The Psychodynamics of Theatrical Spectatorship

The Psychodynamics of Theatrical Spectatorshi

Stability and variability in extinction.

Some studies have found that extinction leaves response structures unaltered; others have found that response variability is increased. Responding by Long-Evans rats was extinguished after 3 schedules. In one, reinforcement depended on repetitions of a particular response sequence across 3 operanda. In another, sequences were reinforced only if they varied. In the third, reinforcement was yoked: not contingent upon repetitions or variations. In all cases, rare sequences increased during extinction— variability increased—but the ordering of sequence probabilities was generally unchanged, the most common sequences during reinforcement continuing to be most frequent in extinction. The rats' combination of generally doing what worked before but occasionally doing something very different may maximize the possibility of reinforcement from a previously bountiful source while providing necessary variations for new learning. The main goal of the present study is to reconcile two competing accounts of extinction. One is that variability increases during extinction of operant responses. Another is that operant structures, manifest in response topographies, sequences, and distributions, are unaffected by extinction and remain intact. How can structure

Effect of a maternal cafeteria diet on the fatty acid composition of milk and offspring red blood cells

Abstract not availableM.A. Vithayathil, J.R. Gugusheff, R.A. Gibson, Z.Y. Ong, B.S. Muhlhausle

Lung stem cell update: Promise and controversy

Currently, there is great enthusiasm about potential stem cell therapies for intractable diseases. We previously reviewed the topic of stem cells in lung injury and repair, including the role of endogenous, tissue (somatic) stem cells and the contribution of circulating cells to the lung parenchyma. Our purpose here is to provide a concise update in this fast-moving field. New information and ongoing debate focus attention on basic issues in lung stem cell biology and highlight the need for additional studies to establish the feasibility of cell therapies to prevent or treat lung diseases

Lung Stem Cell Update: Promise and Controversy

Currently, there is great enthusiasm about potential stem cell therapies for intractable diseases. We previously reviewed the topic of stem cells in lung injury and repair, including the role of endogenous, tissue (somatic) stem cells and the contribution of circulating cells to the lung parenchyma. Our purpose here is to provide a concise update in this fast-moving field. New information and ongoing debate focus attention on basic issues in lung stem cell biology and highlight the need for additional studies to establish the feasibility of cell therapies to prevent or treat lung diseases

Psychopharmacological and Other Treatments in Preschool Children with Attention-Deficit/Hyperactivity Disorder: Current Evidence and Practice

Objective: This article reviews rational approaches to treating attention-deficit/hyperactivity disorder (ADHD) in preschool children, including pharmacological and nonpharmacological treatments. Implications for clinical practice are discussed. Data Sources: We searched MEDLINE, PsychINFO, Cumulative Index to Nursing & Allied Health, Educational Resources Information Center, Cochrane Database of Systematic Reviews and Database of Abstracts of Reviews of Effects for relevant literature published in English from 1967 to 2007 on preschool ADHD. We also reviewed the references cited in identified reports. Study Selection: Studies were reviewed if the sample included at least some children younger than 6 years of age or attending kindergarten, the study participants had a diagnosis of ADHD or equivalent symptoms, received intervention aimed at ADHD symptoms, and included a relevant outcome measure. Data Extraction: Studies were reviewed for type of intervention and outcome relevant to ADHD and were rated for the level of evidence for adequacy of the data to inform clinical practice. Conclusions: The current level of evidence for adequacy of empirical data to inform clinical practice for shortterm treatment of ADHD in preschool children is Level A for methylphenidate and Level B for parent behavior training, child training, and additive-free elimination diet

Age-Related Decline in Rod Phototransduction Sensitivity in Rhesus Monkeys Fed an n-3 Fatty Acid-Deficient Diet

