Tone-induced changes in excitability of abducens motoneurons and of the reflex path of nictitating membrane response in rabbit   (Oryctolagus cuniculus).

Young, Richard A.; Cegavske, Craig F.; Thompson, Richard F.

doi:10.1037/h0077219

Cited by 90 publications

(68 citation statements)

References 12 publications

(21 reference statements)

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“…In contrast, for many forms of conditioning, including fear conditioning, the CR and UR are not the same. Furthermore, there are several reports of decreasing UR amplitudes as conditioning proceeds (Young et al, 1976;Schreurs et al, 1995Schreurs et al, , 2000. Together, these data might be taken to support the claims that LTP cannot support conditioning.…”

Section: Criticisms Of Ltp As a Mechanism For Conditioningsupporting

confidence: 62%

Long‐term potentiation as a substrate for memory: Evidence from studies of amygdaloid plasticity and Pavlovian fear conditioning

Goosens¹,

Maren

2002

Hippocampus

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ABSTRACT:Recent reports have raised concerns about the ability of long-term potentiation (LTP) to account for associative learning and memory. In this paper, we review the many mechanistic similarities between one form of associative learning, Pavlovian fear conditioning, and amygdaloid LTP. We then address many of the criticisms levied against LTP within the framework of fear conditioning. We believe that many of the apparent discrepancies between LTP and behavior can be generally accounted for by a failure to appreciate that learned behavior is supported by multiple synapses in an extensive network of brain structures. We conclude that LTP remains a viable substrate for memory. Hippocampus 2002;12:592-599.

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Section: Criticisms Of Ltp As a Mechanism For Conditioningsupporting

confidence: 62%

Long‐term potentiation as a substrate for memory: Evidence from studies of amygdaloid plasticity and Pavlovian fear conditioning

Goosens¹,

Maren

2002

Hippocampus

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“…We began our analysis with a focus on the motor nerves and nuclei that generated the reflex and learned eyeblink responses , Cegavske et al 1979, Young et al 1976). To oversimplify from our work and the work of others, the sixth nerve was critically important for the nictitating membrane (NM) response, but the third and fourth nerves were also involved and the seventh nerve was critical for closure of the external eyelid (obicularis oculi muscles).…”

Section: Motor Controlmentioning

confidence: 99%

In Search of Memory Traces

Thompson

2005

Annu. Rev. Psychol.

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264

207

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■ Abstract The key issue in analyzing brain substrates of memory is the nature of memory traces, how memories are formed, stored, and retrieved in the brain. In order to analyze mechanisms of memory formation it is first necessary to find the loci of memory storage, the classic problem of localization. Various approaches to this issue are reviewed. A particular strategy is proposed that involves a number of different techniques (electrophysiological recording, lesions, electrical stimulation, pathway tracing) to identify the essential memory trace circuit for a given form of learning and memory. The methods of reversible inactivation can be used to localize the memory traces within this circuit. Using classical conditioning of eye blink and other discrete responses as a model system, the essential memory trace circuit is identified, the basic memory trace is localized (to the cerebellum), and putative higher-order memory traces are characterized in the hippocampus. CONTENTS INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Simplified Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Strategies to Study Memory Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 OUR MODEL SYSTEM: EYEBLINK CONDITIONING . . . . . . . . . . . . . . . . . . . . . 6 Motor Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INTRODUCTIONA major achievement of recent research on brain substrates of learning and memory, to which our work has contributed, is the recognition that there are several different forms or aspects of memory involving different brain systems (Figure 1). Squire (1992) has argued eloquently for the distinction between declarative and nondeclarative forms of memory, as has Schacter (1987). The distinction between episodic and semantic memory-"What did you have for breakfast?" versus "Where is the Eiffel Tower?"-has been stressed by Tulving (1985). LOCALIZATION OF MEMORY TRACES 3Implicit or nondeclarative memory is very much a grab bag. In general, explicit memory involves awareness of the memory whereas implicit memory does not necessarily involve being aware of the memory (aware meaning verbal report). The schema of Figure 1 is of course oversimplified. When an organism learns something, a number of brain systems can become engaged. However, in most cases there is one critical brain system, which when damaged causes permanent impairment in the particular form of learning and memory.Many readers will recall Lashley's (1950) pessimistic conclusion that his series of experiments "has yielded a good bit of information about what and where the memory trace is not" in his famous article, "In Search of the Engram." In all fairness to Lashley, the existence of several different forms of memory with differing neuronal substrates was not recognized at that time, nor were modern analytic techniques ava...

