simultaneous-recordings-cortical-local-field-potentials

Simultaneous Recordings of Cortical Local Field Potentials, Electrocardiogram, Electromyogram, and Breathing Rhythm from a Freely Moving Rat

Monitoring the physiological dynamics of the brain and peripheral tissues is necessary for addressing a number of questions about how the brain controls ...

The University of Tokyo

the university of tokyo

The membrane trafficking pathway has been diversified in a specific way for each eukaryotic lineage, probably to fulfill specific functions in the organisms. In green plants, comparative genomics has supported the possibility that terrestrialization and/or multicellularization could be associated with the elaboration and diversification of membrane trafficking pathways, which have been accomplished by an expansion of the numbers of genes required for machinery components of membrane trafficking, including soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. However, information regarding membrane trafficking pathways in basal land plant lineages remains limited. In the present study, we conducted extensive analyses of SNARE molecules, which mediate membrane fusion between target membranes and transport vesicles or donor organelles, in the liverwort, Marchantia polymorpha. The M. polymorpha genome contained at least 34 genes for 36 SNARE proteins, comprising fundamental sets of SNARE proteins that are shared among land plant lineages with low degrees of redundancy. We examined the subcellular distribution of a major portion of these SNARE proteins by expressing Citrine-tagged SNARE proteins in M. polymorpha, and the results showed that some of the SNARE proteins were targeted to different compartments from their orthologous products in Arabidopsis thaliana. For example, MpSYP12B was localized to the surface of the oil body, which is a unique organelle in liverworts. Furthermore, we identified three VAMP72 members with distinctive structural characteristics, whose N-terminal extensions contain consensus sequences for N-myristoylation. These results suggest that M. polymorpha has acquired unique membrane trafficking pathways associated with newly acquired machinery components during evolution.

SNARE Molecules in Marchantia polymorpha: Unique and Conserved Features of the Membrane Fusion Machinery.

The hippocampus is involved in episodic memories of events including time and space. Many studies have focused on the neuronal processing mechanisms underlying spatial cognition and representation in the hippocampus; however, the time-related aspects of memories have only recently become the focus of research. In this review, we first introduce recent reports demonstrating the importance of the hippocampus in the perception of time and then present the hippocampal neuronal dynamics for the representation of time, revealed by large-scale neuronal recording techniques.

[Representation of Time by Hippocampal Neurons].

The functions of sleep for synaptic plasticity remain elusive. We report that mouse hippocampal sharp wave/ripple oscillations serve as intrinsic events that trigger long-lasting synaptic depression. Silencing of sharp waves/ripples during slow-wave states prevented the spontaneous downregulation of net synaptic weights and impaired the learning of new memories. The synaptic downregulation was-methyl-d-aspartate receptor-dependent and input pathway-selective. Thus, our findings are consistent with the role of slow-wave states in refining memory engrams by reducing recent memory-irrelevant neuronal activity and suggest a new role for sharp waves/ripples.

Hippocampal ripples down-regulate synapses.

Behavioral and cognitive studies have demonstrated that brain functions are affected by the activity states of the peripheral organs, such as the cardiac and respiratory systems. However, detailed neurophysiological mechanisms underlying the body-brain interactions remain unknown. In this study, we developed a method for manipulating activity levels of the heart using direct cardiac stimulation and vagus nerve stimulation that can be combined with recording cerebral local field potentials using a microdrive system, electrocardiograms, electromyograms, in a freely moving rat. With this method, the electrical stimulation to the heart increases heart rates up to 14 Hz, whereas the vagus nerve stimulation decreases heart rates to 3 Hz. Transient electrical artifacts arising from the peripheral stimulation are not contaminated in cortical local field potential signals low-pass filtered at 150 Hz and distinguishable from extracellular multiunit signals. The technique will contribute to understanding the neurophysiological correlate of mind-body associations in health and disease.

Article	Year
SNARE Molecules in Marchantia polymorpha: Unique and Conserved Features of the Membrane Fusion Machinery. Plant & cell physiology\| PubMed ID: 26019268	2016
[Representation of Time by Hippocampal Neurons]. Brain and nerve = Shinkei kenkyu no shinpo\| PubMed ID: 29172189	2017
Hippocampal ripples down-regulate synapses. Science (New York, N.Y.)\| PubMed ID: 29439023	2018
Monitoring brain neuronal activity with manipulation of cardiac events in a freely moving rat. Neuroscience research\| PubMed ID: 29454657	2018

Yu Shikano

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