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Fiori F, Candidi M, Acciarino A, David N, Aglioti SM. The right temporoparietal junction plays a causal role in maintaining the internal representation of verticality. J Neurophysiol 2015; 114:2983-90. [PMID: 26400254 DOI: 10.1152/jn.00289.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 09/21/2015] [Indexed: 11/22/2022] Open
Abstract
Perception of the visual vertical is strongly based on our ability to match visual inflow with vestibular, proprioceptive, tactile, and even visceral information that contributes to maintaining an internal representation of the vertical. An important cortical region implicated in multisensory integration is the right temporoparietal junction (rTPJ), which also is involved in higher order forms of body- and space-related cognition. To test whether this region integrates body-related multisensory information necessary for establishing the subjective visual vertical, we combined a psychophysical task (the rod-and-frame test) with transient inhibition of the rTPJ via continuous theta burst stimulation (cTBS). A Gabor patch visual detection task was used as a control visual task. cTBS of early visual cortex (V1-V3) was used to test whether early visual cortices played any role in verticality estimation. We show that inhibition of rTPJ activity selectively impairs the ability to evaluate the rod's verticality when no contextual visual information, such as a frame surrounding the rod, is provided. Conversely, transient inhibition of V1-V3 selectively disrupts the ability to visually detect Gabor patch orientation. This anatomofunctional dissociation supports the idea that the rTPJ plays a causal role in integrating egocentric sensory information encoded in different reference systems (i.e., vestibular and somatic) to maintain an internal representation of verticality.
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Affiliation(s)
- Francesca Fiori
- Department of Psychology, Sapienza University of Rome, Rome, Italy; IRCCS, Fondazione Santa Lucia, Rome, Italy; and
| | - Matteo Candidi
- Department of Psychology, Sapienza University of Rome, Rome, Italy; IRCCS, Fondazione Santa Lucia, Rome, Italy; and
| | - Adriano Acciarino
- Department of Psychology, Sapienza University of Rome, Rome, Italy; IRCCS, Fondazione Santa Lucia, Rome, Italy; and
| | - Nicole David
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Salvatore Maria Aglioti
- Department of Psychology, Sapienza University of Rome, Rome, Italy; IRCCS, Fondazione Santa Lucia, Rome, Italy; and
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Uithol S, Franca M, Heimann K, Marzoli D, Capotosto P, Tommasi L, Gallese V. Single-pulse Transcranial Magnetic Stimulation Reveals Contribution of Premotor Cortex to Object Shape Recognition. Brain Stimul 2015; 8:953-6. [DOI: 10.1016/j.brs.2015.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 04/28/2015] [Accepted: 04/30/2015] [Indexed: 11/16/2022] Open
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Railo H, Revonsuo A, Koivisto M. Behavioral and electrophysiological evidence for fast emergence of visual consciousness. Neurosci Conscious 2015; 2015:niv004. [PMID: 30774982 PMCID: PMC6368270 DOI: 10.1093/nc/niv004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 05/26/2015] [Accepted: 06/11/2015] [Indexed: 11/14/2022] Open
Abstract
A fundamental unsettled dispute concerns how fast the brain generates subjective visual
experiences. Both early visual cortical activation and later activity in fronto-parietal
global neuronal workspace correlate with conscious vision, but resolving which of the
correlates causally triggers conscious vision has proved a methodological impasse. We show
that participants can report whether or not they consciously perceived a stimulus in just
over 200 ms. These fast consciousness reports were extremely reliable, and did not include
reflexive, unconscious responses. The neural events that causally generate conscious
vision must have occurred before these behavioral reports. Analyses on single-trial neural
correlates of consciousness revealed that the late cortical processing in fronto-parietal
global neuronal workspace (∼300 ms) started after the fastest consciousness reports,
ruling out the possibility that this late activity directly reflects the emergence of
visual consciousness. The consciousness reports were preceded by a negative amplitude
difference (∼160–220 ms) that spread from occipital to frontal cortex, suggesting that
this correlate underlies the emergence of conscious vision.
