scholarly journals High beta rhythm amplitude in olfactory learning signs a well-consolidated and non-flexible behavioral state

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Nicolas Fourcaud-Trocmé ◽  
Laura Lefèvre ◽  
Samuel Garcia ◽  
Belkacem Messaoudi ◽  
Nathalie Buonviso
Keyword(s):  
Beta Activity ◽  
Memory Recall ◽  
Field Potentials ◽  
Connectivity Analysis ◽  
Reversal Task ◽  
Beta Rhythm ◽  
Context Learning ◽  
High Beta ◽  
Contingency Reversal ◽  
The Brain

AbstractBeta rhythm (15–30 Hz) is a major candidate underlying long-range communication in the brain. In olfactory tasks, beta activity is strongly modulated by learning but its condition of expression and the network(s) responsible for its generation are unclear. Here we analyzed the emergence of beta activity in local field potentials recorded from olfactory, sensorimotor and limbic structures of rats performing an olfactory task. Rats performed successively simple discrimination, rule transfer, memory recall tests and contingency reversal. Beta rhythm amplitude progressively increased over learning in most recorded areas. Beta amplitude reduced to baseline when new odors were introduced, but remained high during memory recall. Intra-session analysis showed that even expert rats required several trials to reach a good performance level, with beta rhythm amplitude increasing in parallel. Notably, at the beginning of the reversal task, beta amplitude remained high while performance was low and, in all tested animals, beta amplitude decreased before rats were able to learn the new contingencies. Connectivity analysis showed that beta activity was highly coherent between all structures where it was expressed. Overall, our results suggest that beta rhythm is expressed in a highly coherent network when context learning - including both odors and reward - is consolidated and signals behavioral inflexibility.

scholarly journals Phase shifts in high-beta- and low-gamma-band local field potentials predict the focus of visual spatial attention

2019 ◽  
Vol 121 (3) ◽  
pp. 799-822 ◽  
Author(s):  
Vanessa L. Mock ◽  
Kimberly L. Luke ◽  
Jacqueline R. Hembrook-Short ◽  
Farran Briggs
Keyword(s):  
Spatial Attention ◽  
Cognitive Processes ◽  
Local Field ◽  
Brain Structures ◽  
Phase Shifts ◽  
Field Potentials ◽  
Visual Spatial Attention ◽  
Visual Spatial ◽  
High Beta ◽  
The Brain

The local field potential (LFP) contains rich information about activity in local neuronal populations. However, it has been challenging to establish direct links between LFP modulations and task-relevant behavior or cognitive processes, such as attention. We sought to determine whether LFP amplitude or phase modulations are predictive of the allocation of visual spatial attention. LFPs were recorded simultaneously in multiple early visual brain structures of alert macaque monkeys performing attention-demanding detection and discrimination tasks. Attention directed toward the receptive field of recorded neurons generated systematically larger phase shifts in high-beta- and low-gamma-frequency LFPs compared with LFP phase shifts on trials in which attention was directed away from the receptive field. This attention-mediated temporal advance corresponded to ~10 ms. LFP phase shifts also correlated with reaction times when monkeys were engaged in the tasks. Importantly, attentional modulation of LFP phase was consistent across monkeys, tasks, visual brain structures, and cortical layers. In contrast, attentional modulation of LFP amplitude varied across frequency bands, visual structures/layers, and tasks. Because LFP phase shifts were robust, consistent, and predictive of spatial attention, they could serve as a reliable marker for attention signals in the brain. NEW & NOTEWORTHY Local field potentials (LFPs) reflect the activity of spatially localized populations of neurons. Whether alterations in LFP activity are indicative of cognitive processes, such as attention, is unclear. We found that shifts in the phase of LFPs measured in multiple visual brain areas reliably predicted the focus of spatial attention. LFP phase shifts could therefore serve as a marker for behaviorally relevant attention signals in the brain.

