Alison C Bowling

Effect of nicotine on saccadic eye movement latencies in non-smokers

Alison C. Bowling — Wed, 18 Aug 2010 18:48:26 PDT

Objective Recently, saccadic eye movement tasks have been used to assess the effects of nicotine on higher cognitive processes, including inhibitory control. Saccadic task switching methods suggest that there is prolonged inhibition of the saccadic eye movement system following antisaccade trials. The objective of this research was to examine effects of nicotine on inhibition using saccadic task switching paradigms. Methods Nicotine and placebo lozenges were administered on separate days to 40 non-smokers who performed prosaccade and antisaccade tasks. In addition, participants performed a series of trials in which prosaccade and antisaccade tasks were switched. Eye movement latencies were recorded. Results Participants responded significantly faster for the nicotine condition than for the placebo condition. A switch benefit was observed for only placebo antisaccade trials, in that latencies of repetition trials were significantly longer than those of switch trials. In addition, an analysis of the repetition trials showed an interaction between saccade type and sequence position for the placebo condition, but not the nicotine condition. Conclusion Inhibition persists after antisaccade trials in a switching paradigm, but that the duration of this inhibition is reduced by nicotine.

A comparison of patient clinical and social outcomes before and after the introduction of an extended hours community mental health team

Daphne Habibis — Tue, 26 May 2009 23:06:20 PDT

Objective: The aim of this study was to assess the effectiveness of the addition of standard community treatment to a hospital-based service in a regional district of Australia. Method: The study was a naturalistic investigation of a routine clinical service and utilized a longitudinal panel design. Two matched groups of seriously mentally ill patients were recruited, one before the addition of the community mental health team (CMHT) and one after. Each sample was followed up for one year using a semistructured questionnaire and instruments including the Brief Psychiatric Rating Scale, the Global Assessment Scale, the Life Skills Profile and the Rosenberg Self-Esteem Scale as well as hospital records. Results: Patients in both groups showed similar patterns of improvements. Although the aims of the new service included reducing in-patient utilization and improving social functioning, there were few significant differences between the two groups. While the number of admissions and length of stay were lower in the post-CMHT sample most were admitted rather than treated in their homes by the CMHT. Conclusion: The study concludes that better outcomes might have been achieved if the aims of the CMHT had been limited to either crisis or rehabilitation interventions, but not both. More attention needs to be paid to the service context in which model programmes are introduced so that new developments can be more closely tailored to the realities of what is likely to be achievable.

Early psychosis across the age range - age at first admission with schizophrenia in Tasmania (poster)

Kenneth C. Kirkby — Tue, 26 May 2009 23:06:19 PDT

Psychiatric and social outcomes of a rural district general hospital in the 1990s

Daphne Habibis — Tue, 26 May 2009 23:06:18 PDT

This study investigates the psychiatric and social outcomes of treatment by the psychiatric unit of a district general hospital in a semirural region of Australia. The study is a naturalistic investigation of a routine clinical service, and utilizes a longitudinal panel design. Repeat interviews at admission, 1 month and 1 year later were conducted with all consenting respondents (n = 57) with a diagnosis of schizophrenia, bipolar disorder or related condition, as well as with their nominated relatives. Patients showed significant improvements on clinical measures (P < 0.001) and a high rate of continuation of medication. Most measures of social functioning showed improvement although few were statistically significant. Patients and relative satisfaction was high. Relative worry showed significant improvement in the first month (P < 0.05). There was a high rate of readmission (31 patients) and mean days in hospital were also high at 43 days. These results suggest that basic district general hospital care, operating under both budgetary restrictions and the difficulties associated with recruiting staff can nonetheless provide a credible service. However, the results fall short of what research tells us can be achieved when services are adequately funded and more specifically targeted to meet patient needs.

