Walter Heiligenberg: the jamming avoidance response and beyond

One hundred years of excellence: the top one hundred authors of the Journal of Comparative Physiology A

The Journal of Comparative Physiology A is the premier peer-reviewed scientific journal in comparative physiology, in particular sensory physiology, neurophysiology, and neuroethology. Founded in 1924 by Karl von Frisch and Alfred Kühn, it celebrates its 100th anniversary in 2024. During these 100 years, many of the landmark achievements in these disciplines were published in this journal. To commemorate these accomplishments, we have compiled a list of the Top 100 Authors over these 100 years, representing approximately 1% of all its authors. To select these individuals, three performance criteria were applied: number of publications, total number of citations attracted by these articles, and mean citation rate of the papers published by each author. The resulting list of the Top 100 Authors provides a fascinating insight into the history of the disciplines covered by the Journal of Comparative Physiology A and into the academic careers of many of their leading representatives.

Neuroethology of auditory systems: contributions in memory of Albert S. Feng

Albert (Al) S. Feng (1944 - 1921) was a pioneer in the area of neuroethology of auditory systems. This special issue of the Journal of Comparative Physiology A commemorates his life and work by presenting 15 articles written by friends, students, and colleagues, many of whom have become leading experts themselves in this field. Their contributions not only provide a comprehensive overview of bioacoustics in amphibians and mammals (including bats), but also are intended to inspire a new generation of scientists to advance our understanding of brain mechanisms of acoustic perception.

Genetic and viral approaches to record or manipulate neurons in insects

The development of genetically encoded tools to record and manipulate neurons in vivo has greatly increased our understanding of how neuronal activity affects behavior. Recent advances enable the use of these tools in species not typically considered genetically tractable. This progress is revolutionizing neuroscience in general, and insect neuroethology in particular. Here we cover the latest innovations and some of their applications in phylogenetically diverse insect species. We discuss the importance and implications of these approaches for both basic and translational research. We focus on genetically encoded and virally encoded tools used for calcium imaging, optogenetics, and synaptic silencing. Finally, we discuss potential future developments of universally applicable, modular, and user-friendly genetic toolkits for neuroethological studies of insect behavior.

The Neuroethological Paradox of Animal Consciousness

The more advanced our understanding of the brain of an animal is, the less likely that this animal is a conscious being. This provocative logical paradox is explained and analyzed, leading to the conclusion that to advance understanding of animal consciousness it is necessary to resolve first how our consciousness is produced by our brain.

Finding the Beat: From Socially Coordinated Vocalizations in Songbirds to Rhythmic Entrainment in Humans

Humans and oscine songbirds share the rare capacity for vocal learning. Songbirds have the ability to acquire songs and calls of various rhythms through imitation. In several species, birds can even coordinate the timing of their vocalizations with other individuals in duets that are synchronized with millisecond-accuracy. It is not known, however, if songbirds can perceive rhythms holistically nor if they are capable of spontaneous entrainment to complex rhythms, in a manner similar to humans. Here we review emerging evidence from studies of rhythm generation and vocal coordination across songbirds and humans. In particular, recently developed experimental methods have revealed neural mechanisms underlying the temporal structure of song and have allowed us to test birds' abilities to predict the timing of rhythmic social signals. Surprisingly, zebra finches can readily learn to anticipate the calls of a "vocal robot" partner and alter the timing of their answers to avoid jamming, even in reference to complex rhythmic patterns. This capacity resembles, to some extent, human predictive motor response to an external beat. In songbirds, this is driven, at least in part, by the forebrain song system, which controls song timing and is essential for vocal learning. Building upon previous evidence for spontaneous entrainment in human and non-human vocal learners, we propose a comparative framework for future studies aimed at identifying shared mechanism of rhythm production and perception across songbirds and humans.

Neuroendocrine and behavioral responses to weak electric fields in adult sea lampreys (Petromyzon marinus)

We characterized the behavioral and neuroendocrine responses of adult sea lampreys (Petromyzon marinus) to weak electric fields. Adult sea lampreys, captured during upstream spawning migration, exhibited limited active behaviors during exposure to weak electric fields and spent the most time attached to the wall of the testing arena near the cathode (-). For adult male sea lampreys, exposure to weak electric fields resulted in increased lamprey (l) GnRH-I mRNA expression but decreased lGnRH-I immunoreactivities in the forebrain, and decreased Jun (a neuronal activation marker) mRNA levels in the brain stem. Similar effects were not observed in the brains of female sea lampreys after weak electric field stimulation. The influence of electroreception on forebrain lGnRH suggests that electroreception may modulate the reproductive systems in adult male sea lampreys. The changes in Jun expression may be associated with swimming inhibition during weak electric field stimulation. The results for adult sea lampreys are the opposite of those obtained using parasitic-stage sea lampreys, which displayed increased activity during and after cathodal stimulation. Our results demonstrate that adult sea lampreys are sensitive to weak electric fields, which may play a role in reproduction. They also suggest that electrical stimuli mediate different behaviors in feeding-stage and spawning-stage sea lampreys.

Theodore H. Bullock: pioneer of integrative and comparative neurobiology

Theodore H. Bullock (1905-2005) was a pioneer of integrative and comparative neurobiology and one of the founders of neuroethology. His work--distinguished by the tremendous number of different research themes and animal taxa studied--provided the basis for a comprehensive analysis of brain evolution. Among his major achievements are: one of the first physiological analyses of rhythmic central pattern generators; the first simultaneous recording from both the presynaptic and postsynaptic region of a chemical synapse; the demonstration of intercellular communication through graded potentials; and the discovery of two novel sensory organs formed by infrared receptors in pit vipers and electroreceptors in electric fish. He was also one of the first who applied computational tools to the analysis of complex neural signals and to perform a comparative analysis of cognitive events. His two-volume treatise "Structure and function in the nervous system of invertebrates" (with G. Adrian Horridge) remains the most comprehensive, authoritative review of this topic ever written. In addition to his research merits, his legacy is particularly based on his cosmopolitan way of thinking and acting, his large, worldwide school of students, and his committed advocacy for comparative and systems-oriented neurobiology.

Behavioral guides for sensory neurophysiology

The study of natural behavior is important for understanding the coding schemes of sensory systems. The jamming avoidance response of the weakly electric fish Eigenmannia is an excellent example of a bottom-up approach, in which behavioral analyses guided neurophysiological studies. These studies started from the electroreceptive sense organs to the motor output consisting of pacemaker neurons. Going in the opposite direction, from the central nervous system to lower centers, is the characteristic of the top-down approach. Although this approach is perhaps more difficult than the bottom-up approach, it was successfully employed in the neuroethological analysis of sound localization in the barn owl. In the latter studies, high-order neurons selective for complex natural stimuli led to the discovery of neural pathways and networks responsible for the genesis of the stimulus selectivity. Comparison of Eigenmannia and barn owls, and their neural systems, has revealed similarities in network designs, such as parallel pathways and their convergence to produce stimulus selectivity necessary for detection of natural stimuli.