查看更多>>摘要：Recent psychophysical evidence shows that visual discomfort and unpleasantness are related to particular image features such as the spatial frequency and orientation spectrum. We also have a strong unpleasant feeling toward moving objects such as swarming worms, but it is poorly understood how motion information relates to a feeling of unpleasantness. The present study investigated spatiotemporal frequency characteristics that cause visual unpleasantness using bandpass noise with variable spatial frequencies, temporal frequencies, temporal frequency bandwidths, and orientation bandwidths. Results show that dynamic noise with relatively low temporal frequencies (0.5-2 Hz) was markedly more unpleasant than static noise, including that judged as the most unpleasant in a previous study. Remarkably, translational motion of the noise did not increase the feeling of unpleasantness. A subsequent experiment using a dynamic texture in which elements moved in a variable range of random directions showed that the variegated motion direction plays a critical role in promoting visual unpleasantness. Natural scenes have regularity in that features inside an object usually move in the same direction and rarely at random, and the present results further support the notion that deviation from the statistical regularity of natural scenes in images and movies induces negative emotions.
查看更多>>摘要：Recent psychophysical evidence shows that visual discomfort and unpleasantness are related to particular image features such as the spatial frequency and orientation spectrum. We also have a strong unpleasant feeling toward moving objects such as swarming worms, but it is poorly understood how motion information relates to a feeling of unpleasantness. The present study investigated spatiotemporal frequency characteristics that cause visual unpleasantness using bandpass noise with variable spatial frequencies, temporal frequencies, temporal frequency bandwidths, and orientation bandwidths. Results show that dynamic noise with relatively low temporal frequencies (0.5-2 Hz) was markedly more unpleasant than static noise, including that judged as the most unpleasant in a previous study. Remarkably, translational motion of the noise did not increase the feeling of unpleasantness. A subsequent experiment using a dynamic texture in which elements moved in a variable range of random directions showed that the variegated motion direction plays a critical role in promoting visual unpleasantness. Natural scenes have regularity in that features inside an object usually move in the same direction and rarely at random, and the present results further support the notion that deviation from the statistical regularity of natural scenes in images and movies induces negative emotions.
查看更多>>摘要：Research shows that concussions cause long-term deficits in executive functions when tested using challenging tasks with high cognitive load. The neurophysiological mechanism(s) associated with executive dysfunction are not well understood. Pupillometry provides a non-invasive index of arousal and cognitive load; therefore, the current study investigated whether pupillometry could help explain the persistent deficits in dual-task performance in individuals with a history of concussion (n = 14) compared to controls (n = 13). Participants were tested using a computerized Corsi block task which increased in difficulty as a function of set size (i.e., number of blocks to be remembered) and task condition (i.e., performed alone and concurrently with an auditory task). Pupil size was measured during the initial fixation prior to the Corsi task to assess arousal level, and during the encoding phase to assess task evoked pupil response. Results showed that: 1) in contrast to the control group, pupil size was not modulated by task condition in the concussed group indicating that arousal level was similar in the single and dual task; 2) task evoked pupil dilation increased as a function of set size in the single task in both groups, 3) in contrast to the control group, those with a history of concussion had similar pupil size during the single and dual task conditions. One interpretation of these results is that individuals with a history of concussion exert greater effort when performing relatively easier tasks, and they reach capacity limits when the cognitive load is lower in comparison to non-concussed individuals. In conclusion, pupillometry may provide insight into persisting deficits in executive functions following concussion(s).
查看更多>>摘要：Research shows that concussions cause long-term deficits in executive functions when tested using challenging tasks with high cognitive load. The neurophysiological mechanism(s) associated with executive dysfunction are not well understood. Pupillometry provides a non-invasive index of arousal and cognitive load; therefore, the current study investigated whether pupillometry could help explain the persistent deficits in dual-task performance in individuals with a history of concussion (n = 14) compared to controls (n = 13). Participants were tested using a computerized Corsi block task which increased in difficulty as a function of set size (i.e., number of blocks to be remembered) and task condition (i.e., performed alone and concurrently with an auditory task). Pupil size was measured during the initial fixation prior to the Corsi task to assess arousal level, and during the encoding phase to assess task evoked pupil response. Results showed that: 1) in contrast to the control group, pupil size was not modulated by task condition in the concussed group indicating that arousal level was similar in the single and dual task; 2) task evoked pupil dilation increased as a function of set size in the single task in both groups, 3) in contrast to the control group, those with a history of concussion had similar pupil size during the single and dual task conditions. One interpretation of these results is that individuals with a history of concussion exert greater effort when performing relatively easier tasks, and they reach capacity limits when the cognitive load is lower in comparison to non-concussed individuals. In conclusion, pupillometry may provide insight into persisting deficits in executive functions following concussion(s).