scholarly journals Isoflurane reduces feedback in the fruit fly brain

2017 ◽  
Author(s):  
Dror Cohen ◽  
Bruno van Swinderen ◽  
Naotsugu Tsuchiya
Keyword(s):  
Drosophila Melanogaster ◽  
Spectral Characteristics ◽  
Fruit Fly ◽  
General Anesthetics ◽  
Field Potentials ◽  
Connectivity Analysis ◽  
Low Frequencies ◽  
Isoflurane Anesthesia ◽  
The Brain ◽  
Feedback Pathways

AbstractHierarchically organized brains communicate through feedforward and feedback pathways. In mammals, feedforward and feedback are mediated by higher and lower frequencies during wakefulness. Feedback is preferentially impaired by general anesthetics. This suggests feedback serves critical functions in waking brains. The brain of Drosophila melanogaster (fruit fly) is also hierarchically organized, but the presence of feedback in these brains is not established. Here we studied feedback in the fruit fly brain, by simultaneously recording local field potentials (LFPs) from low-order peripheral structures and higher-order central structures. Directed connectivity analysis revealed that low frequencies (0.1-5Hz) mediated feedback from the center to the periphery, while higher frequencies (10-45Hz) mediated feedforward in the opposite direction. Further, isoflurane anesthesia preferentially reduced feedback. Our results imply that similar spectral characteristics of feedforward and feedback may be a signature of hierarchically organized brains and that general anesthetics may induce unresponsiveness by targeting the mechanisms that support feedback.

BIOELECTRIC ACTIVITY OF THE BRAIN IN PATIENTS WITH ACUTE CEREBROVASCULAR ACCIDENT

Vestnik ◽  
2021 ◽  
pp. 29-34
Author(s):  
Д.А. Митрохин ◽  
М.М. Ибрагимов ◽  
Б.Р. Нурмухамбетова ◽  
Н.Ш. Буйракулова ◽  
В.В. Харченко ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Hemorrhagic Stroke ◽  
Spectral Power ◽  
Spectral Power Density ◽  
Cerebral Stroke ◽  
Beta Activity ◽  
Bioelectric Activity ◽  
Early Recovery ◽  
Coherence Index ◽  
The Brain

Значимость биоэлектрической активности головного мозга в оценке функционального состояния нервной системы при цереброваскулярных заболеваниях широко известна. В настоящей работе показана характеристика биоэлектрической активности головного мозга у больных, перенесших острое нарушение мозгового кровообращения. В данной статье приведены данные о том, что у больных в остром и раннем восстановительном периодах церебрального инсульта биоэлектрическая активность головного мозга характеризовалась, в основном, десинхронным и дезорганизованным типами электроэнцефалограммы. Вместе с тем, отмечались, выраженная дельта и тета активность, а также единичные острые волны, спайки, преимущественно в пораженном полушарии головного мозга, реже в контралатеральном полушарии, межполушарная асимметрия, повышение мощности спектров в сторону преобладания медленных волн. Показатели индекса когерентности по всем отведениям были снижены, что свидетельствует о нарушении функциональных межполушарных взаимосвязей. Более значительное повышение индекса когерентности в дельта и тета диапазонах у пациентов, перенесших геморрагический инсульт, может указывать на более грубые межполушарные нарушения, в сравнении с ишемическим инсультом. Результаты исследования относительной спектральной плотности мощности диапазонов показали, что при геморрагическом инсульте отмечена более высокая дельта и бета активность, а также более значительное снижение мощности альфа ритма, в сравнении с ишемическим инсультом. В тоже время, отмечается повышение интегрального индекса диапазона низкочастотной медленно-волновой активности, особенно выраженное у больных с геморрагическим инсультом р<0,05. The significance of bioelectric activity of the brain in assessing the functional state of the nervous system in cerebrovascular diseases is widely known. In this paper, the characteristics of the bioelectric activity of the brain in patients with acute cerebral circulatory disorders are shown. This article presents data that in patients with acute and early recovery periods of cerebral stroke , the bioelectric activity of the brain was characterized mainly by desynchronous and disorganized types of electroencephalogram. At the, same time, pronounced delta and theta activity was noted , as well as single acute waves, spikes, mainly in the affected hemisphere of the brain, less often in the contralateral hemisphere, interhemispheric asymmetry, increased spectral power in the direction of predominance of slow waves. The coherence index values for all leads were reduced, which indicates a violation of functional interhemispheric relationships. A more significant increase in the coherence index in the delta and theta ranges in patients who have had a hemorrhagic stroke may indicate more severe interhemispheric disorders compared to ischemic stroke. The results of the study of the relative spectral power density of the ranges showed, that in hemorrhagic stroke, there was a higher delta and beta activity, as well as a more significant decrease in the power of the alpha rhythm, in comparison with ischemic stroke. At the same time, there is an increase in the integral index of the range of low-frequency slow-wave activity, especially pronounced in patients with hemorrhagic stroke p < 0.05.

