The Neural Mechanism Of The Brain In Which Semantic Specificity Is Regulated By Tasks

How semantic conceptual knowledge is represented and organized in the brain has attracted extensive attention of researchers.Semantic concreteness is an important attribute of semantic concepts.It is very important to study the representation of semantic concepts.Concrete concepts refer to concepts defined mainly through perception,which can be experienced by the perception of various senses and generalize the meaning of tangible things.The abstract concepts that can not be perceived and experienced.,their meaning comes from the relationship with other abstract concepts.Compared with abstract concepts,concrete concepts have higher semantic concreteness.The study of concrete words and abstract words mostly identifies their cognitive and neurological differences,there are many theories to explain the differences between them.Generally,they can be divided into two categories.One is the theory of feature representation,which holds that the semantic distance between concrete words is closer because of the similarity of features,and that between abstract words and concrete words is farther;the other is the theory of semantic richness,in which concrete words are richer than abstract words.It is still uncertain which of these two theories is reasonable.In this study,two near-infrared spectroscopy(fNIRS)experiments were conducted.In experiment 1,naming task was used,and in experiment 2,semantic category judgment task was used.Three types of semantic stimuli(abstract words,concrete words and pictures)were compared to explore the representation of semantic concreteness in temporal lobe,so as to understand the theoretical mechanism of the differences in concreteness.The results show that in naming tasks,the infratemporal gyrus is more sensitive to concrete words processing than the pictures and abstract words.In contrast,the middle temporal gyrus processes the common features representation.which shows that the activation of concrete words and pictures is greater than that of abstract words.In the task of semantic category judgment,pictorial stimuli activated part of the middle temporal gyrus and infratemporal gyrus more than lexical stimuli,but there was no difference between concrete words and abstract words.We did not find the activation patterns of abstract words,concrete words and pictures increases linearly with richness in any brain regions of the two tasks.In summary,we can see that the results of this study do not support the theory of semantic richness of concreteness differences.Secondly,the processing of semantic concreteness in reading and semantic tasks is regulated by tasks,showing the differences between the three stimulation types in activating brain regions under the two tasks.At the same time,it can provide a theoretical basis for exploring and treating the causes of dyslexia based on brain science.