Figure 15 in Neurobiology and vision of jumping spiders (Araneae: Salticidae)

Figure 15. Hypothetical wiring diagram depicting the connectivity of primary visual centers in the CNS of salticine jumping spiders. Based on studies of Hasarius adansoni (Nagata, Arikawa & Kinoshita 2019), Marpissa muscosa (Steinhoff et al. 2017, 2020), Phidippus (Hill 1975, 2006; Long 2016), Evarcha arcuata/Servaea vestita (Duelli 1980), and Salticus scenicus/Naphrys pulex (Oberdorfer 1977). In salticines, the unipolar receptor somata of the secondary eyes (ALE, PLE, with the possible exception of the PME) are located just outside of the respective eye cup as depicted here (Maddison & Hedin 2003). These synapse with interneurons in the highly convoluted cortex of the AL1 and PL2, and a separate, small PM1 neuropile. Secondary fibers of unipolar neurons with somata in the cortex of the CNS connect these to either the glomerular synapses (lame glomerulee) of the corpora pedunculata (with separate but adjacent AL2 and PL2 lobes as shown here), or to a less structured lateral neuropile (lenp, lateral eye neuropile). The bipolar sensory cells surrounding the retinal layers of the AME send a distal receptor process into the retina, and a proximal axon within the AME optic nerve, terminating in the synapses of the highly-structured AM1. Interneurons connect these to a less-structured, posterior neuropile (AM2). Heavy vertical bars at left indicate where fiber tracts continue into other parts of the CNS. Small neuropiles (PLx and ALx) connecting receptors of the respective lateral eyes to a lateral fiber tract may be either primary (as depicted here) or secondary. The PLx neuropile has only been documented in Marpissa (Steinhoff et al. 2017, 2019).