Development of vicarious trial-and-error behavior in odor discrimination learning in the rat: relation to hippocampal function?

https://doi.org/10.1016/S0166-4328(96)02247-4Get rights and content

Abstract

Previous work from our laboratory has suggested that hippocampal electrolytic lesions result in a deficit in simultaneous, black-white discrimination learning and reduce the frequency of vicarious trial-and-error (VTE) at a choice-point. VTE is a term Tolman used to describe the rat's conflict-like behavior, moving its head from one stimulus to the other at a choice point, and has been proposed as a major nonspatial feature of hippocampal function in both visual and olfactory discrimination learning. Simultaneous odor discrimination and VTE behavior were examined at three different ages. The results were that 16-day-old pups made fewer VTEs and learned much more slowly than 30- and 60-day-olds, a finding in accord with levels of hippocampal maturity in the rat.

Section snippets

Subjects

The subjects were Holtzman Sprague-Dawley rats of both sexes bred in our laboratory. The three groups of subjects consisted of 16-, 30-, and 60-day-old rats at the beginning of behavioral training, n=10, 15 and 17, respectively. The 30- and 60-day-old rats were weaned on PD 21 and pair housed until deprivation. The youngest group stayed in the litter before deprivation. All subjects were kept on a 14:10 light/dark cycle.

Deprivation

The 16-day-old pups were removed from the litter 24 h before to the start

Results

Although a significant main effects of session, F(5,195)=48.53, P<0.001, indicates that, in general, all subjects improved their performance during simultaneous odor discrimination training, a significant sessions×groups interaction, F(10,195)=10.97, P<0.001, shows that the rate of learning differed among groups. As Fig. 1 illustrates, the 16-day-old pups learned much more slowly than the other two groups; in fact they did not reach the level of reward that the other two groups reached at the

Discussion

In this experiment, 16-day-old pups showed significantly slower learning (Fig. 1) and fewer VTEs (Fig. 2) than older animals. If VTE behavior in the rat reflects developing hippocampal function [1], the present results mirror the fact that the 16-day-old hippocampus is not completely functional. The similarity of learning rate at 30 and at 60 days of age (Fig. 1) suggests a functional similarity at these ages, which matches, perhaps, their approximately equal morphological hippocampal

Acknowledgements

We thank Anna Tapsak for her help in the production of this manuscript and for her excellent technical assistance. This research was supported by Grant AA07052 from the National Institute on Alcohol Abuse and Alcoholism and BNS 8609877 from the National Science Foundation.

References (12)

  • Amsel, A., Hippocampal function in the rat: Cognitive mapping or vicarious trial and error? Hippocampus, 3 (1993)...
  • Amsel, A., Frustration Theory: An Analysis of Dispositional Learning and Memory, 1992, Cambridge University Press, New...
  • Amsel, A., Arousal, suppression, and persistence: Frustration theory, attention, and its disorders, Cognition Emotion,...
  • Amsel, A., Daniel Berlyne Memorial Lecture. Developmental psychobiology and behavior theory: reciprocating influences,...
  • Eichenbaum, H. and Mathews, P., Further studies of hippocampal representation during odor learning, Behav. Neurosci.,...
  • Gould, E., Woolley, C.S. and Cameron, H.A., Adrenal steroids regulate postnatal development of the rat dentate gyrus:...
There are more references available in the full text version of this article.

Cited by (15)

  • Noradrenergic signaling in the medial prefrontal cortex and amygdala differentially regulates vicarious trial-and-error in a spatial decision-making task

    2016, Behavioural Brain Research
    Citation Excerpt :

    The ratio of choice of the HR (HR choice), the ratio of alternation of choice from the option in the previous lap (Choice switch), the time spent in the choice area (Choice time) and in the transit area (Transit time), and the number of VTE and VTE trials were recorded. VTE was defined as in previous studies [8,47,48] as: (1) head movements from one side to the other side across the midline of the rat’s body at the T-junction in the choice area; (2) lateral head movements away from and returning to the rat's direction of travel before the T-junction; and (3) pausing within the choice area (Fig. 1B, Supplementary movies1–4). These three behaviors are regarded as functionally equivalent VTE because they show discrete spatial representation of the rat's actual position and extra-place field firing of place cells, suggesting utilization of non-local information [4].

  • Noradrenergic modulation of vicarious trial-and-error behavior during a spatial decision-making task in rats

    2014, Neuroscience
    Citation Excerpt :

    In the previous studies, the difficulty of choice was set by manipulating the brightness of visual stimuli in visual discrimination tasks (Tolman, 1939, 1948), suggesting VTE relates to visual processing. In addition, other previous studies have reported that VTE occurred in various choice situations: in discrimination of other sensory stimuli, such as odor and sound (Hu et al., 1997; Griesbach et al., 1998; Johnson and Redish, 2007), in spatial discrimination (Bett et al., 2012), and in reward-delay discounting (Papale et al., 2012). These studies suggest that VTE is non-specifically induced in choice situations regardless of how the options are differentiated.

View all citing articles on Scopus
View full text