The prefrontal cortex and cognitive control

One of the enduring mysteries of brain function concerns the process of cognitive control. How does complex and seemingly willful behaviour emerge from interactions between millions of neurons? This has long been suspected to depend on the prefrontal cortex--the neocortex at the anterior end of the brain--but now we are beginning to uncover its neural basis. Nearly all intended behaviour is learned and so depends on a cognitive system that can acquire and implement the 'rules of the game' needed to achieve a given goal in a given situation. Studies indicate that the prefrontal cortex is central in this process. It provides an infrastructure for synthesizing a diverse range of information that lays the foundation for the complex forms of behaviour observed in primates.     

The effect of transcendental meditation on right hemispheric functioning

This study reports two experiments investigating the effects of transcendental meditation on right hemispheric functioning. The task used in both experiments was the Seashore Tonal Memory Test. In the first experiment a nonmeditator group and an experienced meditator group were run. The design involved three periods: a pretest, a meditation or rest period, and then a posttest. The results showed the experienced meditators were significantly better in both pretest and posttest performance. There were no pretest-posttest differences. The second experiment was done to replicate the first experiment and to control for possible selection bias. The design was the same as the first experiment, except that an additional group of inexperienced meditators was included. The results again showed significantly superior performance for the experienced meditators compared to the nonmeditators. In addition, the experienced meditators were superior to the inexperienced meditators. There were no significant differences between the nonmeditators and the inexperienced meditators. These results support the hypothesis that meditation facilitates right hemispheric functioning. Alternative explanations, such as selection bias, are also discussed.The authors wish to thank Ms. Michelle Ellis and Ms. Bridget Carr for their assistance in conducting these experiments. We also wish to thank the Seattle SIMS for their cooperation in obtaining subjects.     

Memory trace in prefrontal cortex: theory for the cognitive switch

The dorsolateral prefrontal cortex in human and non-human primates functions as the highest-order executor for the perception-action cycle. According to this view, when perceptual stimuli from the environment are novel or complex, the dorsolateral prefrontal cortex serves to set consciously a goal-directed scheme which broadly determines an action repertory to meet the particular demand from the environment. In this respect, the dorsolateral prefrontal cortex is a short-term activation device with the properties of a cognitive switch', because it couples a particular set of perceptual stimuli to a particular set of actions. Here, I suggest that, in order for the organism to react systematically to the environment, neural traces for the switch function must be stored in the brain. Thus, the highest-order, perception-action interface function of the dorsolateral prefrontal cortex per se depends on permanently stored neural traces in the dorsolateral prefrontal cortex and related structures. Such a memory system may be located functionally between two of the well-documented memory systems in the brain: the declarative memory system and the procedural memory system. Finally, based on available neurophysiological data, the possible mechanisms underlying the formation of cognitive switch traces are proposed.     

The effect of transcendental mediation on right hemispheric functioning.

This study reports two experiments investigating the effects of transcendental mediation on right hemispheric functioning. The task used in both experiments was the Seashore Tonal Memory Test. In the first experiment a nonmediator group and an experienced mediator group were run. The denonmeditator group and an experienced mediator group were run. The design involved three periods: a pretest, a meditation or a rest period, and then a posttest. The results showed the experienced meditators were significantly better in both pretest and posttest performance. There were no pretest--posttest differences. The second experiment was done to replicate the first experiment and to control for possible selection bias. The design was the same as the first experiment, except that an additional group of inexperienced meditators was included. The results again showed significantly superior performance for the experienced meditators compared to the nonmeditators. In addition, the experienced meditators were superior to the inexperienced meditators. There were no significant differences between the nonmeditators and the inexperienced meditators. These results support the hypothesis that meditation facilitates right hemispheric functioning. Alternative explanations, such as selection bias, are also discussed.     

A wearable system for multi-segment foot kinetics measurement

This study aims to design a wearable system for kinetics measurement of multi-segment foot joints in long-distance walking and to investigate its suitability for clinical evaluations.     

A brain-inspired compact cognitive mapping system

In many simultaneous localization and mapping (SLAM) systems, the map of the environment grows over time as the robot explores the environment. The ever-growing map prevents long-term mapping, especially in large-scale environments. In this paper, we develop a compact cognitive mapping approach inspired by neurobiological experiments. Mimicking the firing activities of neighborhood cells, neighborhood fields determined by movement information, i.e. translation and rotation, are modeled to describe one of the distinct segments of the explored environment. The vertices with low neighborhood field activities are avoided to be added into the cognitive map. The optimization of the cognitive map is formulated as a robust non-linear least squares problem constrained by the transitions between vertices, and is numerically solved efficiently. According to the cognitive decision-making of place familiarity, loop closure edges are clustered depending on time intervals, and then batch global optimization of the cognitive map is performed to satisfy the combined constraint of the whole cluster. After the loop closure process, scene integration is performed, in which revisited vertices are removed subsequently to further reduce the size of the cognitive map. The compact cognitive mapping approach is tested on a monocular visual SLAM system in a naturalistic maze for a biomimetic animated robot. Our results demonstrate that the proposed method largely restricts the growth of the size of the cognitive map over time, and meanwhile, the compact cognitive map correctly represents the overall layout of the environment. The compact cognitive mapping method is well suitable for the representation of large-scale environments to achieve long-term robot navigation. Electronic supplementary materialThe online version of this article (10.1007/s11571-020-09621-6) contains supplementary material, which is available to authorized users.     

