title: Visual BOLD Response in Late Blind Subjects with Argus II Retinal Prosthesis.
abstract: Retinal prosthesis technologies require that the visual system downstream of the retinal circuitry be capable of transmitting and elaborating visual signals. We studied the capability of plastic remodeling in late blind subjects implanted with the Argus II Retinal Prosthesis with psychophysics and functional MRI (fMRI). After surgery, six out of seven retinitis pigmentosa (RP) blind subjects were able to detect high-contrast stimuli using the prosthetic implant. However, direction discrimination to contrast modulated stimuli remained at chance level in all of them. No subject showed any improvement of contrast sensitivity in either eye when not using the Argus II. Before the implant, the Blood Oxygenation Level Dependent (BOLD) activity in V1 and the lateral geniculate nucleus (LGN) was very weak or absent. Surprisingly, after prolonged use of Argus II, BOLD responses to visual input were enhanced. This is, to our knowledge, the first study tracking the neural changes of visual areas in patients after retinal implant, revealing a capacity to respond to restored visual input even after years of deprivation.
authors: Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.
authors: E
authors: E
authors: Castaldi
authors: CNR Neuroscience Institute, Pisa, Italy.
authors: G M
authors: GM
authors: Cicchini
authors: Azienda Ospedaliero-Universitaria Careggi, SOD Oculistica, Florence, Italy.
authors: L
authors: L
authors: Cinelli
authors: Stella Maris Scientific Institute, Pisa, Italy.
authors: L
authors: http://orcid.org/0000-0003-2159-439X
authors: L
authors: Biagi
authors: Azienda Ospedaliero-Universitaria Careggi, SOD Oculistica, Florence, Italy.
authors: S
authors: S
authors: Rizzo
authors: Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.|Stella Maris Scientific Institute, Pisa, Italy.
authors: M C
authors: MC
authors: Morrone
mesh_terms: D001766:Blindness / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D005829:Geniculate Bodies / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D012174:Retinitis Pigmentosa / Q000150:complications; D014792:Visual Acuity; D057488:Visual Prosthesis