Neuroscience
-
This study examined the processing of ambiguous morphemes in Chinese word recognition with a masked priming lexical decision task. Both behavioral and event-related potential (ERP) were recorded. All targets were bimorphemic compound words that contained ambiguous morphemes as the first morphemes. ⋯ These results have two implications to the processing of ambiguous morphemes during Chinese compound word recognition. First, the morpheme meanings could be activated rapidly. Second, the more frequently used dominant meanings could be activated more easily than the less frequently used subordinate meanings.
-
Randomized Controlled Trial
Dorsolateral Prefrontal Cortex and Task-Switching Performance: Effects of Anodal Transcranial Direct Current Stimulation.
Task switching refers to the process by which an individual transfers focus from one cognitive task to another. In recent years, transcranial direct current stimulation (tDCS) technology had been used to investigate the causal relationship between the dorsolateral prefrontal cortex (DLPFC) and task-switching performance. However, the effects of anodal-tDCS (a-tDCS) on task switching remain unclear, and the relationship between DLPFC and various task predictabilities have not yet been studied. ⋯ Compared with LA and sham tDCS, increasing the activity of the right DLPFC improved task-switching performance (switch cost) of unpredictable but not predictable tasks. The results suggested there is a causal association between DLPFC and unpredictable task switching and implied a task-specific effect in task switching. We concluded that the DLPFC is not essential for exogenous adjustment in predictable task switching.
-
Melatonin is crucial for protecting neural stem cells (NSCs) from reactive oxygen species (ROS). However, the mechanism underlying these processes is unclear. In this study, we first investigated the significantly upregulated lncRNA MEG3 biomarker in the H2O2-induced NSCs and control groups. ⋯ In addition, the elevated miRNA-27a-3p decreased JNK phosphorylation by targeting MAP2K4. Overexpression of MAP2K4 suppressed the neuroprotective effects of miRNA-27a-3p. Therefore, melatonin appeared to protect NSCs from H2O2-induced ROS by modification of the MEG3/miRNA-27a-3p/MAP2K4 axis.
-
Reciprocal connection between the ventral tegmental area (VTA) and the hippocampus forms a loop that controls information entry into long-term memory. Compared with the widely studied VTA dopamine system, VTA glutamate terminals are anatomically dominant in the hippocampus and less understood. The current study employs anterograde and retrograde labeling of VTA dopamine and glutamate neurons to map the distribution of their terminals within the layers of the hippocampus. ⋯ Conversely, activation of VTA glutamate neurons increased CA1 network firing rate and burst rate. In addition, VTA glutamate inputs reduced the interspike and interburst intervals for putative CA1 neurons. Taken together, we deduced that layer-specific distribution of presynaptic dopamine and glutamate terminals in the hippocampus determinines VTA modulation (dopamine) or regulation (glutamate) of excitability in the CA1 neural network.
-
Perceiving the sensory consequences of our actions with a delay alters the interpretation of these afferent signals and impacts motor learning. For reaching movements, delayed visual feedback of hand position reduces the rate and extent of visuomotor adaptation, but substantial adaptation still occurs. Moreover, the detrimental effect of visual feedback delay on reach motor learning-selectively affecting its implicit component-can be mitigated by prior habituation to the delay. ⋯ Although habituation minimized awareness of the delay, no improvement in adaptation to the spectral perturbation was observed. Thus, short-term habituation to auditory feedback delays is not effective in reducing the negative impact of delay on speech auditory-motor adaptation. Combined with previous findings, the strong negative effect of delay and the absence of an influence of delay awareness suggest the involvement of predominantly implicit learning mechanisms in speech.