Impaired trace eyeblink conditioning in bilateral, medial-temporal lobe amnesia.

Abstract

Trace eyeblink classical conditioning was assessed in patients with bilateral medial-temporal amnesia and matched control participants who had previously shown equivalent delay eyeblink conditioning (J. D. E. Gabrieli et al., 1995). The silent trace interval varied for durations of 500, 750, or 1,000 ms in successive sessions separated by at least 2 weeks; extinction trials followed each session. Patients with amnesia produced significantly fewer conditioned responses (CRs) than did control participants at all trace intervals. Both groups produced fewer CRs as the trace interval lengthened. Thus, the temporal lobe memory system in humans makes an essential contribution to normal acquisition in trace, but not delay, classical eyeblink conditioning.

Standard delay eyeblink classical conditioning is independent of awareness.

“…In delay eyeblink conditioning, the CS and US overlap and coterminate. Trace eyeblink conditioning shares several features with declarative memory, most notably the fact that learning depends on the hippocampus (Clark & Squire, 1998;McGlinchey-Berroth, Carrillo, Gabrieli, Brawn, & Disterhoft, 1997) and on awareness of the stimulus contingencies (Clark & Squire, 1998;Manns, Clark, & Squire, 2000a, 2000b. In contrast, delay eyeblink classical conditioning appears to be a quintessential example of nondeclarative memory.…”

Procedural memory system supports single cue trace eyeblink conditioning in medial temporal lobe amnesia.

“…This finding that was later confirmed by Moyer, Deyo and Disterhoft (1990) who demonstrated that acquisition was eliminated using a 500 ms trace interval (but not a 300 ms trace interval) with rabbits who had relatively complete hippocampectomies. Similarly, our In our original study, we speculated two possible sources of the impaired learning observed in amnesic patients: residual hippocampal function leading to some preserved declarative memory or intact cerebellar function that, when given enough practice, can acquire some level of trace conditioning via procedural learning (McGlinchey-Berroth, Carrillo, Gabrieli, Brawn, & Disterhoft, 1997). The current study is an attempt to distinguish between these two possibilities.…”

“…laboratory has demonstrated impaired trace conditioning in humans using a 500 ms silent trace period in amnesic patients with bilateral medial temporal lobe damage, and little if any acquisition as the trace interval was extended to 1000 ms (McGlinchey-Berroth, Carrillo, Gabrieli, Brawn, & Disterhoft, 1997). Similarly, Woodruff-Pak (1993) demonstrated impaired acquisition in two amnesic patients (one being the patient H.M.), although both eventually achieved criterion performance with additional training.…”

“…In total, eye movements were monitored for 3000 ms. During extinction trials, the corneal airpuff was withheld. As in our previous studies, the intertrial interval during conditioning and extinction averaged 18 seconds, but varied randomly from 16 to 20 seconds (e.g., McGlinchey-Berroth et al, 1997). …”

Neuroscience of Pavlovian Conditioning: A Brief Review

“…These patients acquire eyelid conditioning at a normal rate when a delay paradigm is used (e.g., Weiskrantz & Warrington, 1979). However, acquisition is impaired when a trace paradigm is used and this impairment is more severe the longer the trace interval (McGlinchey-Berroth, 1997). This impairment seems to be specific to the discontinuity between the CS and the US in the trace procedure, given that patients who showed impaired acquisition with a 600 ms trace interval showed, however, perfect conditioning with a 750 ms delay procedure (Gabrieli, McGlinchey-Berroth, Carrillo, & Gluck, 1995).…”