Linked Life Data

3154790

Source:http://linkedlifedata.com/resource/pubmed/id/3154790

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1991-5-23
pubmed:abstractText
Nucleus rotundus and nucleus dorsolateralis posterior (DLP) are the thalamic components of two parallel pathways within the tectofugal division of the pigeon visual system. An earlier study (Hodos, Weiss & Bessette, 1986) had shown that lesions in direct telencephalic recipients of projections from rotundus and DLP produced postoperative elevations in size-difference thresholds only if the lesion included both structures. What was not revealed by their study was whether the integrity of both thalamic components is necessary for pigeons to discriminate small differences in the size of stimuli or whether the birds could still make the discrimination with only one of the two nuclei intact. This question was particularly important because no prior behavioral evidence existed to indicate that DLP plays a role in visual information processing. Therefore, 14 pigeons were tested preoperatively using a variant of the method of constant stimuli to determine the smallest difference between the size of two annuli that the subjects could discern. The comparison stimuli, which were presented in a successive discrimination procedure, ranged from 3.5-15 mm in diameter. After surgery, in which lesions were placed bilaterally in rotundus, DLP, or both structures, the subjects' size-difference thresholds were again determined. Combined lesions of rotundus and DLP resulted in impaired psychophysical performance. The postoperative behavior was characterized by initial elevations in threshold followed by a gradual improvement in performance. Some birds returned to their preoperative level. By comparison, subjects with lesions in rotundus or DLP alone showed an immediate return to their preoperative sensitivity level. These results indicate that both nuclei can process information about the size of visual stimuli. Moreover, the processing that occurs within either nucleus is sufficient for the pigeon to discriminate size differences. The present experiment provides the first behavioral evidence that DLP participates in visual information processing.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:issn
0952-5238
pubmed:author
pubmed:issnType
Print
pubmed:volume
1
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
83-92
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Size-difference thresholds after lesions of thalamic visual nuclei in pigeons.
pubmed:affiliation
Department of Psychology, University of Maryland, College Park 20742.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.