Niina Salminen-Vaparanta

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Humans are able to categorize complex natural scenes very rapidly and effortlessly, which has led to an assumption that such ultra-rapid categorization is driven by feedforward activation of ventral brain areas. However, recent accounts of visual perception stress the role of recurrent interactions that start rapidly after the activation of V1. To study(More)
The localization of visual areas in the human cortex is typically based on mapping the retinotopic organization with functional magnetic resonance imaging (fMRI). The most common approach is to encode the response phase for a slowly moving visual stimulus and to present the result on an individual's reconstructed cortical surface. The main aims of this(More)
In order to study whether there exist a period of activity in the human early visual cortex that contributes exclusively to visual awareness, we applied transcranial magnetic stimulation (TMS) over the early visual cortex and measured subjective visual awareness during visual forced-choice symbol or orientation discrimination tasks. TMS produced one dip in(More)
The primary visual cortex (V1) has been the target of stimulation in a number of transcranial magnetic stimulation (TMS) studies. In this study, we estimated the actual sites of stimulation by modeling the cortical location of the TMS-induced electric field when participants reported visual phosphenes or scotomas. First, individual retinotopic areas were(More)
One way to study the neural correlates of visual consciousness is to localize the cortical areas whose stimulation generates subjective visual sensations, called phosphenes. While there is support for the view that the stimulation of several different visual areas in the occipital lobe may produce phosphenes, it is not clear what the contribution of each(More)
Chromatic information is processed by the visual system both at an unconscious level and at a level that results in conscious perception of color. It remains unclear whether both conscious and unconscious processing of chromatic information depend on activity in the early visual cortex or whether unconscious chromatic processing can also rely on other(More)
The primary visual cortex (V1) has been shown to be critical for visual awareness, but the importance of other low-level visual areas has remained unclear. To clarify the role of human cortical area V2 in visual awareness, we applied transcranial magnetic stimulation (TMS) over V2 while participants were carrying out a visual discrimination task and rating(More)
Studies on the neural basis of visual awareness, the subjective experience of seeing, have found several potential neural correlates of visual awareness. Some of them may not directly correlate with awareness but with post-perceptual processes, such as reporting one's awareness of the stimulus. We dissociated potential electrophysiological correlates of(More)
Transcranial magnetic stimulation (TMS) of early visual cortex can suppresses visual perception at early stages of processing. The suppression can be measured both with objective forced-choice tasks and with subjective ratings of visual awareness, but there is lack of objective evidence on how and whether the TMS influences the quality of representations.(More)
Detecting the presence of an object is a different process than identifying the object as a particular object. This difference has not been taken into account in designing experiments on the neural correlates of consciousness. We compared the electrophysiological correlates of conscious detection and identification directly by measuring ERPs while(More)
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