Recently, resting-state functional magnetic resonance imaging has been used to parcellate the brain into functionally distinct regions based on the information available in functional connectivity maps. However, brain voxels are not independent units and adjacent voxels are always highly correlated, so functional connectivity maps contain redundant information, which not only impairs the computational efficiency during clustering, but also reduces the accuracy of clustering results. The aim of this study was to propose feature-reduction approaches to reduce the redundancy and to develop semisimulated data with defined ground truth to evaluate these approaches. We proposed a feature-reduction approach based on the Affinity Propagation Algorithm (APA) and compared it with the classic featurereduction approach based on Principal Component Analysis (PCA). We tested the two approaches to the parcellation of both semisimulated and real seed regions using the K-means algorithm and designed two experiments to evaluate their noiseresistance. We found that all functional connectivity maps (with/without feature reduction) provided correct information for the parcellation of the semisimulated seed region and the computational efficiency was greatly improved by both featurereduction approaches. Meanwhile, the APA-based feature-reduction approach outperformed the PCAbased approach in noise-resistance. The results suggested that functional connectivity maps can provide correct information for cortical parcellation, and feature-reduction does not significantly change the information. Considering the improvement in computational efficiency and the noise-resistance, feature-reduction of functional connectivity maps before cortical parcellation is both feasible and necessary.
Xiaoguang TianCirong LiuTianzi JiangJoshua RizakYuanye MaXintian Hu
Opiates and dopamine (DA) play key roles in learning and memory in humans and animals. Although interactions between these neurotransmitters have been found, their functional roles remain to be fully elucidated, and their dysfunction may contribute to human diseases and addiction. Here we investigated the interactions of morphine and dopaminergic neurotransmitter systems with respect to learning and memory in rhesus monkeys by using the Wisconsin General Test Apparatus (WGTA) delayed-response task. Morphine and DA agonists (SKF-38393, apomorphine and bromocriptine) or DA antagonists (SKF-83566, haloperidol and sulpiride) were co-administered to the monkeys 30 min prior to the task. We found that dose-patterned co-administration of morphine with D1 or D2 antagonists or agonists reversed the impaired spatial working memory induced by morphine or the compounds alone. For example, morphine at 0.01 mg/kg impaired spatial working memory, while morphine (0.01 mg/kg) and apomorphine (0.01 or 0.06 mg/kg) co-treatment ameliorated this effect. Our findings suggest that the interactions between morphine and dopaminergic compounds influence spatial working memory in rhesus monkeys. A better understanding of these interactive relationships may provide insights into human addiction.
Jian-Hong WangJoshua Dominie RizakYan-Mei ChenLiang LiXin-Tian HuYuan-Ye Ma
TiN,platinum (Pt) black and iridium oxide are introduced to the stimulating sites to improve the performance of the flexible electrode.Low temperature process is used to fabricate the modifying films.TiN is coated on the gold sites by magnetron sputtering while platinum black and iridium oxide are coated by electroplating and electrodeposition,respectively.The im-pedance of the electrode decreases dramatically after modification.The combined analysis of surface morphology and cyclic voltammograms (CV) in phosphate buffer saline (PBS) solution indicates that the modified electrode sites have larger elec-trode-electrolyte capacitance and smaller faradic resistance than unmodified sites,thus they have smaller electrochemical im-pedances.
LI XiaoQianPEI WeiHuaTANG RongYuGUI QiangGUO KaiWANG YuCHEN HongDa
A prototype of hybrid neural recording interface has been developed for extracellular neural recording.It consists of a silicon-based plane microelectrode array and a CMOS low noise neural amplifier chip.The neural amplifier chip is designed and implemented in 0.18 m N-well CMOS 1P6M technology.The area of the neural preamplifier is only 0.042 mm2with a gain of 48.3 dB.The input equivalent noise is 4.73μ Vrms within pass bands of 4 kHz.To avoid cable tethering for high dense multichannel neural recording interface and make it compact,flip-chip bonding is used to integrate the preamplifier chip and the microelectrode together.The hybrid device measures 3 mm×5.5 mm×330μm,which is convenient for implant or in-vivo neural recording.The hybrid device was testified in in-vivo experiment.Neural signals were recorded from hippocampus region of anesthetized Sprague Dawley rats successfully.
