scholarly journals Neurophysiological and Computational Principles of Cortical Rhythms in Cognition

2010 ◽  
Vol 90 (3) ◽  
pp. 1195-1268 ◽  
Author(s):  
Xiao-Jing Wang
Keyword(s):  
Single Cells ◽  
Field Potential ◽  
Neuron Activity ◽  
Long Distance ◽  
Physiological Mechanisms ◽  
Potential Oscillations ◽  
Cortical Rhythms ◽  
Common Observation ◽  
Unifying Principles ◽  
Neuronal Coherence

Synchronous rhythms represent a core mechanism for sculpting temporal coordination of neural activity in the brain-wide network. This review focuses on oscillations in the cerebral cortex that occur during cognition, in alert behaving conditions. Over the last two decades, experimental and modeling work has made great strides in elucidating the detailed cellular and circuit basis of these rhythms, particularly gamma and theta rhythms. The underlying physiological mechanisms are diverse (ranging from resonance and pacemaker properties of single cells to multiple scenarios for population synchronization and wave propagation), but also exhibit unifying principles. A major conceptual advance was the realization that synaptic inhibition plays a fundamental role in rhythmogenesis, either in an interneuronal network or in a reciprocal excitatory-inhibitory loop. Computational functions of synchronous oscillations in cognition are still a matter of debate among systems neuroscientists, in part because the notion of regular oscillation seems to contradict the common observation that spiking discharges of individual neurons in the cortex are highly stochastic and far from being clocklike. However, recent findings have led to a framework that goes beyond the conventional theory of coupled oscillators and reconciles the apparent dichotomy between irregular single neuron activity and field potential oscillations. From this perspective, a plethora of studies will be reviewed on the involvement of long-distance neuronal coherence in cognitive functions such as multisensory integration, working memory, and selective attention. Finally, implications of abnormal neural synchronization are discussed as they relate to mental disorders like schizophrenia and autism.

The Dependence of Spike Field Coherence on Expected Intensity

2011 ◽  
Vol 23 (9) ◽  
pp. 2209-2241 ◽  
Author(s):  
Kyle Q. Lepage ◽  
Mark A. Kramer ◽  
Uri T. Eden
Keyword(s):  
Broad Class ◽  
Phase Locking ◽  
Field Potential ◽  
Neuron Activity ◽  
Potential Oscillations ◽  
Intensity Field ◽  
The Relationship ◽  
Field Oscillation ◽  
Field Coherence ◽  
Specific Phase

The coherence between neural spike trains and local-field potential recordings, called spike-field coherence, is of key importance in many neuroscience studies. In this work, aside from questions of estimator performance, we demonstrate that theoretical spike-field coherence for a broad class of spiking models depends on the expected rate of spiking. This rate dependence confounds the phase locking of spike events to field-potential oscillations with overall neuron activity and is demonstrated analytically, for a large class of stochastic models, and in simulation. Finally, the relationship between the spike-field coherence and the intensity field coherence is detailed analytically. This latter quantity is independent of neuron firing rate and, under commonly found conditions, is proportional to the probability that a neuron spikes at a specific phase of field oscillation. Hence, intensity field coherence is a rate-independent measure and a candidate on which to base the appropriate statistical inference of spike field synchrony.

scholarly journals Systematic functional characterization of antisense eRNA of protocadherin α composite enhancer

2021 ◽  
Vol 35 (19-20) ◽  
pp. 1383-1394
Author(s):  
Yuxiao Zhou ◽  
Siyuan Xu ◽  
Mo Zhang ◽  
Qiang Wu
Keyword(s):  
Gene Expression ◽  
Molecular Mechanisms ◽  
Single Cells ◽  
Functional Characterization ◽  
Three Dimensional ◽  
Elongation Factor ◽  
Locked Nucleic Acid ◽  
Loop Formation ◽  
Long Distance ◽  
Enhancer Region

Enhancers generate bidirectional noncoding enhancer RNAs (eRNAs) that may regulate gene expression. At present, the eRNA function remains enigmatic. Here, we report a 5′ capped antisense eRNA PEARL (Pcdh eRNA associated with R-loop formation) that is transcribed from the protocadherin (Pcdh) α HS5-1 enhancer region. Through loss- and gain-of-function experiments with CRISPR/Cas9 DNA fragment editing, CRISPRi, and CRISPRa, as well as locked nucleic acid strategies, in conjunction with ChIRP, MeDIP, DRIP, QHR-4C, and HiChIP experiments, we found that PEARL regulates Pcdhα gene expression by forming local RNA–DNA duplexes (R-loops) in situ within the HS5-1 enhancer region to promote long-distance chromatin interactions between distal enhancers and target promoters. In particular, increased levels of eRNA PEARL via perturbing transcription elongation factor SPT6 lead to strengthened local three-dimensional chromatin organization within the Pcdh superTAD. These findings have important implications regarding molecular mechanisms by which the HS5-1 enhancer regulates stochastic Pcdhα promoter choice in single cells in the brain.

