Bidirectional avoidance by mice as a function of CS, US, and apparatus variables

Abstract

Acquisition of two-way avoidance by mice was slower with a light CS than with a buzzer CS, with punishment of intertrial responses than without punishment, and with a short CS-CS interval than with a long CS-CS interval (30 vs. 60 sec). Light-cued avoidance was little affected by shock level (.35-1.5 mA), whereas mice trained with the buzzer CS learned faster at 1.5 mA. Animals required to move away from light or toward light showed comparable rates of acquisition. Other CS, US, and apparatus variables (directionality of cue, maximal shock duration, and presence vs. absence of a central partition in the shuttlebox) interacted in a complex fashion with those already mentioned. This resulted in widely differing performances in what may superficially appear to be different versions of the same task. The differences in mouse and rat responses to some of the variables can contribute to an understanding of the interactions between organismic and test factors and the relative explanatory value of alternative avoidance models.

Infrapyramidal mossy fibers and two-way avoidance learning: developmental modification of hippocampal circuitry and adult behavior of rats and mice

“…Its correlation with the IIP-MF was the first to be discovered, and the genetic aspects of this covariation have been studied extensively (Heimrich et al, 1985;Crusio et al, 1986). Given the difficulties in interpreting 2-way avoidance (Anisman, 1978;Lipp and Schwegler, 1982;Bignami et al, 1985), we refrained from a specific behavioral analysis, and accepted the behavioral scores at a phenomenological level, planning further analysis in case of a positive outcome of the experiment. For testing, we selected strains with superior capacities for 2-way avoidance, since it is known that a transient hyperthyroidism produces an irreversible hyperplasia of the IIP-MF fibers (Lauder andMugnaini, 1977, 1980).…”

Appropriate end points for the characterization of behavioral changes in developmental toxicology.

“…This is why active/passive ("go -no go") avoidance tests can provide an adequate control on such a bias: for a catalogue of caveats, induding motor, sensory, and motivational confounders, see Bignami (43) and Bignami et al (44). As concerns active locomotor avoidance, the most frequently used schedules require that an animal reenter the compartment in which it received punishment shortly before, an act that involves considerable stress; therefore, the assessment of genuine learning capability can be hindered by the development of coping responses, such as unconditioned and conditioned freezing, and by the predominance of strong passive avoidance tendencies that act as a brake on active avoidance responding.…”

“…As concerns active locomotor avoidance, the most frequently used schedules require that an animal reenter the compartment in which it received punishment shortly before, an act that involves considerable stress; therefore, the assessment of genuine learning capability can be hindered by the development of coping responses, such as unconditioned and conditioned freezing, and by the predominance of strong passive avoidance tendencies that act as a brake on active avoidance responding. These phenomena can be attenuated, for example, by appropriate adjusting of intertrial intervals or by reducing shock intensity, which also meets the increasingly rigorous ethical requirements (44).…”

“…Unlike the one-way avoidance task in which one compartment always serves as the safe area and the other as the danger area, in the two-way task (43,44) Adultlike learning of one-way active avoidance in rats is reached by 4 to 5 weeks postnatally (46). Two-way active avoidance fully develops at about the same age (47).…”

Comprehensive Neurotoxicity Assessment

“…Active and passive avoidance tasks have been extensively used in pharmacology for many years to examine drug effects on acquisition learning and memory, and several advantages and disadvantages of these approaches have been discussed previously (54,58). One of the principal drawbacks with the use of these techniques is that they do not allow for the repeated evaluation of changes in memory or learning ability during the course of long-term exposures.…”