Operant conditioning of cortical unit activity

The activity of single neurons in precentral cortex of unanesthetized monkeys (Macaca mulatta) was conditioned by reinforcing high rates of neuronal discharge with delivery of a food pellet. Auditory or visual feedback of unit firing rates was usually provided in addition to food reinforcement. After several training sessions, monkeys could increase the activity of newly isolated cells by 50 to 500 percent above rates before reinforcement.     

Operant conditioning of specific patterns of neural and muscular activity

In awake monkeys we recorded activity of single "motor" cortex cells, four contralateral arm muscles, and elbow position, while operantly reinforcing several patterns of motor activity. With the monkey's arm held semiprone in a cast hinged at the elbow, we reinforced active elbow movements and tested cell responses to passive elbow movements. With the cast immobilized we reinforced isometric contraction of each of the four muscles in isolation, and bursts of cortical cell activity with and without simultaneous suppression of muscle activity. Correlations between a precentral cell and specific arm muscles consistently appeared under several behavioral conditions, but could be dissociated by reinforcing cell activity and muscle suppression.     

Taste-aversion conditioning of crows to control predation on eggs

Free-ranging crows (Corvus brachyrhynchos) that ate chicken eggs that were painted green and contained a nonlethal toxin subsequently avoided green eggs at various locations, whether or not they contained toxin. The crows also continued to eat unpainted and nontoxic chicken eggs. Illness-induced aversions among predators in nature may be a powerful determiner of the evolution of Batesian mimicry and, in human hands, serve as a practical tool for wildlife ecologists.     

Local retinal regions control local eye growth and myopia

In chicks, visual deprivation leads to myopia and enlargement of the vitreous chamber of the eye. When chicks were raised with white translucent occluders over their eyes so that either the nasal half, the temporal half, or all of the retina was visually deprived, the resulting myopia (median = -15 diopters) was limited to the deprived part of the retina, regardless of which half of the retina was visually deprived; the nondeprived part remained nearly emmetropic. Correspondingly, the vitreous chamber was elongated only in the region of the visual deprivation, resulting in eyes with different asymmetric shapes depending on which retinal region was deprived. These results argue for a local regulation of ocular growth that is dependent on vision and suggest a hypothesis to explain the epidemiological association of myopia in humans with large amounts of reading. Because most nonfoveal retinal neurons have large receptive fields, they cannot resolve the individual letters on the printed page; this may lead to their activity being less during reading than during most other forms of visual stimulation. Thus, the impoverished stimulus situation of reading may lead to myopia, as do other types of visual form deprivation.     

Cell type-specific loss of BDNF signaling mimics optogenetic control of cocaine reward

The nucleus accumbens is a key mediator of cocaine reward, but the distinct roles of the two subpopulations of nucleus accumbens projection neurons, those expressing dopamine D1 versus D2 receptors, are poorly understood. We show that deletion of TrkB, the brain-derived neurotrophic factor (BDNF) receptor, selectively from D1+ or D2+ neurons oppositely affects cocaine reward. Because loss of TrkB in D2+ neurons increases their neuronal excitability, we next used optogenetic tools to control selectively the firing rate of D1+ and D2+ nucleus accumbens neurons and studied consequent effects on cocaine reward. Activation of D2+ neurons, mimicking the loss of TrkB, suppresses cocaine reward, with opposite effects induced by activation of D1+ neurons. These results provide insight into the molecular control of D1+ and D2+ neuronal activity as well as the circuit-level contribution of these cell types to cocaine reward.     

Facilitation of spindle-burst sleep by conditioning of electroencephalographic activity while awake

A slow-wave electroencephalographic rhythm recorded from the sensorimotor cortex of the waking cat has been correlated behaviorally with the suppression of movement. Facilitation of this rhythm through conditioning selectively enhances a similar pattern recorded during sleep, the familiar spindle burst. The training also produced longer epochs of undisturbed sleep. The specific neural mechanism manipulated during wakefulness appears to function also in sleep and to be involved with the regulation of phasic motor behavior.     