HAN JianQiangZHANG XuPEI WeiHuaGUI QiangLIU MingCHEN HongDa
To proceed from sensation to movement, integration and transformation of information from different senses and reference frames are required. Several brain areas are involved in this transformation process, but previous neuroanatomical and neurophysiological studies have implicated the caudal area 7b as one particular component of this transformation system. In this study, we present the first quantitative report on the spatial coding properties of caudal area 7b. The results showed that neurons in this area had intermediate component characteristics in the transformation system; the area contained bimodal neurons, and neurons in this area encode spatial information using a hybrid reference frame. These results provide evidence that caudal area 7b may belong to the reference frame transformation system, thus contributing to our general understanding of the transformation system.
Hui-Hui JIANGYing-Zhou HUJian-Hong WANGYuan-Ye MAXin-Tian HU
To proceed from sensation to movement,integration and transformation of information from different senses and reference frames are required.Several brain areas are involved in this transformation process,but previous neuroanatomical and neurophysiological studies have implicated the caudal area 7b as one particular component of this transformation system.In this study,we present the first quantitative report on the spatial coding properties of caudal area 7b.The results showed that neurons in this area had intermediate component characteristics in the transformation system;the area contained bimodal neurons,and neurons in this area encode spatial information using a hybrid reference frame.These results provide evidence that caudal area 7b may belong to the reference frame transformation system,thus contributing to our general understanding of the transformation system.
Hui-Hui JIANGYing-Zhou HUJian-Hong WANGYuan-Ye MAXin-Tian HU
Studies estimating eye movements have demonstrated that non-human primates have fixation patterns similar to humans at the first sight of a picture.In the current study,three sets of pictures containing monkeys,humans or both were presented to rhesus monkeys and humans.The eye movements on these pictures by the two species were recorded using a Tobii eye-tracking system.We found that monkeys paid more attention to the head and body in pictures containing monkeys,whereas both monkeys and humans paid more attention to the head in pictures containing humans.The humans always concentrated on the eyes and head in all the pictures,indicating the social role of facial cues in society.Although humans paid more attention to the hands than monkeys,both monkeys and humans were interested in the hands and what was being done with them in the pictures.This may suggest the importance and necessity of hands for survival.Finally,monkeys scored lower in eye-tracking when fixating on the pictures,as if they were less interested in looking at the screen than humans.The locations of fixation in monkeys may provide insight into the role of eye movements in an evolutionary context.
Ying-Zhou HuHui-Hui JiangCi-Rong LiuJian-Hong WangCheng-Yang YuSynnve CarlsonShang-Chuan YangVeli-Matti SaarinenJoshua D RizakXiao-Guang TianHen TanZhu-Yue ChenYuan-Ye MaXin-Tian Hu
In this paper,a silicon-based neural probe with microfluidic channels was developed and evaluated.The probe can deliver chemicals or drugs to the target neurons while simultaneously recording the electrical action of these neurons extracellularly.The probe was fabricated by double-sided deep reactive ion etching(DRIE) from a silicon-on-insulator(SOI) wafer.The flu-idic channels were formed with V-shape groove etching on the silicon probe and sealed with silicon nitride and parylene-C.The shank of the probe is 4 mm long and 120 μm wide.The thickness of the probe is 100 μm.The probe has two fluidic chan-nels and two recording sites.The microfluidic channels can withstand a pressure drop as much as 30 kPa and the flow resistiv-ity of the microfluidic channel is 0.13 μL min-1 kPa-1.The typical impedance of the neural electrode is 32.3 kΩ at 1 kHz at room temperature.
GUO Kai PEI WeiHua LI XiaoQian GUI Qiang TANG RongYu LIU Jian CHEN HongDa
