Which structure is NOT part of the limbic circuit as described (choose the non-member)?

• A. Thalamus
• B. Septum
• C. Olfactory bulb
• D. Fornix

Answer: (A)

Think of the limbic circuit as the network that underpins emotion and memory, built from hippocampal connections (via the fornix) to subcortical and cortical limbic areas such as mammillary bodies, septal regions, and parts of the cingulate/olfactory-linked networks. The olfactory bulb is tied directly into these limbic pathways, reflecting how smell can powerfully influence memory and emotion. The septal area also participates in limbic regulation of motivation and reward, reinforcing its role in this system. The thalamus, on the other hand, is best described as a relay hub that channels sensory and cortical information to many regions, rather than a core limbic structure. In the particular framing used here, that relay role places the thalamus outside the limbic circuit, so it’s considered the non-member.