Developmental Brain Research, 59 119911 23-29 23 Elsevier BRESD 51230 Temporal limits of the susceptibility of depth perception to proprioceptive deafferentations of extraocular muscles Yves Trotter, Jean-Chrlstophe Beaux, Alexandre Pouget* and Michel Imbert Instltut des Neurosctencer, Laboratotre des Neurosclences de la Vtston, Umversttd P e t M Curie, Paris (France) (Accepted 13 November 1990) Key words Depth perception, Binocular WSlOn, Extraocular propnoceptlon, Critical period, Behawor In a prewous study, extraocular muscle propnoceptlon (E O M P ) was shown to play an important role in the postnatal development of depth perception following unilateral or bdateral sections of the ophthalmic branch of the trlgemmal nerve (V:h nerve) performed at 6-8 weeks of age, the binocular thresholds were 2 to 3 times higher than m control animals Since the Vl-Sectlons produced no deficits when performed m adults, the temporal hmlts of a period of susceptibility remained to be determined In order to assess the lower and upper hmlts of the period during which these perceptual deficits could be induced, unilateral or bilateral V:secttons were performed in k~ttens at different ages Depth perception thresholds were measured by using the lumping stand techmque Sections of the V 1 nerve only produced significant impairments of the binocular depth thresholds when performed after 3 weeks of age They could be observed when umlateral sections were performed at up to 13 weeks of age and with bdateral sections at up to 10 weeks of age These functional impairments appeared to remain permanently through adult hfe INTRODUCTION Previous studies 3 5 27,28 have shown that extraocular muscle proprloceptton (E O.M P) played an important role m the development of area 17 cell properties All these studies used dark reared kittens in which rapid modifications of orientation selectivity or ocular domi- nance were obtained following a brief period of visuo- motor experience delayed until the middle of the period of susceptibility of cortical cells to manipulations of visual envtronmentt°; the section of the proprioceptlve afferents performed just before the visual experience prevented or slowed down these functtonal modifications In addition, it was shown that m similar rearing conditions, kittens were not able to acquire normal visually guided behavior unless the E O M.P. afferents of at least one eye were mtact during the visual exposure 13 Thus the main hypothesis of the role of E O M P afferents, as revealed by these experiments, is that they gate visual experience dependent modifications of receptive fields and visuo- motor coordination during postnatal development An- other important role of E O M P_, specifically related to binocular visual perception, was recently demonstrated in the development of depth perception in kittens 11 the E O.M_P deafferentatlons performed around 6-8 weeks of age prevented the development of normal binocular depth thresholds which remained close to monocular levels of performance While deafferentations performed in adult cats produced a deficit in some cases 8'9, In others it they did not Thus the existence of a period of susceptibility of depth perception to V 1 sections remained to be determined The purpose of the present study was to dehmtt the lower and upper temporal limits of this period MATERIALS AND METHODS Ammals Twelve kittens were used in this study Nine of them were subjected to a undateral V:sectlon at 3 weeks of age (n = 3), 10-13 weeks (n = 3), 14 weeks (n = 2), an addlhonal kitten was operated at 4 5 weeks of age The last 3 kittens were subjected to a bdateral V:sectlon at 3weeks of age (n = 1), 95-115 weeks (n = 2) of age (For the detaded surgical procedures, see ref_ 29 ) Briefly, the surgery was performed under general anesthesia reduced by intramuscular mlect~on of Althesln (Glaxo, 1 2 ml-kg 1, l e_ 10 8 mg kg ~ of alfaxolone and 3 6 mg kg ~ of alfadolone acetate) and maintained by continuous rejection of mlthesln through a catheter inserted m the radial vein A temporal approach was used to reach the V~ nerve and a piece of it (2-3 ram) was removed near the junction with the Gassenan ganglion After the surgery was complete, antibiotics were apphed locally (soframycm) and by intramuscular rejection (terramycin) Behavtoural tests The kittens were tramed to discriminate differences m depth using the jumping stand technique 1~ 1~ They had to discriminate the * Present address Computational Neuroblology Laboratory, Salk Institute, La Jolla, CA, U S A Correspondence Y Trotter, Laboratolre de Neurosoences de la VLslon, Insmut des Neurosclences. Umverslt6 Pierre et Marie Curie, 9 Qual Saint Bernard, 75005 Pans, France 0165-3806/91/$113 50 © 1991 Elsevier Science Publishers B V (Biomedical Division)