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At least 19 recordsLinked to original sources
PubMedDate not supplied

A comparison of the effects of vicariously instigated classical conditioning and direct classical conditioning procedures.

Two groups of Ss received either two or 16 paired classical conditioning trails beyond the peak CR. A third group received the same stimuli as the 16 postpeak condition but in an unpaired and random order. The stimuli in all three groups were delivered directly to S. Subsequently, all three groups, including a fourth which was not given any prior direct classical conditioning, were exposed to vicariously instigated classical conditioning. This consisted of having S observe someone (model) employed by E who received the same CS as was delivered during direct conditioning. The CS was paired with the feigned arm movement of the model, simulating a reaction to shock. This vicarious classical conditioning procedure when compared to direct classical conditioning resulted in smaller GSR magnitudes for both the CRs and UCRs. Previous experience with direct classical conditional seems to have had an attenuating effect on GSR magnitude during the vicarious situation. A postexperimental questionnaire tended to support the results, and the relationship between the present study and current classical conditioning theory is discussed.

Conditioning, Classical↗
PubMed1991

A neural network approach to hippocampal function in classical conditioning.

Hippocampal participation in classical conditioning in terms of Grossberg's (1975) attentional theory is described. According to the present rendition of this theory, pairing of a conditioned stimulus (CS) with an unconditioned stimulus (US) causes both an association of the sensory representation of the CS with the US (conditioned reinforcement learning) and an association of the sensory representation of the CS with the drive representation of the US (incentive motivation learning). Sensory representations compete among themselves for a limited-capacity short-term memory (STM) that is reflected in a long-term memory storage. The STM regulation hypothesis, which proposes that the hippocampus controls incentive motivation, self-excitation, and competition among sensory representations thereby regulating the contents of a limited capacity STM, is introduced. Under the STM regulation hypothesis, nodes and connections in Grossberg's neural network are mapped onto regional hippocampal-cerebellar circuits. The resulting neural model provides (a) a framework for understanding the dynamics of information processing and storage in the hippocampus and cerebellum during classical conditioning of the rabbit's nictitating membrane, (b) principles for understanding the effect of different hippocampal manipulations on classical conditioning, and (c) numerous novel and testable predictions.

Animals↗
PubMedDate not supplied

External inhibition in a goldfish (Carassius auratus) classical conditioning situation.

Goldfish were classically conditioned with a light as the CS and shock as the US. The UR was a decrease in respiration. After 15 or 60 conditioning trials the fish were tested with novel stimuli (clicks) during the CS-US interval. High and moderate intensity novel stimuli produced a significant decrease in CRs (external inhibition) for fish with 60 conditioning trials (5.5 or 10.5 sec CS-US interval), but not fish with 15 conditioning trials. Low intensity novel stimuli produced no evidence for disinhibition (an increase in CRs). Control groups (e.g., groups with random presentations of the CS and US) showed that the external inhibition for fish with 60 conditioning trials was inhibition of a true CR.

Acoustic Stimulation↗
PubMed1992

Stimulus configuration, classical conditioning, and hippocampal function.

Hippocampal participation in classical conditioning is described in terms of a multilayer network that portrays stimulus configuration. The network (a) describes behavior in real time, (b) incorporates a layer of "hidden" units positioned between input and output units, (c) includes inputs that are connected to the output directly as well as indirectly through the hidden-unit layer, and (d) uses a biologically plausible backpropagation procedure to train the hidden-unit layer. Nodes and connections in the neural network are mapped onto regional cerebellar, cortical, and hippocampal circuits, and the effect of lesions of different brain regions is formally studied. Computer simulations of the following classical conditioning paradigms are presented: acquisition of delay and trace conditioning, extinction, acquisition-extinction series of delay conditioning, blocking, over-shadowing, discrimination acquisition, discrimination reversal, feature-positive discrimination, conditioned inhibition, negative patterning, positive patterning, and generalization. The model correctly describes the effect of hippocampal and cortical lesions in many of these paradigms, as well as neural activity in hippocampus and medial septum during classical conditioning. Some of these results might be extended to the description of anterograde amnesia in human patients.

