Exploring the temporal dynamics of the spatial working memory n-back task using steady state visual evoked potentials (SSVEP)

Amplitude modulation of steady-state visual evoked potentials by event-related potentials in a working memory task

“…In fact, the 8.3-Hz SSVEP activities identified in this study clearly indicate that they concentrate at the occipital and frontal lobes as well. On the other hand, the neural activities revealed by the absolute amplitude of ERP in this work concentrate mainly at the frontal lobe and partially at the occipital lobe, and this is consistent with the conclusion that the activity in the frontal lobe was found to be distinctly stronger than that in other regions in a similar memory task [3,5].…”

“…In other words, the SSVEP amplitude includes two parts: one induced by the background noise and the other induced by the repetitive stimulus, with the latter bigger than the former [20]. So, even if the SSVEP has been used to study the long-time cognitive task process in many studies [2,4,5], we still strongly suggest that the explanation about the variance of SSVEP amplitude and phase should be made with more care.…”

“…Thus, the obtained average ERP may be a mixed one with the component induced by the cognitive task as the main part. This may explain why scientists do not use the ERP to study the process of a relatively long-time cognitive task directly [2,5]. During a short-time cognitive task, other neural activities might be asynchronous and smaller compared with the ERP, yet the average method does not necessarily improve the amplitudes of these signals.…”

“…SSVEP has been used more and more in the study of cognitive tasks including memory [2][3][4][5][6], decision selecting [7], emotional processing [8], and of various clinical diseases [9][10][11][12][13]. In these studies, the amplitude and phase changes were thought of as indicators of the modulation of SSVEP by a cognitive task, but none had ever studied the mechanism of this modulation.…”

The feature extraction and estimation of a steady-state visual evoked potential by the Karhunen-Loeve expansion

“…Consequently, the field of using the SSVEP is not limited to ophthalmological problems (assessment of visual acuity, an injury of the brain visual centers, optic neuritis, amblyopia, etc. [2]), but it is used to solve problems of cognitive (assessment of visual attention, working memory, and binocular vision [3]) and clinical (schizophrenia, autism, epilepsy, depression, migraine [4]) neurosciences, brain-computer interfaces [5], and neuromarketing [6]. Research on the SSVEP to use it further in the information technology of the ophthalmological diagnostics is an essential problem as its solving contributes to detailed visual analyzer research and appropriate complex treatment.…”