Effects of chronic in utero exposure to cocaine on behavioral adaptability in rhesus monkey offspring when examined in adulthood.
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Adaptation, Psychological↗
Biomedical subjects
J J Chelonis
Publications and source records attributed to J J Chelonis.
The effect of variable delays on self-control.
Five pigeons served as subjects in an experiment that examined the effects of variable as opposed to fixed delays on preference in a self-control paradigm (choice between larger, more delayed and smaller, less delayed reinforcers). Nonindependent concurrent variable-interval schedules were used to measure choice. When delays to the larger, more delayed reinforcers were variable as opposed to fixed, the subjects showed an increased preference for that alternative (the self-control alternative). A series of regressions revealed that the hyperbolic decay model and incentive theory provided poor fits to the data, but a modified version of the generalized matching law provided an adequate fit. Together, consistent with a general prediction made by discounting models, the data supported the conclusion that variable delays can increase self-control. However, specific discounting models were not able to explain the present data well.
Journal Article↗
Cocaine decreases self-control in rats: a preliminary report.
Cocaine abuse is often associated with behavior that takes into account short-term, but not long-term consequences. However, there has been no empirical research concerning the effects of cocaine on self-control (choice of a larger, more delayed reinforcer over a smaller, less delayed reinforcer). In the present research, when food-deprived rats repeatedly chose between a larger, more delayed food reinforcer and a smaller, less delayed food reinforcer, chronic intraperitoneal injections of 15 mg/kg cocaine (but not 10 mg/kg fluoxetine) decreased the rats' choices of the larger, more delayed reinforcer. Cocaine can decrease rats' self-control.
Animals↗
Developmental aspects of delayed matching-to-sample task performance in children.
The influence of age, sex, and intelligence (IQ) on performance of a delayed matching-to-sample (DMTS) task, commonly used with animals and adult human subjects to study aspects of short-term memory, was examined for 674 children, 5 to 13 years old. The data suggest that younger children were less accurate at short delays and displayed a greater decrease in accuracy as recall delay increased than older children. Children with lower IQs demonstrated consistent impairment in recall of information when compared to children with higher IQs. No significant differences in task performance were observed between boys and girls. These normative data provide insights into the developmental time course of behaviors thought to serve as metrics of short-term memory. These data will be critical for ongoing and future studies in determining whether specific clinical diagnoses, drug treatments, or other risk factors (e.g., perinatal drug exposure, pregnancy complications, exposure to toxicants) are associated with differences on specific aspects of task performance. The use of tasks that are also applicable to animal models provides great opportunities for the conduct of important comparative studies.
Adolescent↗
Attention deficit/hyperactivity disorder: characteristics, interventions and models.
An epidemiological study of Attention Deficit/Hyperactivity Disorder (ADHD) suggests that the prevalence may be two to three times higher than the figure of 3-5% often cited. In addition, the data suggest that both underdiagnosis and overdiagnosis occur frequently. Rodent animal models of ADHD, like the Spontaneously Hypertensive Rat (SHR) and other rat models such as those with chemical and radiation-induced brain lesions and cerebellar stunting, and the Coloboma mouse model exhibit clear similarities with several aspects of the human disorder and should prove useful in studying specific traits. Operant behavioral tasks that model learning, short-term memory and simple discriminations are sensitive to ADHD and methylphenidate has been shown to normalize ADHD performance in a short-term memory task. Recent findings challenge not only the current postulate that response inhibition is a unique deficit in ADHD, but also the concepts of ADHD and its treatment, which presume intact perceptual abilities. Time perception deficits may account, in part, for the excessive variability in motor response times on speeded reaction time tasks, motor control problems and motor clumsiness associated with ADHD. The Multimodality Treatment Study of ADHD (MTA) provided data suggesting that pharmacological interventions that included systematic and frequent follow-up with parents and teachers, with or without psychosocial interventions, are superior to psychosocial interventions or standard community care alone. Additionally, the MTA was one of the first studies to demonstrate benefits of multimodal and pharmacological interventions lasting longer than 1 year. Imaging studies have demonstrated differences in brain areas in children with ADHD: anterior corpus callosum, right anterior white matter, and cerebellar volumes are all decreased in children with ADHD and there is less brain asymmetry in ADHD subjects. Additionally, functional imaging studies, coupled with pharmacological manipulations, suggest decreased blood flow and energy utilization in prefrontal cortex and striatum and the dysregulation of catecholamine systems in persons with ADHD.
Animals↗
Symposium overview: the use of delayed matching-to-sample procedures in studies of short-term memory in animals and humans.
Behavioral paradigms applicable for use in both human and nonhuman subjects for investigating aspects of working/short-term memory are presented with a view towards exploring their strengths, weaknesses, and utility in a variety of experimental situations. Such procedures can be useful in teasing out specific aspects of mnemonic processes including discrimination, encoding, and retention. Delayed matching-to-position, delayed matching-to-sample (DMTS), and titrating matching-to-sample procedures are highlighted. Additionally, the application of DMTS tasks in preclinical and clinical settings is presented: drug effects on memory processes can be explored preclinically in animal models; normative data have been developed in human populations where they have been used in adults to explore the relationships between mnemonic processes and specific clinical entities such as Parkinsonism, senile dementia of the Alzheimer's type, schizophrenia, and depression. Studies in children indicate that encoding and retention processes improve rapidly in the early years, plateauing prior to puberty. Noninvasive imaging techniques such as positron emission tomography (PET) indicate that activity in specific brain areas is associated with DMTS task performance and may serve to confirm roles for such structures in mnemonic processes.
Animals↗
Operant test battery performance in children: correlation with IQ.
The relationship between intelligence and money-(nickel-)reinforced operant behaviors were compared in 115 six year old children. The Operant Test Battery (OTB) consists of tasks thought to engender responses dependent upon specific brain functions that include motivation, color and position discrimination, learning, short-term memory, and time estimation. OTB endpoints were compared with Full Scale, Verbal and Performance IQ scores. Highly significant correlations were noted between several OTB measures (e.g., color and position discrimination accuracy) and IQ scores, but not in others (e.g., motivation task response rate). The results demonstrate the relevance of these measures as metrics of important brain functions. Additionally, since laboratory animals can readily perform these same tasks, these kinds of behaviors in laboratory animals should be useful in studying the effects of neuroactive/neurotoxic compounds on aspects of cognitive function in animals and in predicting adverse effects of such agents on related brain functions in humans.
Brain↗
The use of timing behaviors in animals and humans to detect drug and/or toxicant effects.
Behavioral paradigms applicable for use in both human and nonhuman subjects for investigating aspects of timing behavior are presented with a view towards exploring their strengths, weaknesses, and utility in a variety of experimental situations. Tri-peak, peak interval, differential reinforcement of low rate responding, and temporal response differentiation procedures are highlighted. In addition, the application of timing tasks in preclinical and clinical settings is discussed: pharmacological manipulations are providing information on the neurotransmitters involved and species differences; normative data for children are being developed; and noninvasive imaging procedures are being employed in adult human subjects to explore the involvement of specific brain areas.
Animals↗