Assessing the encoding specificity of associations with sensory preconditioning procedures.

Abstract

Three experiments examined the encoding specificity of associations using sensory preconditioning procedures in rats. In Experiment 1a, after exposure to two compounds (AX and BY), X (but not Y) was either followed by shock after a trace interval (Group Trace) or immediately followed by shock (Group Immediate). AX elicited less activity than BX (i.e., more fear) in Group Trace, but equivalent activity levels in Group Immediate. These results, replicated using a within-subjects design in Experiment 1b, indicate that the presence of A (on AX trials) generates fear because it associatively evokes X's memory into the same state as it was associated with the shock during (trace) conditioning. In Experiment 2, after exposure to AX and BY, X (but not Y) was immediately followed by shock. As in Experiment 1a, presentations of AX and BX elicited equivalent levels of fear, but there was more fear in the trace period after AX than in the trace period after BX. This finding suggests that during aversive conditioning, the associatively provoked memory of A was part of the conditioned complex, and that the trace of AX was more likely to activate this memory than was the trace of BX.

Novel sensory preconditioning procedures identify a specific role for the hippocampus in pattern completion

“… Iordanova, Burnett, Good, & Honey, 2011 ; see also, Holland, 1981 ). Additional support for this analysis can be derived from the simpler observation that after exposure to AX and BY, conditioning with X results in greater fear to AX than BX (see Lin, Dumigan, Dwyer, Good, & Honey, 2013 ; see also, Ward-Robinson et al, 2005 , Ward-Robinson and Hall, 1996 ). The associative chain analysis does not predict this outcome because A is only held to provoke more fear than B by dint of its capacity to activate X, and the presence of X with A and B will now mean that both compounds will have this capacity.…”

“…The apparatus used was that described in Lin et al (2013) and consisted of 8 operant chambers (Test chamber 80004-D001; Campden Instruments Ltd., Loughborough, England; 30.5 cm × 26 cm × 20 cm; width × depth × height) arranged in 4 × 2 array. Each chamber was housed within a sound-attenuating shell, had two aluminum side walls, a transparent Perspex back wall and ceiling.…”

“…It was assumed that lower levels of activity were indicative of greater fear during the final test. Previous experiments have established the utility of this measure in providing automated measures of standard behavioral effects based on fear conditioning (see Dumigan et al, 2015 , Lin et al, 2013 ). A computer (Mark II Control Unit) controlled the apparatus, operated the program (using Behavioural Net Controller Control 1.0) and recorded ambulatory movement (all equipment was supplied by Campden Instruments Ltd., Loughborough, England).…”

Mediated configural learning in rats

“…Instead, the fact that AX provokes more conditioned responding than BX suggests that conditioning trials with X had resulted in the evoked memory of AX becoming associated with the memory of illness generated by lithium chloride. This analysis, in terms of mediated configural learning, receives additional support from the results of a recent study by Lin, Dumigan, Good and Honey (2013). Lin et al (2013) gave rats exposure to two audio-visual compounds, AX and BY, prior to presentations of X that were paired with shock and Y that were not.…”

“…This analysis, in terms of mediated configural learning, receives additional support from the results of a recent study by Lin, Dumigan, Good and Honey (2013). Lin et al (2013) gave rats exposure to two audio-visual compounds, AX and BY, prior to presentations of X that were paired with shock and Y that were not. After these treatments, rats showed more fear (less activity) to AX than BX.…”