Mormyrid fish as fashions for investigating sensory-motor integration – Journal of Zoology Weblog

Skeels, S., von der Emde, G. and Burt de Perera, T. (2023). Mormyrid fish as fashions for investigating sensory-motor integration: A behavioural perspective. Journal of Zoology, vol. 319, pp. 243-253. https://doi.org/10.1111/jzo.13046

Weakly electrical fish epitomise what’s strange concerning the pure world. They possess a singular sense which is alien to us. These fish generate and detect low voltage electrical fields which they use to navigate, forage, and talk of their dimly lit, watery environments. There are two lineages which have developed this wonderful capacity independently: the Gymnotiformes from the Neotropics and the Mormyriformes from Africa. There are various a whole lot of species of weakly electrical fish, they usually exhibit a various vary of morphologies, electrical signalling patterns, feeding behaviours, and ranges of sociality. For the reason that Nineteen Fifties, nice steps have been made in understanding electrosensing in these fish. Weakly electrical fish have now grow to be vital fashions within the life sciences, contributing to the fields of neuroscience, evolution and growth, physiology, and behavior, to call however a couple of. Though this sense may be difficult to review as we ourselves don’t expertise the world on this means, we will rigorously design experiments which allow us to interrogate this sense and assist us perceive the perceptual skills of those charismatic animals.

Determine 1. The Peter’s elephantnose fish (Gnathonemus petersii), a weakly electrical fish which makes use of low voltage electrical fields for navigation, foraging, and communication. This species is discovered throughout central and western Africa. They’re characterised by their elongated chin appendage proven right here (referred to as a Schnauzenorgan). They use their Schnauzenorgan for a wide range of duties, corresponding to discovering prey buried underneath sediment. Photograph by Sarah Skeels
Determine 2. Sarah Skeels within the Electrical Fish Lab in Oxford. Photograph by Sarah Skeels

I’ve labored with weakly electrical fish for round seven years on the College of Oxford within the UK. I’m an experimental biologist by coaching, with an curiosity in understanding how these animals coordinate the actions of their sensory and motor techniques to optimise their behaviour. Weakly electrical fish are nice candidates for finding out any such interplay, as they’ve a well-characterised electrosensory system and present behaviours that appear to be related to sensing. Within the lab, it’s doable to not solely document the behaviour of those fish while sensing, however you may also document the electrical alerts generated by them. To do that, I put electrodes within the tank with the freely behaving animal. The electrodes decide up the electrical alerts that are amplified after which despatched to a pc for evaluation. These alerts may be visualised on the pc with specialised software program. I can even connect a speaker to the amplifier which permits me to acquire an audio illustration of the electrical discipline. Since my fish produce discrete electrical pulses, the sound could possibly be in comparison with that of a typewriter! These visible and audio representations of the electrical alerts assist me to get a way of this distinctive sensory system with which I’ve no first-hand expertise.

I primarily research sensory-motor interactions within the Peter’s elephantnose fish (Gnathonemus petersii). These fish are characterised by their elongated chin appendage (referred to as the Schnauzenorgan) which is commonly mistaken for a trunk- therefore the title! The Schnauzenorgan performs an vital half in sensing, significantly for locating invertebrate prey hidden underneath substrate. These fish is usually a problem to maintain within the laboratory as they’re delicate to modifications of their surroundings. Nevertheless, they’re extremely inquisitive with wonderful reminiscences, making them well-suited for behavioural experiments that require coaching. I take advantage of these types of experiments to research how their very own physique actions can alter the electrosensory panorama which they expertise.

Determine 3. The setup used to document the electrical alerts produced by G. petersii throughout exploration. Two electrodes are positioned at both finish of the tank. These electrodes decide up the alerts that are then despatched to the pc for evaluation. Photograph by Sarah Skeels

I design experiments the place I modify the sensory enter that the animal receives after which document their motor output (behaviour). I can then make inferences on how these streams of knowledge are processed and built-in collectively. To get to the guts of this drawback, I take advantage of operant conditioning to coach fish to finish a puzzle (normally within the type of an object recognition activity), the place people are rewarded for making the correct selection and are mildly punished for making an incorrect selection. This will increase their behaviour that yields a optimistic response and reduces their behaviour that ends in a unfavorable consequence. I take advantage of meals (bloodworm) as a reward since these fish (like lots of animals) are extremely meals motivated! When a person makes a mistake, I present a light punishment, normally within the type of a mild faucet on the tank glass adopted by a shoo to the beginning space. I’m very cautious when deciding on a light punishment to decide on one thing aversive for the fish however not sufficient to inflict stress. It is very important restrict stress as a lot as doable as this could have a unfavorable affect on well-being and the behaviours you are attempting to document.

Animal coaching may be very time consuming, however additionally it is very rewarding! One among my favorite elements of doing these types of experiments is seeing the second when a person lastly learns the duty and may full it efficiently and persistently. It makes all of the onerous work value it! As soon as I’m assured the fish have realized the duty, I can change one of many parameters of the duty and take a look at if this has an affect on their behaviour. Throughout these exams, I’m cautious to not reward or punish, as I don’t need the fish to bear additional studying and for this to affect their behaviour. I need to have the ability to attribute any modifications in behaviour to the parameter modified and to not studying. It’s unimaginable to take away all different variables that may affect the fish’s behaviour, however controls are included to restrict these as a lot as doable. Trials the place rewards and gentle punishment are given may be interspliced with testing to make sure motivation stays excessive and efficiency is maintained. By means of these experiments I’ve realized the significance of a person’s personal actions in facilitating extraction of cues from the surroundings. Nevertheless, these findings aren’t solely related to understanding electrosensing in these fish, however they’ve applicability for understanding the behaviour of different animals with totally different senses who use motion to reinforce notion, since among the core ideas are the identical. Once more, this highlights how finding out weakly electrical fish can have a far-reaching affect.

Determine 4. A typical setup used for object recognition duties. A person begins within the ready space (compartment on the far proper). They then transfer into the center compartment, the place they will sense the positioned objects (within the far-left compartments). They make a selection by shifting the door of their chosen compartment and swimming by. Throughout coaching trials, they obtain a reward or gentle punishment relying on whether or not they made an accurate or incorrect selection. Photograph by Sarah Skeels
Determine 5. Typical objects the fish are educated and examined with. These objects are constituted of aluminium. Photograph by Sarah Skeels

In sum, I strongly advocate the usage of paradigms just like the one described above for serving to to grasp basic questions in behaviour (from operate to mechanism). They take pleasure in being non-invasive, and up to date developments in expertise now imply that we will document behaviours at very excessive decision and analyse them with extra subtle strategies. This implies we will extract extra significant info from the information, permitting for higher interpretations of various behaviours. Behavioural work offers an vital and important framework from which different approaches can construct off on (e.g. mathematical modelling). As such, working within the discipline of animal behaviour is an thrilling place, because it lends itself to collaboration with folks from a spread of backgrounds and experiences. I can’t wait to see the place the sphere goes subsequent, and what different issues we will be taught from these really exceptional fish!

Sarah Skeels (Postdoctoral researcher)

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