Geenen, L. | Search bioRxiv

bioRxiv2025

Novel dopaminergic neurotransmission in the Octopus visual system

Octopus vulgaris, the common octopus, has a complex brain that evolved independently from that of vertebrates, raising the possibility that it may be built using novel circuit motifs or non-canonical neurochemistry. Through systematic characterization of octopus ligand-gated ion channel genes, we identified novel ionotropic receptors for two neurotransmitters, dopamine and acetylcholine, that play key roles in visual circuits. One of these, DopC1, encodes a dopamine-gated cation channel expressed in deeper layers of the optic lobe (inner granular layer and medulla). A second, AChRB1, encodes an acetylcholine-gated anion channel expressed in photoreceptors and dopaminergic outer granular layer neurons. Dopamine drives excitation, particularly in deeper, DopC1 enriched layers, and thereby may play an important role in feed-forward excitation, whereas acetylcholine evokes inhibition, possibly mediating negative feedback from deeper layers. The octopus visual system thus shows fundamental differences in both neurochemistry and wiring compared to mammals, implying distinct mechanisms of visual information processing.

neuroscience↗

bioRxiv2024

Altered Socio-Affective Communication and Amygdala Development in mice with Protocadherin10-deficient Interneurons

Autism Spectrum Disorder (ASD) is a group of neurodevelopmental conditions associated with deficits in social interaction and communication, together with repetitive behaviors. The cell adhesion molecule Protocadherin10 (Pcdh10) has been implicated in the etiology of ASD. Pcdh10 is expressed in the nervous system during embryonic and early postnatal development and has been linked to neural circuit formation. Here, we show strong expression of Pcdh10 in the ganglionic eminences and in the basolateral complex of the amygdala at mid and late embryonic stages, respectively. Both inhibitory and excitatory neurons expressed Pcdh10 in the basolateral complex at perinatal stages and genes linked to vocalization behavior were enriched in Pcdh10- expressing neurons in adult mice. To further investigate the involvement of Pcdh10 in neurodevelopment with relevance to ASD, and to assess the functional and behavioral consequences of loss of Pcdh10 in basolateral amygdala interneurons, we combined a ubiquitous and a conditional Pcdh10 knockout mouse model. Conditional knockout of Pcdh10 reduced the number of interneurons in the basolateral complex. Both models exhibited altered developmental trajectories of socio-affective communication through isolation-induced ultrasonic vocalizations in neonatal pups, characterized by increased emission rates in heterozygous pups. Furthermore, acoustic call features were affected and heterozygous conditional knockout pups emitted calls characterized by reduced peak frequencies but increased frequency modulation. Additionally, we identified distinct clusters of call subtypes with specific developmental trajectories, suggesting the vocalization repertoire is extensive and dynamic during early life. The nuanced alterations in socio-affective communication at the level of call emission rates, acoustic call features, and clustering of call subtypes were primarily seen in heterozygous pups of the conditional knockout and less prominent in the ubiquitous Pcdh10 knockout, suggesting that changes in anxiety levels associated with Gsh2-lineage interneurons might drive the observed behavioral effects. Together, this demonstrates that loss of Pcdh10 specifically in interneurons contributes to behavioral alterations in socio-affective communication with relevance to ASD.

neuroscience↗