Biomedical subjects

Günter Reinhard

Publications and source records attributed to Günter Reinhard.

7 recordsLinked to original sources

PubMed2006

Tracking stimulus processing in Pavlovian pupillary conditioning.

The aim of the present study was to evaluate whether the anticipatory pupillary dilation response is a useful indicator for the examination of complex differential conditioning problems like patterning. A human fear conditioning procedure with six groups (n=20 each) was used to examine conditioned stimulus (CS) processing when a compound stimulus was reinforced, but not its elements (positive patterning) or when the elements were reinforced, but not the compound (negative patterning), as well as modifications in which the compound was replaced by either a new compound or by a new element. We found evidence for conditioning within 2 s after CS onset. Group differences in differential conditioning indicated systematic differences in CS processing due to different discrimination task difficulties. This study showed that the pupil response is a suitable indicator for human Pavlovian conditioning with high time resolution within and between trials.

Adolescent↗

PubMed2003

Cellular immunotherapy after autologous hematopoietic stem cell transplantation: experimental strategies and clinical experiences.

Recurrence of disease after autologous hematopoietic stem cell transplantation is at least partly due to contamination of the reinfused transplant with tumor cells, thereby limiting the clinical outcome after transplantation. On the other hand, immunological effector cells are capable of purging bone marrow transplants in vitro and of destroying disseminated tumor cells in vivo. Cellular immunotherapy subsequent to autologous stem cell transplantation is therefore expected to have a major impact on recurrence rates of the disease. In this review, we present various strategies utilizing immunologic effector cells for elimination of disseminated tumor cells and discuss the advantages and limitations of cellular immunotherapy after autologous hematopoietic stem cell transplantation.

CD3 Complex↗

PubMed2002

Differential conditioning of anticipatory pupillary dilation responses in humans.

The purpose of the present experiments was to demonstrate conditioning of anticipatory pupillary dilation responses in humans as previous efforts to condition pupillary dilation had yielded inconsistent results. In those studies, using an aversive unconditioned stimulus (US) had yielded more promising results than using non-aversive USs. In three experiments we utilized a reaction time task as a non-aversive US and observed reliable differential conditioning of anticipatory pupillary dilation. Differential responding was evident within very few trials and was largest late in the anticipatory interval. Experiment 4 replicated these findings using an aversive US (electric shock). In measuring anticipatory responses in a differential conditioning preparation all four experiments provided clear evidence for Pavlovian conditioning of pupillary dilation in humans.

Adult↗

PubMed2002

The effect of stimulus probability on pupillary response as an indicator of cognitive processing in human learning and categorization.

Stimuli presented with a low probability of occurrence elicit larger pupillary dilations than those presented with a high frequency. Utilizing this stimulus probability effect, we conducted two Go/NoGo reaction time experiments to analyze category learning and compound coding in the context of associative learning. Experiment 1 showed no stimulus probability effect when participants used an abstract rule to classify stimuli with different probabilities into the same category. When no rules could be applied, however, the stimulus probability effect was observed. Hence, this effect can be utilized to identify the application of rules in category learning. Experiment 2 demonstrated that the stimulus probability effect can also be used in determining whether compounds are processed in terms of elemental stimuli or as new entities. The results of Experiment 2 supported elemental rather than configural processing. Obviously, the probability effect can be used as a tool for the evaluation of categorization and compound processing.

Adult↗

PubMed2002

Evidence for the utilization of distinctive features in nonlinear discrimination problems.

There is evidence that in human Pavlovian conditioning positive patterning (A-, B-, AB+) as well as negative patterning (A+, B+, AB-) are solved by applying abstract rules. In the present report we further investigated how humans solve patterning discriminations by conducting two Go/NoGo reaction time experiments that utilized the stimulus probability effect: stimuli presented with a low probability of occurrence elicit larger pupil dilations than those presented with a high frequency. In decreasing the ratio of compound and elemental trials from 1/1 (24 A, 24 B, 48 AB) in Experiment 1 to 1/2 (32 A, 32 B, 32 AB) in Experiment 2 we manipulated stimulus probability. The results of both experiments indicate that humans utilize distinctive features such as number information in order to classify the stimuli.

Adult↗

PubMed2002

The impact of reinforcement density on response differentiation in configural discrimination problems.

Two human Pavlovian conditioning experiments investigated the impact of reinforcement density (the number of reinforced trials divided by the total number of trials) on discrimination learning. Experiment 1 used a negative patterning problem (A+, B+, AB-) and Experiment 2 used a positive patterning problem (A-, B-, AB+). In both experiments, reinforcement density varied across four levels. Response differentiation between reinforced and non-reinforced stimuli was linearly related to the decrease in reinforcement density. Responses to nonreinforced stimuli did not differ between the four groups in either experiment. In contrast to this, responses to reinforced stimuli were considerably more pronounced in conditions with lower reinforcement density. For negative patterning, this replicates and extends similar observations from other species. For positive patterning, this is a finding that has not yet been reported in other experiments. The results are in agreement with the comparator hypothesis (Miller & Matzel, 1988) and with Wagner's (1981) "standard operating procedures" (SOP) model.

Adult↗

PubMed2002

Are rules applied in Pavlovian electrodermal conditioning with humans general or outcome specific?

There is growing evidence that in human skin conductance response (SCR) conditioning positive patterning (A-, B-, AB+) and negative pattering (A+, B+, AB-) are solved by applying two different rules. The present experiments investigated whether the representations of such rules are specific or general with regard to outcomes and response systems. In Experiment 1, we investigated SCR and eyelid conditioning with different types of training administered in an interleaved fashion. We found that positive patterning SCR conditioning interfered with negative patterning SCR conditioning, whereas eyeblink conditioning had no effect on SCR conditioning. In Experiment 2, in which eyeblink and SCR conditioning were administered in sequential fashion, the same result was obtained. We conclude that the rules involved in solving patterning tasks might be specific to outcomes and/or response systems.

Adult↗