Hearing sounds,understanding actions: action representation in mirror neurons

Many object-related actions can be recognized by their sound. We found neurons in monkey premotor cortex that discharge when the animal performs a specific action and when it hears the related sound. Most of the neurons also discharge when the monkey observes the same action. These audiovisual mirror neurons code actions independently of whether these actions are performed, heard, or seen. This discovery in the monkey homolog of Broca's area might shed light on the origin of language: audiovisual mirror neurons code abstract contents-the meaning of actions-and have the auditory access typical of human language to these contents.     

Storage and executive processes in the frontal lobes

The human frontal cortex helps mediate working memory, a system that is used for temporary storage and manipulation of information and that is involved in many higher cognitive functions. Working memory includes two components: short-term storage (on the order of seconds) and executive processes that operate on the contents of storage. Recently, these two components have been investigated in functional neuroimaging studies. Studies of storage indicate that different frontal regions are activated for different kinds of information: storage for verbal materials activates Broca's area and left-hemisphere supplementary and premotor areas; storage of spatial information activates the right-hemisphere premotor cortex; and storage of object information activates other areas of the prefrontal cortex. Two of the fundamental executive processes are selective attention and task management. Both processes activate the anterior cingulate and dorsolateral prefrontal cortex.     

Parietal lobe: from action organization to intention understanding

Inferior parietal lobule (IPL) neurons were studied when monkeys performed motor acts embedded in different actions and when they observed similar acts done by an experimenter. Most motor IPL neurons coding a specific act (e.g., grasping) showed markedly different activations when this act was part of different actions (e.g., for eating or for placing). Many motor IPL neurons also discharged during the observation of acts done by others. Most responded differentially when the same observed act was embedded in a specific action. These neurons fired during the observation of an act, before the beginning of the subsequent acts specifying the action. Thus, these neurons not only code the observed motor act but also allow the observer to understand the agent's intentions.     

Complementary process to response bias in the centromedian nucleus of the thalamus

Activity in several areas of the human brain and the monkey brain increases when a subject anticipates events associated with a reward, implicating a role for bias of decision and action. However, in real life, events do not always appear as expected, and we must choose an undesirable action. More than half of the neurons in the monkey centromedian (CM) thalamus were selectively activated when a small-reward action was required but a large-reward option was anticipated. Electrical stimulation of the CM after a large-reward action request substituted a brisk performance with a sluggish performance. These results suggest involvement of the CM in a mechanism complementary to decision and action bias.     

Activation of extrastriate and frontal cortical areas by visual words and word-like stimuli

Visual presentation of words activates extrastriate regions of the occipital lobes of the brain. When analyzed by positron emission tomography (PET), certain areas in the left, medial extrastriate visual cortex were activated by visually presented pseudowords that obey English spelling rules, as well as by actual words. These areas were not activated by nonsense strings of letters or letter-like forms. Thus visual word form computations are based on learned distinctions between words and nonwords. In addition, during passive presentation of words, but not pseudowords, activation occurred in a left frontal area that is related to semantic processing. These findings support distinctions made in cognitive psychology and computational modeling between high-level visual and semantic computations on single words and describe the anatomy that may underlie these distinctions.     

烤烟C3F等级合格率低存在的问题及对策分析

通过分析安康烟区烟叶C3F等级收购过程中存在的合格率低的问题,提出了烟叶收购过程中提高C3F等级合格率的主要措施,即应加大宣传培训力度,提高从业人员技能,加强质量监控规范收购行为,准确把握标准从源头杜绝混级,在此一系列措施下烤烟C3F等级合格率得到了显著提高.     

Breakdown of cortical effective connectivity during sleep

When we fall asleep, consciousness fades yet the brain remains active. Why is this so? To investigate whether changes in cortical information transmission play a role, we used transcranial magnetic stimulation together with high-density electroencephalography and asked how the activation of one cortical area (the premotor area) is transmitted to the rest of the brain. During quiet wakefulness, an initial response (approximately 15 milliseconds) at the stimulation site was followed by a sequence of waves that moved to connected cortical areas several centimeters away. During non-rapid eye movement sleep, the initial response was stronger but was rapidly extinguished and did not propagate beyond the stimulation site. Thus, the fading of consciousness during certain stages of sleep may be related to a breakdown in cortical effective connectivity.     