scholarly journals Groundwater cable bacteria conserve energy by sulfur disproportionation

2019 ◽  
Vol 14 (2) ◽  
pp. 623-634 ◽  
Author(s):  
Hubert Müller ◽  
Sviatlana Marozava ◽  
Alexander J. Probst ◽  
Rainer U. Meckenstock
Keyword(s):  
16S Rrna ◽  
Electron Donor ◽  
Nitrate Reduction ◽  
Elemental Sulfur ◽  
Single Cells ◽  
Sulfur Oxidation ◽  
Metabolic Reconstruction ◽  
Rrna Gene ◽  
Long Distance ◽  
Sulfur Disproportionation

AbstractCable bacteria of the family Desulfobulbaceae couple spatially separated sulfur oxidation and oxygen or nitrate reduction by long-distance electron transfer, which can constitute the dominant sulfur oxidation process in shallow sediments. However, it remains unknown how cells in the anoxic part of the centimeter-long filaments conserve energy. We found 16S rRNA gene sequences similar to groundwater cable bacteria in a 1-methylnaphthalene-degrading culture (1MN). Cultivation with elemental sulfur and thiosulfate with ferrihydrite or nitrate as electron acceptors resulted in a first cable bacteria enrichment culture dominated >90% by 16S rRNA sequences belonging to the Desulfobulbaceae. Desulfobulbaceae-specific fluorescence in situ hybridization (FISH) unveiled single cells and filaments of up to several hundred micrometers length to belong to the same species. The Desulfobulbaceae filaments also showed the distinctive cable bacteria morphology with their continuous ridge pattern as revealed by atomic force microscopy. The cable bacteria grew with nitrate as electron acceptor and elemental sulfur and thiosulfate as electron donor, but also by sulfur disproportionation when Fe(Cl)2 or Fe(OH)3 were present as sulfide scavengers. Metabolic reconstruction based on the first nearly complete genome of groundwater cable bacteria revealed the potential for sulfur disproportionation and a chemo-litho-autotrophic metabolism. The presence of different types of hydrogenases in the genome suggests that they can utilize hydrogen as alternative electron donor. Our results imply that cable bacteria not only use sulfide oxidation coupled to oxygen or nitrate reduction by LDET for energy conservation, but sulfur disproportionation might constitute the energy metabolism for cells in large parts of the cable bacterial filaments.

scholarly journals Two subdivisions of macaque LIP process visual-oculomotor information differently

2016 ◽  
Vol 113 (41) ◽  
pp. E6263-E6270 ◽  
Author(s):  
Mo Chen ◽  
Bing Li ◽  
Jing Guang ◽  
Linyu Wei ◽  
Si Wu ◽  
...  
Keyword(s):  
Visual Stimulation ◽  
Field Potential ◽  
Frontal Eye Field ◽  
Express Saccades ◽  
Long Distance ◽  
Lateral Intraparietal Cortex ◽  
Persistent Memory ◽  
Deep Layers ◽  
Eye Field ◽  
Saccade Task

Although the cerebral cortex is thought to be composed of functionally distinct areas, the actual parcellation of area and assignment of function are still highly controversial. An example is the much-studied lateral intraparietal cortex (LIP). Despite the general agreement that LIP plays an important role in visual-oculomotor transformation, it remains unclear whether the area is primary sensory- or motor-related (the attention-intention debate). Although LIP has been considered as a functionally unitary area, its dorsal (LIPd) and ventral (LIPv) parts differ in local morphology and long-distance connectivity. In particular, LIPv has much stronger connections with two oculomotor centers, the frontal eye field and the deep layers of the superior colliculus, than does LIPd. Such anatomical distinctions imply that compared with LIPd, LIPv might be more involved in oculomotor processing. We tested this hypothesis physiologically with a memory saccade task and a gap saccade task. We found that LIP neurons with persistent memory activities in memory saccade are primarily provoked either by visual stimulation (vision-related) or by both visual and saccadic events (vision-saccade–related) in gap saccade. The distribution changes from predominantly vision-related to predominantly vision-saccade–related as the recording depth increases along the dorsal-ventral dimension. Consistently, the simultaneously recorded local field potential also changes from visual evoked to saccade evoked. Finally, local injection of muscimol (GABA agonist) in LIPv, but not in LIPd, dramatically decreases the proportion of express saccades. With these results, we conclude that LIPd and LIPv are more involved in visual and visual-saccadic processing, respectively.

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