Even though the eyes constantly change position, the location of a stimulus can be accurately represented by a population of neurons with retinotopic receptive fields modulated by eye position gain fields. Recent electrophysiological studies, however, indicate that eye position gain fields may serve an additional function since they have a non-uniform spatial distribution that increases the neural response to stimuli in the straight-ahead direction. We used functional magnetic resonance imaging and a wide-field stimulus display to determine whether gaze modulations in early human visual cortex enhance the blood-oxygenation-level dependent (BOLD) response to stimuli that are straight-ahead. Subjects viewed rotating polar angle wedge stimuli centered straight-ahead or vertically displaced by ±20° eccentricity. Gaze position did not affect the topography of polar phase-angle maps, confirming that coding was retinotopic, but did affect the amplitude of the BOLD response, consistent with a gain field. In agreement with recent electrophysiological studies, BOLD responses in V1 and V2 to a wedge stimulus at a fixed retinal locus decreased when the wedge location in head-centered coordinates was farther from the straight-ahead direction. We conclude that stimulus-evoked BOLD signals are modulated by a systematic, non-uniform distribution of eye-position gain fields.

Eye position modulates retinotopic responses in early visual areas: a bias for the straight-ahead direction / Strappini, F.; Pitzalis, S.; Snyder, A. Z.; Mcavoy, M. P.; Sereno, M. I.; Corbetta, M.; Shulman, G. L.. - In: BRAIN STRUCTURE AND FUNCTION. - ISSN 1863-2653. - 220:5(2015), pp. 2587-2601. [10.1007/s00429-014-0808-7]

Eye position modulates retinotopic responses in early visual areas: a bias for the straight-ahead direction

Strappini F.
Primo
;
Pitzalis S.;Corbetta M.;
2015

Abstract

Even though the eyes constantly change position, the location of a stimulus can be accurately represented by a population of neurons with retinotopic receptive fields modulated by eye position gain fields. Recent electrophysiological studies, however, indicate that eye position gain fields may serve an additional function since they have a non-uniform spatial distribution that increases the neural response to stimuli in the straight-ahead direction. We used functional magnetic resonance imaging and a wide-field stimulus display to determine whether gaze modulations in early human visual cortex enhance the blood-oxygenation-level dependent (BOLD) response to stimuli that are straight-ahead. Subjects viewed rotating polar angle wedge stimuli centered straight-ahead or vertically displaced by ±20° eccentricity. Gaze position did not affect the topography of polar phase-angle maps, confirming that coding was retinotopic, but did affect the amplitude of the BOLD response, consistent with a gain field. In agreement with recent electrophysiological studies, BOLD responses in V1 and V2 to a wedge stimulus at a fixed retinal locus decreased when the wedge location in head-centered coordinates was farther from the straight-ahead direction. We conclude that stimulus-evoked BOLD signals are modulated by a systematic, non-uniform distribution of eye-position gain fields.
2015
gain field; gaze; retinotopy; vertical meridian; wide-field
01 Pubblicazione su rivista::01a Articolo in rivista
Eye position modulates retinotopic responses in early visual areas: a bias for the straight-ahead direction / Strappini, F.; Pitzalis, S.; Snyder, A. Z.; Mcavoy, M. P.; Sereno, M. I.; Corbetta, M.; Shulman, G. L.. - In: BRAIN STRUCTURE AND FUNCTION. - ISSN 1863-2653. - 220:5(2015), pp. 2587-2601. [10.1007/s00429-014-0808-7]
File allegati a questo prodotto
File Dimensione Formato  
Strappini_Eye-position_2015.pdf

accesso aperto

Tipologia: Versione editoriale (versione pubblicata con il layout dell'editore)
Licenza: Creative commons
Dimensione 2 MB
Formato Adobe PDF
2 MB Adobe PDF

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1605024
Citazioni
  • ???jsp.display-item.citation.pmc??? 13
  • Scopus 20
  • ???jsp.display-item.citation.isi??? 19
social impact