Morphology of the central nervous system of the Norway lobster, <i>Nephrops norvegicus</i> (Linnaeus, 1758) (Decapoda: Astacidea: Nephropidae): the first step to understand its functionality

Abstract We provide a detailed morphological map of central nervous system (CNS) of the Norway lobster, Nephrops norvegicus (Linnaeus, 1758), to support understanding of its neurobiological capacities, including potential for cognitive processes and sentience. Norway lobsters were collected, sexed, measured, and their CNS dissected for gross and histological analysis performed using standard fixation, sectioning, staining, and imaging techniques. The macro and microscopical analysis reveal that the CNS consists of paired longitudinal nerve cords with segmentally arranged ganglia, including a complex brain, suboesophageal, thoracic, and abdominal ganglia. Detailed anatomical and histological analysis revealed highly organized neuropils, soma clusters, and nerve tracts specific to each ganglion type. Notably, the brain displays distinct functional subdivisions and specialised olfactory and visual structures, while thoracic and abdominal ganglia exhibit conserved architecture. This study provides the first detailed morphological description of the CNS of N. norvegicus, highlighting brain complexity, adult neurogenesis, and specialised ganglia. The morphology of the CNS compared to other crustaceans suggest potential for complex sensory integration and behaviour, supporting future investigations about brain functionality. Further molecular, physiological, and behavioural research in decapod crustaceans is essential to clarify the functional roles of CNS structures and their relation to sentience.