ABSTRACT
Visual object recognition in humans and nonhuman primates is achieved by the ventral visual pathway (ventral occipital-temporal cortex, VOTC), which shows a well-documented object domain structure. An on-going question is what type of information is processed in the higher-order VOTC that underlies such observations, with recent evidence suggesting effects of certain visual features. Combining computational vision models, fMRI experiment using a parametric-modulation approach, and natural image statistics of common objects, we depicted the neural distribution of a comprehensive set of visual features in the VOTC, identifying voxel sensitivities with specific feature sets across geometry/shape, Fourier power, and color. The visual feature combination pattern in the VOTC is significantly explained by their relationships to different types of response-action computation (fight-or-flight, navigation, and manipulation), as derived from behavioral ratings and natural image statistics. These results offer a comprehensive visual feature map in the VOTC and a plausible theoretical explanation as a mapping onto different types of downstream response-action systems.
Subject(s)
Animals , Humans , Brain Mapping , Magnetic Resonance Imaging , Occipital Lobe , Pattern Recognition, Visual , Photic Stimulation , Temporal Lobe , Visual Pathways/diagnostic imaging , Visual PerceptionABSTRACT
Visual object recognition in humans and nonhuman primates is achieved by the ventral visual pathway (ventral occipital-temporal cortex, VOTC), which shows a well-documented object domain structure. An on-going question is what type of information is processed in the higher-order VOTC that underlies such observations, with recent evidence suggesting effects of certain visual features. Combining computational vision models, fMRI experiment using a parametric-modulation approach, and natural image statistics of common objects, we depicted the neural distribution of a comprehensive set of visual features in the VOTC, identifying voxel sensitivities with specific feature sets across geometry/shape, Fourier power, and color. The visual feature combination pattern in the VOTC is significantly explained by their relationships to different types of response-action computation (fight-or-flight, navigation, and manipulation), as derived from behavioral ratings and natural image statistics. These results offer a comprehensive visual feature map in the VOTC and a plausible theoretical explanation as a mapping onto different types of downstream response-action systems.
ABSTRACT
Oxidant imbalance is one of the causative mechanisms of aluminum-induced neurotoxicity. In this study, we investigated aluminum-induced oxidant imbalance in non-neuronal tissues (liver, kidney and testis) and temporal cortex in rats. The differences in adaptations to superoxide and peroxide handling capacities (SPHC) of studied organs due to aluminum insult were also evaluated. Male Wistar rats were exposed to aluminum (10 mg/Kg body wt/day) for 4 weeks through orogastric intubation. Liver showed significant decrease in reduced glutathione level, while significant alteration in lipid peroxidation was observed in temporal cortex in aluminium-exposed animals. Superoxide dismutase activity was significantly altered in liver and temporal cortex and catalase activity significantly reduced in the liver due to aluminum exposure, while glutathione reductase and glutathione peroxidase activities were altered in all the tested organs. Among the organs, glutathione-independent SPHC was relatively higher in liver and kidney, while glutathione-dependent SPHC was relatively higher in testis and temporal cortex. As compared to control, aluminum-exposed rats demonstrated reduction in glutathione-dependent SPHC in temporal cortex and increment of the same in testis, while increment in glutathione-independent SPHC was observed in liver. In conclusion, aluminum-induced alteration in oxidant handling capacity could be the cause of oxidative stress both in the neuronal and non-neuronal tissues.
Subject(s)
Aluminum/poisoning , Aluminum/toxicity , Neurotoxicity Syndromes , Glutathione Reductase/metabolism , Glutathione Peroxidase/metabolism , Liver , Kidney , Superoxides/metabolism , Peroxides/metabolism , Temporal Lobe , TestisABSTRACT
@#ObjectiveTo study the effect of 8 Hz infrasound on the expression of 5-hydroxytryptamine (5-HT) in rats' hippocampus and temporal cortex.Methods140 male SD rats were randomly divided into the control group, and experimental groups that exposed to infrasound of 8Hz,90dB,100dB and 130dB for 1,7,14,21,28,35,42 days. Experimental groups were exposed to infrasound for 2 hours each day. The control group was only placed in the infrasonic storehouse but without infrasound. Rats' brains were taken as soon as the exposure finished and strained by immunohistochemistry. The content of 5-HT in hippocampus and temporal cortex was detected under an optical microscope.ResultsInfrasound groups had less expression of 5-HT in hippocampus and temporal cortex than the control group (P<0.01), and the least were at the 28th day for 90 dB and 100 dB groups and the 21st day for 130 dB group. Then the expression of 5-HT had an increase in each group.ConclusionThe deceased expression of 5-HT in rats' hippocampus and temporal cortex could result from infrasound of 8 Hz. Rules of change are related to the parameter of infrasound and the 130 dB 8 Hz infrasound can induce greater changes compared with that of 100 dB and 90 dB.
ABSTRACT
Objective To study the effect of 8Hz infrasound on the expression of 5-HTR of hippocampus and temporal cortex in rats. Methods SD rats were exposed to 8Hz, 90dB,100dB or 130dB infrasound, respectively for 2 hours daily. Then the rats' brains were taken and given stained immunohistochemically for (5-hydroxy tryptamine receptor,5-HTR). The content of 5-HTR in hippocampus and temporal cortex were detected under an optical microscope. Results The animals in the infrasound groups had less expression of 5-HTR in hippocampus and temporal cortex, and the least were at the 35th day for 90dB group and 100dB group and the 28th day for 130dB group (P
ABSTRACT
Objective:To analyze neuropsychological characteristics of a Chinese patient with semantic dementia (SD)。Methods:A patient with SD was selected to finish 11 neuropsychological tests and MRI and XeCT。Results:(1)Selective impairment of semantic memory caused severe anomia, impaired spoken and written single-word comprehension, reduced generation of exemplars on category fluency tests and an impoverished fund of general knowledge; (2)relative sparing of other components of language output and comprehension; normal perceptual skill and non-verbal problem-solving abilities; relatively preserved episodic memory; (3)a reading disorder with pattern of surface dyslexia;(4) radiological investigations (MRI and XeCT) have shown severe left temporal neocortex atrophy.Conclusion:There are similar clinical and neuropsychological characteristics for SD between the Chinese patient and the sample of Western. Selective impairment of semantic memory may bring about by left temporal neocortex atrophy。
ABSTRACT
The projections of the hippocampus onto the cerebral cortex were studied in 31 rats after injections of horseradish peroxidase(HRP) into the parietal, frontal, and temporal lobes of the cerebral cortex respectively. The results were as follows:1) HRP labelled pyramidal cells were found in the CA1~CA3 of the dorsal and ventral hippocampus on both sides, more numerous on the ipsi-lateral side in all the cases. However, no HRP labelled cells could be identified in the CA4 or dentate gyrus in any case.2) Labelled neusons of hippocampo-temporal projection were more numerous than those of hippocampo-parietal or hippocampo-frontal projection. However, no difference could be revealed between those of hippocampo-parietal and hippocampo-frontal projections.The anatomical and functional significance of our findings were discussed