title: Intensity difference thresholds after lesions of ectostriatum in pigeons.
abstract: Seven pigeons were trained to perform in a psychophysical procedure to determine the smallest difference in luminous intensity (intensity difference threshold) that they could discriminate. When their performance stabilized, lesions were made in the ectostriatum in 4 birds and in the neostriatum in the remaining 3 birds. After surgery, the pigeons with ectostriatum lesions showed markedly elevated thresholds. The neostriatum control cases showed only trivial threshold changes as a consequence of the surgery. A psychophysical scaling analysis showed that the ectostriatum-lesioned pigeons had lost from 50% to 83% of their preoperative capacity to discriminate differences in the intensity of visual stimuli. A multiple-regression analysis based on quantitative reconstructions of the lesions revealed that only damage to the core region of the ectostriatum contributed to the postoperative threshold changes.
authors.affiliation: Department of Psychology, University of Maryland, College Park 20742.
authors.forename: W
authors.initials: W
authors.lastname: Hodos
authors.forename: S R
authors.initials: SR
authors.lastname: Weiss
authors.forename: B B
authors.initials: BB
authors.lastname: Bessette
mesh_terms: D000818:Animals; D001931:Brain Mapping; D010856:Columbidae; D004193:Discrimination Learning / Q000502:physiology; D011601:Psychophysics; D012684:Sensory Thresholds; D013477:Superior Colliculi / Q000502:physiology*; D013787:Thalamic Nuclei / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*