Comparative morphology of serotonin‐immunoreactive neurons innervating the central complex in the brain of dicondylian insects

Homberg, Uwe; Kirchner, Michelle; Kowalewski, Kevin; Pitz, Vanessa; Kinoshita, Michiyo; Kern, Martina; Seyfarth, Jutta

doi:10.1002/cne.25529

Cited by 6 publications

(2 citation statements)

References 108 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 5-HT antibody is widely used and verified across insects and other taxa, hence we were confident in its use to identify substructures (e.g. [81]).…”

Section: Methodsmentioning

confidence: 99%

Mosaic evolution of a learning and memory circuit in Heliconiini butterflies

Farnworth,

Loupasaki,

Couto

et al. 2024

Preprint

View full text Add to dashboard Cite

A critical function of central neural circuits is to integrate sensory and internal information to cause a behavioural output. Evolution modifies such circuits to generate adaptive change in sensory detection and behaviour, but it remains unclear how selection does so in the context of existing functional and developmental constraints. Here, we explore this question by analysing the evolutionary dynamics of insect mushroom body circuits. Mushroom bodies are constructed from a conserved wiring logic, mainly consisting of Kenyon cells, dopaminergic neurons and mushroom body output neurons. Kenyon cells carry sensory identity signals, which are modified in strength by dopaminergic neurons and carried forward into other brain areas by mushroom body output neurons. Despite the conserved makeup of this circuit, there is huge diversity in mushroom body size and shape across insects. However, an empirical framework of how evolution modifies the function and architecture of this circuit is largely lacking. To address this, we leverage the recent radiation of a Neotropical tribe of butterflies, the Heliconiini (Nymphalidae), which show extensive variation in mushroom body size over comparatively short phylogenetic timescales, linked to specific changes in foraging ecology, life history and cognition. To understand the mechanism by which such an extensive increase in size is accommodated through changes in lobe circuit architecture, we first combined immunostainings of structural markers, neurotransmitters and neural injections to generate, to our knowledge, the most detailed description of a Papilionoidea butterfly mushroom body lobe. We then provide a comparative, quantitative dataset which shows that some Kenyon cell populations expanded with a higher rate than others inHeliconius, providing an anatomical parallel to specific shifts in behaviour. Finally, we identified an increase in GABA-ergic feedback neurons essential for non-elemental learning and sparse coding, but conservation in dopaminergic neuron number. Taken together, our results demonstrate mosaic evolution of functionally related neural systems and cell types and identify that evolutionary malleability in an architecturally conserved parallel circuit guides adaptation in cognitive ability.

show abstract

“…The 5-HT antibody is widely used and verified across insects and other taxa, hence we were confident in its use to identify substructures (e.g. [81]).…”

Section: Methodsmentioning

confidence: 99%

Mosaic evolution of a learning and memory circuit in Heliconiini butterflies

Farnworth,

Loupasaki,

Couto

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…Its function per se is difficult to pin down but has been described as centred around four main tasks: representing an insects' orientation in space by generating an internal signal, representations of goals, the selection of goals and directing a motor outcome [102]. At first, it is surprising to observe that central complex circuitry is so strictly conserved across large phylogenetic distances [105][106][107][108], but considering that so many circuits are integrated with the central complex, stabilizing selection caused by the constraint of conserving disparate functions must play a major role in its evolution, with interspecific divergence limited to (superficially) minor changes in anatomy [44,106].…”

Section: The Cognitive Circuit Of Mushroom Bodies and Central Complexmentioning

confidence: 99%

Evolution of neural circuitry and cognition

Farnworth,

Montgomery

2024

Biol. Lett.

View full text Add to dashboard Cite

Neural circuits govern the interface between the external environment, internal cues and outwardly directed behaviours. To process multiple environmental stimuli and integrate these with internal state requires considerable neural computation. Expansion in neural network size, most readily represented by whole brain size, has historically been linked to behavioural complexity, or the predominance of cognitive behaviours. Yet, it is largely unclear which aspects of circuit variation impact variation in performance. A key question in the field of evolutionary neurobiology is therefore how neural circuits evolve to allow improved behavioural performance or innovation. We discuss this question by first exploring how volumetric changes in brain areas reflect actual neural circuit change. We explore three major axes of neural circuit evolution—replication, restructuring and reconditioning of cells and circuits—and discuss how these could relate to broader phenotypes and behavioural variation. This discussion touches on the relevant uses and limitations of volumetrics, while advocating a more circuit-based view of cognition. We then use this framework to showcase an example from the insect brain, the multi-sensory integration and internal processing that is shared between the mushroom bodies and central complex. We end by identifying future trends in this research area, which promise to advance the field of evolutionary neurobiology.

show abstract

Neuroarchitecture of the Central Complex in the Madeira Cockroach Rhyparobia maderae: Tangential Neurons

Jahn,

Althaus,

Seip

et al. 2024

J of Comparative Neurology

View full text Add to dashboard Cite

Navigating in diverse environments to find food, shelter, or mating partners is an important ability for nearly all animals. Insects have evolved diverse navigational strategies to survive in challenging and unknown environments. In the insect brain, the central complex (CX) plays an important role in spatial orientation and directed locomotion. It consists of the protocerebral bridge (PB), the central body with upper (CBU) and lower division (CBL), and the paired noduli (NO). As shown in various insect species, the CX integrates multisensory cues, including sky compass signals, wind direction, and ego‐motion to provide goal‐directed vector output used for steering locomotion and flight. While most of these data originate from studies on day‐active insects, less is known about night‐active species such as cockroaches. Following our analysis of columnar and pontine neurons, the present study complements our investigation of the cellular architecture of the CX of the Madeira cockroach by analyzing tangential neurons. Based on single‐cell tracer injections, we provide further details on the internal organization of the CX and distinguished 27 types of tangential neuron, including three types of neuron innervating the PB, six types of the CBL, and 18 types of the CBU. The anterior lip, a brain area unknown in flies and highly reduced in bees, and the crepine are strongly connected to the cockroach CBU in contrast to other insect species. One tangential neuron of the CBU revealed a direct connection between the mushroom bodies and the CBU.

show abstract

Comparative morphology of serotonin‐immunoreactive neurons innervating the central complex in the brain of dicondylian insects

Cited by 6 publications

References 108 publications

Mosaic evolution of a learning and memory circuit in Heliconiini butterflies

Mosaic evolution of a learning and memory circuit in Heliconiini butterflies

Evolution of neural circuitry and cognition

Neuroarchitecture of the Central Complex in the Madeira Cockroach Rhyparobia maderae: Tangential Neurons

Contact Info

Product

Resources

About