Resting Brain Functional Magnetic Resonance Study After Taste Stimulation

Taste processing is one of the most important functions for human survival.Taste perception not only helps us feel the quality of food and bring pleasant experiences,but also studies have found that taste perception can affect emotional face recognition across channels.Due to the limitations of previous experimental conditions,most studies on human taste have focused on the behavioral level,with relatively few studies involving the neurophysiological level.Combining animal models and relatively limited human physiological experimental data,scholars have preliminarily understood the taste perception information processing pathways from the facial nerve to the primary taste cortex.However,the mechanism of taste perception information processing on a larger spatiotemporal scale is far from known.Some scholars have attempted to use task state functional magnetic resonance imaging(TFMRI)technology to investigate the neural mechanisms of taste information processing by observing the activated brain regions in taste related tasks.However,some researchers have found that performing tasks themselves can also have different effects on the neural activity of taste processing.Therefore,using resting state functional imaging technology to scan the spontaneous neural activity of the brain after taste stimulation to avoid the so-called impact of the task itself is the initial motivation of this study,which can provide a new perspective to observe the brain’s processing of taste stimulation.In addition,combining the algorithmic advantages of resting state data mining,this study can deeply explore the neural activity of the brain after taste stimulation in a broader scale of temporal and spatial dimensions.In this study,a total of 22 subjects(including 10 female students)were recruited to participate in the experiment using an intra subject experimental design.They were scanned for brain spontaneous neural activity(6 minutes)after stimulation(2 ml,5 seconds)with sweet,sour,and artificial saliva(control conditions).The order of administration of the three taste solutions was balanced among different subjects.After preprocessing,fractional low frequency amplitude(f ALFF)and percentage amplitude(Per AF)analyses at voxel level were performed on the data from resting functional magnetic resonance scans;Whole-brain level degree centrality(DC)analysis and dynamic fractional low frequency amplitude(df ALFF)analysis based on sliding window technology.The results showed that,at the voxel level,the f ALFF and Per AF values of the central posterior gyrus of the oral somatosensory cortex were significantly decreased after sweet and sour stimulation compared to the odorless condition(t=-5.6979),while the Per AF values of the putamen involved in reward treatment were significantly increased after sweet stimulation(t=4.5366).No differences in brain regions were found between sour and sweet conditions.At the whole brain level,compared to the odorless condition,the DC value of the precuneate lobe,which is related to the processing of advanced cognitive functions in the brain,was significantly reduced after sweet stimulation(t=-4.3792);After acid stimulation,the DC value of the left central posterior gyrus significantly decreased(t=-4.6837);There was a significant difference in DC values between sour and sweet conditions in the left fusiform gyrus(t=-4.3577).The results of dynamic fractional low-frequency amplitude analysis showed that there was a significant difference in df ALFF between the lingual gyrus and the middle frontal gyrus under sweet taste conditions compared to the odorless condition(t=-4.2917);After acid stimulation,the df ALFF values in the fusiform gyrus and lingual gyrus increased(t=4.4035),while the df ALFF values in the posterior cingulate gyrus decreased(t=-4.2203).There was a significant difference in df ALFF between the middle occipital gyrus and the middle temporal gyrus after stimulation with sour and sweet taste(t=4.5869).In summary,this experiment uses resting state functional magnetic resonance imaging to compare the spontaneous neural activity of the brain after different taste stimuli,and attempts to explore the neural activity state of the brain after taste stimuli from a new perspective.On the one hand,studies have shown that the brain is still further processing taste related information activities after taste stimulation,and this spontaneous activity state pattern of the brain may be a key factor in taste cross channel interaction;On the other hand,this study has also expanded the understanding of the neural mechanisms of taste perception processing.