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Size-difference thresholds after lesions of thalamic visual nuclei in pigeons

Published online by Cambridge University Press:  02 June 2009

Caroline Kertzman
Affiliation:
Department of Psychology, University of Maryland, College Park
William Hodos
Affiliation:
Department of Psychology, University of Maryland, College Park

Abstract

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.

Type
Research Articles
Copyright
Copyright © Cambridge University Press 1988

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References

Benowitz, L.I. & Karten, H.J. (1976). Organization of the tectofugal visual pathway in the pigeon: a retrograde transport study. Journal of Comparative Neurology 167, 503520.CrossRefGoogle Scholar
Delius, J.D. & Bennetto, K. (1972). Cutaneous sensory projections to the avian forebrain. Brain Research 37, 205221.CrossRefGoogle Scholar
Fellows, B.J. (1967). Chance stimulus sequences for discrimination tasks. Psychological Bulletin 67, 8792.CrossRefGoogle ScholarPubMed
Gamlin, P.D.R. & Cohen, D.H. (1986). A second ascending visual pathway from the optic tectum to the telencephalon in the pigeon (Columba livia). Journal of Comparative Neurology 250, 296310.CrossRefGoogle Scholar
Hodos, W., Bessette, B.B., Macko, K.A. & Weiss, S.R.B. (1985). Normative data for pigeon vision. Vision Research 25, 15251527.CrossRefGoogle ScholarPubMed
Hodos, W. & Bobko, P. (1984). A weighted index of bilateral brain lesions. Journal of Neuroscience Methods 12, 4347.CrossRefGoogle ScholarPubMed
Hodos, W. & Bonbright, J.C. (1972). The detection of visual intensity differences by pigeons. Journal of the Experimental Analysis of Behavior 18, 471479.CrossRefGoogle ScholarPubMed
Hodos, W., Weiss, S.R.B. & Bessette, B.B. (1986). Size-threshold changes after lesions of the visual telencephalon in pigeons. Behavioural Brain Research 21, 203214.CrossRefGoogle ScholarPubMed
Hunt, S.P. & Kunzle, H. (1976). Observations, on the projections and intrinsic organization of the pigeon optic tectum: an autoradio-graphic study based on anterograde and retrograde, axonal and dendritic flow. Journal of Comparative Neurology 170, 153172.CrossRefGoogle Scholar
Karten, H.J. & Hodos, W. (1967). A Stereotaxic Atlas of the Brain of the Pigeon (Columba livia). Baltimore: Johns Hopkins University Press.Google Scholar
Karten, H.J. & Hodos, W. (1970). Telencephalic projections of the nucleus rotundus in the pigeon (Columba livia). Journal of Comparative Neurology 140, 3552.CrossRefGoogle ScholarPubMed
Karten, H.J. & Revzin, A. (1966/1967). The afferent connections of the nucleus rotundus in the pigeon. Brain Research 2, 368377.CrossRefGoogle ScholarPubMed
Kitt, C.A. & Brauth, S.E. (1982). A paleostriatal-thalamic-telencephalic path in pigeons. Neuroscience 7, 27352751.CrossRefGoogle ScholarPubMed
Klüver, H. & Barrera, E. (1953). A method for the combined staining of cells and fibers in the nervous system. Journal of Neuropathology and Experimental Neurology 12, 400403.CrossRefGoogle ScholarPubMed
Macko, K.A. & Hodos, W. (1984). Near-field acuity after visual system lesions in pigeons, I: Thalamus. Behavioural Brain Research 13, 114.CrossRefGoogle ScholarPubMed
Nixdorf, B.E. & Bischof, H-J. (1982). Afferent connections of the ectostriatum and visual wulst in the zebra finch (Taeniopygia guttata castanotis Gould) –an HRP study. Brain Research 248, 917.CrossRefGoogle Scholar
Pedhazur, E.J. (1982). Multiple Regression in Behavioral Research. Explanation and Prediction (2nd ed.). New York: CBS College Publishing.Google Scholar
Watanabe, M., Ito, H. & Ikushima, M. (1985). Cytoarchitecture and ultrastructure of the avian ectostriatum: afferent terminals from the dorsal telencephalon and some nuclei in the thalamus. Journal of Comparative Neurology 236, 241257.CrossRefGoogle ScholarPubMed