The Studies Of Neural Specificity Of Top-down Face Processing Based On Functional Neuroimaging

Faces are one of the upmost important visual stimuli that we can percevie. We can obtain the important social information such as personal identity, emotion, age, gender, race and so on through the perception and recognition of faces. Humans are highly social creatures, what makes the recognitions of faces play a very important role in social communication. Since childhood, people have accumulated a large number of expert knowledge in face processing. With these specialized face processing experience, we can not only easily complete the face recognition, but also complete the process of face processing by virtue of information such as vision and memory in the case of the face image or the defect of the fuzzy. This kind of face processing method, which is called top-down processing, is based on a combination of low-level visual information processing and advanced cognitive processing.Since the extraction of signal flow in the top-down processing mode is vulnerable to interference from the signal of bottom-up processing mode, the research on the top-down processing mode of the opposite hole is very little. In this paper, we design a novel experimental paradigm. By training participants performed face perception from pure noise in the image, then they complete the processing of face processing methods in pure top-down processing. In this paper, functional magnetic resonance imaging data were collected. And the English letters were used as the control object to stimulate the top-down processing.Firstly, in this experimental paradigm, we found that the fusiform gyrus and occipital gyrus obtain a significant activation in the two ways of bottom-up and top-down processing. It is assumed that they are the core area of the face processing network, which plays an important role in the process of acquiring, processing and outputting the faces information. In addition, inferior parietal lobule, precuneus and other brain regions were activated in top-down face processing mode. We found that these brain areas are responsible for the processing of low frequency information, decision making, working memory, and the realization of attentional modulation. The role of the brain areas, together with the completion of the processing of the face of this complex and efficient processing.Then, we use the Granger causality model to extract the time series signals of the brain regions of interest in the bottom-up and top-down face processing methods, so as to study the interaction of the information in these areas. The results showed that in the top-down expectation of face processing, left parietal lobule and left precuneus between leaf exists bidirectional Granger causal connection information interaction; left parietal lobule and the right fusiform gyrus between bidirectional Granger causal connection information interaction; there top small leaves to the left inferior occipital gyrus; left precuneus leaves to the left inferior occipital gyrus; left precuneus leaves to the right fusiform to unidirectional Granger causal connection. The results further validate our conjecture: there is a template for memory in the brain. The activation of the template prompted the brain to send top-down signals to the visual area. Under the guidance of the signal, the input of the bottom-up visual information can be matched with the signal. And in the process, we will make the judgement of whether there is a face information. Top-down processing and bottom-up processing methods exist in face processing to complete machining for fast and accurate face information.Finally, we used the Granger causal model to study the interaction between brain regions that are responsible for the processing of faces in the resting state.The results found that in the resting state, the fusiform face area located in the ventral visual processing pathway exists a one-way Granger causal input to the left inferior parietal lobule. There is a two-way information flow pattern between the left anterior parietal lobe and the left precuneus. The left precuneus shows significant Granger causal input to the left inferior occipital gyrus brain region. The results show that the brain areas responsible for face processing even in the absence of any external stimulus conditions, still exist dynamic interactive information circulation mode. In the resting state, there is a visual processing brain network which is in preparation of face processing.This paper focuses on exploring the process of face processing in top-down mode. The results show that top-down information has a promotion effect on the recognition of face recognition. According to the comparison of the correspondence condition, it is found that the face processing in top-down mode exists specificity. Then, we used the Granger causal model to analyze the information model of the brain regions involved in the processing of facial processing. Finally, we completed the framework of the processing of illusory faces.