Temporal maps in appetitive Pavlovian conditioning

Abstract

Previous research suggests animals may integrate temporal information into mental representations, or temporal maps. We examined the parameters under which animals integrate temporal information in three appetitive conditioning experiments. In Experiment 1 the temporal relationship between 2 auditory cues was established during sensory preconditioning (SPC). Subsequently, rats were given first order conditioning (FOC) with one of the cues. Results showed integration of the order of cues between the SPC and FOC training phases. In subsequent experiments we tested the hypothesis that quantitative temporal information can be integrated across phases. In Experiment 2, SPC of two short auditory cues superimposed on a longer auditory cue was followed by FOC of either one of the short cues, or of the long cue at different times in the cue. Contrary to our predictions we did not find evidence of integration of temporal information across the phases of the experiment and instead responding to the SPC cues in Experiment 2 appeared to be dominated by generalization from the FOC cues. In Experiment 3 shorter auditory cues were superimposed on a longer duration light cue but with asynchronous onset and offset of the superimposed cues. There is some evidence consistent with the hypothesis that quantitative discrimination of whether reward should be expected during the early or later parts of a cue could be integrated across experiences. However, the pattern of responding within cues was not indicative of integration of quantitative temporal information. Generalization of expected times of reward during FOC seems to be the dominant determinant of within-cue response patterns in these experiments. Consequently, while we clearly demonstrated the integration of temporal order in the modulation of this dominant pattern we did not find strong evidence of integration of precise quantitative temporal information.

Associative learning and timing

“…This leads to the prediction that second-order conditioning should be comparatively weak given that simultaneous conditioning generally results in weak anticipatory CR's (see above). Indeed, Cole et al [57] confirmed that this is the case [see also 32,54 for related evidence in appetitive conditioning] by comparing standard second-order conditioning with trace second-order conditioning (Figure 1B). Trace conditioning resulted in weaker initial conditioning, and thus should support weaker mediated association transfer to CS2.…”

“…A related piece of evidence that times are encoded comes from demonstrations that animals can integrate information about time across separate experiences [52-54]. In second-order conditioning, a CS1 is followed by the US, and then CS1 is later paired with a novel CS2 in the absence of the US (Figure 1A).…”

Transitions in the temporal parameters of sensory preconditioning during infancy

“…A review of the animal literature suggests that there may be ontogenetic differences in the parameters that support the formation of an association during phase 1 of SPC. In studies of SPC with adult organisms, S 1 and S 2 are typically preexposed sequentially (e.g., Brogden, ; Taylor, Joseph, Zhao, & Balsam, ). Although mature organisms exhibit evidence of SPC following simultaneous preexposure (Matzel, Held, & Miller, ; Rescorla, ), the magnitude of SPC is often greater with sequential preexposure (Hoffeld, Thompson, & Brogden, ; Silver & Meyer, ; Wynne & Brogden, ).…”

Problems with the dual-systems approach to temporal cognition

“…Various permutations of this basic design have extended this effect (Molet & Miller 2014), which we cannot detail for brevity. However, these experiments strongly suggest that animals not only order the shuffled fragments of an implied sequence, they also represent the continuous intervals that separate each event it contains (Molet et al 2012;Taylor et al 2014). In other words, animals represent the temporal locations of items within a continuous temporal map, much like they track the spatial locations of items within a spatial map.…”