Visual Discrimination Learning in the Small Octopus Octopus ocellatus

Abstract

Octopus ocellatus is a small benthic species of octopus that is easy to rear and spawns large eggs during a short life cycle. These and other features of O. ocellatus may make it an advantageous subject for a broad range of behavioral studies, including those involving various types of learning. However, no type of learning has been studied in O. ocellatus. In a successive visual discrimination task, in which a ‘positive’ or ‘negative’ stimulus (white or black rectangle) was presented to a subject octopus and appropriate rewards or punishments were given to the subject, the rate of ‘correct’ responses (i.e., touches to the positive stimulus or refraining from the negative stimulus) gradually increased. Moreover, ‘observer’ octopuses that observed another octopus performing a visual discrimination task in which reward was also given to the ‘incorrect’ responses (touches to the negative stimulus) showed a higher ratio of incorrect responses in their test sessions. These results, coupled with the physical characteristics of O. ocellatus, indicate that this species is potentially suitable for neurogenetic and neuroembryological studies of learning.

Comparative brain structure and visual processing in octopus from different habitats

“…3,7 Apart from a few studies focused on the diurnal and partially social species (e.g., A. aculeatus and O. cyanea), 35,37,39,53 our current knowledge around octopus behavior and cognitive ability is mainly based on those predominantly nocturnal and asocial species with the 5-gyrus VL (e.g., O. vulgaris and O. bimaculoides). 10,21,25,55,[106][107][108][109] The 5-gyrus VL could contain approximately 13% of CNS nervous cells to form what has been called ''the fan-out fan-in neural network'' in charge of visual and tactile learning and memory along with other cognitive activities. 10,11,21,25,28,41,44,45,49,56 Recently, Shigeno and Ragsdale 15 demonstrated heterogeneities of neurochemical distribution patterns in the 5-gyrus VL where the transmitter 5-HT was found mainly in neurons of the two lateral gyri.…”

Novel Object Recognition in Octopus maya.

“…For the "young" group, a counterbalance was made with the objects, for the familiarization, it was presented on one occasion two opaque white objects and on another occasion two translucent red objects. This was done to avoid a phenomenon described in the literature of preference for some colors in other octopus species (Tomita and Aoki 2014). Regarding, it was observed that although there is a greater exploration of the familiar object when it is translucent red, this difference is not statistically signi cant (p > 0.05); also, the differential response is maintained with the tactile exploration between the novel object and the familiar object (Fig.…”

“…To integrate the knowledge of how the octopus brain is working, studies were made, dividing the supraesophageal region of the octopus brain into two systems; one that includes the vertical lobe and the superior frontal lobe (VL-SF) responsible for visual memory tasks, and another that involves the buccal lobe and the inferior frontal lobe (Bu-IF), responsible for somatosensory memory tasks (Wells & Young 1975). This division is useful when evaluating tasks such as visual discrimination (Sutherland 1962;Tomita et al 2014) or fear to condition (Shomrat et al 2008), however, in the results of this work it is clear that in the NOR task, O. maya uses visual and tactile exploration. So possibly this task involves both systems, the VL-SF and the Bu-IF.…”

“…Cephalopods are a group of invertebrates that show a wide variety of behaviors; these behaviors manifest cognitive capacities such as learning (Fiorito and Scotto, 1992;Tomita and Aoki, 2014;Bublitz et al 2017), emotions (Kuba et al 2006), puzzle-solving (Richter et al 2016) and individual recognition (Tricarico et al 2011). These abilities are shared by different taxonomic groups, for example, insects (Simons and Tibbetts 2019), crustaceans, arachnids, and vertebrates (Roth 2013).…”

Tropical OctopusAbdopus aculeatusCan Learn to Recognize Real and Virtual Symbolic Objects

“…Most studies on learning abilities in octopuses have been performed on a single species, namely, Octopus vulgaris (Boycott and Young, 1950;Wells, 1966), with some also performed on O. bimaculoides (Boal, 1991), O. ocellatus (Tomita and Aoki, 2014), O. aegina (Kawamura et al, 2001), and O. cyanea (Crancher et al, 1972;Papini and Bitterman, 1991).…”