Calendars in the brain; their perceptual characteristics and possible neural substrate

• Published in: Neurocase Vol. 22; no. 5; pp. 461 - 465
• Main Authors: Ramachandran, Vilayanur S., Vajanaphanich, Melissa, Chunharas, Chaipat
• Format: Journal Article
• Language: English
• Published: England Routledge 02.09.2016
• Subjects: Attention - physiology; Brain - physiology; Brain Mapping; Calendar form; calendar lines; Eye Movements - physiology; Female; Humans; Motion; number form; number lines; synesthesia; Visual Perception - physiology; Young Adult; synesthesia; Calendar form; calendar lines; number lines; number form
• ISSN: 1355-4794; 1465-3656
• DOI: 10.1080/13554794.2016.1250913

When we visualize a calendar, we have a vague impression of a rectangular grid hovering in front. But 1% of the population "see" vivid, crisp "calendar form" - e.g. an odd V shape as in subject ML. We found that (1) ML could "read off", months of her calendar - or alternate months - backward, unlike controls; (2) her eyes and index finger unconsciously "tracked" her reading; (3) her calendar moved with her gaze and tilted with her head; (4) after looking at a contracting spiral, her calendar expanded. In a second subject EA, the calendar was body centered and the access to episodic memories was partially "blocked" when she "looked away". Our experiments provide, for the first time, clear unambiguous proof for the veracity and true perceptual nature of the phenomenon. We suggest the calendar is constructed in the angular gyrus and its connections with the hippocampus via the inferior longitudinal fasciculus.