, Hejna GM, Lorens SA. Androgen inhibits neurotransmitter turnover in the medial prefrontal cortex of the rat following exposure to a novel environment. Brain Res 1997; 751:131-8. [PMID: 9098576 DOI: 10.1016/s0006-8993(96)01394-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Previous studies have demonstrated that gonadal steroid hormones affect the neuroendocrine response to a novel environment and other stressors. Introduction to a novel environment also increases neurotransmitter turnover in the medial prefrontal cortex (MPFC). In this study, we examined the possibility that gonadal steroid hormones could similarly modulate the neurotransmitter response to a novel environment in the MPFC of the male rat. Male Fischer 344 rats at 3 months of age were gonadectomized (GDX'd) and implanted with Silastic capsules containing dihydrotestosterone propionate (DHTP, a non-aromatizable form of androgen), 17 beta-estradiol (E), or placebo. Control animals were left intact. Each of these groups was further divided into a group introduced to a novel environment or a home cage control group. Animals exposed to a novel environment were killed after spending 20 min in a novel open field, whereas control animals were killed immediately upon removal from their home cage. Using high performance liquid chromatography, the MPFC was assayed for tissue levels of dopamine (DA) and its metabolites, 3,4-dihydroxyphenylalanine (DOPAC) and homovanillic acid (HVA); norepinephrine (NE) and its metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG); or serotonin (5-HT) and its metabolite 5-hydroxyindole acetic acid (5-HIAA). The introduction to a novel environment caused significant increases in turnover of all three neurochemicals examined as estimated by metabolite/precursor ratios. These increases were characterized by increases in DOPAC, HVA, MHPG and 5-HIAA coupled with decreases in DA, NE and 5-HT. There was no effect of GDX on neurotransmitter turnover, however, treatment of GDX animals with DHTP prevented the open field induced increase in DOPAC/DA, MHPG/NE, and 5-HIAA/5-HT ratio. Treatment of GDX animals with estrogen had the opposite effect of DHTP, DOPAC/DA and MHPG/NE ratios increased to a greater level following the introduction to a novel environment than in GDX or intact animals. Examination of behavior in the open field showed significant decreases in activity in the DHTP-treated group but not in any other behavioral parameter (rears, nose pokes). Since the non-aromatizable androgen, DHTP, is presumably acting via androgen receptors, and E is presumably acting via estrogen receptors, these data suggest that, in the MPFC of male rats, androgen and estrogen receptors act in an opposing fashion to modify neurotransmitter turnover. This suggests that local changes in the relative levels of androgen and estrogen can have profound effects on the neurobiological response of the medial prefrontal cortex to stimuli.
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Affiliation(s)
- R J Handa
- Department of Cell Biology, Loyola University, Chicago, Stritch School of Medicine, Maywood, IL 60153, USA.
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Glenthøj BY, Hemmingsen R. Dopaminergic sensitization: implications for the pathogenesis of schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 1997; 21:23-46. [PMID: 9075257 DOI: 10.1016/s0278-5846(96)00158-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
1. Which transmitters are primarily or secondarily involved in the pathogenesis of schizophrenia has been extensively studied during the last years. This review concentrates on the two systems, that most constantly have been found dysfunctioning in patients; that are the dopaminergic and glutamatergic systems. 2. Numerous neuropathological defects have been found in schizophrenia, but it is as yet unknown which changes are causative and which reflect maladaptive reactions. 3. All findings, however, involve the cortico-striato-thalamo-cortical circuits, which are central for attention and information processing. 4. The article focuses on the consequence of transmitter dysfunction for perception and for the ability of the individual to adapt to a constantly changing environment. Both clinical and experimental studies point to a primary/early cortical defect involving the glutamatergic system, and to a later developed intermittent hyperactivity of the dopaminergic system superimposed on a basal hypodopaminergic state. 5. The authors have previously demonstrated, how it is possible to potentiate mesolimbic dopaminergic activity by intermittent electrical stimulations of the cells in the ventral tegmental area, and that influence on the central mesolimbic dopamine cells is essential for the strengthened neuroplastic response. A changed neuroplastic response to environmental stimulation due to dopaminergic sensitization can explain how an episodic, subcortical hyperactivity can act on a basic glutamatergic and dopaminergic hypofunction to produce psychotic symptoms. Based on our own and others clinical and experimental findings, the "filter" hypothesis for schizophrenia and the state-dependence of schizophrenic symptoms, the authors present a hypothesis for spontaneous mesolimbic dopaminergic sensitization and progressive evolution of psychosis.
