Biology subjects

Ben-Shahar, O.

Publications and source records attributed to Ben-Shahar, O..

3 recordsLinked to original sources

bioRxiv2021

Recognition of natural objects in the archerfish

Recognition of individual objects and their categorization is a complex computational task. Nevertheless, visual systems are able to perform this task in a rapid and accurate manner. Humans and other animals can efficiently recognize objects despite countless variations in their projection on the retina due to different viewing angles, distance, illumination conditions, and other parameters. Numerous studies conducted in mammals have associated the recognition process with cortical activity. Although the ability to recognize objects is not limited to mammals and has been well-documented in other vertebrates that lack a cortex, the mechanism remains elusive. To address this gap, we explored object recognition in the archerfish, which lack a fully developed cortex. Archerfish hunt by shooting a jet of water at aerial targets. We leveraged this unique skill to monitor visual behavior in archerfish by presenting fish with a set of images on a computer screen above the water tank and observing the behavioral response. This methodology served to characterize the ability of the archerfish to perform ecologically relevant recognition of natural objects. We found that archerfish can recognize an individual object presented under different conditions and that they can also categorize novel objects into known categories. Manipulating features of these objects revealed that the fish were more sensitive to object contours than texture and that a small number of features was sufficient for categorization. Our findings suggest the existence of a complex visual process in the archerfish visual system that enables object recognition and categorization.

animal behavior and cognition↗

bioRxiv2020

Downward Gazing for Steadiness

When walking on an uneven surface or complex terrain, humans tend to gaze downward. Previous investigations indicate that visual information can be used for online control of stepping. Behavioral investigations suggest that, during walking, the availability of visual information increases stepping accuracy, but probably through a feedforward control mechanism. Consequently, downward gazing (DWG) is usually interpreted as a strategy used to acquire useful information for online and/or feedforward control of stepping. Visual information is not exclusively used for guiding locomotion; a wealth of literature has been published on the usefulness of visual information for feedback postural control. Critically, postural control has been shown to be sensitive to the visual flow arising from the respective motion of the individual and the 3D environment. To investigate whether DWG can be used to enhance feedback control of posture, rather than feedforward/online control of gait, we conducted a series of experiments that explore this possible interplay. Through these experiments we were able to show that DWG, just a few steps ahead, results in a steadier standing and walking posture, without the need for accuracy. Moreover, we were able to demonstrate that humans resort to DWG when walking stability is compromised, even when destabilizing features were visually unpredictable. This series of experiments provides sufficient evidence of the possible interplay between visual information used for guiding locomotion and that used for postural control. Moreover, this evidence raises concerns regarding the way we interpret gaze behavior without the knowledge of the type and use of the information gathered.

neuroscience↗

bioRxiv2018

Representation of Border, Velocity and Speed in the Goldfish Brain

Like most animals, the survival of fish depends crucially on navigation in space. This capacity has been documented in numerous behavioral studies that have revealed navigation strategies and the sensory modalities used for navigation. However, virtually nothing is known about how freely swimming fish represent space and locomotion in the brain to enable successful navigation. Using a novel wireless neural recording system, we measured the activity of single neurons in the goldfish lateral pallium, a brain region known to be involved in spatial memory and navigation, while the fish swam freely in a two-dimensional water tank. Four cell types were identified: border cells, head direction cells, speed cells and conjunction head direction with speed. Border cells were active when the fish was near the boundary of the environment. Head direction cells were shown to encode head direction. Speed cells only encoded the absolute speed independent of direction suggestive of an odometry signal. Finally, the conjunction of head direction with speed cells represented the velocity of the fish. This study thus sheds light on how information related to navigation is represented in the brain of swimming fish, and addresses the fundamental question of the neural basis of navigation in this diverse group of vertebrates. The similarities between our observations in fish and earlier findings in mammals may indicate that the networks controlling navigation in vertebrate originate from an ancient circuit common across vertebrates.\n\nSummaryNavigation is a fundamental behavioral capacity facilitating survival in many animal species. Fish is one lineage where navigation has been explored behaviorally, but it remains unclear how freely swimming fish represent space and locomotion in the brain. This is a key open question in our understanding of navigation in fish and more generally in understanding the evolutionary origin of the brains navigation system. To address this issue, we recorded neuronal signals from the brain of freely swimming goldfish and successfully identified representations of border and swimming kinematics in a brain region known to be associated with navigation. Our findings thus provide a glimpse into the building blocks of the neural representation underlying fish navigation. The similarity of the representation in fish with that of mammals may be key evidence supporting a preserved ancient mechanism across brain evolution.

neuroscience↗