Central inhibitory dysfunctions: mechanisms and clinical implications

Injury to the central or peripheral nervous system is often associated with persistent pain. After ischemic injury to the spinal cord, rats develop severe mechanical allodynia-like symptoms, expressed as a pain-like response to innocuous stimuli. In its short-lasting phase the allodynia can be relieved with the gamma-aminobutyric acid (GABA)-B receptor agonist baclofen, which also reverses the hyperexcitability of dorsal horn interneurons to mechanical stimuli. Furthermore, there is a reduction in GABA immunoreactivity in the dorsal horn of allodynic rats. Clinical neuropathic pain of peripheral and central origin often cannot be relieved by opiates at doses that do not cause side effects. The loss of sensitivity to opiates may be associated with the up-regulation of endogenous antiopioid substances, such as the neuropeptide cholecystokinin (CCK). CCK and its receptor (CCK-R) protein is normally not detectable in rat dorsal root ganglion cells. After peripheral nerve section, both CCK and CCK-R are up-regulated in the dorsal root ganglia. Furthermore, CI 988, an antagonist of the CCK-B receptor, chronically coadministered with morphine, reduces autotomy, a behavior that may be a sign of neuropathic pain following peripheral nerve section. Thus, opiate insensitivity may be due to the release of CCK from injured primary afferents. Similarly, in the chronic phase of the spinal ischemic model of central pain, the allodynia-like symptom is not relieved by systemic morphine, but is significantly reversed by the CCK-B antagonist. Consequently, up-regulation of CCK and CCK-R in the CNS may also underlie opiate drug insensitivity following CNS injury. Thus, dysfunction of central inhibition involving GABA and endogenous opioids may be a factor underlying the development of sensory abnormalities and/or pain following injury to neural tissue.     

Focus of attention and placebo utility

The effects of focus of attention and expected drug effects on reactions to a placebo were examined in two experiments. In the first experiment self-aware and non-self-aware subjects were given a placebo that was said to be either performance-facilitating or inhibiting and then they worked on a set of arithmetic problems. It was expected that the non-self-aware subjects, but not the self-aware subjects, would display a self-serving bias in their attributions regarding the effects of the placebo. Specifically, it was predicted that non-self-aware subjects would attribute more arousal to the performance-inhibiting drug than the performance-facilitating drug since such attributions would be more psychologically beneficial or “useful” in the sense that they would make actual performance on the task look more impressive. Consistent with these predictions, there was evidence of a self-serving bias in drug reactions only among the non-self-focused subjects. Those who were made self-aware did not respond differentially to the two types of drug information. Instead, they appeared to respond in line with their actual (aroused) internal states by attributing some arousal to both drugs. In the second experiment arousal was reduced by eliminating the task, and this time self-focused subjects again appeared to be more aware of their actual internal states, as they reported less reaction to the placebo, regardless of the effects ascribed to it. Two conclusions are drawn from these results: (a) perceived drug utility does effect placebo responsiveness, and (b) self-focused attention increases awareness of internal states, but not necessarily the causes of those states.     

Unitary classification in a comparison task.

Sequential effects were used to diagnose whether elements in a two-object comparison task are represented as a perceptual unit or separately. The presence of sequential effects and absence of influences of individual elements on the subsequent trial in a successive comparison task favor the hypothesis that the elements in a pair are represented as a unit, and that a response is made to the perceptual unit. The patterns of response times on same and different trials differed in several ways; these suggested that the quality of the representations of same and different trials may differ.     

Behavioral expectations of retarded and nonretarded children

Two experiments were conducted to examine the effect of the mental retardation (MR) label on impression formation among retarded and nonretarded children and adolescents. The first experiment, conducted with nonretarded children in a mainstreamed school, indicated that they have pessimistic expectations of retarded children with regard to cognitive and ability-related behaviorsand, to a lesser extent, social behaviors (i.e., getting married). However, their reactions were not as pessimistic nor as “patronizing” as were those demonstrated by college students in previous research. In the second experiment, mentally retarded adolescents indicated that they also have negative behavioral expectations of retarded children, however, their self expectations were negative only for social behaviors. The results suggest that, among retarded persons, the expectations associated with the MR label are negative for social behavior, but apparently less pessimistic for cognitive and ability related tasks.     

Selective exposure to self

Male undergraduates received either an accepting or unaccepting communication from a coed. Then each subject had the opportunity to listen to his own voice or the voice of another male, and it was found that preference for listening to one's own voice was higher among subjects who had received positive feedback from the coed. There was also evidence that this pattern of selective exposure is weakened when feedback is less impactful. The results were interpreted through a theory of objective self awareness.     

Using images to increase exercise behavior: prototypes versus possible selves

This study investigated the impact of health-related prototypes and possible selves on exercise behavior. In addition, this study examined if these effects might be moderated by individual differences-specifically social comparison (SC) and consideration of future consequences (CFC). One hundred and fifty-two students participated in all three waves of the study-premanipulation, manipulation, and follow-up. As expected, results indicated that individuals who were high on SC and exposed to a prototype manipulation increased their exercise behavior at follow-up. Furthermore, individuals who were future-oriented and exposed to a possible selves manipulation increased their exercise behavior at follow-up. Overall, results revealed that health images have an important impact on health behavior. Implications for behavior change are discussed.     

Homily at the Opening Prayer of the 11th Assembly of the World Council of Churches

This is the text of the homily at the opening prayer of the 11th Assembly of the World Council of Churches on 31 August 2022. The homily was based on Jesus' encounter with the Samaritan woman at the well, a narrative in the fourth chapter of the Gospel of John. Despite wide gaps of religious belief, gender, culture, and lifestyle, Jesus took the woman seriously and spoke to her on a personal level.     

The brief Reasons for Living Inventory for adolescents (BRFL-A)

This study modified and evaluated the psychometric properties of the Reasons for Living Inventory (RFL) in samples of adolescents. Internal consistency reliability, corrected item-total scale correlation, and exploratory factor analysis procedures were used with a mixed sample of 260 adolescents to identify 14 items for the brief version of the RFL (BRFL-A). Confirmatory factor analyses provided support for the five-factor oblique structure of the BRFL-A in a psychiatric inpatient sample with a range of suicidal behaviors. Reliabilities of the BRFL-A subscales were satisfactory. Four of the five subscales differentiated between suicidal and nonsuicidal adolescents. Significant correlations were found between three BRFL-A subscales and several suicide indices. Convergent-discriminant validity was examined by correlating the BRFL-A subscales with the Minnesota Multiphasic Personality Inventory—Adolescents (MMPI-A) Content Scales. Limitations of the study are discussed.This study was supported in part by a Project Grant from the Graduate College, The University of Northern Iowa.