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Affiliation(s)
- B Y Glenthøj
- Department of Psychiatry, Bispebjerg Hospital, University of Copenhagen, Denmark
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Enhanced amphetamine sensitivity and increased expression of dopamine D2 receptors in postpubertal rats after neonatal excitotoxic lesions of the medial prefrontal cortex. J Neurosci 1996. [PMID: 8929443 DOI: 10.1523/jneurosci.16-22-07366.1996] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Functional and structural abnormalities in the medial prefrontal cortex (MPFC) and overactive dopamine (DA) neurotransmission are thought to be the key pathologies in schizophrenia. To understand the role of MPFC in the pre- and postpubertal development of the subcortical DA system, the effects of neonatal [postnatal day 7 (PD7)] MPFC excitotoxic lesions on locomotor behaviors and the expression of DA receptor subtypes and DA transporter were investigated in Sprague Dawley rats at PD35 and PD56, respectively. No significant differences in the novelty of d-amphetamine-induced locomotion were observed between sham-operated and ibotenic acid-lesioned rats at PD35. Postpubertally (at PD56), however, the locomotor activity of lesioned rats in the novel environment and after d-amphetamine administration was enhanced significantly compared with controls. The expressions of DA D1, D2, D3, and D4 receptors and DA transporter were then estimated in MPFC-lesioned and sham-operated rats at PD59 and PD60. The levels of DA D2 receptors, measured using [3H]-YM-09151-2 binding, and its mRNA by in situ hybridization, were observed to be significantly increased at PD60 in striatal and limbic areas of lesioned rats. Levels of other DA receptor subtypes were not significantly affected at any time points. Lesioned rats at PD39 show a small increase in DA transporter level in the shell of nucleus accumbens; however, this effect seems to wear off at PD60. The data suggest that neonatal MPFC lesions may alter the functional development and maturation of mesolimbic/nigrostriatal DA systems in that neonatally lesioned rats grow into a behavioral/neurochemical deficit.
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Lipska BK, Swerdlow NR, Geyer MA, Jaskiw GE, Braff DL, Weinberger DR. Neonatal excitotoxic hippocampal damage in rats causes post-pubertal changes in prepulse inhibition of startle and its disruption by apomorphine. Psychopharmacology (Berl) 1995; 122:35-43. [PMID: 8711062 DOI: 10.1007/bf02246439] [Citation(s) in RCA: 248] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Neonatal excitotoxic hippocampal damage in the rat results in postpubertal onset of a variety of abnormal behaviors related to excessive dopaminergic transmission in the mesolimbic/nigrostriatal system, and thus may be considered an animal model of some aspects of schizophrenia. Because sensorimotor gating is impaired in adult patients with schizophrenia and in rats with experimentally induced mesolimbic dopamine hyperactivity, the present experiments investigated the effects of neonatal (postnatal day 7, PD7) ibotenic acid (3 micrograms) lesions of the ventral hippocampus (VH) on the amplitude and prepulse inhibition (PPI) of acoustic startle in prepubertal (PD35) and postpubertal (PD56) rats. Startle was elicited using 105 and 118-dB pulses alone or preceded by 4, 8, or 16 dB above-background prepulses in rats treated with vehicle or apomorphine (APO; 0.025 or 0.1 mg/kg SC). At PD35, PPI in VH-lesioned rats did not differ significantly from these measures in sham operated rats. Apomorphine significantly increased startle amplitude and reduced PPI in both sham operated and VH-lesioned rats at PD35. At PD56, startle amplitude in VH-lesioned rats was not significantly different from controls, but PPI was reduced significantly compared to controls. Ventral hippocampus lesioned rats also exhibited an exaggerated reduction in PPI after treatment with APO. These findings provide further evidence of postpubertal impairments that may be related to increased mesolimbic dopamine transmission and receptor sensitivity in rats with neonatal hippocampal damage, and provide further support for the fidelity of this animal model of schizophrenia.
