The article I chose to explore and summarize for this assignment was ‘Voluntary attention modulates fMRI activity in human MT-MST’, by O’Craven, K.M., Rosen, B.R., Kwong, K.K., Triesman, A., & Savoy, R.L. The basic theory behind this study is that the visual system receives copious amounts of information. Attention permits the visual system to pinpoint a “subset” of that information for further processing and attention, dependent on either the properties of the stimulus (bottom up processing) or on a voluntary choice by the subject (top down processing). This article further examines these processes by looking at the influence of voluntary attention on the neural activity of the MT-MST complex, an area of the human visual cortex that is dedicated
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The region of interest - the MT-MST complex - is located at the temporal-parietal-occipital juncture, which is found in the slice below the calcarine fissure. The researchers used a statistical map for that slice in one subject, which showed the results of a Kolmogorov-Smirnov test for Experiment 1. This test compared, at each location, the degree of “the MR signal during the time points when the subject was attending to the white (moving) dots to the magnitude of the signal during the time points when the subject was attending to the back (stationary) dots”. There is a significant difference between the experimental and control group so that the change in activation can be determined as a purely attentional effect. This is in part due to the fact that the visual stimulus remained the exact same throughout every time point. When comparing these results to other studies, the location of the activated area is consistent with the location of human MT. This suggests that under these experimental conditions, “attention modulates activation in the MT-MST complex”. The area of interest in each individual was determined by selecting the voxels that met a threshold of P < .0001. The time course statistic for each was then converted to “percent signal change from baseline”, and then the data was averaged together. The fMRI activation shows …show more content…
The use of stimuli in both experiments allowed for an accurate and credible depiction of brain activity in the subjects. The researchers directly addressed the hypothesis by locating the activation in the MT-MST complex below the calcarine fissure and there is little to no indication in my mind that the results found could be due to an alternative explanation. A possible follow-up study to this experiment would be one that examines eye movements. In this study the researchers touch on this subject briefly in order to rule out any possible role they have in the results, however, a more comprehensive overview would make this research even more
The region of interest - the MT-MST complex - is located at the temporal-parietal-occipital juncture, which is found in the slice below the calcarine fissure. The researchers used a statistical map for that slice in one subject, which showed the results of a Kolmogorov-Smirnov test for Experiment 1. This test compared, at each location, the degree of “the MR signal during the time points when the subject was attending to the white (moving) dots to the magnitude of the signal during the time points when the subject was attending to the back (stationary) dots”. There is a significant difference between the experimental and control group so that the change in activation can be determined as a purely attentional effect. This is in part due to the fact that the visual stimulus remained the exact same throughout every time point. When comparing these results to other studies, the location of the activated area is consistent with the location of human MT. This suggests that under these experimental conditions, “attention modulates activation in the MT-MST complex”. The area of interest in each individual was determined by selecting the voxels that met a threshold of P < .0001. The time course statistic for each was then converted to “percent signal change from baseline”, and then the data was averaged together. The fMRI activation shows …show more content…
The use of stimuli in both experiments allowed for an accurate and credible depiction of brain activity in the subjects. The researchers directly addressed the hypothesis by locating the activation in the MT-MST complex below the calcarine fissure and there is little to no indication in my mind that the results found could be due to an alternative explanation. A possible follow-up study to this experiment would be one that examines eye movements. In this study the researchers touch on this subject briefly in order to rule out any possible role they have in the results, however, a more comprehensive overview would make this research even more