Superior performance for visually guided pointing in the lower visual field

• Published in: Experimental brain research 2001-04, Vol.137 (3-4), p.303-308
• Main Authors: DANCKERT, James, GOODALE, Melvyn A
• Format: Article
• Language: English
• Subjects: Adult; Algorithms; Biological and medical sciences; Female; Fundamental and applied biological sciences. Psychology; Ganglion cells; Humans; Information processing; Male; Motion Perception; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Motor skill; Photic Stimulation; Primates; Psychomotor Performance - physiology; Retinal Ganglion Cells - physiology; sensorimotor integration; Space Perception - physiology; Vertebrates: nervous system and sense organs; Visual field; Visual Fields - physiology
• ISSN: 0014-4819; 1432-1106
• DOI: 10.1007/s002210000653

The superior hemiretina in primates and humans has a greater density of ganglion cells than the inferior hemiretina, suggesting a bias towards processing information in the lower visual field (loVF). In primates, this over-representation of the loVF is also evident at the level of striate and extrastriate cortex. This is particularly true in some of the visual areas constituting the dorsal "action" pathway, such as area V6A. Here we show that visually guided pointing movements with the hand are both faster and more accurate when performed in the loVF when compared to the same movements made in the upper visual field (upVF). This was true despite the fact that the biomechanics of the movements made did not differ across conditions. The loVF advantage for the control of visually guided pointing movements is unlikely to be due to retinal factors and may instead reflect a functional bias for controlling skilled movements in this region of space. Possible neural correlates for this loVF advantage for visually guided pointing are discussed.