我国集约化家禽养殖中鸡白细胞介素-2 的应用前景分析

鸡白细胞介素-2(IL-2)是由激活的T细胞分泌产生的糖蛋白,具有显著的免疫增强作用,不仅在T、B细胞的生长与分化和NK细胞的激活等方面发挥重要作用,而且与其他细胞因子一起发挥免疫功能,是一种能影响机体免疫反应各个方面的调节因子,因而在疾病的治疗上发挥着重要作用。我国集约化家禽养殖集现代遗传育种、饲料饲养、疾病防疫、环境控制等先进技术于一体,鸡IL-2的应用可实现有效的组装配套与综合利用。     

牛精子原位杂交DTT去凝集条件优化

[目的]确定牛精子原位杂交DTT去凝集处理的优化浓度及时同.[方法]牛精子解冻后经密度梯度离心优选并制片,采用0、5、10、20、40、80和100 mmol/L六个DTT浓度以及15、30、45和60 min4个时间段的28个组合进行去凝集处理,Motic Images Advanced 3.2软件测量精子解聚后头部面积.[结果]40 mmol/L DTT处理45min精子头部面积为(52.32±4.68 )μm2,浓度＜ 40 mmol/L的16个处理组及浓度≥40 mmol/L、处理时间＜45 min的6个处理组,精子头部面积小于(52.32±4.68) μm2(p＜ 0.01);浓度＞40 mmol/L、时间≥45 min的5个处理组,精子头部面积与40 mmol/L DTT 45 min组差异不显著(P＞0.05),但精子形态不完整.[结论]40mmol/L DTT 45 min为较优处理组合.     

Neuronal correlates of goal-based motor selection in the prefrontal cortex

Choosing an action that leads to a desired goal requires an understanding of the linkages between actions and their outcomes. We investigated neural mechanisms of such goal-based action selection. We trained monkeys on a task in which the relation between visual cues, action types, and reward conditions changed regularly, such that the monkeys selected their actions based on anticipated reward conditions. A significant number of neurons in the medial prefrontal cortex were activated, after cue presentation and before motor execution, only by particular action-reward combinations. This prefrontal activity is likely to underlie goal-based action selection.     

川金丝猴笼舍容纳量的初步研究

[目的]在川金丝猴的驯养中合理利用笼舍空间和资源。[方法]将笼舍划分为9个区域,采用瞬时扫描取样法记录其活动频次。通过极限笼养密度估算笼舍容纳量。[结果]1#笼舍的个体大部分在6区和9区活动;5#笼舍内个体的活动覆盖区域主要是1区和4区,其次是3区;3#笼舍内的个体主要在1、3、7区内活动;4#笼舍内的个体主要在1、5、9区内活动;2#笼舍有4只个体,每个个体的活动区域都较广泛。[结论]在4 m×5 m×6 m的笼舍内,在金丝猴个体间冲突较小的前提下,笼养量为3～4只时较为合适,笼养量较少时造成空间的浪费,太大则易造成金丝猴个体之间的空间冲突。     

Strategy-dependent encoding of planned arm movements in the dorsal premotor cortex

The kinematic strategy encoded in motor cortical areas for classic straight-line reaching is remarkably simple and consistent across subjects, despite the complicated musculoskeletal dynamics that are involved. As tasks become more challenging, however, different conscious strategies may be used to improve perceived behavioral performance. We identified additional spatial information that appeared both in single neurons and in the population code of monkey dorsal premotor cortex when obstacles impeded direct reach paths. The neural correlate of movement planning varied between subjects in a manner consistent with the use of different strategies to optimize task completion. These distinct planning strategies were manifested in the timing and strength of the information contained in the neural population code.     

Human neuroelectric patterns predict performance accuracy

In seven right-handed adults, the brain electrical patterns before accurate performance differed from the patterns before inaccurate performance. Activity overlying the left frontal cortex and the motor and parietal cortices contralateral to the performing hand preceded accurate left- or right-hand performance. Additional strong activity overlying midline motor and premotor cortices preceded left-hand performance. These measurements suggest that brief, spatially distributed neural activity patterns, or "preparatory sets," in distinct cognitive, somesthetic-motor, and integrative motor areas of the human brain may be essential precursors of accurate visuomotor performance.     