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“…In the motor pathways, reflex facilitation derives from a partial depolarization or increased conductance of the neurons, so that subsequent input is more likely to be effective in driving the cell past its threshold for discharge. Facilitation of the rabbit's nictitating membrane (NM) reflex by auditory stimuli seems to result from this sort of process (Young, Cegavske, & Thompson, 1976). The rat's acoustic startle reflex and the rabbit's cutaneous NM reflex respond similarly to antecedent noise conditions (Ison & Leonard, 1971), and so it is not unreasonable to ascribe facilitation of the startle reflex to a similar mechanism which provides for what we call "arousal" at a molar level of analysis.…”

Section: Discussionmentioning

confidence: 99%

Reflex inhibition and reflex strength

Ison

Reiter

1980

Psychobiology

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In Experiment 1. the amplitude of the acoustic startle reflex in rats was shown to increase linearly with increases in the intensity of the eliciting stimulus (Se). A preliminary stimulus (Si), a light flash, inhibited the reflex. The amplitude of the reflex was reduced by an equal amount regardless of Se intensity. In Experiment 2. the amplitude of the same reflex was shown to have a biphasic relation to the intensity of a white noise background (Sn) and reflex amplitudes peaked at the intermediate noise levels. Although the vigor of the reflex elicited in the presence of the most intense noise approximated that elicited by the weak Se in Experiment 1, in this condition the reflex was unaffected by the occurrence of the otherwise inhibitory light flash. It has been previously hypothesized that the decrement in reflex vigor obtained at high Sn results because sensory masking of Se by Sn reduces the effective intensity of Se. The different effect of Si in these two conditions suggests that this hypothesis is incorrect. A hypothetical neural model was devised to account for the difference between the two reflexes in their susceptibility to a preliminary stimulus. and the model was extended to other effects of stimulus strength and background noise on reflexive behavior.The strength of the acoustic startle reflex in the rat is substantially affected by the intensity of the eliciting stimulus (Se), by the level of the background noise present at the time of reflex elicitation (Sn), and by the occurrence of irrelevant stimuli just prior to that time (Si simple assumptions produce an invariant decrement in reflex amplitudes regardless of reflex strength, unless the amount of inhibition produced by Si is large relative to the strength of the reflex (i.e., a "floor effect" may deform the relationship). The present experiment assessed the generality of this invariance by examining the effectiveness of Si on the variously sized reflexes that occur in different noise backgrounds. The descending upper limb of the biphasic curve relating response amplitude to Sn intensity has been ascribed to a process akin to that responsible for the relationship between Se intensity and reflex strength. It has been proposed that, at noise levels higher than the optimum, the background noise increasingly masks Se and reduces its effective intensity (Davis, 1974; Ison & Hammond, 1971): an increment in Sn is formally identified with a decrement in Se. If this hypothesis is correct, then, in this range of relatively high noise levels past the optimal value, the preliminary stimulus should subtract a constant amount from reflex amplitude. METHOD SubjectsThe subjects were albino male rats of the Holtzman strain weighing 350-500 g at the time of testing. They were maintained on an ad-lib food and water schedule. ApparatusThe rats were restrained during testing in a small perforated Plexiglas stabilimeter cage (8 x 6 x 9 cm high) that was mounted on compression springs in an aluminum frame. An accelerator mounted on the back of the stabilimeter de...

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Tone-induced changes in excitability of abducens motoneurons and of the reflex path of nictitating membrane response in rabbit (Oryctolagus cuniculus).

Cited by 90 publications

References 12 publications

Long‐term potentiation as a substrate for memory: Evidence from studies of amygdaloid plasticity and Pavlovian fear conditioning

Long‐term potentiation as a substrate for memory: Evidence from studies of amygdaloid plasticity and Pavlovian fear conditioning

In Search of Memory Traces

Reflex inhibition and reflex strength

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