PURPOSE. Docosahexaenoic acid (DHA), an n-3 fatty acid, is the major polyunsaturate in rod outer segments. The effect of long-term n-3 fatty acid deficiency on rod and cone phototransduction was investigated in the rhesus monkey. METHODS. From birth to Х9 years rhesus monkeys were fed an n-3-deficient diet (n ϭ 9) known to reduce retinal DHA by 80%. Monkeys in the control group (n ϭ 12) received either 8% ␣-linolenic acid (ALA) or 0.6% DHA, both of which support normal retinal DHA levels. None of the diets contained carotenoids. Photoactivation kinetics were assessed from the rate of increase and a P3 model fit of the ERG a-wave. Maximal cone amplitude and sensitivity were measured from the cone a-wave at 4 ms. The rod photoresponse and rod recovery were derived by using a paired flash method. RESULTS. Rod sensitivity was reduced by 40% in the n-3-deficient monkeys at 9 but not 4.5 years. The onset of the rising phase of the photoresponse was significantly delayed (P Ͻ 0.004) at 9 years. Rod recovery was delayed by 20% in n-3-deficient monkeys at both ages, but only for bright saturating flashes. Cone phototransduction was not altered by n-3 deficiency. CONCLUSIONS. Long-term dietary n-3 deficiency in the rhesus monkey was associated with two changes in retinal function. First, there was a delay in rod recovery that has remained relatively constant throughout life. Second, there was an agedependent loss in rod phototransduction sensitivity; the lack of dietary carotenoids may have contributed to this decline. (Invest Ophthalmol Vis Sci. 2009;50:4360 -4367) DOI:10.1167/ iovs.09-3640 D ocosahexaenoic acid (DHA or 22:6n-3), an n-3 fatty acid with six double bonds, is the major polyunsaturated fatty acid in rod outer segments (ROS). The highest concentration of DHA is found in the retina, particularly within the ROS where DHA accounts for up to 60% of phosphatidylethanolamine (PE) acyl chains. 1 PE is the major phospholipid class of the outer bi-lipid layer of ROS discs. The cone-dominated retinas of the goldfish and chick are also highly enriched in DHA. 1,2 The effects of dietary n-3 deficiency on retinal lipid composition have been well described. The most consistent change in retinal function in n-3-deficient rodents, as measured with the ERG, is a reduction in ERG amplitude. 7 described a nonlinear function that related the reduction in rod sensitivity to retinal DHA levels, but only at 16 weeks of age, by which time guinea pigs are adults. In contrast, there were no significant losses of rod sensitivity from n-3-deficient guinea pigs at 6 or 11 weeks of age, despite 35% to 40% reductions in retinal DHA at these time points. At 16 weeks, similar reductions in retinal DHA levels were associated with significantly reduced rod sensitivity. The results indicate lower retinal DHA in combination with aging alters rod photoreceptor function in the guinea pig. In our earlier studies of the rhesus monkey, the most consistent change in retinal function of n-3-deficient animals was a delay in rod recovery as measured from either ERG a-or b-waves, a change seen starting in infancy. 5,8 However, we found no alteration in rod phototransduction sensitivity in n-3-deficient rhesus monkeys at 4.5 years of age when these animals were juveniles or subadults. 8 Given the interaction between age and n-3 deficiency in guinea pigs, the purpose of the present study was to investigate the effect of long-term n-3 deficiency on phototransduction mechanisms in our rhesus monkeys, now mature adults aged 9.2 Ϯ 1.2 years. The monkeys examined in the present study are of particular interest, as their diets were also free of carotenoids, including the xanthophylls lutein and zeaxanthin, which form the macular pigment. In a previous study of monkeys fed the same diets as we used, no lutein or zeaxanthin was present in the serum, and there was no detectable macular pigment. 10 Although the effects of varying dietary carotenoid levels were not examined in the monkeys described herein, the effect of long-term deficiency of both carotenoids and n-3 fatty acids on retinal function and aging is of particular interest. These two nutrients have been identified as risk factors for age-related macular degeneration (AMD) and are being evaluated in a large-scale trial of AMD progression 11 (www.areds2.org/ Age-Related Eye Disease Study)

Persistence and Relapse of Reinforced Behavioral Variability

The present study examined persistence and relapse of reinforced behavioral variability in pigeons. Pigeons emitted four‐response sequences across two keys. Sequences produced food according to a lag schedule, in which a response sequence was followed by food if it differed from a certain number of previous sequences. In Experiment 1, food was delivered for sequences that satisfied a lag schedule in both components of a multiple schedule. When reinforcement was removed for one component (i.e., extinction), levels of behavioral variability decreased for only that component. In Experiment 2, food was delivered for sequences satisfying a lag schedule in one component of a multiple schedule. In the other component, food was delivered at the same rate, but without the lag variability requirement (i.e., yoked). Following extinction, levels of behavioral variability returned to baseline for both components after response‐independent food delivery (i.e., reinstatement). In Experiment 3, one group of pigeons responded on a lag variability schedule, and the other group responded on a lag repetition schedule. For both groups, levels of behavioral variability increased when alternative reinforcement was suspended (i.e., resurgence). In each experiment, we observed some evidence for extinction‐induced response variability and for variability as an operant dimension of behavior