A specialized forebrain circuit for vocal babbling in the juvenile songbird

Young animals engage in variable exploratory behaviors essential for the development of neural circuitry and adult motor control, yet the neural basis of these behaviors is largely unknown. Juvenile songbirds produce subsong-a succession of primitive vocalizations akin to human babbling. We found that subsong production in zebra finches does not require HVC (high vocal center), a key premotor area for singing in adult birds, but does require LMAN (lateral magnocellular nucleus of the nidopallium), a forebrain nucleus involved in learning but not in adult singing. During babbling, neurons in LMAN exhibited premotor correlations to vocal output on a fast time scale. Thus, juvenile singing is driven by a circuit distinct from that which produces the adult behavior-a separation possibly general to other developing motor systems.     

Functional mapping of the primate auditory system

Cerebral auditory areas were delineated in the awake, passively listening, rhesus monkey by comparing the rates of glucose utilization in an intact hemisphere and in an acoustically isolated contralateral hemisphere of the same animal. The auditory system defined in this way occupied large portions of cerebral tissue, an extent probably second only to that of the visual system. Cortically, the activated areas included the entire superior temporal gyrus and large portions of the parietal, prefrontal, and limbic lobes. Several auditory areas overlapped with previously identified visual areas, suggesting that the auditory system, like the visual system, contains separate pathways for processing stimulus quality, location, and motion.     

Neuroscience. Where the brain monitors the body

Researchers haven't known exactly where in the brain all the signals that allow an animal to keep track of its limbs are located, but now a team may have located some of the neurons that first make these multisensory connections. On page 1782, researchers report evidence that a small region of the parietal cortex of the monkey brain known as area 5 may enable the monkey to integrate many sources of information about its body and thereby update its mental model of what the body is doing. The researchers based this conclusion on their finding that some area 5 neurons fire at their fastest rates when the visual feedback from a monkey's arm matches the sensory feedback, an indication that the neurons are sensitive to both streams of information.     

Auditory pathways to the frontal cortex of the mustache bat, Pteronotus parnellii

In primates, certain areas of the frontal cortex play a role in guiding movements toward visual or auditory objects in space. The projections from auditory centers to the frontal cortex of the bat Pteronotus parnellii were examined because echolocating bats utilize auditory cues to guide their movements in space. An area in the frontal cortex receives a direct projection from a division of the auditory thalamus, the suprageniculate nucleus, which in turn receives input from the anterolateral peri-olivary nucleus, an auditory center in the medulla. This pathway to the frontal cortex bypasses the main auditory centers in the midbrain and cortex and could involve as few as four neurons between the cochlea and the frontal cortex. The auditory cortex is also a major source of input to the frontal cortex. This area of the frontal cortex may link the auditory and motor systems by its projections to the superior colliculus.     

Scale errors offer evidence for a perception-action dissociation early in life

We report a perception-action dissociation in the behavior of normally developing young children. In adults and older children, the perception of an object and the organization of actions on it are seamlessly integrated. However, as documented here, 18- to 30-month-old children sometimes fail to use information about object size and make serious attempts to perform impossible actions on miniature objects. They try, for example, to sit in a dollhouse chair or to get into a small toy car. We interpret scale errors as reflecting problems with inhibitory control and with the integration of visual information for perception and action.     

Neuronal activity in the lateral intraparietal area and spatial attention

Although the parietal cortex has been implicated in the neural processes underlying visual attention, the nature of its contribution is not well understood. We tracked attention in the monkey and correlated the activity of neurons in the lateral intraparietal area (LIP) with the monkey's attentional performance. The ensemble activity in LIP across the entire visual field describes the spatial and temporal dynamics of a monkey's attention. Activity subtending a single location in the visual field describes the attentional priority at that area but does not predict that the monkey will actually attend to or make an eye movement to that location.     

Time-dependent central compensatory mechanisms of finger dexterity after spinal cord injury

Transection of the direct cortico-motoneuronal pathway at the mid-cervical segment of the spinal cord in the macaque monkey results in a transient impairment of finger movements. Finger dexterity recovers within a few months. Combined brain imaging and reversible pharmacological inactivation of motor cortical regions suggest that the recovery involves the bilateral primary motor cortex during the early recovery stage and more extensive regions of the contralesional primary motor cortex and bilateral premotor cortex during the late recovery stage. These changes in the activation pattern of frontal motor-related areas represent an adaptive strategy for functional compensation after spinal cord injury.