A glutamatergic deficiency model of schizophrenia

1999 ◽  
Vol 174 (S37) ◽  
pp. 2-6 ◽  
Author(s):  
A. Carlsson ◽  
L. O. Hansson ◽  
N. Waters ◽  
M. L. Carlsson
Keyword(s):  
Cerebral Cortex ◽  
Sensory Input ◽  
Inhibitory Effect ◽  
Sensory Overload

Although the presence of hyperdopaminergia has been demonstrated in the brains of people with schizophrenia, at least in some circumstances, other neurotransmitters are important in this disorder, and a glutamatergic deficiency model of schizophrenia is proposed. It is suggested that the amount of sensory input allowed to reach the cerebral cortex is restricted by an inhibitory effect of the striatal complexes on the thalamus, thereby protecting it from being overwhelmed. Several strands of evidence are presented to support the concept that a weakened glutamatergic tone increases the risk of sensory overload and of exaggerated responses in the monoaminergic systems that could result in psychosis.

Inhibitory Effect of Novel Pyrimidines on ATP and ADP Hydrolysis in Synaptosomes from Rat Cerebral Cortex

2003 ◽  
Vol 16 (11) ◽  
pp. 1433-1439 ◽  
Author(s):  
Sirlene R. Cechin ◽  
Maria Rosa C. Schetinger ◽  
Nilo Zanatta ◽  
Claudia C. Madruga ◽  
Iraci L. Pacholski ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Inhibitory Effect ◽  
Rat Cerebral Cortex

scholarly journals Monoaminergic Involvement in Decreased Locomotor Activity of Mice Treated with α and β-amyrin from Protium heptaphyllum

2018 ◽  
Vol 13 (8) ◽  
pp. 1934578X1801300
Author(s):  
Gislei F. Aragão ◽  
Manoel O. de Moraes Filho ◽  
Paulo N. Bandeira ◽  
Antônio P. Frota Junior ◽  
Yasmin Ingrid S. Oliveira de ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Locomotor Activity ◽  
Open Field ◽  
Field Test ◽  
High Performance ◽  
Open Field Test ◽  
Inhibitory Effect ◽  
Pharmacological Agents ◽  
Tissue Homogenates ◽  
The Central Nervous System

A triterpenic mixture of α and β-amyrin (AMY) extracted from Protium heptaphyllum has demonstrated several pharmacological effects, including activity in the central nervous system. The aim of this study was to evaluate the effect of AMY administration on locomotor activity of mice by the open field test using some monoaminergic agonists and antagonists and the cerebral cortex levels of monoamines and their major metabolites by high-performance liquid chromatography. Mice were treated acutely with AMY at doses of 1, 2.5 and 5 mg/kg given intraperitoneally and with the pharmacological agents and placed in open field test, then the animals were sacrificed and the cerebral cortex extracted, and monoamines were assayed in tissue homogenates. AMY at 1, 2.5 and 5 mg/kg decreased locomotor activity of animals by 25, 31 and 39%, respectively in the open field test. Ondasentron, doxazosin, oxymetazoline and clonidine did not reverse the inhibitory effect of 5 mg/kg AMY. Venlafaxine and yohimbine reversed the inhibitory effect of 5 mg AMY. In the cortex, the 5-HT and 5-HIAA were significantly reduced by the administration of AMY. NE and HVA were also reduced with 2.5 and 5 mg/kg AMY, while Dopamine and DOPAC were not increased with AMY. In conclusion, AMY decreased locomotor activity of animals accompanied by a decrease in 5-HT and NE levels in the cerebral cortex, this locomotor effect is reversed by drug that blocker the α-2-adrenoreceptor.

scholarly journals Inhibitory Effect of Several Nitric Oxide-Generating Compounds on Purified Na+,K+-ATPase Activity from Porcine Cerebral Cortex

2002 ◽  
Vol 68 (3) ◽  
pp. 1312-1318 ◽  
Author(s):  
Tomoaki Sato ◽  
Yoshiko Kamata ◽  
Masahiro Irifune ◽  
Takashige Nishikawa
Keyword(s):  
Nitric Oxide ◽  
Cerebral Cortex ◽  
Atpase Activity ◽  
Inhibitory Effect

scholarly journals Adjudicating Between Local and Global Architectures of Predictive Processing in the Subcortical Auditory Pathway

2021 ◽  
Vol 15 ◽  
Author(s):  
Alejandro Tabas ◽  
Katharina von Kriegstein
Keyword(s):  
Cerebral Cortex ◽  
Prediction Error ◽  
Sensory Input ◽  
Generative Models ◽  
Predictive Processing ◽  
Auditory Modality ◽  
Processing Stage ◽  
Information Encoding ◽  
Global View ◽  
Local View