Diagnostic shift from schizophrenia to affective disorder (poster)

Brett A. Daniels — Tue, 26 May 2009 23:06:16 PDT

Admission history prior to first inpatient diagnosis of bipolar disorder

Kenneth C. Kirkby — Fri, 01 May 2009 15:46:45 PDT

The effect of stimulus duraton on the persistence of gratings

Alison C. Bowling — Wed, 08 Apr 2009 22:38:13 PDT

The persistence of gratings varying in spatial frequency and exposure duration was measured using a stimulus-blank alternation method. Persistence was found to lengthen with increasing spatial frequency and to shorten with increasing exposure duration. For each spatial frequency, persistence decreased linearly with a slope of approximately -.75 as duration increased for short stimulus durations. For longer stimulus durations, the rate of decline in persistence with increasing duration was reduced, the slope being approximately -.13. The stimulus duration at which the change in slope of the persistence-duration relationship occurred was shown to increase with increasing spatial frequency and was approximately equivalent to the critical duration for each spatial frequency. The data were consistent with an interpretation of persistence in terms of a temporal integration component and a second, possibly cortically located, component.

Peroxidase activity and lignification in the pod membranes of Pisum sativum L

Alison C. Bowling — Wed, 08 Apr 2009 22:38:12 PDT

An investigation of four mutant lines of peas showed an inverse relationship between peroxidase activity and lignification of the pod membrane. From developmental studies, it appeared that the main role of peroxidase was in cellular growth and differentiation. It was suggested that peroxidase may predispose cells to lignification without being directly involved in the lignification process.

Response times to different spatial frequencies:

Alison Bowling — Wed, 08 Apr 2009 22:38:11 PDT

Stanley, Howell, and Smith (1980) present an alternative analysis of the persistence data obtained by Bowling and Lovegrove (1980). They argue that stimulus onset asynchrony (SOA) is a more appropriate measure of persistence than interstimulus interval (ISI). In addition, they propose that the use of this measure alters the conclusion made by Bowling and Lovegrove (1980) that the stimulus duration at which persistence ceases to decline steeply with increasing stimulus duration increases with spatial frequency and is related to temporal integration. We consider that SOA is a measure of the total duration of the response to a stimulus, rather than of persistence, and use of this measure does not affect the major conclusions of Bowling and Lovegrove (1980). Stanley et al. (1980) also mentioned that a nonlinear continuous function may provide a better fit to Bowling and Lovegrove’s data than a two-limb linear function. This possibility was evaluated by fitting linear, quadratic, and logarithmic functions to the data by the method of least squares. The sums of the squared deviations of the data points from each of these regression relationships and from the two-limb linear relationship were calculated. Table 1 shows that, for each spatial frequency, the deviation of the data points from the two-component linear relationship was lower than that for any other relationship. The two-limb relationship is therefore a better fit to the data than any of the other possibilities investigated.

An investigation of the determinants of body image shame

Ted Thompson — Wed, 08 Apr 2009 22:38:10 PDT

Iconic memory: Fallacies persist (?)

Alison C. Bowling — Wed, 08 Apr 2009 22:38:08 PDT

Two recent papers (Coltheart, 1980; Long, 1980) have evaluated literature on the relationship between "iconic memory" and "visible persistence." In doing this, both writers focused on methods of measurement of these phenomena and the influence on them of luminance and duration. On the basis of his literature review, Coltheart (p. 210) concluded "the distinction between iconic memory and visible persistence is not merely terminological: they are actually different psychological processes." In comparison, Long concluded (p.814) that "the appealing parsimony of equating visible persistence and iconic memor)’, which has been the traditional view (e.g., Neisser, 1967), need not be abandoned." The present paper evaluates the strength of Long’s arguments, and concludes that: (1) conflict arises over problems of definition; (2) the data from experiments using methods considered inappropriate by Long are very consistent and yield useful information about visible persistence; (3) it consequently cannot be claimed that the bulk of the evidence supports a positive relationship between stimulus intensity (or duration) and persistence duration; (4)it is misleading to claim that Long’s data, usually collected under a specific combination of somewhat extreme experimental conditions, is representative of data in the area; and (5)iconic memory and visible persistence cannot be readily equated.

The effects of the contrast, spatial frequency, and

Alison C. Bowling — Wed, 08 Apr 2009 22:38:07 PDT

Three experiments, in which the temporal and spatial characteristics of square-wave gratings surrounding a central test field were varied, are reported. The detection thresholds of 1-sec presentations of a 5-Hz counterphase flickering .5-cycle/deg (cpd) sinusoidal grating were measured under the different surround conditions. Threshold was found to increase with increasing surround contrast, and to be confined to surround spatial frequencies of 2 cpd and below. Maximum threshold elevation occurred with surround drift frequencies at about 8 Hz, irrespective of spatial frequency. It was concluded that the surround effect is probably due to an inhibitory interaction between transient-type mechanisms in the central visual field and the pheriphery.