Single unit activity of anterior hypothalamus during local heating

There are heat-sensitive units in the anterior hypothalamus which respond with an increase of discharge frequency to a rise in hypothalamic temperature of less than 1 degrees C. The increase of unit discharge occurred in advance of the onset of polypnea , and the unit has little phasic response or after discharge, and shows little adaptation.     

液体发酵局域环境温度的智能控制系统

研制了一种基于数字温度传感器DS1621的液体发酵局域环境温度智能控制系统，介绍了其工作原理、硬件设计及软件工作流程．     

Clonal production and organization of inhibitory interneurons in the neocortex

The neocortex contains excitatory neurons and inhibitory interneurons. Clones of neocortical excitatory neurons originating from the same progenitor cell are spatially organized and contribute to the formation of functional microcircuits. In contrast, relatively little is known about the production and organization of neocortical inhibitory interneurons. We found that neocortical inhibitory interneurons were produced as spatially organized clonal units in the developing ventral telencephalon. Furthermore, clonally related interneurons did not randomly disperse but formed spatially isolated clusters in the neocortex. Individual clonal clusters consisting of interneurons expressing the same or distinct neurochemical markers exhibited clear vertical or horizontal organization. These results suggest that the lineage relationship plays a pivotal role in the organization of inhibitory interneurons in the neocortex.     

Identified interneurons produce both primary afferent depolarization and presynaptic inhibition

Crayfish interneurons were identified that appear to be directly responsible for presynaptic inhibition of primary afferent synapses during crayfish escape behavior. The interneurons are fired by a polysynaptic pathway triggered by the giant escape command axons. When directly stimulated, these interneurons produce short-latency, chloride-dependent primary afferent depolarizations and presynaptically inhibit primary afferent input to mechanosensory interneurons.     

Role of EphA4 and EphrinB3 in local neuronal circuits that control walking

Local circuits in the spinal cord that generate locomotion are termed central pattern generators (CPGs). These provide coordinated bilateral control over the normal limb alternation that underlies walking. The molecules that organize the mammalian CPG are unknown. Isolated spinal cords from mice lacking either the EphA4 receptor or its ligand ephrinB3 have lost left-right limb alternation and instead exhibit synchrony. We identified EphA4-positive neurons as an excitatory component of the locomotor CPG. Our study shows that dramatic locomotor changes can occur as a consequence of local genetic rewiring and identifies genes required for the development of normal locomotor behavior.     

Flight interneurons in the locust and the origin of insect wings

Interneurons involved in the generation of motor activity for flight in the locust were found in the first three abdominal ganglia as well as in thoracic ganglia. The evidence that sets of homologous flight interneurons occur in abdominal and thoracic ganglia supports theories that insect wings originated from movable appendages which were serially distributed along the thorax and abdomen and which were under central nervous control.     

Cholinergic enhancement and increased selectivity of perceptual processing during working memory

Using functional magnetic resonance imaging, we investigated the mechanism by which cholinergic enhancement improves working memory. We studied the effect of the cholinesterase inhibitor physostigmine on subcomponents of this complex function. Cholinergic enhancement increased the selectivity of neural responses in extrastriate cortices during visual working memory, particularly during encoding. It also increased the participation of ventral extrastriate cortex during memory maintenance and decreased the participation of anterior prefrontal cortex. These results indicate that cholinergic enhancement improves memory performance by augmenting the selectivity of perceptual processing during encoding, thereby simplifying processing demands during memory maintenance and reducing the need for prefrontal participation.     