Predictive processing, a leading theoretical framework for sensory processing, suggests that the brain constantly generates predictions on the sensory world and that perception emerges from the comparison between these predictions and the actual sensory input. This requires two distinct neural elements: generative units, which encode the model of the sensory world; and prediction error units, which compare these predictions against the sensory input. Although predictive processing is generally portrayed as a theory of cerebral cortex function, animal and human studies over the last decade have robustly shown the ubiquitous presence of prediction error responses in several nuclei of the auditory, somatosensory, and visual subcortical pathways. In the auditory modality, prediction error is typically elicited using so-called oddball paradigms, where sequences of repeated pure tones with the same pitch are at unpredictable intervals substituted by a tone of deviant frequency. Repeated sounds become predictable promptly and elicit decreasing prediction error; deviant tones break these predictions and elicit large prediction errors. The simplicity of the rules inducing predictability make oddball paradigms agnostic about the origin of the predictions. Here, we introduce two possible models of the organizational topology of the predictive processing auditory network: (1) the global view, that assumes that predictions on the sensory input are generated at high-order levels of the cerebral cortex and transmitted in a cascade of generative models to the subcortical sensory pathways; and (2) the local view, that assumes that independent local models, computed using local information, are used to perform predictions at each processing stage. In the global view information encoding is optimized globally but biases sensory representations along the entire brain according to the subjective views of the observer. The local view results in a diminished coding efficiency, but guarantees in return a robust encoding of the features of sensory input at each processing stage. Although most experimental results to-date are ambiguous in this respect, recent evidence favors the global model.

scholarly journals A FRAMEWORK FOR INTERNEURAL DYNAMICS IN A CEREBRAL CORTEX CENTER

2013 ◽  
Vol 23 (09) ◽  
pp. 1350151
Author(s):  
ABRAHAM BOYARSKY ◽  
ZHENYANG LI ◽  
PAWEŁ GÓRA
Keyword(s):  
Cerebral Cortex ◽  
Steady State ◽  
Probability Measure ◽  
Discrete Time ◽  
Sensory Input ◽  
Invariant Probability Measure ◽  
Chaotic State ◽  
Time Map

We model the innervation dynamics of interneurons in a cerebral cortex center A between the time of initial sensory input and acquisition of a sustained steady state. The model assumes that interneurons in A are heavily interconnected allowing synchronization. This invites modeling the dynamics by means of a discrete time map. The model takes into account the influence of excitatory and inhibitory cells and reflects the architecture of synapses along the axons. The acquisition of a sustained chaotic state is characterized by means of a natural invariant probability measure. The time to attain this probability measure can be estimated.

scholarly journals Inhibitory effect of nociceptin on [3 H]-5-HT release from rat cerebral cortex slices

1999 ◽  
Vol 128 (1) ◽  
pp. 119-123 ◽  
Author(s):  
Anna Siniscalchi ◽  
Donata Rodi ◽  
Lorenzo Beani ◽  
Clementina Bianchi
Keyword(s):  
Cerebral Cortex ◽  
Inhibitory Effect ◽  
Rat Cerebral Cortex ◽  
Cortex Slices

scholarly journals Ouabain Induced Seizures: Site of Production and Response to Anticonvulsants

1978 ◽  
Vol 5 (4) ◽  
pp. 405-411 ◽  
Author(s):  
Duncan L.W. Davidson ◽  
Yasuo Tsukada ◽  
André Barbeau
Keyword(s):  
Cerebral Cortex ◽  
Reticular Formation ◽  
Dorsal Hippocampus ◽  
Mesencephalic Reticular Formation ◽  
Cerebellar Nuclei ◽  
Inhibitory Effect ◽  
Transport Mechanisms ◽  
Limbic Seizures ◽  
Temporal Lobe Seizures ◽  
Low Volume

SUMMARY:Ouabain, an inhibitor of Na+-K+-ATP'ase, has been administered intraventricularly to rats to study the effect of impairment of membrane transport mechanisms on the genesis of seizures. Running and leaping seizures occur rapidly after injection oj ouabain in a low volume (10μl) when the maximal uptake of ouabain (39.8%) is in the hippocampus. Generalized clonic-lonic seizures are induced by higher volume injections (50μl) associated with wider distribution of ouabain, including the cerebellum and brainstem.Ouabain was injected into cerebral cortex, caudate nucleus, dorsal hippocampus, fastigeal nucleus, ventrolateral mesencephalic reticular formation and cerebellar cortex. The cerebellar injections produced both running and leaping and generalized clonic-lonic seizures. It is suggested that this results from decreased inhibitory effect of vermal and paravermal Purkinje cells on intra-cerebellar nuclei, which alters cerebellar influence on the reticular formation and the limbic system.Diphenylhydantoin, phenobarbitone, phenacemide, carbamezepine and clonazepam but not ethosuximide are effective against generalized clonic-lonic seizures, suggesting that this is a model for “grand mat” but not “petit mal” seizure mechanisms. It is furthermore suggested that running and leaping are subcortical, probably limbic, seizures that are most relevant as a model for temporal lobe seizures.

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