Implementation of pigment‐dispersing factor‐immunoreactive neurons in a standardized atlas of the brain of the cockroach Leucophaea maderae

Abstract

The cockroach Leucophaea maderae is an established model in circadian rhythm research. Its circadian clock is located in the accessory medulla of the brain. Pigment‐dispersing factor‐immunoreactive (PDF‐ir) neurons of the accessory medulla act as circadian pacemakers controlling locomotor activity rhythms. To characterize the neuronal network of the circadian system in L. maderae, the PDF‐ir neurons were implemented into a standardized three‐dimensional atlas of the cockroach brain. Serial confocal images from 20 wholemount brains were used for the construction of the atlas comprising 21 neuropils. Two different standardization protocols were employed: the iterative shape averaging (ISA) procedure using an affine transformation followed by iterative non‐rigid registrations, and the virtual insect brain (VIB) protocol employing local non‐rigid transformations after global and local rigid transformations. Quantitative analysis of the 20 brains revealed that volumes of the accessory medulla are directly correlated with the volumes of the medulla, the protocerebral bridge, and the upper division of the central body, suggesting functional connections among these neuropils. For a standardized reconstruction of the circadian pacemaker network, the ISA protocol was used to register PDF‐ir neurons in the standard cockroach brain. The registration revealed that two PDF‐ir arborization areas in the brain are highly interconnected with other PDF‐ir projection sites and appear to be contacted both by fibers in the posterior and the anterior optic commissures. The distances between PDF‐ir branching areas show specific numerical relationships that might be physiologically relevant for temporal encoding. J. Comp. Neurol. 518:4113–4133, 2010. © 2010 Wiley‐Liss, Inc.

Brain composition in Godyris zavaleta, a diurnal butterfly, Reflects an increased reliance on olfactory information

“…Combined with recent genomic (Zhan et al, 2011;Dasmahapatra et al, 2012) and neurophysiological and ecological evidence (Andersson et al, 2007;Costanzo and Monteiro, 2007;Carlsson et al, 2013) this reinforces the importance of olfaction in some diurnal butterflies, a group traditionally perceived as relying primarily on visual information. To the extent that brain composition reflects adaptations rather than developmental or functional constraints, the relative sizes of brain structures should differ according to their importance to an organism's behavior (Barton et al, 1995;Gronenberg and H€ olldobler, 1999;De Winter and Oxnard, 2001;El Jundi et al, 2009a,b;Wei et al, 2010;Heinze and Reppert, 2012). We found that the size of the sensory neuropil can be directly related to a species' diel pattern of activity and habitat preference across four species of Lepidoptera.…”

“…The relative size of different neuropil is thought to directly reflect their functional importance (Gronenberg and H€ olldobler, 1999;El Jundi et al, 2009b;Wei et al, 2010;Heinze and Reppert, 2012). As such, the greater relative size of the visual neuropils in D. plexippus, and the smaller relative size of its olfactory neuropils, likely indicate a greater importance of visual information to diurnal butterflies (Hamb€ ack et al, 2007).…”

Adaptations for nocturnal and diurnal vision in the hawkmoth lamina

“…The antibody has successively been used to label synaptic neuropils in hawkmoths, for example by El Jundi et al (2009). It also labels synaptic neuropils in several other insect species, such as honeybees (Brandt et al, 2005), cockroaches (Wei et al, 2010), locusts (Leitinger et al, 2004), and butterflies (Heinze and Reppert 2012;Montgomery et al, 2015). We followed the staining protocol described by Heinze and Reppert (2012): brains were embedded in albumin-gelatin and cut using a vibratome (Leica VT1000S, Leica Microsystems, Nussloch, Germany).…”

Brain composition inHeliconiusbutterflies, posteclosion growth and experience‐dependent neuropil plasticity

“…Finally, we extended our phylogenetic analysis across insects using a similar approach. We restricted this analysis to volumetric data collected with a similar methodology (Rein et al, 2002;Brandt et al, 2005;Kurylas et al, 2008;Dreyer et al, 2010;Ott and Rogers, 2010;Wei et al, 2010). The phylogenetic relationship of these insects was taken from Trautwein et al (2012).…”