Related Experiment Video
Updated: Jan 24, 2026

Intratracheal Inoculation of Fischer 344 Rats with Francisella tularensis
Published on: September 30, 2017
Pair Housing Alters Delay Discounting in Lewis and Fischer 344 Rats
Marissa Turturici1, Jenny E Ozga1, Karen G Anderson1
1Department of Psychology, West Virginia University, P.O. Box 6040,Morgantown, WV 26506, USA.
Abstract:
Impulsive choice underlies several psychological disorders and can be assessed in laboratory rats using delay-discounting tasks, in which choice is for either one food pellet immediately or three food pellets after a delay. Choice for the smaller, immediate reinforcer is considered the impulsive choice. Lewis (LEW) and Fischer 344 (F344) rats differ in the number of impulsive choices made during this task when singly housed, with LEW choosing the impulsive option more often. Due to increasing recommendations to provide environmental enrichment as a component of animal-husbandry practices, a systematic replication of two previous studies was conducted using pair-housed LEW and F344. Delay discounting was assessed with pair-housed LEW and F344 and compared to previous data from singly housed LEW and F344 collected from the same laboratory. Results showed that differences in impulsive choice between the two strains were attenuated with pair housing. The main result driving this change appears to be an increase in impulsive choice in pair-housed F344 relative to singly housed F344.
Related Concept Videos
Lewis Acids and Bases
A coordinate covalent bond (or dative bond) occurs when one of the atoms in the bond provides both bonding electrons. For example, a coordinate covalent bond occurs when a water molecule combines with a hydrogen ion to form a hydronium ion. A coordinate covalent bond also results when...
Lewis Acids and Bases
Covalent Bonding and Lewis Structures
Lewis Symbols and the Octet Rule
Lewis Structures of Molecular Compounds and Polyatomic Ions
Fischer Projections

