The superior colliculi were removed in rats at either one or five days of age or in adulthood. Seven months later they were tested on four successively presented two-choice intensity discriminations. The intensity difference between the discriminanda was reduced across the four problems to encourage choice by comparison. The purpose was to establish whether impoverished scanning is a feature of rats with collicular lesions and whether the age at which the lesion is incurred is important. The number of door-push and approach errors made in reaching criterion were used as measures of performance and the number of head-scans during acquisition was counted. The results provide no evidence that either one- or five-day operated rats exhibit sparing or recovery of the ability to scan discriminanda since all operated animals were impaired. Furthermore, novel retinal projections, present in one-day operated animals, fail to mediate such sparing. Finally, the results did not demonstrate a selective increase in approach errors following collicular lesions and were therefore inconsistent with the view that the impairment is one of visually-guided locomotion. It is concluded that visual discrimination learning is impaired following collicular lesions in circumstances where scanning of discriminanda is required for efficient performance.
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Barnes PJ, Smith LM, Latto RM (1970) Orientation to visual stimuli and superior colliculus in the rat. Q J Exp Psychol 22: 239–247
Berlucchi G, Sprágue JM, Levy J, DiBerardino AC (1972) Pretectum and superior colliculus in visually guided behavior and in flux and form discrimination in the cat. J Comp Physiol Psychol 78: 123–172
Dean P, Pope SG (1981) Visual discrimination learning in rats with lesions of the superior colliculus: door-push and approach errors in modified jumping stand. Q J Exp Psychol 33B: 141–157
Dean P, Key C (1981) Spatial deficits on radial maze after large tectal lesions in rats: possible role of impaired scanning. Behav Neural Biol 32: 170–190
Dyer RS, Marino MF, Johnson C, Kruggel T (1976) Superior colliculus lesions do not impair orienttion to pattern. Brain Res 112: 176–179
Goodale MA, Foreman NP, Milner AD (1978) Visual orientation in the rat: a dissociation of deficits following cortical and collicular lesions. Exp Brain Res 31: 445–457
Goodale MA, Murison RCC (1975) The effect of lesions of the superior colliculus on locomotor orientation and the orienting reflex in the rat. Brain Res 88: 243–261
Goss AE, Wischner GJ (1956) Vicarious trial and error and related behaviour. Psychol Bull 53: 35–54
Heywood CA, Cowey A (1985) A comparison of the effects of superior collicular ablation in infant and adult rats. Exp Brain Res 59: 302–312
Mlinar EJ, Goodale MA (1984) Cortical and tectal control of visual orientation in the gerbil: evidence for parallel channels. Exp Brain Res 55: 33–48
Mort E, Cairns S, Hersch H, Finlay B (1980) The role of the superior colliculus in visually guided locomotion and visual orienting in the hamster. Physiol Psychol 8: 20–28
Overton P, Dean P, Redgrave P (1985) Detection of visual stimuli in far periphery by rats: possible role of superior colliculus. Exp Brain Res 59: 559–569
Perry VH, Cowey A (1979a) The effects of unilateral cortical and tectal lesions on retinal ganglion cells in rats. Exp Brain Res 35: 85–95
Perry VH, Cowey A (1979b) Changes in the retino-fugal pathways following cortical and tectal lesions in neonatal and adult rats. Exp Brain Res 35: 97–108
Saldhanka EL, Bitterman ME (1951) Relational learning in the rat. Am J Psychol 64: 37–53
Schneider GE (1967) Contrasting visuomotor functions of tectum and cortex in the golden hamster. Psychol Forsch 31: 52–62
Schneider GE (1969) Two visual systems: brain mechanisms for localization and discrimination are dissociated by tectal and cortical lesions. Science 163: 895–902
Smith CJ, Weldon DA (1976) Hyperactivity and deficits in problem solving following superior colliculus lesions in the rat. Physiol Behav 16: 381–385
Tolman EC, Minium E (1942) Vicarious trial and error in rats: overlearning and difficulty of discrimination. J Comp Psychol 34: 301–306
Weinberg DW, Stein DG (1978) Impairment and recovery of visual functions after bilateral lesions of superior colliculus. Physiol Behav 20: 323–329
Weldon DA, Smith CJ (1979) Superior colliculus lesions and enviromental experience: nonvisual effects on problem solving and locomotor activity. Physiol Behav 23: 159–165
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Heywood, C.A., Cowey, A. The nature of the visual discrimination impairment after neonatal or adult ablation of superior colliculi in rats. Exp Brain Res 61, 403–412 (1986). https://doi.org/10.1007/BF00239529
- Superior colliculus
- Infant vs adult lesions