Interstimulus interval functions in different response systems during classical discrimination conditioning of rabbits

Abstract

Each of four groups of rabbits received nictitating membrane (NM), heart rate (HR) and respiration rate (RR) classical discrimination conditioning to tones and shocks at inters timulus intervals of .25, .75, 2.25.and 6.75 sec. Percentages of NM CRs were inversely related to lSI; whereas magnitude of RR responding was directly related to lSI, and maximum HR conditioning occurred at 2.25 sec. Discrimination conditioning failed to occur in acquisition in the RR response system, and occurred maximally at. 75 sec in the NM system and 2.25 sec in the HR system.

Dissociation of the blocking of conditioned eyeblink and conditioned fear following a shift in US locus

“…Thus, when a tone or light CS is paired with a paraorbital-shock US, as in the present experiments, one can observe a conditioned eyeblink and a conditioned potentiation of the startle response and can reasonably assume that these two measures are but among many other indices of conditioning that might have been employed. In this context, the results of Experiments I and 2 are significant in supporting those studies (e.g., Tait & Saladin, 1986;Vandercar & Schneiderman, 1967) that indicate that there are important systematic dissociations among distinguishable classes of these measures.…”

Divergence of conditioned eyeblink and conditioned fear in backward Pavlovian training

“…The backward CS ex-GENERAL DISCUSSION The data of Experiments I and 2 increase our confidence that the phenomenon reported by Tait and Saladin (1986) represents a reproducible dissociation of measures of eyeblink conditioning and measures of conditioned fear. Vandercar and Schneiderman (1967) made the point some years ago that variation in the interval by which the CS precedes the US has notably different effects upon simultaneously recorded measures ofnictitating membrane conditioning and heart rate conditioning. It appears that a "divergence ofresponse systems," as they called it, is even more obvious when backward US-CS intervals are surveyed.…”

“…Considerable data now document the separability of conditioned eyeblink and conditioned fear during Pavlovian conditioning with an aversive paraorbital US. In addition to the aforementioned behavioral observations of Vandercar and Schneiderman (1967;see also Brandon, Betts, &Wagner, 1994, and showing differential variation as a function of the CS-US interval, there is substantial literature attesting to the differential speed ofacquisition ofthe two measures (see review by Lennartz & Weinberger, 1992; but see also Kehoe &Macrae, 1994, andWeinberger, 1994), and the report of Betts, Brandon, and Wagner (1996) showing that shift of the US from one eye to the other spares blocking ofconditioned fear but not blocking of conditioned eyeblink. These behavioral observations are supported by neurobiological investigations that suggest that the locus of neural convergence essential for eyeblink conditioning is different from that for fear conditioning (e.g., Thompson, 1986): Instructive is the fact that cerebellar damage that prevents eyeblink conditioning does not prevent fear conditioning (Thompson et a!., 1986), whereas amygdala lesions that interfere with fear conditioning do not preclude eyeblink conditioning (e.g., Weisz, Harden, & Xiang, 1992).…”

Compound-component differentiation as a function of CS-US interval and CS duration in the rabbit’s conditioned nictitating membrane response

“…In differential conditioning between CSs varying along a simple physical dimension, differentiation increases as the CS-US interval on CS+ trials increases. For example, Vandercar and Schneiderman (1967) reported that tone frequency discrimination in the rabbit NMR preparation improved when the CS-US interval on CS+ trials was 750 msec rather than 250 msec (cf. Chisholm, Hupka, & Moore, 1969;Frey, 1969;Hartman & Grant, 1962).…”