Whole-brain atlas of the wall lizard, Hemidactylus flaviviridis: A histo-anatomical perspective.

The current study provides the first histological whole-brain atlas of the lizard, Hemidactylus flaviviridis. Macroscopic analysis of the lizard brain demonstrates its gross morphology, including various fissures and major divisions, forebrain, midbrain, and hindbrain. Serial coronal sections stained with cresyl violet provided a detailed insight into the architecture of the lizard brain with a well-defined ventricular system featuring lateral ventricles in the telencephalon, third ventricle in the diencephalon, and fourth ventricle in the rhombencephalon. The forebrain comprised telencephalon and diencephalon, wherein telencephalon was further subdivided into pallium and subpallium. The dorsal pallium consisted of cortical region divided into medial, dorsal, dorsomedial, and lateral cortex, while ventral pallium contained anterior dorsal ventricular and posterior dorsal ventricular ridge. At the posterior ends of telencephalon, anterior commissure, optic tract, diagonal band of Broca, and preoptic area were observed. The diencephalon included epithalamus, thalamus, and hypothalamus. On either side of the third ventricle various hypothalamic nuclei were present. The midbrain housed optic tectum, torus semicircularis, and substantia nigra, while the hindbrain included cerebellum as well as different nuclei (vestibular, anterior raphe, reticular and lateral reticular). The study demonstrates that the major subdivisions as well as anatomical details of the wall lizard brain follows general vertebrate brain plan and provide an essential reference for neurobiological studies in reptiles.