Animals↗
PubMed1975

Factors affecting the measurement of classically conditioned fear in rats following exposure to escapable versus inescapable signaled shock.

Three experiments are reported in which rats first received 50 escapable or inescapable signaled-shock trials. Experiment 1 (n = 22) employed an acquired-drive paradigm and found inescapable shock subjects learned a hurdle-jump response to escape the signal less rapidly than did escapable-shock subjects. Experiment 2 (n = 24) employed a conditioned emotional response paradigm and found inescapable-shock subjects suppressed more when the signal was introduced in the appetitive bar-pressing task. Both experiments measured spontaneous activity immediately following conditioning and found no group differences. Experiment 3 (n = 39) employed the same activity task and found no difference between escapable- and inescapable-shock groups when the signal was introduced into the activity task. Both groups displayed less activity than a nonshock control group during the signal. The results suggest that lack of control over the shock in the conditioning phase did not result in an increase of conditioned fear. The results are discussed in terms of a learned active-inactive predisposition to respond.

Animals↗
PubMed1991

Classical conditioning after temporal lobe lesions in man: impairment in conditional discrimination.

Left and right temporal lobectomy patients, patients with frontal lobe lesions, and healthy control subjects participated in an eyelid conditioning study based on conditional discrimination learning. All groups acquired the first conditioned response at a similar time during learning, but both temporal lobectomy groups showed poorer discrimination than control subjects. The results support models that relate hippocampal function to operation of if-then rules.

Adult↗
PubMedDate not supplied

An experimental analysis of classically conditioned nausea during cancer chemotherapy.

This study investigated classical conditioning in women undergoing outpatient adjuvant chemotherapy for breast cancer. Breast cancer chemotherapy outpatients were randomly assigned either to an Experimental Group (exposed to a distinctive stimulus before each infusion of chemotherapy) or to a Control Group. After repeated infusions of chemotherapy, patients' responses to the experimental stimulus were assessed in a location not associated with chemotherapy. Experimental Group patients had increased nausea (self-reported on a visual analog scale) following the presentation of the experimental stimulus at this test trial, whereas Control Group patients did not. Two other measures of nausea corroborated these results. Post hoc statistical analyses confirmed predictions based on conditioning theory. This conditioning model of anticipatory nausea bears witness to the relevance of classical conditioning in clinical medicine.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Conditioning of skin conductance levels through a combined instrumental-classical conditioning procedure.

A paucity of studies and inconsistent results characterize attempts to instrumentally condition tonic electrodermal activity. The present study was conducted to further explore the classical and instrumental conditioning of skin conductance levels (SCLs) through auditory analogue feedback. Fifty undergraduates were randomly assigned to one of five groups of equal size: instrumental conditioning alone, classical conditioning alone, instrumental and classical conditioning combined, and two control groups. The combined training group achieved significantly higher SCLs relative to the group receiving instrumental conditioning alone.

Analysis of Variance↗
PubMed1992

No evidence of classical conditioning of electrodermal responses during anesthesia.

Classical conditioning of skin conductance responses was studied in 26 healthy volunteers and 31 patients who received general anesthesia (0.5 MAC isoflurane-70% nitrous oxide) for minor gynecologic surgery to determine whether there was autonomic evidence of new learning during anesthesia. In the conditioning phase, a loud noise was paired with a target word (conditioned stimulus [CS]). Conditioning was established if the CS produced conditioned responses, i.e., greater skin conductance responses than other, "filler words." In the subsequent elicitation phase, we investigated whether it was possible to elicit similar conditioned responses to the CS when it was presented without noise about 3 h later. Conditioning was established in the control group, who received no anesthesia. There were differences in response magnitudes of 0.32 and 0.27 mu siemen between responses to the CS and filler words, P less than 0.001. In contrast, there was no evidence that conditioning was established during anesthesia. In the elicitation phase, conditioned responses to the CS could be elicited in volunteers; i.e., response magnitudes were greater for the CS than other words (during the first two blocks of trials), with differences of 0.19 to 0.48 mu siemen, P less than 0.05 to P less than 0.001. In contrast, responses to the CS could not be elicited in patients after anesthesia. There was also no evidence of recognition of words that were presented during anesthesia in patients, but recognition was manifested in volunteers. Thus, in contrast to our previous demonstration of conditioning in subjects who received 30% nitrous oxide in oxygen, there was no evidence of conditioning in anesthetized patients.