Spinomuscular Coherence in Monkeys Performing a Precision Grip Task

2008 ◽  
Vol 99 (4) ◽  
pp. 2012-2020 ◽  
Author(s):  
Tomohiko Takei ◽  
Kazuhiko Seki
Keyword(s):  
Spinal Cord ◽  
Sensorimotor Integration ◽  
Unique Feature ◽  
Cervical Spinal Cord ◽  
Precision Grip ◽  
Muscle Physiology ◽  
Field Potentials ◽  
Spinal Interneurons ◽  
Arm Muscles ◽  
The Brain

We recorded local field potentials (LFPs) from cervical spinal cord (C5–C8) in monkeys performing a precision grip task and examined their coherence with electromyographic (EMG) activities (spinomuscular coherence) recorded from hand and arm muscles. Among 164 LFP-EMG pairs, significant coherence was found in 34 pairs (21%). We classified the coherence into two groups based on its frequency range, narrowband coherence, and broadband coherence. The narrowband coherence was restricted to discrete frequencies in the range of 14–55 Hz and was widespread throughout the superficial and deep gray matter. In contrast, the broadband coherence distributed between 10 and 95 Hz and was found only in the ventral half of the spinal cord. The narrowband coherence suggests that oscillations, which have been described in many motor control areas of the brain, could also pass though spinal interneurons to affect motor output and sensorimotor integration. On the other hand, the broadband coherence could be a unique feature of spinal motoneuron-muscle physiology.

scholarly journals Evidence of Intermittency in the Local Field Potentials Recorded from Patients with Parkinson's Disease: A Wavelet-Based Approach

2007 ◽  
Vol 8 (3) ◽  
pp. 165-171 ◽  
Author(s):  
Asok K. Sen ◽  
Jonathan O. Dostrovsky
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Local Field ◽  
Local Field Potentials ◽  
Temporal Variations ◽  
Beta Activity ◽  
Field Potentials ◽  
Time Frequency ◽  
Intermittent Behavior ◽  
Complex Interactions

Using a continuous wavelet transform we have detected the presence of intermittency in the beta oscillations of the local field potentials (LFPs) that were recorded from the subthalamic nucleus (STN) of patients with Parkinson's disease. The intermittent behavior was identified by plotting the wavelet power spectrum of the LFP signal on a time–frequency plane. We also computed the temporal variations of scale-averaged wavelet power and wavelet entropy (WE). An intermittent pattern is characterized by large amounts of power over very short periods of time separated by almost quiescent periods. Time-localized changes in WE further support the evidence of intermittency. The cause and significance of the intermittent beta activity are presently unclear. It may be due to complex interactions of the cortico-basal-ganglia networks converging at the STN level.

scholarly journals Generation of field potentials and modulation of their dynamics through volume integration of cortical activity

2015 ◽  
Vol 113 (1) ◽  
pp. 339-351 ◽  
Author(s):  
Yoshinao Kajikawa ◽  
Charles E. Schroeder
Keyword(s):  
Current Source ◽  
Quantitative Description ◽  
Critical Issue ◽  
Synaptic Activity ◽  
Field Potentials ◽  
Cortical Layers ◽  
Physiological Processes ◽  
Volume Conductor Model ◽  
The Relationship ◽  
The Brain