过氧乙酸对池塘水体的增氧抑菌抑藻效果研究

为寻找一种既安全可靠,又能增加水体溶氧、杀灭水体病原菌并改善水体环境的抑藻试剂,用多功能水质分析仪检测在10、20、30℃条件下,过氧乙酸(体积分数为15%)在池塘水和蒸馏水中的放氧效果。结果表明:温度越高放氧越快,但温度越高氧气的饱和量越低,气体外溢,故测出的溶解氧浓度数值较低;采用滤纸片法和二倍稀释法测定过氧乙酸和3种常用杀菌剂对6种常见水产病原菌(副溶血弧菌、维氏气单胞菌、嗜水气单胞菌、溶藻弧菌、沃氏葡萄球菌和腐生葡萄球菌)的抑菌效果,结果显示,抑菌效果依次为恩诺沙星过氧乙酸聚维酮碘高锰酸钾;对暂养的黄丝藻藻华进行毒杀,结果显示,随着时间的延长,加入高浓度过氧乙酸的试验组水体开始混浊,藻丝体开始断裂,叶绿素a含量减少;各时段下,过氧乙酸浓度组叶绿素a含量明显低于对照组(P0.05),随着时间的延长各浓度组超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量均呈先增长后下降的趋势,说明黄丝藻藻丝体受到了过氧乙酸的破坏,开始解体甚至死亡。研究表明,在水产养殖池塘中使用过氧乙酸,增氧、抑菌、抑藻效果明显。     

虫溃啶对水稻三化螟的生物活性和田间防治研究

经室内生测和田间试验结果表明,虫溃啶对三化螟具有较高的毒力,其LC50为3.35mg/L,均高于对照药剂三唑磷和杀虫单,对二代,三代三代螟具有较好的控制效果;生产应用时,防治二代三化螟适宜用量为60-80ml/667m^2,三代三化螟为80-100ml/667m^2,防治适期在卵孵高峰前。     

过氧乙酸对池塘水体的增氧抑菌抑藻效果研究

为寻找一种既安全可靠,又能增加水体溶氧、杀灭水体病原菌并改善水体环境的抑藻试剂,用多功能水质分析仪检测在10、20、30℃条件下,过氧乙酸(体积分数为15%)在池塘水和蒸馏水中的放氧效果。结果表明:温度越高放氧越快,但温度越高氧气的饱和量越低,气体外溢,故测出的溶解氧浓度数值较低;采用滤纸片法和二倍稀释法测定过氧乙酸和3种常用杀菌剂对6种常见水产病原菌(副溶血弧菌、维氏气单胞菌、嗜水气单胞菌、溶藻弧菌、沃氏葡萄球菌和腐生葡萄球菌)的抑菌效果,结果显示,抑菌效果依次为恩诺沙星>过氧乙酸>聚维酮碘>高锰酸钾;对暂养的黄丝藻藻华进行毒杀,结果显示,随着时间的延长,加入高浓度过氧乙酸的试验组水体开始混浊,藻丝体开始断裂,叶绿素a含量减少;各时段下,过氧乙酸浓度组叶绿素a含量明显低于对照组(P<0.05),随着时间的延长各浓度组超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量均呈先增长后下降的趋势,说明黄丝藻藻丝体受到了过氧乙酸的破坏,开始解体甚至死亡。研究表明,在水产养殖池塘中使用过氧乙酸,增氧、抑菌、抑藻效果明显。     

Decreased hippocampal inhibition and a selective loss of interneurons in experimental epilepsy

The occurrence of seizure activity in human temporal lobe epilepsy or status epilepticus is often associated with a characteristic pattern of cell loss in the hippocampus. An experimental model that replicates this pattern of damage in normal animals by electrical stimulation of the afferent pathway to the hippocampus was developed to study changes in structure and function that occur as a result of repetitive seizures. Hippocampal granule cell seizure activity caused a persistent loss of recurrent inhibition and irreversibly damaged adjacent interneurons. Immunocytochemical staining revealed unexpectedly that gamma-aminobutyric acid (GABA)-containing neurons, thought to mediate inhibition in this region and predicted to be damaged by seizures, had survived. In contrast, there was a nearly complete loss of adjacent somatostatin-containing interneurons and mossy cells that may normally activate inhibitory neurons. These results suggest that the seizure-induced loss of a basket cell-activating system, rather than a loss of inhibitory basket cells themselves, may cause disinhibition and thereby play a role in the pathophysiology and pathology of the epileptic state.