查看更多>>摘要：Our purpose was to compare the clinical and injury characteristics of concussion patients with a receded near point of convergence (NPC) vs those without a receded NPC. Concussion patients were seen within 14 days of injury. We compared those with receded a NPC (>6 cm) break point distance and those with a normal NPC distance on symptom, behavioral, and clinical assessments. We also compared NPC break points between those who did/did not recover within 28 days of injury. 123 patients completed the assessment. 77/123 (63%) of participants demonstrated a receded NPC when tested within 14 days of injury. Those with receded a NPC break point (n = 77; mean = 14.9, SD = 1.5 years; 47% female) were significantly younger than those with a normal NPC break point (n = 46; mean = 15.7, SD = 1.7 years; 46% female). The receded NPC break point group had a significantly greater proportion of patients reporting headaches (86% vs. 61%), as well as significantly greater cognitive (mean = 13.4, SD = 8.7 vs. mean = 8.8, SD = 8.6), somatic (mean = 10.0, SD = 5.9 vs. mean = 6.9, SD = 6.6), and overall (mean = 23.7, SD = 13.6 vs. mean = 15.8, SD = 14.4) symptom severity. Our multivariable model indicated among all potential predictor variables, more severe somatic symptoms were significantly associated with a greater NPC break point (beta = 0.26; 95% CI = 0.01, 0.52). The group who went onto experience persistent symptoms had a significantly greater NPC break point at initial evaluation than those without persistent symptoms (mean = 9.7, SD = 7.5 cm vs. mean = 7.0, SD = 4.0 cm). Those with a receded NPC break point at initial evaluation showed an increased symptom burden, most notable with somatic symptoms, compared with those without a receded NPC break point.
查看更多>>摘要：Our purpose was to compare the clinical and injury characteristics of concussion patients with a receded near point of convergence (NPC) vs those without a receded NPC. Concussion patients were seen within 14 days of injury. We compared those with receded a NPC (>6 cm) break point distance and those with a normal NPC distance on symptom, behavioral, and clinical assessments. We also compared NPC break points between those who did/did not recover within 28 days of injury. 123 patients completed the assessment. 77/123 (63%) of participants demonstrated a receded NPC when tested within 14 days of injury. Those with receded a NPC break point (n = 77; mean = 14.9, SD = 1.5 years; 47% female) were significantly younger than those with a normal NPC break point (n = 46; mean = 15.7, SD = 1.7 years; 46% female). The receded NPC break point group had a significantly greater proportion of patients reporting headaches (86% vs. 61%), as well as significantly greater cognitive (mean = 13.4, SD = 8.7 vs. mean = 8.8, SD = 8.6), somatic (mean = 10.0, SD = 5.9 vs. mean = 6.9, SD = 6.6), and overall (mean = 23.7, SD = 13.6 vs. mean = 15.8, SD = 14.4) symptom severity. Our multivariable model indicated among all potential predictor variables, more severe somatic symptoms were significantly associated with a greater NPC break point (beta = 0.26; 95% CI = 0.01, 0.52). The group who went onto experience persistent symptoms had a significantly greater NPC break point at initial evaluation than those without persistent symptoms (mean = 9.7, SD = 7.5 cm vs. mean = 7.0, SD = 4.0 cm). Those with a receded NPC break point at initial evaluation showed an increased symptom burden, most notable with somatic symptoms, compared with those without a receded NPC break point.
Luna, RaulSerrano-Pedraza, IgnacioGegenfurtner, Karl R.Schuetz, Alexander C....
16页
查看更多>>摘要：During smooth pursuit eye movements, the visual system is faced with the task of telling apart reafferent retinal motion from motion in the world. While an efference copy signal can be used to predict the amount of reafference to subtract from the image, an image-based adaptive mechanism can ensure the continued accuracy of this computation. Indeed, repeatedly exposing observers to background motion with a fixed direction relative to that of the target that is pursued leads to a shift in their point of subjective stationarity (PSS). We asked whether the effect of exposure reflects adaptation to motion contingent on pursuit direction, recalibration of a reference signal or both. A recalibration account predicts a shift in reference signal (i.e. predicted reafference), resulting in a shift of PSS, but no change in sensitivity. Results show that both directional judgements and confidence judgements about them favor a recalibration account, whereby there is an adaptive shift in the reference signal caused by the prevailing retinal motion during pursuit. We also found that the recalibration effect is specific to the exposed visual hemifield.
Luna, RaulSerrano-Pedraza, IgnacioGegenfurtner, Karl R.Schuetz, Alexander C....
16页
查看更多>>摘要：During smooth pursuit eye movements, the visual system is faced with the task of telling apart reafferent retinal motion from motion in the world. While an efference copy signal can be used to predict the amount of reafference to subtract from the image, an image-based adaptive mechanism can ensure the continued accuracy of this computation. Indeed, repeatedly exposing observers to background motion with a fixed direction relative to that of the target that is pursued leads to a shift in their point of subjective stationarity (PSS). We asked whether the effect of exposure reflects adaptation to motion contingent on pursuit direction, recalibration of a reference signal or both. A recalibration account predicts a shift in reference signal (i.e. predicted reafference), resulting in a shift of PSS, but no change in sensitivity. Results show that both directional judgements and confidence judgements about them favor a recalibration account, whereby there is an adaptive shift in the reference signal caused by the prevailing retinal motion during pursuit. We also found that the recalibration effect is specific to the exposed visual hemifield.
NSTL
Elsevier