Whisker movements evoked by stimulation of single pyramidal cells in rat motor cortex

Neuronal activity in the motor cortex is understood to be correlated with movements, but the impact of action potentials (APs) in single cortical neurons on the generation of movement has not been fully determined. Here we show that trains of APs in single pyramidal cells of rat motor cortex can evoke long sequences of small whisker movements. For layer-5 pyramids, we find that evoked rhythmic movements have a constant phase relative to the AP train, indicating that single layer-5 pyramids can reset the rhythm of whisker movements. Action potentials evoked in layer-6 pyramids can generate bursts of rhythmic whisking, with a variable phase of movements relative to the AP train. An increasing number of APs decreases the latency to onset of movement, whereas AP frequency determines movement direction and amplitude. We find that the efficacy of cortical APs in evoking whisker movements is not dependent on background cortical activity and is greatly enhanced in waking rats. We conclude that in vibrissae motor cortex sparse AP activity can evoke movements.     

Attention modulates synchronized neuronal firing in primate somatosensory cortex

A potentially powerful information processing strategy in the brain is to take advantage of the temporal structure of neuronal spike trains. An increase in synchrony within the neural representation of an object or location increases the efficacy of that neural representation at the next synaptic stage in the brain; thus, increasing synchrony is a candidate for the neural correlate of attentional selection. We investigated the synchronous firing of pairs of neurons in the secondary somatosensory cortex (SII) of three monkeys trained to switch attention between a visual task and a tactile discrimination task. We found that most neuron pairs in SII cortex fired synchronously and, furthermore, that the degree of synchrony was affected by the monkey's attentional state. In the monkey performing the most difficult task, 35% of neuron pairs that fired synchronously changed their degree of synchrony when the monkey switched attention between the tactile and visual tasks. Synchrony increased in 80% and decreased in 20% of neuron pairs affected by attention.     

Plasticity in single neuron and circuit computations

Plasticity in neural circuits can result from alterations in synaptic strength or connectivity, as well as from changes in the excitability of the neurons themselves. To better understand the role of plasticity in the brain, we need to establish how brain circuits work and the kinds of computations that different circuit structures achieve. By linking theoretical and experimental studies, we are beginning to reveal the consequences of plasticity mechanisms for network dynamics, in both simple invertebrate circuits and the complex circuits of mammalian cerebral cortex.     

神经元控制调速系统鲁棒性分析

分析了调速系统面临的鲁棒性挑战，用自学习神经元调节器替代常规PI调节器提高了调速系统的鲁棒性。     

Long-term sensory deprivation prevents dendritic spine loss in primary somatosensory cortex

A substantial decrease in the number of synapses occurs in the mammalian brain from the late postnatal period until the end of life. Although experience plays an important role in modifying synaptic connectivity, its effect on this nearly lifelong synapse loss remains unknown. Here we used transcranial two-photon microscopy to visualize postsynaptic dendritic spines in layer I of the barrel cortex in transgenic mice expressing yellow fluorescent protein. We show that in young adolescent mice, long-term sensory deprivation through whisker trimming prevents net spine loss by preferentially reducing the rate of ongoing spine elimination, not by increasing the rate of spine formation. This effect of deprivation diminishes as animals mature but still persists in adulthood. Restoring sensory experience after adolescent deprivation accelerates spine elimination. Similar to sensory manipulation, the rate of spine elimination decreases after chronic blockade of NMDA (N-methyl-D-aspartate) receptors with the antagonist MK801, and accelerates after drug withdrawal. These studies of spine dynamics in the primary somatosensory cortex suggest that experience plays an important role in the net loss of synapses over most of an animal's lifespan, particularly during adolescence.     

