Cross-modal savings in the contralateral eyelid conditioned response.

Abstract

The present experiment monitored bilateral eyelid responses during eyeblink conditioning in rats trained with a unilateral unconditioned stimulus (US). Three groups of rats were used to determine if cross-modal savings occurs when the location of the US is switched from one eye to the other. Rats in each group first received paired or unpaired eyeblink conditioning with a conditioned stimulus (tone or light; CS) and a unilateral periorbital electrical stimulation US. All rats were subsequently given paired training, but with the US location (Group 1), CS modality (Group 2), or US location and CS modality (Group 3) changed. Changing the location of the US alone resulted in an immediate transfer of responding in both eyelids (Group 1) in rats that received paired training prior to the transfer session. Rats in groups 2 and 3 that initially received paired training showed facilitated learning to the new CS modality during the transfer sessions, indicating that cross-modal savings occurs whether or not the location of the US is changed. All rats that were initially given unpaired training acquired conditioned eyeblink responses similar to de novo acquisition rate during the transfer sessions. Savings of CR incidence was more robust than savings of CR amplitude when the US switched sides, a finding that has implications for elucidating the neural mechanisms of cross-modal savings.

Neurons of the inferior olive respond to broad classes of sensory input while subject to homeostatic control

“…However, the conditioned stimulus does not generalize: subjects trained with a visual conditioned stimulus will not blink after receiving an auditory stimulus for instance, although the associative learning process for a second stimulus goes faster than for the first (Kehoe & Holt, ; Campolattaro & Freeman, ; Campolattaro et al . ). Such a flexible arrangement would be very much in line with our data.…”