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web:publications [2017/06/10 11:55]
arman 		web:publications [2018/09/03 01:29]
arman
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 ====== Peer-reviewed publications ====== ====== Peer-reviewed publications ======
-   * **Reliability of TMS Phosphene Threshold Estimation: Toward a Standardized Protocol** \\ Mazzi C., Savazzi, S.,  Abrahamyan, A., Ruzzoli, M. (2017) \\ Brain Stimulation. Available online 2 February. ++More |\\ //Abstract.// **Background**+   * **Reliability of TMS Phosphene Threshold Estimation: Toward a Standardized Protocol** \\ Mazzi C., Savazzi, S.,  Abrahamyan, A., Ruzzoli, M. (2017) \\ Brain Stimulation. Available online 2 February. ++ More | \\ //Abstract.// **Background**
 Phosphenes induced by transcranial magnetic stimulation (TMS) are a subjectively described visual phenomenon employed in basic and clinical research as index of the excitability of retinotopically organized areas in the brain. Phosphenes induced by transcranial magnetic stimulation (TMS) are a subjectively described visual phenomenon employed in basic and clinical research as index of the excitability of retinotopically organized areas in the brain.
 \\ **Objective** \\ **Objective**
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 //Abstract.// A dissociation between visual awareness and visual discrimination is referred to as “blindsight”. Blindsight results from loss of function of the primary visual cortex (V1) which can occur due to cerebrovascular accidents (i.e. stroke-related lesions). There are also numerous reports of similar, though reversible, effects on vision induced by transcranial Magnetic Stimulation (TMS) to early visual cortex. These effects point to V1 as the “gate” of visual awareness and have strong implications for understanding the neurological underpinnings of consciousness. It has been argued that evidence for the dissociation between awareness of, and responses to, visual stimuli can be a measurement artifact of the use of a high response criterion under yes-no measures of visual awareness when compared with the criterion free forced-choice responses. This difference between yes-no and forced-choice measures suggests that evidence for a dissociation may actually be normal near-threshold conscious vision. Here we describe three experiments that tested visual performance in normal subjects when their visual awareness was suppressed by applying TMS to the occipital pole. The nature of subjects’ performance whilst undergoing occipital TMS was then verified by use of a psychophysical measure (d') that is independent of response criteria. This showed that there was no genuine dissociation in visual sensitivity measured by yes-no and forced-choice responses. These results highlight that evidence for visual sensitivity in the absence of awareness must be analysed using a bias-free psychophysical measure, such as d', In order to confirm whether or not visual performance is truly unconscious. //Abstract.// A dissociation between visual awareness and visual discrimination is referred to as “blindsight”. Blindsight results from loss of function of the primary visual cortex (V1) which can occur due to cerebrovascular accidents (i.e. stroke-related lesions). There are also numerous reports of similar, though reversible, effects on vision induced by transcranial Magnetic Stimulation (TMS) to early visual cortex. These effects point to V1 as the “gate” of visual awareness and have strong implications for understanding the neurological underpinnings of consciousness. It has been argued that evidence for the dissociation between awareness of, and responses to, visual stimuli can be a measurement artifact of the use of a high response criterion under yes-no measures of visual awareness when compared with the criterion free forced-choice responses. This difference between yes-no and forced-choice measures suggests that evidence for a dissociation may actually be normal near-threshold conscious vision. Here we describe three experiments that tested visual performance in normal subjects when their visual awareness was suppressed by applying TMS to the occipital pole. The nature of subjects’ performance whilst undergoing occipital TMS was then verified by use of a psychophysical measure (d') that is independent of response criteria. This showed that there was no genuine dissociation in visual sensitivity measured by yes-no and forced-choice responses. These results highlight that evidence for visual sensitivity in the absence of awareness must be analysed using a bias-free psychophysical measure, such as d', In order to confirm whether or not visual performance is truly unconscious.
 \\ http://doi.org/10.1371/journal.pone.0082828  \\ http://doi.org/10.1371/journal.pone.0082828 
-\\ {{http://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0082828&type=printable|PDF}}+\\ [[http://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0082828&type=printable|PDF]]
  
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 ====== Conference Presentations ====== ====== Conference Presentations ======
-   * **Sensation and Superstition in Human Perceptual Decisions** \\ Abrahamyan A, Silva LL, Dakin CD, Carandini M, Gardner JL \\ Stanford Neurosciences Institute Symposium, Stanford University, CA, 2015  +   * **Sensation and superstition in human perceptual decisions** \\ Abrahamyan A, Silva LL, Dakin CD, Carandini M, Gardner JL \\ Stanford Neurosciences Institute Symposium, Stanford University, CA, 2015  
-   * **Naturally Occurring and Experimentally Induced Choice History Biases in Human Observers** \\ Abrahamyan A, Gardner JL \\ Neuroscience Meeting Planner, Society for Neuroscience, Abstract. San Diego, CA, 2013. +   * **Naturally occurring and experimentally induced choice history biases in human observers** \\ Abrahamyan A, Gardner JL \\ Neuroscience Meeting Planner, Society for Neuroscience, Abstract. San Diego, CA, 2013. 
    * **Past failures can bias human decisions** \\ Abrahamyan A, Gardner JL \\ The 36th Annual Meeting of Japan Neuroscience Society, Kyoto, Japan, 2013    * **Past failures can bias human decisions** \\ Abrahamyan A, Gardner JL \\ The 36th Annual Meeting of Japan Neuroscience Society, Kyoto, Japan, 2013
    * **Past failures bias human decisions** \\ Abrahamyan A, Gardner JL \\ 10th Annual Meeting, Computational and Systems Neuroscience (COSYNE) Conference Abstracts, Salt Lake City, UT, 2013    * **Past failures bias human decisions** \\ Abrahamyan A, Gardner JL \\ 10th Annual Meeting, Computational and Systems Neuroscience (COSYNE) Conference Abstracts, Salt Lake City, UT, 2013