A microcomputer-based binaural measurement system

A microcomputer is used to control a dual-channel, sine-wave generator as the excitation to both the left and right ears in experimental subjects, and for on-line measurement of the neuronal spike counts. The effects of varying the walking pattern and phase angle between the two channels can be investigated. After normalisation of spike counts, the result can be displayed as a 3-D plot on a CRT or an x-y plotter. The system is useful for general steady state and transient binaural measurement     

α2肾上腺素受体与前额叶皮层认知功能

灵长类动物上的一系列研究表明,去甲肾上腺素通过作用于前额叶皮层突触后α２Ａ受体增强前额叶皮层的认知功能,如注意力调节,工作记忆及反应抑制等。这些基础性的研究结果有助于开发新的药物治疗方法,用于治疗前额叶皮层认知功能障碍（如注意力缺损多动症）。     

A new system for automatic measurement of Permanganate Time

Permanganate Time (PT) is a standard quality control test for oxidisable impurities in products such as ethanol, acetic acid, acetic anhydride, acetone, methanol, pyridine, propionic acid and tricresyl phosphate. The test relies on visual assessment of the change in pink colouration over a period of time of a sample of product to which has been added a standard solution of potassium permanganate. Typically, this time period is between 30 min and 2 h. The standard test, therefore, is very time-consuming as well as being highly susceptible to operator error and bias. An automated measurement system has been developed that employs a photodiode array spectrophotometer to monitor the colour of the mixture. Pre-processing of the spectrum eliminates any interference and provides accurate estimates of the PT, even in the presence of a heavy precipitate. The method by which the software determines the test result can be tailored by the user to suit particular products. Any number of such user configurations can be saved for future use.     

A high sensitivity system for luminescence measurement of materials

A unique combined and multi‐disciplinary wavelength multiplexed spectrometer is described. It is furnished with high‐sensitivity imaging plate detectors, the power to which can be gated to provide time‐resolved data. The system is capable of collecting spectrally resolved luminescence data following X‐ray excitation [radioluminescence (RL) or X‐ray excited optical luminescence (XEOL)], electron irradiation [cathodoluminescence (CL)] and visible light from light emitting diodes (LEDs) [photoluminescence (PL)]. Time‐resolved PL and CL data can be collected to provide lifetime estimates with half‐lives from microsecond timeframes. There are temperature stages for the high and low temperature experiments providing temperature control from 20 to 673 K. Combining irradiation, time resolved (TR) and TR‐PL allows spectrally‐resolved thermoluminescence (TL) and optically stimulated luminescence (OSL). The design of two detectors with matched gratings gives optimum sensitivity for the system. Examples which show the advantages and multi‐use of the spectrometer are listed. Potential future experiments involving lifetime analysis as a function of irradiation, dose and temperature plus pump‐probe experiments are discussed.     

A microcomputer system for the measurement of finger forces

In the analysis of hand functions, the production and control of forces exerted during voluntary contraction of the finger muscles plays an important role; unfortunately such an analysis is rarely seen in routine clinical examinations of neurological patients. A microcomputer controlled system for the measurement and analysis of finger forces is described. The system consists of a modified Z80 based microcomputer, a commercially available high precision force transducer, a specially designed force signal amplifier and a suite of menu-driven user interactive programs. A variety of tasks is implemented by means of the computer programs. In addition to the measurement of maximum hand grip force, the system is able to record forces continuously as a function of time. Task characteristics and the type of feedback presented to the subject are under user control; they can be varied to meet clinical or experimental requirements. Examples of programs and clinical applications are presented and discussed.     

Being at the right place at the right time

I am tremendously honored to receive the 2012 Women in Cell Biology Junior Award. In this essay, I recount my career path over the past 15 years. Although many details are specific to my own experiences, I hope that some generalizations can be made to encourage more women to pursue independent scientific careers. Mine is a story of choosing a captivating question, making the most of your opportunities, and finding a balance with life outside the lab.It is a great honor to have been awarded the 2012 Women in Cell Biology Junior Award from the ASCB. Looking back at the 15 years I have spent doing research in cell biology, my overwhelming feeling is that it has been and still is a lot of fun. I am extremely fortunate to have a job that I truly enjoy and that gives me complete intellectual freedom. My lab choices over the years were motivated by scientific curiosity and enthusiasm for new environments and topics, rather than by career building. It is thus truly amazing to be rewarded for (rather a lot of) work enjoyed.     

Being in the right location at the right time

Taking each coding sequence from the human genome in turn and identifying the subcellular localization of the corresponding protein would be a significant contribution to understanding the function of each of these genes and to deciphering functional networks. This article highlights current approaches aimed at achieving this goal.     

New anthelmintics for livestock: the time is right

The viability of small-ruminant enterprises is under threat in some locations because anthelmintic resistance continues to increase in prevalence and severity. Despite this, no new anthelmintic group has been developed for many years, and animal health companies seem unconvinced of the commercial justification for new compounds for the ruminant market. It is now argued, however, that market conditions are becoming favourable because of increases in multiple-drug resistance in nematodes of ruminants and other hosts and because few non-chemical options exist. A new anthelmintic is urgently needed and will find ready acceptance in an increasing market, and with better knowledge of resistance management, greater product longevity can be achieved.     

A neural correlate of the processing of multi-second time intervals in primate prefrontal cortex

Several areas of the brain are known to participate in temporal processing. Neurons in the prefrontal cortex (PFC) are thought to contribute to perception of time intervals. However, it remains unclear whether the PFC itself can generate time intervals independently of external stimuli. Here we describe a group of PFC neurons in area 9 that became active when monkeys recognized a particular elapsed time within the range of 1-7 seconds. Another group of area 9 neurons became active only when subjects reproduced a specific interval without external cues. Both types of neurons were individually tuned to recognize or reproduce particular intervals. Moreover, the injection of muscimol, a GABA agonist, into this area bilaterally resulted in an increase in the error rate during time interval reproduction. These results suggest that area 9 may process multi-second intervals not only in perceptual recognition, but also in internal generation of time intervals.