Neuroethology: what is it and what does it research?

Neuroethology is a science that is responsible for studying animal behavior from the point of view of the nervous system. To do this, it uses two scientific disciplines: neurobiology, which studies the organization and structure of nerve cells and their relationship with behavior; and ethology, the branch of science that studies the behavior of animals in their natural habitat.

In this article we explain what is neuroethology, what are its origins, as well as its most relevant scientists and the main contributions to this discipline.

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What is neuroethology and what does it study?

Neuroethology is a scientific discipline that studies, from an evolutionary and comparative approach, the neurophysiological mechanisms involved in animal behavior. This relatively new neuroscience focuses on applying strategies to unravel which structures and functions of the nervous system are involved in the deployment of typical behaviors of the different species animals.

As its name suggests, this discipline combines the knowledge of neurobiology, which studies the functioning and organization of the cells of the nervous system that mediate the behaviour; Y ethology, the branch of science that deals with investigating how and why animals act the way they do.

The German neuroscientist Jörg-Peter Ewert, one of the pioneers in neuroethological research, believes that this science aims to try to answer relevant questions, such as what physiological mechanisms explain the conduct; how this behavior develops in the animal; how a certain behavior favors the adaptation of a specimen and its offspring, or what is the phylogenetic history of a certain behavior.

The specialists in neuroethology they use animals with unique abilities in their scientific studies that can serve as a comparative model when studying the properties of your nervous system and how it has been able to adapt throughout development ontogenetic (and at the phylogenetic level, in all its species) to be able to display certain behaviors that adjust to contexts specific.

Background: Ethology and Tinbergen's 4 Questions

As we have commented previously, neuroethology draws on ethology, which is responsible for studying animal behavior. One of the greatest contributions to this discipline was made during the first half of the last century by the Dutch zoologist, Nikolaas Tinbergen, considered one of the greatest exponents of it.

Tinbergen understood the behavior of animals as stereotyped motor patterns that are controlled both by internal physiological mechanisms and by certain external stimuli. According to him, each animal would be endowed with a strictly limited and highly complex behavioral machinery, which is constant throughout a species or population.

The key for Tinbergen, and for ethologists in general, was to answer the question of why animals behave as they do and, in turn, try to understand the following keys related to said question:

What is the control mechanism underlying animal behavior?

The answer to this question would imply take into account internal (hormonal or neural) and external factors (tactile or visual stimuli, p. ex.).

How is this behavior achieved in the ontogenetic development of the animal specimen?

This answer would mean inquiring into the history of the animal, determining the possible genetic and environmental influences that have favored said development.

What is the adaptive or survival value of a certain behavior?

In this answer, aspects such as the evolutionary meaning or the selective advantage of certain animal behaviors should be taken into consideration.

How has this behavior evolved in the course of the history of the animal species?

In this case, the answer would be account for the evolutionary history of the behavior in question, analyzing the evolutionary factors necessary for the appearance of behavior in the species.

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Contributions of neurobiology

Neurobiology, which studies the biological mechanisms by which the nervous system regulates behavior, is another of the scientific disciplines from which neuroethology is nourished. This science owes its origin, mainly, to a series of technical and theoretical advances in research on the nervous system, which also occurred in the middle of the 20th century.

In this sense, there were several milestones that marked the rise of neurobiology: the appearance of the doctrine of the neuron by Ramón y Cajal, the presentation of the Hodgkin and Huxley action potential model, as well as the development of histological, stimulation, recording and connection tracing techniques neural.

These advances made it easier for Tinbergen to call in the 1970s for a synthesis between ethology and neurobiology. to give way to neuroethology, although at first it was not easy given that there were great difficulties in obtaining the methods suitable for relating the activities of individual neurons or neural tissues to the behavior of the animal in its habitat natural.

Finally, several scientists promoted the development of neuroethology; For example, Erich von Holst, with his focal brain stimulation technique, was able to demonstrate by several animal experiments that stimulation of certain areas of the brain of chickens could elicit patterns of aggressive behavior; o Karl Von Frisch, Hansjochem Autrum and Ted Bullock, who were pioneers in research on the neurophysiological aspects underlying the specific behavior of bees, arthropods and fishes.

The investigations of Jorg-Peter-Ewert

As we mentioned at the beginning, Jorg-Peter-Ewert is one of the most researched scientists in the field of neuroethology. One of the most relevant studies of him was carried out with amphibians, specifically with specimens of the common toad, with the aim of investigate the neural mechanisms involved in the selective response capacity of these animals.

The German scientist studied two types of visually controlled behaviors: those of orientation or capture of prey and those of avoidance or escape. To elicit capture responses, he used visual stimuli such as long, thin, dark bars. (pretending to be worms), which caused a rapid reaction in the toad when moving through its retinas.

As soon as two sidebars were added to the stimulus (in the shape of an "l"), the toad's attack response tended to be inhibited (the "worm" became a "non-worm"). Ganglion cells in the animal's retina responded to objects with the right speed and shape, but they were unable to discriminate between the worm and non-worm stimulus.

The study found that stimulating a structure called optic tectum generated the behavioral pattern associated with the toad's attack response; and on the other hand, through electrical stimulation of certain parts of the thalamus, defensive escape and flight responses are elicited.

This research is just one example of what was once a pioneering study that contributed great insights to neuroethology. At present, animal behavior and its neural correlates are still being investigated in numerous animal species: from aggressive behavior in birds, the predatory behavior of lizards or the social behavior of primates.

Bibliographic references:

• Ewert, J. P. (1987). Neuroethology of releasing mechanisms: prey-catching in toads. Behavioral and Brain Sciences, 10 (3), 337-368.
• Pflüger, H. J., & Menzel, R. (1999). Neuroethology, its roots and future. Journal of Comparative Physiology A, 185 (4), 389-392.