Selective responses to specular surfaces in the macaque visual cortex revealed by fMRI
نویسندگان
چکیده
The surface properties of objects, such as gloss, transparency and texture, provide important information about the material characteristics of objects in our visual environment. However, because there have been few reports on the neuronal responses to surface properties in primates, we still lack information about where and how surface properties are processed in the primate visual cortex. In this study, we used functional magnetic resonance imaging (fMRI) to examine the cortical responses to specular surfaces in the macaque visual cortex. Using computer graphics, we generated images of specular and matte objects and prepared scrambled images by locally randomizing the luminance phases of the images with specular and matte objects. In experiment 1, we contrasted the responses to specular images with those to matte and scrambled images. Activation was observed along the ventral visual pathway, including V1, V2, V3, V4 and the posterior inferior temporal (IT) cortex. In experiment 2, we manipulated the contrasts of images and found that the activation observed in these regions could not be explained solely by the global or local contrasts. These results suggest that image features related to specular surface are processed along the ventral visual pathway from V1 to specific regions in the IT cortex. This is consistent with previous human fMRI experiments that showed surface properties are processed in the ventral visual pathway.
منابع مشابه
Short-latency category specific neural responses to human faces in macaque inferotemporal cortex
In this article I would present evidence to show that timing of the flow of neural signals within the ventral visual stream is a crucial part of the neural code for categorization of faces. We recorded the activity of 554 inferotemporal neurons from two macaque monkeys performing a fixation task. More than 1000 object images including human and non-primate animal faces were presented up to 10 t...
متن کاملShort-latency category specific neural responses to human faces in macaque inferotemporal cortex
In this article I would present evidence to show that timing of the flow of neural signals within the ventral visual stream is a crucial part of the neural code for categorization of faces. We recorded the activity of 554 inferotemporal neurons from two macaque monkeys performing a fixation task. More than 1000 object images including human and non-primate animal faces were presented up to 10 t...
متن کاملHuman visual cortical responses to specular and matte motion flows
Determining the compositional properties of surfaces in the environment is an important visual capacity. One such property is specular reflectance, which encompasses the range from matte to shiny surfaces. Visual estimation of specular reflectance can be informed by characteristic motion profiles; a surface with a specular reflectance that is difficult to determine while static can be confident...
متن کاملAn fMRI study of human visual cortex in response to spatiotemporal properties of visual stimuli
ABSTRACT Background: The brain response to temporal frequencies (TF) has been already reported, but with no study reported for different TF with respect to various spatial frequencies (SF). Materials and Methods: fMRI was performed by 1.5T GE-system in 14 volunteers during checkerboard, with TFs of 4, 6, 8 and 10Hz in low and high SFs of 0.5 and 8cpd. Results: Average percentage BOLD signa...
متن کاملFMRI analysis of contrast polarity processing in face-selective cortex in humans and monkeys
Recognition is strongly impaired when the normal contrast polarity of faces is reversed. For instance, otherwise-familiar faces become very difficult to recognize when viewed as photographic negatives. Here, we used fMRI to demonstrate related properties in visual cortex: 1) fMRI responses in the human Fusiform Face Area (FFA) decreased strongly (26%) to contrastreversed faces across a wide ran...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- NeuroImage
دوره 63 3 شماره
صفحات -
تاریخ انتشار 2012