Early motor activity drives spindle bursts in the developing somatosensory cortex

Sensorimotor coordination emerges early in development. The maturation period is characterized by the establishment of somatotopic cortical maps, the emergence of long-range cortical connections, heightened experience-dependent plasticity and spontaneous uncoordinated skeletal movement. How these various processes cooperate to allow the somatosensory system to form a three-dimensional representation of the body is not known. In the visual system, interactions between spontaneous network patterns and afferent activity have been suggested to be vital for normal development. Although several intrinsic cortical patterns of correlated neuronal activity have been described in developing somatosensory cortex in vitro, the in vivo patterns in the critical developmental period and the influence of physiological sensory inputs on these patterns remain unknown. We report here that in the intact somatosensory cortex of the newborn rat in vivo, spatially confined spindle bursts represent the first and only organized network pattern. The localized spindles are selectively triggered in a somatotopic manner by spontaneous muscle twitches, motor patterns analogous to human fetal movements. We suggest that the interaction between movement-triggered sensory feedback signals and self-organized spindle oscillations shapes the formation of cortical connections required for sensorimotor coordination.     

单神经元自适应PID控制器的研究

将二次型性能指标引入单神经元并利用自学习功能构成了自适应ＰＩＤ控制器;分析了神经元自适应控制系统的稳定性和学习算法的收敛性。仿真结果表明,这种控制方案具有良好的自适应性。     

Behavioural improvements with thalamic stimulation after severe traumatic brain injury

Widespread loss of cerebral connectivity is assumed to underlie the failure of brain mechanisms that support communication and goal-directed behaviour following severe traumatic brain injury. Disorders of consciousness that persist for longer than 12 months after severe traumatic brain injury are generally considered to be immutable; no treatment has been shown to accelerate recovery or improve functional outcome in such cases. Recent studies have shown unexpected preservation of large-scale cerebral networks in patients in the minimally conscious state (MCS), a condition that is characterized by intermittent evidence of awareness of self or the environment. These findings indicate that there might be residual functional capacity in some patients that could be supported by therapeutic interventions. We hypothesize that further recovery in some patients in the MCS is limited by chronic underactivation of potentially recruitable large-scale networks. Here, in a 6-month double-blind alternating crossover study, we show that bilateral deep brain electrical stimulation (DBS) of the central thalamus modulates behavioural responsiveness in a patient who remained in MCS for 6 yr following traumatic brain injury before the intervention. The frequency of specific cognitively mediated behaviours (primary outcome measures) and functional limb control and oral feeding (secondary outcome measures) increased during periods in which DBS was on as compared with periods in which it was off. Logistic regression modelling shows a statistical linkage between the observed functional improvements and recent stimulation history. We interpret the DBS effects as compensating for a loss of arousal regulation that is normally controlled by the frontal lobe in the intact brain. These findings provide evidence that DBS can promote significant late functional recovery from severe traumatic brain injury. Our observations, years after the injury occurred, challenge the existing practice of early treatment discontinuation for patients with only inconsistent interactive behaviours and motivate further research to develop therapeutic interventions.     

单神经元自适应控制器在液位控制中的应用

介绍了单神经元自适应控制器在液位控制中的应用;在控制算法中提出了自调整学习速率和学习初期的分层控制方法。     

单神经元PID控制器在永磁同步电机控制中的应用研究

永磁同步电机是一个非线性、强耦合、高阶的多变量系统,使用传统的PID控制难以满足精度高、反应快、鲁棒性好的要求.根据人工神经元的自学习功能建立了基于单神经元的PID控制器,并对其学习算法加以改进,实现了单神经元PID控制器参数在线自调整.仿真与实验结果表明:该控制方法无超调, 响应快, 具有良好的动态特性,具有比常规PID控制器更好的控制品质.     

Immediate and chronic changes in responses of somatosensory cortex in adult flying-fox after digit amputation

The somatosensory cortex of adult mammals has been shown to have a capacity to reorganize when inputs are removed by cutting afferent nerves or amputating a part of the body. The area of cortex that would normally respond to stimulation of the missing input can become responsive to inputs from other parts of the body surface. Although a few animals have been studied with repeat recording, no attempt has been made to follow the time-course of changes at cortical loci and the immediate effects of a small amputation have not been reported. We have followed the changes in response in the primary somatosensory cortex in the flying-fox following amputation of the single exposed digit on the forelimb. Immediately after amputation, neurons in the area of cortex receiving inputs from the missing digit were not silent but responded to stimulation of adjoining regions of the digit, hand, arm and wing. In the week following amputation, the enlarged receptive fields shrank until they covered only the skin around the amputation wound. The immediate response is interpreted as a removal of inhibition and the subsequent shrinking of the field may be due to re-establishment of the inhibitory balance in the affected cortex and its inputs.     