Field potentials (FPs) recorded within the brain, often called “local field potentials” (LFPs), are useful measures of net synaptic activity in a neuronal ensemble. However, due to volume conduction, FPs spread beyond regions of underlying synaptic activity, and thus an “LFP” signal may not accurately reflect the temporal patterns of synaptic activity in the immediately surrounding neuron population. To better understand the physiological processes reflected in FPs, we explored the relationship between the FP and its membrane current generators using current source density (CSD) analysis in conjunction with a volume conductor model. The model provides a quantitative description of the spatiotemporal summation of immediate local and more distant membrane currents to produce the FP. By applying the model to FPs in the macaque auditory cortex, we have investigated a critical issue that has broad implications for FP research. We have shown that FP responses in particular cortical layers are differentially susceptible to activity in other layers. Activity in the supragranular layers has the strongest contribution to FPs in other cortical layers, and infragranular FPs are most susceptible to contributions from other layers. To define the physiological processes generating FPs recorded in loci of relatively weak synaptic activity, strong effects produced by synaptic events in the vicinity have to be taken into account. While outlining limitations and caveats inherent to FP measurements, our results also suggest specific peak and frequency band components of FPs can be related to activity in specific cortical layers. These results may help improving the interpretability of FPs.

Dexterous Finger Movements in Primate Without Monosynaptic Corticomotoneuronal Excitation

2004 ◽  
Vol 92 (5) ◽  
pp. 3142-3147 ◽  
Author(s):  
Shigeto Sasaki ◽  
Tadashi Isa ◽  
Lars-Gunnar Pettersson ◽  
Bror Alstermark ◽  
Kimisato Naito ◽  
...  
Keyword(s):  
Precision Grip ◽  
Field Potentials ◽  
Finger Movements ◽  
Complete Transection ◽  
Electrophysiological Recordings ◽  
Upper Cervical ◽  
Propriospinal Neurons ◽  
The Brain ◽  
Observation Period ◽  
Made In

It is generally accepted that the precision grip and independent finger movements (IFMs) in monkey and man are controlled by the direct (monosynaptic) corticomotoneuronal (CM) pathway. This view is based on previous observations that pyramidotomy causes near permanent deficits of IFMs. However, in addition to the direct CM pathway, pyramidotomy interrupts several corticofugal connections to the brain stem and upper cervical segments. Indirect (oligosynaptic) CM pathways, which are phylogenetically older, have been considered to be of little or no importance in prehension. In three adult macaque monkeys, complete transection of the direct CM pathway was made in C4/C5, which is rostral to the forelimb segments (C6–Th1). Electrophysiological recordings revealed lack of the direct lateral corticospinal tract (LCST) volley, monosynaptic extracellular field potentials in the motor nuclei, and monosynaptic CM excitation. However, a disynaptic volley, disynaptic field potentials and disynaptic CM excitation mediated via C3–C4 propriospinal neurons remained after the lesion. Thus the lesion interrupted the monosynaptic CM pathway and oligosynaptic LCST pathways mediated by interneurons in the forelimb segments. Precision grip and IFMs were observed already after 1–28 days postoperatively. Weakness in force and deficits in preshaping remained for an observation period of 3 mo. Indirect CM pathways may be important for neuro-rehabilitation.

Is Brain Research Relevant for Music Education?

1986 ◽  
Vol 3 (2) ◽  
pp. 175-179 ◽  
Author(s):  
Arthur W. Harvey
Keyword(s):  
Music Education ◽  
Brain Research ◽  
Body Movement ◽  
The United States ◽  
Memory Recall ◽  
Musical Performances ◽  
The Past ◽  
Basic Understanding ◽  
Musical Elements ◽  
The Brain

During the past several years Dr Harvey has presented seminars on ‘Music and the Brain’ throughout the United States and Canada. In the course of a weekend seminar in 1985 he was, once again, particularly impressed with the power of music to affect individuals in many different ways; musical performances (live and taped) evoked responses as diverse as excitement, tears, loneliness, increases in pulse rate, changes in breathing rate, spontaneous body movement, memory recall and imagery experiences. To understand just how the brain produces both biophysical and psychological responses to music requires a basic understanding of the human brain, the areas of the human personality affected through brain processes, and an awareness of the interactions of musical elements affecting us. In this article Dr Harvey outlines some of the directions of recent research.

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