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Recent observations on the plasticity of brain and behavior relationships indicate that the temporary connections between environmental and neuroanatomical substrates have tremendous specificity but at the same time are very plastic. Establishment of a conditional reflex by stimulation of the hippocampal pyramidal layer and/or the mesencephalic reticular formation did not interfere with the differential stimulation of very near points in the same structures. These correlations between brain and behavior confirmed the earlier belief that the development of temporary connections between environment and brain is an elementary process of the central nervous system. Complex behavioral functions are organized through both neuronal and humoral afferentation. Data accumulated recently indicate that the descending forebrain influence is inhibitory in the brain stem and diencephalon and controls the sensory input in a somatomotor-specific and situation-specific manner. Humoral factors affecting thresholds can change the dynamic equilibrium existing between ascending excitatory and descending inhibitory systems; these alterations always follow the rule of situation and somatomotor specificity.  相似文献   

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In 12 birds used in a CO2 conditioning experiment there was no evidence of the formation of either a respiratory or a cardiac conditional reflex. Tone and light separately or together were used as conditional stimuli. CS-US intervals ranging from 0.5 to 10 seconds were used. CO2 concentrations up to 7.4% were also employed. In the shock conditioning experiments six of seven birds showed a respiratory change to the conditional stimulus. In one pigeon perfect differentiation was obtained between the reinforced and nonreinforced tones. The marked difference in conditionability of sensory and chemical stimuli to the “respiratory center” is discussed in relation to the central nervous system connections of the respiratory control mechanism.  相似文献   

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This paper makes a theoretical analysis of the process of formation of neural associations among sensory changes produced in the brain by environmental stimuli; it also analyzes the origin of classical and instrumental conditional reactions. It has been proposed that sensory traces of stimuli “intermingle,” forming patterns of associations in “polymodal” structures of the brain. The sensory traces of stronger stimulus dominate over the sensory traces of weaker stimulus in the pattern. An activation of a pattern of associations by any of the stimuli involved releases a reaction typical of the stronger stimulus (called a reinforcing or unconditional stimulus) before the latter is presented. That type of reaction, called classical conditional reaction, is dispensable; it is one of post-reinforcement origin and therefore, is not represented in the pattern of associations. When a physiological act, such as a definite movement (e.g., pressing a bar) must precede the obtaining of the reinforcing stimulus, this physiological act, called an instrumental conditional reaction, is also evoked each time the pattern of associations has been activated. The instrumental conditional reaction is indispensable and, because of its pre-reinforcement origin, belongs, through its sensory feedback, to the pattern of associations.  相似文献   

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Some of the problems and concerns which initiated and motivated the development of typological research in Pavlov’s laboratories are reviewed. Explanations are developed as to the basic theme underlying the typing methods. Two outstanding methods of typing dogs, the “large standard” and the “small standard,” are presented in considerable detail. The basic four types that emerge from the testing procedures and some of their shortcomings are discussed. The importance to Western investigators of acquiring a first hand knowledge of this methodology is stressed.  相似文献   

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The cardiac component of the motor conditional reflex to a faradic stimulus to the hind leg in three dogs was measured. The leg was paralyzed by crushing 4 to 5 anterior roots of the lumbar nerves (second to sixth). The cardiac experiments were repeated beginning four days after operation and measurements were taken of the cardiac conditional reflex. A comparison of the increase in cardiac rate to the conditional stimulus before and after operating showed no significant difference in spite of the fact that the dog was unable to lift his leg to the stimulus. From this we conclude that the execution of the movement is not necessary for the increase of heart rate in the cardiac conditional reflex.  相似文献   

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Two experiments tested the effect of context on figure perception. Subjects were shown rapid sequences of three figures: a prime, a whole, and a part. They were asked to decide if the third figure was a part of the second (Experiment 1) or if the second and third figures were the same or different with respect to a particular angle (Experiment 2). The prime served to establish a context for stimuli that followed to be compared. Priming had influence on the part—whole comparison in Experiment 1, but not on the local comparison in Experiment 2. The results of Experiment 1 were interpreted as evidence for a role of prior information in perceptual organization. Experiment 2 showed that the task must require an integrative perceptual organization strategy for the priming effects to occur.  相似文献   

