Pavlov's position on the effects of decortication on conditional reflexes.

This paper examined D. Joravsky's (1989) hypothesis that I.P. Pavlov dogmatically refused to acknowledge that classical conditioning can be mediated by subcortical regions of the large cerebral hemispheres. Decortication literature from 1901 to 1936 was reviewed. The early studies available to Pavlov, who died in 1936, showed that decortication does not allow the establishment of new or retaining of old conditional reflexes (CRs). G.P. Zeleny?'s later experiments(1930) suggested that the establishment of primitive CRs in decorticated dogs was possible. Pavlov never denied this possibility but cautioned that Zeleny?'s experiments could have been methodologically flawed. Although Joravsky's original hypothesis on Pavlov's position on the relation between decortication and the establishment of CRs is by and large accepted, it must be stressed that Pavlov's theory of higher nervous activity was primarily concerned with the function of the brain in the higher organism's struggle for existence. Within this context the cortical, rather than subcortical, processes play the decisive role in the organism's adaptation to the changing external environment.     

The functional architecture of instrumental conditional reflexes

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:

1. 1.
   In the establishment of classical and operant conditional reflexes, two-way conditional connections—direct and reverse—are formed.     
   
   

The influence of experimental neurosis on the conditional reflexes and the content of blood catecholamines and acetylcholine in dogs

Using experimental neurosis as a model, we investigated the mode of adaptive behavior, conditional reflexes and the blood level of neuromediators in four dogs placed in certain versus uncertain conditions in a Pavlovian laboratory. The research consisted of a two year training program with predictable (ordered partial reinforcement) followed by unpredictable (probabilistic reinforcement) situations. As a result, there was a decline in the acetylcholine as compared to a rise of catecholamine levels of the peripheral blood of some of these dogs. There were varied autonomic responses indicating a possible individual response specificity. In one dog, there was a disappearance of motor defense reflexes. The results support the hypothesis that probabilistic reinforcement following ordered partial reinforcement contributed to the dogs’ neurotic disintegration,i.e., uncertainty is a cause of neurotic development.     

The P300 component of the event-related brain potential as an indicator in the study of information processing

Event-related bioelectrical brain activity plays an important role in psychophysiological investigations of mental processes. One of the so-called endogenous components of ERP, the P300, occurring in the time range from 300 ms to 800 ms after stimulus presentation accompanies the selective call on cognitive processing of stimulus information. An overview of some influencing factors and of hypotheses according functional significance of P300 is given. Although functional significance of P300 is only partly known there are interesting possibilities of application, e.g. in Neurology, Psychiatry and Occupational medicine.     

Context influence on the perception of figures as conditional upon perceptual organization strategies

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.     

Predictors of willingness to register as an organ donor among dutch adolescents

Abstract

In order to identify relevant determinants of organ donor registration among Dutch adolescents, a school-based cross-sectional survey was conducted among 145 high school students. Fifty-one percent of respondents indicated they were willing to register as organ donors and 80% reported a positive general attitude towards registration. Various misconceptions about the registration and donation procedure were identified. On average only moderate knowledge levels related to organ donation were found. In order of strongest association, negative outcome expectancies, past behaviour and experience, positive outcome expectancies, and social outcome expectancies proved to be significant predictors of willingness to register as organ donors. Self-efficacy was indirectly associated with willingness via outcome expectancies. Knowledge about organ donation was not significantly associated with willingness. The results suggest that in order to persuade adolescents to register as organ donors, refutational messages will have to be developed to counterargue the prevailing negative outcome expectancies related to organ donation and registration as an organ donor.     

Body temperature as a conditional response measure for pavlovian fear conditioning

On six days rats were exposed to each of two contexts. They received an electric shock in one context and nothing in the other. Rats were tested later in each environment without shock. The rats froze and defecated more often in the shock-paired environment; they also exhibited a significantly larger elevation in rectal temperature in that environment. The rats discriminated between each context, and we suggest that the elevation in temperature is the consequence of associative learning. Thus, body temperature can be used as a conditional response measure in Pavlovian fear conditioning experiments that use footshock as the unconditional stimulus.     

Intention to consent to living organ donation: an exploratory study

Living organ donation, that is the removal and transplantation of whole organs or segments of organs that a volunteering donor can live without, has been proposed as an effective and sustainable source of transplantable organs to mitigate the deficit in supply from the traditional cadaveric donor pool. In 2006, the Irish government deemed the development of a national Living Transplant Programme a service priority. The current study aimed to investigate the efficacy of the theory of planned behaviour (TPB) in the context of living organ donation intentions in an Irish sample. One hundred and thirty five undergraduate students (75 females, 60 males; mean age 20.6 years, SD 3.76) completed a self-report questionnaire assessing TPB variables while imagining themselves in a potential living liver donation scenario. In general, attitudes towards living donation were favourable. TPB components explained 44.8% of the variance in intentions. Attitude towards living donation emerged as the strongest predictor of intention. Self-reported levels of knowledge regarding living donation were generally poor. In light of recent EU Communications proposing the expansion of the use of living donors greater understanding of the determinants, psychological implications and ethical considerations in living donation decisions is necessary.     

How the brain responds to any: an MEG study

The word any may appear in some sentences, but not in others. For example, any is permitted in sentences that contain the word nobody, as in Nobody ate any fruit. However, in a minimally different context any seems strikingly anomalous: ^*Everybody ate any fruit. The aim of the present study was to investigate how the brain responds to the word any in such minimally different contexts - where it is permitted (licensed) and where it is not permitted (unlicensed). Brain responses were measured from adult readers using magnetoencephalography (MEG). The results showed significantly larger responses to permissible contexts in the left posterior temporal areas between 400-500 ms and 590-660 ms. These results clarify the anatomy and timing of brain processes that contribute to our judgment that a word such as any is or is not permitted in a given context.     

Incubation of conditional suppression is an associatively-based phenomenon

Ten rats were deprived of water and trained to lick a tube for saccharin reinforcement. In each of the two sessions that followed, the rats received six contiguous pairings of a 30-second illumination of the houselight and a 0.75 second, 0.10 mA electric shock while licking. No sign of conditioning was observed during the first experimental session, but profound conditioning was observed on the first and subsequent trials of the second conditioning session. No comparable change in the rate of licking was observed in groups of rats that received only presentations of the visual stimulus, only presentations of the electric shock, or random presentation of the visual stimulus and electric shock during the first conditioning session. These data establish that the incubation of conditional suppression is an associative phenomenon.