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Life Sciences	50%

Selected Abstracts

CLINICAL STUDY: Attentional bias in alcohol-dependent patients: the role of chronicity and executive functioning

ADDICTION BIOLOGY, Issue 2 2009
Sabine Loeber
ABSTRACT It has been suggested that the attention towards alcohol-related stimuli increases with the duration of drinking and alcohol dependence. The present study aimed to assess whether an attentional bias was present in detoxified alcohol-dependent patients, and if the magnitude of the attentional bias depended on the subject's drinking history and variables of executive functioning. Attentional bias was assessed in 30 alcohol-dependent patients using a visual dot-probe task with a picture presentation time of 50 ms. In addition, patients completed a variety of different cognitive tasks such as attention, continuous performance, working memory, set shifting and inhibitory control tests. Based on correlation analysis we split the patient sample on the median with regard to the duration of alcohol dependence and our results indicated a significant attentional bias towards alcohol-associated pictures in patients dependent for less than 9 years, but not in patients with a longer duration of dependence. The two patient samples differed significantly with regard to attention and working memory functioning with patients who were dependent for more than 9 years showing a greater impairment. When impairment of attention and working memory were controlled for, the group differences in attentional bias were no longer significant. Our results indicate that differences with regard to drinking-related variables as well as cognitive functioning seem to modulate attentional bias and need to be taken into account in models of drinking maintenance. [source]

Processing of emotionally toned pictures in dementia

INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 9 2006
P. A. T. M. Eling
Abstract Background Apathy is a common symptom in dementia and is often associated with reduced emotional reactivity. This study examined whether reduced emotional reactivity can be demonstrated in dementia patients using a picture viewing task. Methods The viewing time of three different types of visual stimuli was measured in 24 elderly participants, half of which suffered from dementia. The participants had to make a target response to an emotionally neutral target stimulus that was intermixed with a frequently occurring non-target or ,background' stimulus and infrequently presented emotional stimuli. All participants could control the presentation time of each stimulus, but one half of the participants were explicitly instructed to perform the task quickly. Results The main measure was a ratio score in which the viewing time for emotional stimuli was expressed relative to the viewing time for the neutral non-target stimulus. Using this measure, the instigation of a time-pressure condition proved to significantly reduce the viewing time for emotional stimuli in the healthy subjects. Irrespective of time-pressure condition, the dementia patients showed a similar short viewing time for emotional stimuli as did the healthy subjects in the time-pressure condition. However, both dementia patients and healthy controls displayed longer viewing times for unpleasant than for pleasant stimuli. Conclusion These results suggest the ability of the present task to reveal the simultaneous occurrence of an overall reduced interest for novel stimuli and an intact differential emotional reactivity to stimuli with a negative versus positive valence in the dementia patients. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Repetition effect in visual recognition of letters1

JAPANESE PSYCHOLOGICAL RESEARCH, Issue 2 2004
TOSHINORI KUWANA
Abstract:, This study examined the influence of the repetitive presentation of a letter on the recognition of two letters. In two experiments4, two letters, which were either identical or not, were presented successively for a short duration at different spatial locations, and the subjects were required to identify them. In Experiment 1, the presentation time of the first letter was varied, whereas that of the second letter was constant. The results revealed that a reduced performance in identifying a second letter was observed in the case that the first letter, which was identical to the second letter, could be identified correctly. Experiment 2 examined whether or not this reduction was due to the identity of the visual shape of two letters. The first letter was presented either in the usual vertical orientation or rotated orientation by 180 degrees and the second letter was constantly presented in the usual orientation. The results revealed that a reduced performance in identifying a repeated letter was observed, regardless of the orientation of the first letter. The findings from the two experiments suggested that the identity of the information in memory was a main cause of the interference effect by repetition. [source]

Changes in mitogen-activated protein kinase activity occur in the maize pulvinus in response to gravistimulation and are important for the bending response

PLANT CELL & ENVIRONMENT, Issue 7 2003
A. M. CLORE
ABSTRACT The maize (Zea mays L.) pulvinus was used as a model system to study the signalling events that lead to differential growth in response to gravistimulation in plants. The pulvinus functions to return tipped plants to vertical via differential elongation of the cells on its lower side. By performing immunokinase assays using total soluble protein extracts and an antibody against mammalian ERK1, a mitogen-activated protein kinase (MAPK)-like activity was assayed in pulvini halves harvested at various time points after tipping. We detected a reproducible alternation of higher levels of activity occurring between the upper and lower halves of the pulvinus between 75 and 180 min after tipping, with a sustained increase in the upper half occurring at the end of the time-course. This timing roughly corresponds to the presentation time for maize (i.e. the amount of time that the plant needs to be tipped before it is committed to bend), which occurs between 2 and 4 h. Treatment of maize stem explants with an inhibitor of MAPK activation, U0126, led to a reduction in the activity of this kinase, as well as an almost 65% reduction in bending as measured at 20 h. Rinsing out of the inhibitor resulted in recovery of both bending and kinase activity. It is possible that changes in MAPK activity in the gravistimulated pulvinus are part of a signalling cascade that may help to distinguish between minor perturbations in plant orientation and more significant and long-term changes, and may also help to determine the direction of bending. [source]