Vibration-processing interneurons in the honeybee brain

Abstract

The afferents of the Johnston's organ (JO) in the honeybee brain send their axons to three distinct areas, the dorsal lobe, the dorsal subesophageal ganglion (DL-dSEG), and the posterior protocerebral lobe (PPL), suggesting that vibratory signals detected by the JO are processed differentially in these primary sensory centers. The morphological and physiological characteristics of interneurons arborizing in these areas were studied by intracellular recording and staining. DL-Int-1 and DL-Int-2 have dense arborizations in the DL-dSEG and respond to vibratory stimulation applied to the JO in either tonic excitatory, on-off-phasic excitatory, or tonic inhibitory patterns. PPL-D-1 has dense arborizations in the PPL, sends axons into the ventral nerve cord (VNC), and responds to vibratory stimulation and olfactory stimulation simultaneously applied to the antennae in long-lasting excitatory pattern. These results show that there are at least two parallel pathways for vibration processing through the DL-dSEG and the PPL. In this study, Honeybee Standard Brain was used as the common reference, and the morphology of two types of interneurons (DL-Int-1 and DL-Int-2) and JO afferents was merged into the standard brain based on the boundary of several neuropiles, greatly supporting the understanding of the spatial relationship between these identified neurons and JO afferents. The visualization of the region where the JO afferents are closely appositioned to these DL interneurons demonstrated the difference in putative synaptic regions between the JO afferents and these DL interneurons (DL-Int-1 and DL-Int-2) in the DL. The neural circuits related to the vibration-processing interneurons are discussed.

Bee positive: the importance of electroreception in pollinator cognitive ecology

“…Interestingly, if only the antennal articulations were free of wax, bees could detect vibrations and were able to discriminate and learn electrical cues to some extent. Electrophysiological recordings of the mechanosensory neurons in the Johnston's organ, a structure located in the second antennal segment involved in detecting acoustic vibrations (Ai, 2010), confirmed that electric stimulation induces neuronal responses. Therefore, much in the same way as body hairs are thought to contribute to human electric field perception (Chapman et al, 2005), passive antennal deflection caused by electrical stimulation may activate mechanosensory organs responsible for electroreception in bees.…”

Sensors and Sensory Processing for Airborne Vibrations in Silk Moths and Honeybees

“…This neuron has arborizations in the ipsilateral PPL, contralateral PPL and dSEG (Figure 7A,B) [44]. This neuron did not respond to the 265 Hz vibration, but responded instead to vibrations with long-lasting excitation during olfactory stimulation to the contralateral antenna (Figure 7C) [45].…”

“…Moreover studies using a honeybee standard brain (HSB) [46] found that DL-Int-1 was close to JO afferents in the center of the DL, while DL-Int-2 was close to JO afferents in the anterior region of the DL [44]. DL-Int-1 shows on-off phasic excitation or tonic inhibition to vibration stimuli at 265 Hz, while DL-Int-2 shows tonic excitation to vibration at 265 Hz [43].…”

The Right Sensory Mix

“…5 that vision is also traveling via frequencies. Some researchers recently highlighted that odor is a vibration too (Ai 2010).…”