Von Economo neurons (VENs)

Large spindle-shaped projection neurons (also called spindle neurons or, with fork cells, a distinctive frontoinsular morphology) clustered among layer-5 pyramidal cells at the anterior insula / frontal-operculum junction and in the anterior-cingulate-cortex. Featured prominently in Craig (2009) and referenced in Seth (2013). See insular-cortex, ad-craig.

Why they matter

• Phylogeny tracks self-awareness. VENs are present in humans, progressively fewer in great apes, absent in macaques; also reported in elephants and whales. This distribution parallels the mirror test for self-recognition, and Craig ties it to the human expansion of the AIC and the emergence of the global-emotional-moment.
• Proposed function: fast, long-range interconnections between the physically separated limbic sensory (AIC) and motor (ACC) cortices — analogous to the U-fibres linking somatosensory and motor cortex — enabling the highly integrated “emotional moments” that Craig’s model requires. Their actual connections remain largely unmapped (a stated limitation).
• Clinical anchor: in behavioural-variant frontotemporal dementia, selective VEN degeneration correlates with loss of self-conscious behaviour and emotional awareness (Seeley et al.) — the strongest evidence linking VENs to awareness, and cited in both Craig 2009 and Seth 2013.

Caveats

The connectivity and “language” of VENs are unknown; their proposed role in awareness is inferential (morphology + phylogenetic + lesion correlation), not demonstrated by tracing their circuits.