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Affiliation(s)
- B K Lipska
- Clinical Brain Disorders Branch, National Institute of Mental Health, NIH, Washington, DC 20032, USA
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Lipska BK, Jaskiw GE, Braun AR, Weinberger DR. Prefrontal cortical and hippocampal modulation of haloperidol-induced catalepsy and apomorphine-induced stereotypic behaviors in the rat. Biol Psychiatry 1995; 38:255-62. [PMID: 8547448 DOI: 10.1016/0006-3223(94)00261-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Effects of prefrontal cortical or hippocampal excitotoxic lesions on behavioral parameters related to dopaminergic transmission in the basal ganglia were investigated in the rat. We examined haloperidol-induced catalepsy and apomorphine-induced stereotypic behaviors after ibotenic acid lesions of the medial prefrontal cortex (MPFC), dorsal (DH), or ventral hippocampus (VH) in adult rats. Haloperidol-induced (1 mg/kg) catalepsy was decreased in rats with either MPFC or VH but not DH lesions. While both DH and VH lesioned animals demonstrated a reduction in apomorphine-induced (0.75 mg/kg) stereotypic behaviors, the VH lesioned animals also showed an enhancement of locomotor activity. MPFC lesioned rats tended towards potentiation of stereotypic behaviors and reduced locomotion after apomorphine administration. These data indicate that loss of prefrontal cortical or hippocampal modulation leads to an enhancement of DA transmission within the basal ganglia, though the pattern of augmentation depends on the area lesioned.
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Affiliation(s)
- B K Lipska
- National Institute of Mental Health, Clinical Brain Disorders Branch, Washington, DC, USA
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Weinberger DR, Lipska BK. Cortical maldevelopment, anti-psychotic drugs, and schizophrenia: a search for common ground. Schizophr Res 1995; 16:87-110. [PMID: 7577773 DOI: 10.1016/0920-9964(95)00013-c] [Citation(s) in RCA: 334] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Two of the favorite hypotheses of schizophrenia research-maldevelopment of cerebral cortex and malfunction of brain dopamine systems-have often seemed difficult to reconcile. This article reviews recent research that suggests a heuristically useful reconciliation centered on the functional neuroanatomical concept of prefrontal-temporolimbic cortical connectivity. Anatomical findings from postmortem studies and neuropsychological and neuroimaging studies of brain function in patients with schizophrenia have implicated a developmental 'dysconnection' of temporolimbic-prefrontal cortices. The possibility that such dysconnection can account for the principal phenomenology of the illness, including its delayed onset and its treatment, is suggested by neurologic disease analogies such as metachromatic leukodystrophy and by recent studies in animals with developmental cortical lesions. Studies mapping neuronal gene expression indicate that all antipsychotic drugs modulate DNA transcription in a region of the nucleus accumbens that receives converging inputs from prefrontal and temporolimbic cortices, suggesting that indirect compensation for dysfunctional communication between prefrontal and temporolimbic cortices is a therapeutic mechanism of these drugs. Treatments aimed at direct cortical compensation may be more effective.
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Affiliation(s)
- D R Weinberger
- Clinical Brain Disorders Branch, National Institute of Mental Health, NIH, Neurosciences Center at Saint Elizabeths, Washington, DC 20032, USA
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