Biomedical subjects

Neri Kafkafi

Publications and source records attributed to Neri Kafkafi.

5 recordsLinked to original sources

PubMed2004

The dynamics of spatial behavior: how can robust smoothing techniques help?

A variety of setups and paradigms are used in the neurosciences for automatically tracking the location of an animal in an experiment and for extracting features of interest out of it. Many of these features, however, are critically sensitive to the unavoidable noise and artifacts of tracking. Here, we examine the relevant properties of several smoothing methods and suggest a combination of methods for retrieving locations and velocities and recognizing arrests from time series of coordinates of an animal's center of gravity. We accomplish these by using robust nonparametric methods, such as Running Median (RM) and locally weighted regression methods. The smoothed data may, subsequently, be segmented to obtain discrete behavioral units with proven ethological relevance. New parameters such as the length, duration, maximal speed, and acceleration of these units provide a wealth of measures for, e.g., mouse behavioral phenotyping, studies on spatial orientation in vertebrates and invertebrates, and studies on rodent hippocampal function. This methodology may have implications for many tests of spatial behavior.

Algorithms↗

PubMed2003

Darting behavior: a quantitative movement pattern designed for discrimination and replicability in mouse locomotor behavior.

In the open-field behavior of rodents, Software for Exploring Exploration (SEE) can be used for an explicit design of behavioral endpoints with high genotype discrimination and replicability across laboratories. This ability is demonstrated here in the development of a measure for darting behavior. The behavior of two common mouse inbred strains, C57BL/6J (B6) and DBA/2J (D2), was analyzed across three different laboratories, and under the effect of cocaine or amphetamine. "Darting" was defined as having higher acceleration during progression segments while moving less during stops. D2 mice darted significantly more than B6 mice in each laboratory, despite being significantly less active. These differences were maintained following cocaine administration (up to 20mg/kg) and only slightly altered by amphetamine (up to 5mg/kg) despite a several fold increase in activity. The replicability of darting behavior was confirmed in additional experiments distinct from those used for its design. The strategy leading to the darting measure may be used to develop additional discriminative and replicable endpoints of open-field behavior.

Amphetamine↗

PubMed2003

SEE locomotor behavior test discriminates C57BL/6J and DBA/2J mouse inbred strains across laboratories and protocol conditions.

Conventional tests of behavioral phenotyping frequently have difficulties differentiating certain genotypes and replicating these differences across laboratories and protocol conditions. This study explores the hypothesis that automated tests can be designed to quantify ethologically relevant behavior patterns that more readily characterize heritable and replicable phenotypes. It used SEE (Strategy for the Exploration of Exploration) to phenotype the locomotor behavior of the C57BL/6 and DBA/2 mouse inbred strains across 3 laboratories. The 2 genotypes differed in 15 different measures of behavior, none of which had a significant genotype-laboratory interaction. Within the same laboratory, most of these differences were replicated in additional experiments despite the test photoperiod phase being changed and saline being injected. Results suggest that well-designed tests may considerably enhance replicability across laboratories.

Animals↗

PubMed2003

Extending SEE for large-scale phenotyping of mouse open-field behavior.

SEE (Software for the Exploration of Exploration) is a visualization and analysis tool designed for the study of open-field behavior in rodents. In this paper, I present new extensions of SEE that were designed to facilitate its use for mouse behavioral phenotyping and, especially, for the problems of discrimination of genotypes and the replication of results across laboratories and experimental conditions. These extensions were specifically designed to promote a new approach in behavioral phenotyping, reminiscent of the approach that has been successfully employed in bioinformatics during recent years. The path coordinates of all animals from many experiments are stored in a database. SEE can be used to query, visualize, and analyze any desirable subsection of this database and to design new measures (endpoints) with increasingly better discriminative power and replicability. The use of the new extensions is demonstrated here in the analysis of results from several experiments and laboratories, with an emphasis on this approach.

Animals↗

PubMed2002

Repeated maternal separation does not alter sucrose-reinforced and open-field behaviors.

Repeated separation of rat pups from their mothers has been reported to increase behavioral fearfulness and hypothalamic-pituitary-adrenal (HPA) response to stress. Recently, it was suggested that it might also alter behavioral responses to natural and drug rewards. Here, we studied whether maternal separation (MS) would alter behavioral responses to a sucrose reward. We also tested whether MS would alter behavioral responses in an open-field test using a novel method of analysis [Software for the Exploration of Exploration (SEE)]. Long-Evans rat pups were exposed to either 180 min of MS, 15 min of separation [early handling (EH)] or left undisturbed [nonhandled (NH)] from postnatal day (PND) 3 to 14. The adult male offspring were tested for sucrose solution preference using a two-bottle free-choice test, operant response for sucrose under fixed ratio and progressive ratio (PR) schedules of reinforcement and response to a novel environment (open-field test). MS had no effect on sucrose preference or operant responding for sucrose reward. In the open-field test, NH rats showed a brief decrease in locomotor response, but MS rats did not differ from the NH and EH groups in the other behavioral measures. Thus, under the conditions of the present study, MS did not appear to alter reward-related processes and also had a minimal effect on open-field behavior.

Animals↗