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Motion Processing in Human Visual Cortex
Published in Jon H. Kaas, Christine E. Collins, The Primate Visual System, 2003
Randolph Blake, Robert Sekuler, Emily Grossman
In a similar demonstration of unique patterns of brain activity associated with point-light stimuli, Howard et al.111 compared neural activity while viewing coherent motion, optic flow, and point-light biological motion. Observers in this study first viewed a high-contrast checkerboard either stationary or moving coherently. The resulting areas with higher neural activity during the coherent motion condition consisted of a large region extending over the ascending limb of the lateral occipital sulcus and into posterior parietal cortex, the region corresponding to area MT+. Observers also viewed optic flow displays and point-light biological motion displays, and the resulting neural activity was compared to that measured in a condition involving the same individual dot motions only now spatially randomized to destroy their coherence. Howard and colleagues found that viewing optic flow resulted in increased neural activity in a region overlapping and adjacent along the superior boundary of MT+. Biological motion sequences also produced increased neural activity superior to MT+, and this region overlapped with the cortical regions active during viewing the coherent motion and optic flow animations. Howard and colleagues interpreted their results as evidence for specialization of motion perception within MT+. Outside of the MT+ region, they also found activation on the superior temporal gyrus (STG) during the biological motion and optic flow conditions. Anterior regions on the STG are known to be involved in auditory perception,112,113 and the site of activation on STG during biological motion perception overlapped with neural areas active during listening to a book-on-tape. Howard and colleagues suggest either that MT+ is connected to auditory cortex associated with interpretation of language, or that the overlapping region on STG corresponds to a polysensory area active during visual or auditory stimulation.
No Common Factor Underlying Decline of Visual Abilities in Mild Cognitive Impairment
Published in Experimental Aging Research, 2023
Simona Garobbio, Karin S. Pilz, Marina Kunchulia, Michael H. Herzog
Our results show a strong relationship between cognitive abilities and visual functions in general. The most promising visual tasks to detect early cognitive impairments are orientation discrimination, biological motion, motion detection and/or visual search. When performance in these tasks was compared between the MCI group and the healthy group, they showed a Cohen’s d effect size larger than 0.7. The same tasks showed the strongest correlations with the MoCa score (r > 0.3). It is difficult to conclude if our results are supported by previous studies because, to the best of our knowledge, there are only very few studies which tested perceptual tasks in older adults with mild cognitive decline. For example, in agreement with the current work, patients with mild cognitive impairment as well as patients with Alzheimer’s disease have been shown to perform worse in a visual search task compared to healthy older adults (Landy et al., 2015; Tales, Haworth, Nelson, Snowden, & Wilcock, 2005). However, in a study by Henry et al., (2012), patients with dementia, but not those with mild cognitive impairment, were impaired in a biological motion task. The difference to our findings, which did found impairments in biological motion perception in the MCI group, may be that in our study participants had to identify the walking direction and not actions (e.g., cycling, drinking).
The effects of preterm birth on visual development
Published in Clinical and Experimental Optometry, 2018
Myra Ps Leung, Benjamin Thompson, Joanna Black, Shuan Dai, Jane M Alsweiler
Motion coherence thresholds measured using RDKs are correlated with reading rate in school‐aged children;2012 nevertheless, the evidence between impaired motion perception and poorer reading performance is controversial.2015 Impaired biological motion perception has also been linked to social cognition.2015 Williamson and colleagues found that children born preterm performed worse on biological motion tasks and displayed more autistic‐like traits when compared to their peers in the term control group.2015 Despite the complexity of these relationships, the combined effect of global motion and biological motion deficits may be associated with the lower educational achievement2011 and poorer social relations2008 that have been reported in long‐term follow‐up studies of preterm birth. More data that test this possibility are needed.