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The interaction of food-based memories and food-event outcome expectancies in pigeons was assessed using a simultaneous, delayed-symbolic-matching-to-sample procedure. The components of the compound sample were presented in sequence, and consisted of a food-based event (food or no-food) followed by a color cue (red or green). Choice of a pattern of horizontal lines was "correct" following presentation of the red cue, while choice of a vertical line pattern was "correct" after green. In all but a control condition, the food-based event with which a trial began, or the food-event outcome with which a trial concluded, or both, were also correlated with the correct pattern. Of particular interest was the relative accuracy of two groups for whom both memories and expectancies were correlated with the correct choice-pattern. For one group, the memories and expectancies corresponding to the pre- and postchoice food-related events were similar, whereas for the other they were dissimilar. Outcome expectancies supported a higher level of performance than food-based memories, and subjects with both outcome expectancies and food-based memories chose more accurately than those with memories or expectancies only. In addition, subjects with dissimilar food-based memories and outcome expectancies chose more accurately than those with similar memories and expectancies. The implications of the above findings for the nature of event representation in pigeons are discussed.  相似文献   

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In France, beginning with 1946, the method of Ivanov-Smolenski was used to study schizophrenia, but after 1957, sensory conditioning procedures have been employed (EEG sound-light, evoked potentials in children, SAE conditioning in adults) and more recently eye blink and operant conditioning).  相似文献   

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Both types of conditioning are based on the general laws of associations-connections between the centers involved. Whereas the experimental procedures of classical conditioning expose mainly the conditioned stimulus (CS)-unconditioned stimulus (US) connection, those of instrumental conditioning expose the conditioned stimulus (CS)-response (R) connection. Thus, the main differences between the two types of conditioning are those associated with the different centers involved in each, not the associative-connective laws themselves.  相似文献   

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The present study evaluated the interaction between preference for a focus of attention and instructions for focusing attention. 4 experienced billiard players had to shoot a billiard ball into a target area and received a focus instruction either corresponding or opposite to their preferred focus of attention. Two-dimensional error scores of accuracy and consistency were obtained. Accuracy of performance increased between Phase 1 without instructions and Phase 2 with focus instructions, independent of preference or instruction. However, participants with a preference for an external focus receiving an internal focus instruction showed less consistent performance.  相似文献   

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The author holds the opinion that the so-called operant, or instrumental, conditional reflexes, in spite of differences in specific features, do not differ in principle from classical conditional reflexes, and therefore they should not be opposed to them, or be placed in a special or separate group. In support of this opinion, this paper presents data which show that:
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    In the establishment of classical and operant conditional reflexes, two-way conditional connections—direct and reverse—are formed.  相似文献   

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The purpose of the experiment was to study the relation between what an organism does in a setting that demands temporal patterning of behavior and what it reports it has done. More specifically, a pigeon produced two classes, shorter and longer, of temporal patterns of key pecks (interresponse times) on a center key. Occasionally, a symbolic matching-to-sample probe arranged on side keys asked the pigeon whether its most recent pattern was a shorter or longer one. The longer reinforced pattern was always three times as long as the shorter one and the two patterns were reinforced equally often. Absolute duration of reinforced patterns was varied. In some conditions, interresponse-time distributions on the center key were bimodal, indicating a clear behavioral adaptation to the contingency, yet a bird did not report very well by appropriate side-key responding what its most recent interresponse time had been. In other conditions, the interresponse-time distributions were less clearly bimodal, yet a bird reported more accurately its previous interresponse time as shorter or longer. Thus, there was a dissociation between how well behavior on the center key conformed to the schedule requirement and how well a bird reported what it was doing on the center key. In addition, as absolute duration of the reinforced patterns was increased, a bird categorized its most recent pattern less well even as its preference for the shorter pattern increased dramatically. These results were interpreted as an example of the phenomenon of dissociation between tacit knowledge and knowledge.  相似文献   

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