Biomaterial Database

Psychopharmacology of latent inhibition: a neural network approach. 1998

N A Schmajuk, and C V Buhusi, and J A Gray

Department of Psychology: Experimental, Duke University, Durham, North Carolina 27706, USA. nestor@acpub.duke.edu

A neural network model of classical conditioning is applied to the description of some aspects of the psychopharmacology of latent inhibition (LI). According to the model, LI is manifested because preexposure of the conditioned stimulus (CS) reduces Novelty, defined as proportional to the sum of the mismatches between predicted and observed events, thereby reducing attention to the CS and retarding conditioning. In the framework of the model, it is assumed that indirect dopaminergic (DA) agonists (e.g. amphetamine and nicotine) increase, and DA receptor antagonists (e.g. haloperidol and alpha-flupenthixol) decrease, the effect of Novelty on attention. Computer simulations demonstrate that, under these assumptions, the model correctly describes: (1) the impairment of LI by amphetamine when a strong unconditioned stimulus (US) is used, (2) the impairment of LI by amphetamine when a nonsalient CS is used, (3) the impairment of LI by amphetamine administration when a short CS is used, (4) the facilitation of LI by alpha-flupenthixol when a weak US is used, (5) the facilitation of LI by haloperidol when a nonsalient CS is used, (6) the facilitation of LI by haloperidol with a strong US, and (7) the facilitation of LI by haloperidol with extended conditioning.

UI	MeSH Term	Description	Entries
D007266	Inhibition, Psychological	The interference with or prevention of a behavioral or verbal response even though the stimulus for that response is present; in psychoanalysis the unconscious restraining of an instinctual process.	Inhibition (Psychology),Inhibition, Psychology,Psychological Inhibition,Inhibitions (Psychology),Inhibitions, Psychological,Inhibitions, Psychology,Psychological Inhibitions,Psychology Inhibition,Psychology Inhibitions
D009538	Nicotine	Nicotine is highly toxic alkaloid. It is the prototypical agonist at nicotinic cholinergic receptors where it dramatically stimulates neurons and ultimately blocks synaptic transmission. Nicotine is also important medically because of its presence in tobacco smoke.	Nicotine Bitartrate,Nicotine Tartrate
D003198	Computer Simulation	Computer-based representation of physical systems and phenomena such as chemical processes.	Computational Modeling,Computational Modelling,Computer Models,In silico Modeling,In silico Models,In silico Simulation,Models, Computer,Computerized Models,Computer Model,Computer Simulations,Computerized Model,In silico Model,Model, Computer,Model, Computerized,Model, In silico,Modeling, Computational,Modeling, In silico,Modelling, Computational,Simulation, Computer,Simulation, In silico,Simulations, Computer
D003214	Conditioning, Classical	Learning that takes place when a conditioned stimulus is paired with an unconditioned stimulus.	Reflex, Conditioned,Classical Conditioning,Classical Conditionings,Conditioned Reflex,Conditionings, Classical
D003463	Cues	Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond.	Cue
D005475	Flupenthixol	A thioxanthene neuroleptic that, unlike CHLORPROMAZINE, is claimed to have CNS-activating properties. It is used in the treatment of psychoses although not in excited or manic patients. (From Martindale, The Extra Pharmacopoeia, 30th ed, p595)	Emergil,Fluanxol,Flupentixol,alpha-Flupenthixol,cis-Flupenthixol
D006220	Haloperidol	A phenyl-piperidinyl-butyrophenone that is used primarily to treat SCHIZOPHRENIA and other PSYCHOSES. It is also used in schizoaffective disorder, DELUSIONAL DISORDERS, ballism, and TOURETTE SYNDROME (a drug of choice) and occasionally as adjunctive therapy in INTELLECTUAL DISABILITY and the chorea of HUNTINGTON DISEASE. It is a potent antiemetic and is used in the treatment of intractable HICCUPS. (From AMA Drug Evaluations Annual, 1994, p279)	Haldol
D000661	Amphetamine	A powerful central nervous system stimulant and sympathomimetic. Amphetamine has multiple mechanisms of action including blocking uptake of adrenergics and dopamine, stimulation of release of monamines, and inhibiting monoamine oxidase. Amphetamine is also a drug of abuse and a psychotomimetic. The l- and the d,l-forms are included here. The l-form has less central nervous system activity but stronger cardiovascular effects. The d-form is DEXTROAMPHETAMINE.	Desoxynorephedrin,Levoamphetamine,Phenopromin,l-Amphetamine,Amfetamine,Amphetamine Sulfate,Amphetamine Sulfate (2:1),Centramina,Fenamine,Mydrial,Phenamine,Thyramine,levo-Amphetamine,Sulfate, Amphetamine,l Amphetamine,levo Amphetamine
D001288	Attention	Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.	Focus of Attention,Selective Attention,Social Attention,Attention Focus,Attention, Selective,Attention, Social,Selective Attentions
D016571	Neural Networks, Computer	A computer architecture, implementable in either hardware or software, modeled after biological neural networks. Like the biological system in which the processing capability is a result of the interconnection strengths between arrays of nonlinear processing nodes, computerized neural networks, often called perceptrons or multilayer connectionist models, consist of neuron-like units. A homogeneous group of units makes up a layer. These networks are good at pattern recognition. They are adaptive, performing tasks by example, and thus are better for decision-making than are linear learning machines or cluster analysis. They do not require explicit programming.	Computational Neural Networks,Connectionist Models,Models, Neural Network,Neural Network Models,Neural Networks (Computer),Perceptrons,Computational Neural Network,Computer Neural Network,Computer Neural Networks,Connectionist Model,Model, Connectionist,Model, Neural Network,Models, Connectionist,Network Model, Neural,Network Models, Neural,Network, Computational Neural,Network, Computer Neural,Network, Neural (Computer),Networks, Computational Neural,Networks, Computer Neural,Networks, Neural (Computer),Neural Network (Computer),Neural Network Model,Neural Network, Computational,Neural Network, Computer,Neural Networks, Computational,Perceptron