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Affiliation(s)
- Henry Railo
- Department of Psychology, University of Turku, 20014, Finland.,Centre for Cognitive Neuroscience, University of Turku, 20014, Finland.,Brain and Mind Centre, University of Turku, 20014, Finland
| | - Antti Revonsuo
- Department of Psychology, University of Turku, 20014, Finland.,Centre for Cognitive Neuroscience, University of Turku, 20014, Finland.,Brain and Mind Centre, University of Turku, 20014, Finland.,School of Bioscience, University of Skövde, SE-54128, Sweden
| | - Mika Koivisto
- Department of Psychology, University of Turku, 20014, Finland.,Centre for Cognitive Neuroscience, University of Turku, 20014, Finland.,Brain and Mind Centre, University of Turku, 20014, Finland
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de Graaf TA, Duecker F, Fernholz MHP, Sack AT. Spatially specific vs. unspecific disruption of visual orientation perception using chronometric pre-stimulus TMS. Front Behav Neurosci 2015; 9:5. [PMID: 25688194 PMCID: PMC4311643 DOI: 10.3389/fnbeh.2015.00005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 01/08/2015] [Indexed: 11/13/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) over occipital cortex can impair visual processing. Such "TMS masking" has repeatedly been shown at several stimulus onset asynchronies (SOAs), with TMS pulses generally applied after the onset of a visual stimulus. Following increased interest in the neuronal state-dependency of visual processing, we recently explored the efficacy of TMS at "negative SOAs", when no visual processing can yet occur. We could reveal pre-stimulus TMS disruption, with results moreover hinting at two separate mechanisms in occipital cortex biasing subsequent orientation perception. Here we extended this work, including a chronometric design to map the temporal dynamics of spatially specific and unspecific mechanisms of state-dependent visual processing, while moreover controlling for TMS-induced pupil covering. TMS pulses applied 60-40 ms prior to a visual stimulus decreased orientation processing independent of stimulus location, while a local suppressive effect was found for TMS applied 30-10 ms pre-stimulus. These results contribute to our understanding of spatiotemporal mechanisms in occipital cortex underlying the state-dependency of visual processing, providing a basis for future work to link pre-stimulus TMS suppression effects to other known visual biasing mechanisms.
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Affiliation(s)
- Tom A de Graaf
- Faculty of Psychology and Neuroscience, Department of Cognitive Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Centre Maastricht, Netherlands
| | - Felix Duecker
- Faculty of Psychology and Neuroscience, Department of Cognitive Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Centre Maastricht, Netherlands
| | - Martin H P Fernholz
- Faculty of Psychology and Neuroscience, Department of Cognitive Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Centre Maastricht, Netherlands
| | - Alexander T Sack
- Faculty of Psychology and Neuroscience, Department of Cognitive Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Centre Maastricht, Netherlands
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55
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Tapia E, Beck DM. Probing feedforward and feedback contributions to awareness with visual masking and transcranial magnetic stimulation. Front Psychol 2014; 5:1173. [PMID: 25374548 PMCID: PMC4204434 DOI: 10.3389/fpsyg.2014.01173] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 09/26/2014] [Indexed: 11/13/2022] Open
Abstract
A number of influential theories posit that visual awareness relies not only on the initial, stimulus-driven (i.e., feedforward) sweep of activation but also on recurrent feedback activity within and between brain regions. These theories of awareness draw heavily on data from masking paradigms in which visibility of one stimulus is reduced due to the presence of another stimulus. More recently transcranial magnetic stimulation (TMS) has been used to study the temporal dynamics of visual awareness. TMS over occipital cortex affects performance on visual tasks at distinct time points and in a manner that is comparable to visual masking. We draw parallels between these two methods and examine evidence for the neural mechanisms by which visual masking and TMS suppress stimulus visibility. Specifically, both methods have been proposed to affect feedforward as well as feedback signals when applied at distinct time windows relative to stimulus onset and as a result modify visual awareness. Most recent empirical evidence, moreover, suggests that while visual masking and TMS impact stimulus visibility comparably, the processes these methods affect may not be as similar as previously thought. In addition to reviewing both masking and TMS studies that examine feedforward and feedback processes in vision, we raise questions to guide future studies and further probe the necessary conditions for visual awareness.
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Affiliation(s)
- Evelina Tapia
- Beckman Institute, University of Illinois Urbana-Champaign Urbana, IL USA
| | - Diane M Beck
- Beckman Institute, University of Illinois Urbana-Champaign Urbana, IL USA ; Department of Psychology, University of Illinois Urbana-Champaign Urbana, IL, USA
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56
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de Graaf TA, Sack AT. Using brain stimulation to disentangle neural correlates of conscious vision. Front Psychol 2014; 5:1019. [PMID: 25295015 PMCID: PMC4171988 DOI: 10.3389/fpsyg.2014.01019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Accepted: 08/26/2014] [Indexed: 02/03/2023] Open
Abstract
Research into the neural correlates of consciousness (NCCs) has blossomed, due to the advent of new and increasingly sophisticated brain research tools. Neuroimaging has uncovered a variety of brain processes that relate to conscious perception, obtained in a range of experimental paradigms. But methods such as functional magnetic resonance imaging or electroencephalography do not always afford inference on the functional role these brain processes play in conscious vision. Such empirical NCCs could reflect neural prerequisites, neural consequences, or neural substrates of a conscious experience. Here, we take a closer look at the use of non-invasive brain stimulation (NIBS) techniques in this context. We discuss and review how NIBS methodology can enlighten our understanding of brain mechanisms underlying conscious vision by disentangling the empirical NCCs.
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Affiliation(s)
- Tom A de Graaf
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Centre Maastricht, Netherlands
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands ; Maastricht Brain Imaging Centre Maastricht, Netherlands
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