Comparing microCT Staining and Scanning Methodology for Brain Studies in Various Sizes of Spiders

Area of Science:

• * Arachnology
• * Neuroanatomy
• * Micro-computed Tomography (microCT)

Background:

• * MicroCT technology enables detailed investigation of spider and insect neuroanatomy.
• * Effective microCT imaging of soft tissues like neural tissues requires optimized preparation and scanning.
• * Existing microCT protocols are challenging to apply to spiders due to significant size variation.

Purpose of the Study:

• * To develop and consolidate microCT imaging protocols for spider central nervous systems (CNS).
• * To address challenges posed by the wide size range of spider specimens.
• * To facilitate future neuroanatomical studies in spiders.

Main Methods:

• * Tested three preparation and imaging techniques on 216 spiders (1.25–13.33 mm prosoma length).
• * Evaluated specimen preparation, staining methods (including phosphotungstic acid - PTA), and scan settings.
• * Compared image quality of dorsal and lateral microCT scans for different spider sizes.

Main Results:

• * Phosphotungstic acid (PTA) staining provided complete visualization of the prosoma and CNS across all spider sizes.
• * Image averaging, increased projections, exposure timing, and detector binning reduced noise but had minor effects on image quality for small/large spiders.
• * Medium spiders benefited from higher resolutions and an aluminum filter, alongside optimized settings.

Conclusions:

• * PTA staining is essential for effective microCT imaging of spider CNS, regardless of size.
• * Specific scan settings require adjustments based on spider size for optimal image quality.
• * Standardized protocols will accelerate research into spider neuroanatomy.