Adult↗
PubMed1991

[Modulatory role of the cerebellar cortex during the classically conditioned nictitating membrane response in rabbit].

Classical conditioning of the rabbit nictitating membrane(NM) response was accomplished by standard delay procedure of paired tone (CS) and airpuff (US) stimuli. Upon reaching a criterion of 90% conditioned responses (CRs) in 3 consecutive blocks, an electrolytic lesion was made at the hemicerebellar VI cortical lobule on the training side. Results showed that the learned response of the dentate-interpositus (D-I) nuclei and the conditioned NM response were completely or almost completely eliminated without affecting the unconditioned response. However, cerebellar cortical lesion performed on animals being over 1 week overtrained produced no effect on CRs and the learned response of the D-I nuclei. Meanwhile, the spontaneous activity of the D-I nuclei during consolidation reduced in frequency as a result of the cortical lesion at the early stage of learning. Our findings indicate that the cerebellar cortex plays a modulatory role in the generation of the conditioned NM response and the development of the learned response of the D-I nuclei at an early stage of learning. With consolidation, the D-I nuclei become free of control from the cerebellar cortex and serve as the essential component of the memory trace for this model system.

Animals↗
PubMed1979

Classical conditioning in Aplysia californica.

A form of aversive classical conditioning is described in which a chemosensory conditioned stimulus rapidly acquires the ability to modulate a defensive response (escape locomotion). Because Aplysia show both sensitization and classical conditioning, it is now possible to begin to examine the relationship between nonassociative and associative learning on behavioral and cellular levels.

Animals↗
PubMed1992

Influence of the cerebellar posterior vermis on the acquisition of the classically conditioned bradycardic response in the rabbit.

The magnitude of classically conditioned bradycardia was studied in rabbits in which various cerebellar regions (lobule IX or the posterior vermis or the hemispheres) had been removed surgically. Lesions were shown histologically to be restricted to the cortex and the underlying white matter without any damage to the deep cerebellar nuclei. In the conditioning procedure, tones were employed as conditioned stimuli (CS) and ear shocks as unconditioned stimuli (US). Cerebellar lesions did not affect the characteristics of the bradycardic orienting response, baseline heart rate or the unconditioned tachycardic response to US. The conditioned bradycardia was significantly reduced in magnitude with respect to controls in rabbits submitted to removal of posterior vermis, while it was unaffected in lobule IX and hemispheric lesioned rabbits. The temporal pattern of development and habituation of the bradycardiac response through the conditioning session, as well as its topography, did not differ from controls in any of the lesioned rabbits. After the first conditioning session, some control rabbits were submitted to removal of the posterior vermis and then conditioned again, following an identical procedure. Their pre- and post-lesion conditioned responses did not exhibit any appreciable differences and were similar to the responses exhibited by a group of unoperated controls which were submitted to a reconditioning session. It is concluded that in the rabbit the cerebellar posterior vermis is involved in the initial acquisition of the classically conditioned bradycardia, but it is not the site of its memory trace.

Animals↗
PubMed1991

Classical conditioning of ventilatory responses in humans.

A classical conditioning experiment, in which an auditory stimulus was paired with a hypoxic stimulus, was carried out on 34 normal subjects assigned to two groups (experimental and control). Each subject took part in one session divided into two phases, acquisition and test. In the acquisition phase, eight hypoxic and eight auditory stimuli were paired in the experimental group and unpaired in the control group. In the test phase, which was identical for the two groups, the hypoxic stimuli were suppressed and three purely auditory stimuli were presented. Significant differences between the two groups in ventilatory response to these auditory stimuli provided evidence for conditioning. In the control group, no significant changes were elicited by the auditory stimuli, whereas a conditioned increase in total cycle duration was observed in the experimental group. The conditioned response closely resembled the first component of the hypoxic response. Analysis of the pattern of the conditioned response, along with postexperimental interviews, strongly suggests that this response was not mediated by volitional factors.

Acoustic Stimulation↗