| The effects of aging on motion detection and direction identification. | |
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MedLine Citation:
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PMID: 17289106 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Random dot cinematograms were used to probe motion perception in human observers ranging from 23 to 81 years of age. Stimuli were either broadband directional Noise, which produces no experience of global motion flow, or a narrower band directional Signal, which tended to produce experiences of coherent, global direction flow. On each trial, subjects rated their certainty that a Signal had been presented, and used a computer mouse to indicate the direction of perceived global flow. At all ages, sensitivity to motion and accuracy of perceived direction improved significantly as stimulus duration increased from 75 to 470 ms. However, older subjects (>70 years of age) were significantly less sensitive to motion, and were significantly less accurate at identifying the direction of movement. A control experiment, which found that older subjects accurately perceived and remembered the orientation of a line, ruled out the possibility that the observed deficits in motion perception were due to an inability on the part of older subjects to manipulate the computer mouse. Those control results also showed that both younger and older observers maintained robust visual representations over durations ranging from .24 to 6.0s. The motion detection and identification results obtained from subjects less than 70 years of age were well fit by a simple multichannel model of motion, although different levels of additive internal noise were needed to fit detection data and direction-identification data, suggesting that motion direction and identification are constrained by different mechanisms. To fit the data from the oldest subjects, however, the values of model parameters had to be significantly altered, either by increasing the level of additive internal noise substantially, or by a smaller increase in noise coupled with an increase in the bandwidth of the model's directionally selective channels. These results are qualitatively consistent with recent neurophysiological studies showing weaker directional selectivity and higher spontaneous noise in visual neurons of senescent monkeys and cats. |
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Authors:
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Patrick J Bennett; Robert Sekuler; Allison B Sekuler |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't Date: 2007-02-07 |
Journal Detail:
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Title: Vision research Volume: 47 ISSN: 0042-6989 ISO Abbreviation: Vision Res. Publication Date: 2007 Mar |
Date Detail:
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Created Date: 2007-03-06 Completed Date: 2007-06-18 Revised Date: 2007-12-03 |
Medline Journal Info:
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Nlm Unique ID: 0417402 Medline TA: Vision Res Country: England |
Other Details:
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Languages: eng Pagination: 799-809 Citation Subset: IM |
Affiliation:
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Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada L8S 4K1. bennett@mcmaster.ca |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Aged Aged, 80 and over Aging / psychology* Female Humans Male Memory / physiology Middle Aged Models, Psychological* Motion Perception / physiology* Orientation Photic Stimulation / methods Psychophysics Vision, Binocular / physiology |
| Grant Support | |
ID/Acronym/Agency:
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MH 068404/MH/NIMH NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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