Behavioural Brain Research 259 (2014) 1–8 Contents lists available at ScienceDirect Behavioural Brain Research j ourna l h om epage: www.elsevier.com/locate/bbr Research report Cerebellum and spatial cognition in goldfish Emilio Durán ∗ , Francisco M. Oca ˜ na, Isabel Martín-Monzón, Fernando Rodríguez, Cosme Salas Laboratory of Psychobiology, Campus Santiago Ramón y Cajal, University of Sevilla, Sevilla, Spain h i g h l i g h t s • Goldfish cerebellum contributes to spatial cognition. • Cerebellar lesions impairs the procedural and the declarative component of navigation. • Cerebelloctomized goldfish are unable to elaborate a cognitive map. • Cognitive functions of the cerebellum are conserved across vertebrates. a r t i c l e i n f o Article history: Received 2 August 2013 Received in revised form 16 October 2013 Accepted 24 October 2013 Available online 31 October 2013 Keywords: Goldfish Cerebellum Spatial learning “Hole-board” task Vertebrate brain evolution a b s t r a c t The cerebellum of mammals has recently been linked to spatial navigation, as indicated by the results of a number of studies performed in animal models with cerebellar abnormalities. However, nothing is known about the contribution of this structure to spatial cognition in other vertebrate groups such as teleost fish. To investigate the involvement of the teleostean cerebellum in navigation, sham-operated (Sh) and cerebellum-ablated (Cb) goldfish were trained in a “hole-board” task in which they had to locate the baited feeder within a 5 × 5 feeder matrix surrounded by visual cues. Cb goldfish were significantly impaired in the acquisition and performance of the task, as revealed by their low spatial accuracy, the number of errors committed, and the stereotyped searching pattern exhibited relative to Sh goldfish. Probe tests, performed during the final training sessions, showed that Cb animals could not integrate experimental cues into an internal representation of the environment (as an allocentric strategy would require) and they resorted to a guiding strategy to locate the goal. The results of this experiment demon- strated that the cerebellum might have a modulatory role in the declarative component of navigation by which an animal develops an internal spatial representation. Our results constitute the first evidence of the involvement of the fish cerebellum in spatial cognition. Our results also suggest that the cogni- tive functions of the cerebellum may have appeared early in vertebrate evolution and been conserved throughout the phylogenetic history of extant vertebrates. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Traditionally, the cerebellum has been considered a neural structure devoted to motor control. However, many studies gathered during the previous two decades indicate that cerebellar functions extend beyond this specific motor domain. Thus, imaging and clinical studies in humans, and those performed in animal models of cerebellar abnormalities, reveal that the cerebellum serves critical roles in different cognitive functions, such as atten- tion, emotion, perception, language, working memory, procedural learning, and spatial navigation [1,2]. ∗ Corresponding author at: Laboratorio de Psicobiología, Facultad de Psicología, C/Camilo José Cela s/n, 41018 Sevilla, Spain. Tel.: +34 954557746; fax: +34 954557752. E-mail address: durang@us.es (E. Durán). Spatial function of the cerebellum has been clearly demon- strated by a variety of experiments performed on rats and mice. Studies involving different strains of cerebellar mutant mice have reported a selective deficit in the spatial orientation of these ani- mals when they are required to locate a hidden platform from random departure locations in the traditional Morris water maze paradigm [3–7]. Similar results were obtained in other studies using the hidden version of the Morris water maze when gran- ular cell depletion was induced in rats by X-irradiation of the cerebellum [8,9] or immunotoxin OX7-saporin was used to selec- tively destroy cerebellar Purkinje cells [10]. Other authors using hemicerebellectomy combined with a wide range of protocols, notably the Morris water maze paradigm, have demonstrated that hemicerebellectomised rats displayed a severe impairment in coping with spatial information, executing only a characteristic peripheral displacement denoted circling [11–14]. Some of these studies have explicitly proposed that such a noticeable impairment 0166-4328/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.bbr.2013.10.039