AF-DX 116, a Presynaptic Muscarinic Receptor Antagonist, Potentiates the Effects of Glucose and Reverses the Effects of Insulin on Memory

Male Swiss mice were tested 24 h after training in a one-trial step-through inhibitory avoidance task. Low subeffective doses of -(+)-glucose (10 mg/kg, ip), but not its stereoisomer -(−)-glucose (30 mg/kg, ip), administered immediately after training, and AF-DX 116 (0.3 mg/kg, ip), a presynaptic muscarinic receptor antagonist, given 10 min after training, interact to improve retention. Insulin (8 IU/kg, ip) impaired retention when injected immediately after training, and the effects were reversed, in a dose-related manner, by AF-DX 116 (0.3, 1.0, or 3.0 mg/kg, ip) administered 10 min following insulin. Since AF-DX 116 possibly blocks autoreceptors mediating the inhibition of acetylcholine release from cholinergic nerve terminals, the present data support the view that changes in the central nervous system glucose availability, subsequent to modification of circulating glucose levels, influence the activity of central cholinergic mechanisms involved in memory storage of an inhibitory avoidance response in mice.     

Ethical attentiveness

Kantian virtue can be construed as a condition of an agent which secures adherence to the requirements of morality in the face of the ever-present possibility of inner conflict with counter-ethical considerations. This paper claims that this conception of virtue does not fit in well with one essential characteristic of the virtuous agent; that he or she is attentive to the well-being of others. After some preliminary remarks about virtue-related evaluations, the paper criticises the Kantian conception of virtue in the light of certain characteristics of ethical attentiveness. The paper concludes by developing a notion of ethical habituation which includes the training of attention.     

MMPI-2 Assessment of Varying Levels of Posttraumatic Stress in Vietnam Combat Veterans

The effectiveness of the MMPI-2 in the detection of posttraumatic stress (PTS) symptomatology was investigated. Forty-nine veterans at a VA posttraumatic stress clinic were evaluated for PTS symptomatology according to DSM-III-R criteria. The ability of the MMPI-2 to differentiate between Vietnam combat veterans (VCV) who met DSM-III-R criteria for posttraumatic stress disorder (PTSD; N = 36) and those who reported varying levels of posttraumatic stress symptoms (PTSS; N = 13) was examined. Overall, the MMPI-2 was effective in differentiating between the two groups of veterans. Of the 15 MMPI-2 scales used to evaluate PTS symptomatology, 12 significantly differentiated veterans with PTSD from those with PTSS. Diagnostic efficiency statistics for the MMPI-2 PTSD scales (PS and PK) were calculated at four cutoff points (T 65, 70, 75, and 80). The PS Scale was the most robust and effective index in differentiating between veterans with PTSD and those with PTSS. Implications for the assessment of varying degrees of PTS are discussed.     

Effect of sentence structure on stuttering

The elicited speech of 20 adult male stutterers was analyzed to determine the effect of the number, type, and location of relative clause structures on the frequency of stuttering. The selected structures were identified on the basis of transformational grammar. The findings indicate that the frequency of stuttering increases significantly with an increase in the number of relative clauses included in a matrix sentence structure. The results also indicate that the more severe the stuttering is, the more the stutterer is likely to be affected by this variable. Trends toward more frequent stuttering in the postverbal relative clause and the adjectival form of the relative clause were observed.     

Recipient mood states and helping behavior

Three studies investigated the effects of perceived recipient mood on helping behavior. Based upon Schwartz' (in Advances in experimental social psychology, Vol. 10, N.Y.: Academic Press, 1977) discussion of need-based helping, it was predicted that donors would perceive greater psychological need and would help more when the recipient's mood was negative than when it was neutral. These predictions were confirmed for females but not for males. The results also confirmed the hypothesis, derived from Schwartz (1977), that a negative recipient mood would elicit greater helping than a neutral recipient mood when this mood is perceived as changeable but not when it is perceived as unchangeable.     

Left hemisphere selectivity for processing duration in normal subjects

The role of the left cerebral hemisphere for the discrimination of duration was examined in a group of normal subjects. Two tasks were presented: the first required a reaction-time response to the offset of monaural pulse sequences varying in interpulse duration, and the second required the discrimination of small differences in durations, within a delayed-comparison paradigm. In each task a right-ear advantage was obtained when the durations were 50 msec or less. No ear advantage was obtained for the larger durations of 67 to 120 msec. Since the perceptual distinctiveness of phonemes may be provided by durations approximating 50 msec, the nature of the relationship between the left hemisphere's role in temporal processing and speech processing may be elaborated.     

Order of partial and consistent reward,reward magnitude shift,and resistance to extinction

In a separate-phase runway experiment with rats, four schedules involving partial (P) and consistent (C) reward (CC, CP, PC, and PP) were crossed with three reward magnitude shift conditions (upshift, nonshift, and downshift). The data revealed three major findings: (a) Reward magnitude downshift generally led to rapid extinction; (b) consistent reward prior to partial reward (CP) resulted in slower extinction than the reverse order (PC) under conditions of reward magnitude shift (particularly downshift); and (c) the relative performance of PC and CP under conditions of reward magnitude shift was reversed from postshift to extinction. On the basis of these data it was suggested that processes not presently identified by reinforcement level theory and stimulus analyzer theory influence extinction following separate-phase acquisition. A modification of reward level theory was presented to provide an account of extinction performance following separate-phase reward reduction.     

Increasing and decreasing intrinsic interest with contingent rewards: A test of cognitive evaluation theory

The study examined Deci's (Deci, E. L. Intrinsic motivation. New York: Plenum Press, 1975) hypotheses regarding the effects of contingent rewards on intrinsic task interest. Seventy-two male university students worked on a series of puzzles and were given either a high value reward ($1.50) or a low value reward ($.45). The money was given either contingent upon the simple execution of the task (task-contingent), contingent upon the ostensible attainment of a performance criterion level (criterion-contingent), or noncontingent and unexpected (control). Compared to the high payment control subjects, subjects who received the task-contingent high reward rated the task as less interesting, while subjects who received the criterion-contingent high reward rated it as more interesting. Also, subjects expressed less interest in the task after receiving the high task-contingent reward than the low task-contingent reward, but indicated greater interest after receiving the high criterion-contingent reward than the low criterion-contingent reward. It was concluded that substantial support was obtained for Deci's (1975) cognitive evaluation theory.     

Development of strategies for recalling letter sequences

Kindergarten, second-grade, and fourth-grade children (6, 8, and 10 years of age, respectively) were asked to recall letter sequences on a task that required the use of: (a) a verbal strategy; (b) a positional strategy; or (c) either strategy. Additional trials, allowing either strategy, were interspersed among those requiring a verbal or positional strategy; strategy use was determined from performance on these interspersed trials. The results show that children at all grade levels attempted to use a task-appropriate strategy. Performance on the verbal task showed a more marked developmental increase than did performance on the positional task. A second experiment replicated the first with the interspersed trials removed. A third experiment was designed to determine whether letter names interfered with older children's efficient use of a positional strategy. Even with this source of interference removed, the developmental pattern of Experiments 1 and 2 was replicated. There was a Sex by Condition interaction in Experiments 2 and 3 which showed that males do better in the condition requiring a positional strategy, and females do better in the condition requiring a verbal strategy.