云调节增益自适应单神经元PID的应用

提出了一种单神经元自适应PID控制器，并给出了控制结构模型。首先探讨了单神经元自适应PID控制学习算法，进而通过分析单神经元PID控制算法与系统动态响应及超调量的关系，利用云模型控制器修改神经元控制器的比例系数K，并根据系统误差在线实时修改控制系数，提高了系统响应性能。仿真结果表明，增益自适应单神经元PID控制器是一种具有自学习、自适应、鲁棒性强的控制器。     

噪声诱导下单热敏神经元信号检测

利用热敏神经元动作电位发放图、ISI分叉图、功率谱密度(PSD)等,系统地研究了单热敏神经元在噪声诱导下的随机共振现象.通过对比分析发现分岔周期数为1或者2的情况下,存在一最优输入信号频率fopt,使得神经元输出信噪比(rSNR)最高.不同噪声强度D下,热敏神经元对输人信号检测能力各异,低噪声强度下检测能力较好.     

单神经元自适应PID控制器的实现与仿真研究

给出了单神经元自适应PID控制器的算法与控制系统仿真模型.利用单神经元PID控制器的自学习、自适应能力实现PID控制参数的自整定.并对被控对象进行了仿真研究,仿真结果表明,该控制方法与常规PID控制方法相比,具有更好的自适应性和更强的鲁棒性.     

基于单神经元PID控制器的闭环控制系统

目的 解决传统PID控制器对时变系统控制能力不强的弊病。方法 利用神经网络理论与传统PID控制理论相结合。结果 设计了一种单神经元PID控制器，将其应用于被控制对象是快时变和慢时变的两类闭环控制系统。结论 实验证明这种单神经元PID控制器通过在线边学习边控制的方式，实现了实时控制。     

云调节增益自适应单神经元PID的应用

提出了一种单神经元自适应PID控制器,并给出了控制结构模型。首先探讨了单神经元自适应PID控制学习算法,进而通过分析单神经元PID控制算法与系统动态响应及超调量的关系,利用云模型控制器修改神经元控制器的比例系数K,并根据系统误差在线实时修改控制系数,提高了系统响应性能。仿真结果表明,增益自适应单神经元PID控制器是一种具有自学习、自适应、鲁棒性强的控制器。     

一种基于单个神经元的摄像机标定自适应算法

传统的标定算法利用标准的参照物与图像点的对应约束关系来求取摄像机参数,其中非线性优化方法标定精度较高,但计算繁琐.为此提出一种基于单个自适应神经元的摄像机传统标定算法,应用一种结构简单、抗干扰能力很强的单个神经元自适应算法代替通常的非线性优化算法进行摄像机标定.实验结果表明该算法无需计算雅可比矩阵,且精度较高,简单可行.     

基于单神经元自适应PID的煤气混合解耦控制

针对煤气混合加压过程中混合煤气压力和热值控制问题具有强耦合、非线性和较大时滞的特点,利用单神经元自适应PID控制器具有参数自学习能力,提出一种单神经元自适应PID解耦控制方法.仿真结果证明了设计方案比传统的控制方案具有较好的动态性能,验证该方法的可行性.     

基于单神经元自适应PID的煤气混合解耦控制

针对煤气混合加压过程中混合煤气压力和热值控制问题具有强耦合、非线性和较大时滞的特点,利用单神经元自适应PID控制器具有参数自学习能力,提出一种单神经元自适应PID解耦控制方法。仿真结果证明了设计方案比传统的控制方案具有较好的动态性能,验证该方法的可行性。