Cognitive dimensions of orthographic stimuli affect occipitotemporal dynamics

• Published in: Experimental brain research Vol. 167; no. 2; pp. 141 - 147
• Main Authors: Wilson, Tony W., Leuthold, Arthur C., Lewis, Scott M., Georgopoulos, Apostolos P., Pardo, Patricia J.
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.11.2005; Springer Nature B.V
• Subjects: Adolescent; Adult; Biological and medical sciences; Cognition - physiology; Electrooculography - methods; Eye and associated structures. Visual pathways and centers. Vision; Female; Fundamental and applied biological sciences. Psychology; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Magnetoencephalography; Male; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Nonlinear Dynamics; Numerical Analysis, Computer-Assisted; Occipital Lobe - physiology; Pattern Recognition, Visual - physiology; Photic Stimulation - methods; Reaction Time; Temporal Lobe - physiology; Time Factors; Vertebrates: nervous system and sense organs; Human; Word; Language; Magnetoencephalography; Occipitotemporal; Central nervous system; Fusiform; Spatiotemporal dynamics; MEG; Encephalon
• ISSN: 0014-4819; 1432-1106; 1432-1106
• DOI: 10.1007/s00221-005-0011-4

Previous research documented letter-string specific cortices in the ventral visual stream near the left occipitotemporal junction (i.e., anterior fusiform gyrus). These neural areas potentially code the perceptual elements comprising orthographic stimuli, and thus function as feature detectors in high-level vision. While abundant evidence supports this region's role in detecting isomorphic perceptual features, any influence cognitive dimensions (e.g., the lexicality of letter-strings) may play in modulating this area's processing remains an open question. To investigate this, we examined the spatiotemporal dynamics of high-density magnetoencephalographic signals, recorded as subjects completed a rhyme-judgment task on stimuli varying in the cognitive property of lexicality. Our data demonstrate that the time course of occipitotemporal cortices discriminates cognitive attributes of orthographic stimuli. The dynamics in this brain region may indicate interactive processes unfolding later in the time course, when more anterior fronto-temporal circuits are activated by semantic correlates of real words.