The olfactory tubercle of the cat. I. Morphological components

Area of Science:

• Neuroanatomy
• Olfactory System Research
• Mammalian Brain Structure

Background:

• The olfactory tubercle (OT) is a key component of the olfactory system.
• Understanding its regional organization and cellular composition is crucial for olfactory processing.
• Previous studies have suggested regional variations within the OT, but detailed cellular morphology and interconnections require further elucidation.

Purpose of the Study:

• To delineate the structural and cellular organization of the cat olfactory tubercle.
• To investigate the distinct components of the OT: the cortical part and the cap/hilus regions.
• To identify neuronal types and potential interconnections within and between these regions.

Main Methods:

• Morphological analysis of cell types and their arrangement within the cat olfactory tubercle.
• Comparative examination of the lateral and medial aspects of the cortical part.
• Histological investigation of the cap regions and their relationship with adjacent structures like the granule islands of Calleja and ventral pallidum.

Main Results:

• The cat olfactory tubercle is divided into a cortical part and cap/hilus regions.
• The cortical part shows a gradient from cortex-like (lateral) to striatum-like (medial) organization.
• Cap regions contain dwarf and small pyramidal-like neurons, with a reversed proportion of dwarf to granule cells from lateral to medial; no interconnections were found between the two main components.

Conclusions:

• The olfactory tubercle exhibits significant regional specialization in cell morphology and organization.
• Distinct neuronal populations in the cap regions suggest specific functional roles.
• The lack of interconnections between the cortical and cap/hilus components highlights their potential functional independence within the olfactory tubercle.