The effect of spatial frequency and contrast on visual persistence

Alison C. Bowling — Wed, 08 Apr 2009 22:38:06 PDT

The visual persistence of sinusoidal gratings of varying spatial frequency and contrast was measured. It was found that the persistence of low-contrast gratings was longer than that of high-contrast stimuli for all spatial frequencies investigated. At higher contrast levels of 1 and 4 cycles deg-1 gratings, a tendency for persistence to be independent of contrast was observed. For 12 cycles deg-1 gratings, however, persistence continued to decrease with increasing contrast. These results are compared with recently published data on other temporal responses, and are discussed in terms of the different properties of sustained and transient channels.

Physical fitness, exercise, age and human sleep

John Trinder — Wed, 08 Apr 2009 22:38:04 PDT

A number of studies have reported that physically fit individuals have more slow wave sleep (SWS) than unfit individuals on nights following non-exercise days. However these studies have failed to control for residual exercise effects from previous days. The present study was designed to replicate the original finding and to determine if the reported difference was due to a chronic fitness effect or to a residual exercise effect. In addition the fitness effect was tested in an older population than had previously been tested. The design consisted of two levels of fitness, two age groups (22-0 and 31-8 years of age) and 3 measurements occasions, the first following afternoon exercise and the second and third following 2 and 4 days of exercise deprivation for fit subjects and 3 non-exercise days for unfit subjects. The conditions were arranged in a 223 design. The results indicated a significant effect of physical fitness on SWS in the younger age group but not the older. As there was no immediate effect of exercise, the elevation of SWS in the younger fit group appears to represent a chronic difference between young fit and unfit populations. The results have implications for the nature of restorative processes occurring during sleep.

Specific reading disability: differences in contrast sensitivity as a function of spatial frequency

William Lovegrove — Wed, 08 Apr 2009 22:38:03 PDT

Contrast thresholds for sine-wave gratings of spatial frequencies of 2, 4, 12, and 16 cycles per degree were determined for normal and disabled readers at a range of stimulus durations. Normal readers demonstrated monotonically decreasing sensitivity with increasing spatial frequency at exposure durations between 40 and 100 milliseconds. At exposure durations of 150 to 1000 milliseconds, they showed peak sensitivity at 4 cycles per degree. In comparison, disabled readers showed monotonically decreasing sensitivity with increasing spatial frequency at all stimulus durations. The difference in sensitivity pattern across spatial frequencies was greatest at stimulus durations approximately equal to fixation durations during reading.

The effects of peripheral movement and flicker

Alison C. Bowling — Wed, 08 Apr 2009 22:38:01 PDT

Contrast sensitivity functions were obtained in the presence of temporally modulated surrouads. Sensitivity to low spatial frequencies was depressed below that found with a steady surround when the surround was either a sinusoidally flickering field or a drifting vertical square-wave grating. This effect was observed both with 1-sec presentations of 5- and 0.5-Hz counterphase flicker and with 60-msec pulsed gratings. In addition, reaction time histograms became more characteristic of sustained mechanisms in the presence of temporal modulation. The data were considered in terms of the activity of a nonlinear network of retinal subunits

Problems for an after-image explanation of monocular rivalry

Barry Mapperson — Wed, 08 Apr 2009 22:38:00 PDT

Implicit memory for non-attended stimuli

Alison C. Bowling — Wed, 08 Apr 2009 22:37:58 PDT

Spatial frequency processing and the prediction of reading ability : a preliminary investigation

William Lovegrove — Wed, 08 Apr 2009 22:37:57 PDT

Measures of vocabulary, digit span, and pattern-contrast sensitivity for low- to medium-spatialfrequency gratings were collected from 123 representative prereaders. A multiple regression analysis showed that these were moderate predictors of reading ability 2 years later. The contrastsensitivity measure made a significant unique contribution to the regression equation. The results are interpreted in terms of recent data that indicate a transient-system deficit in specifically disabled readers

Admission history prior to first inpatient diagnosis of bipolar disorder (poster)

Kenneth C. Kirkby — Wed, 08 Apr 2009 22:37:56 PDT