Slow rhythm with Nomsa Dhlamini in Steven Cohen'sCradle of Humankind

de arte ◽  
2015 ◽  
Vol 50 (92) ◽  
pp. 34-49
Author(s):  
Irene Bronner
Keyword(s):  
Slow Rhythm

Selective Interareal Synchronization through Gamma Frequency Differences and Slower-Rhythm Gamma Phase Reset

2017 ◽  
Vol 29 (3) ◽  
pp. 643-678
Author(s):  
Thomas Burwick ◽  
Alexandros Bouras
Keyword(s):  
Cortical Area ◽  
Phase Locking ◽  
Gamma Phase ◽  
Phase Reset ◽  
Common Site ◽  
Top Down ◽  
Intrinsic Frequency ◽  
Gamma Frequency ◽  
Communication Through Coherence ◽  
Slow Rhythm

The communication-through-coherence (CTC) hypothesis states that a sending group of neurons will have a particularly strong effect on a receiving group if both groups oscillate in a phase-locked (“coherent”) manner (Fries, 2005 , 2015 ). Here, we consider a situation with two visual stimuli, one in the focus of attention and the other distracting, resulting in two sites of excitation at an early cortical area that project to a common site in a next area. Taking a modeler’s perspective, we confirm the workings of a mechanism that was proposed by Bosman et al. ( 2012 ) in the context of providing experimental evidence for the CTC hypothesis: a slightly higher gamma frequency of the attended sending site compared to the distracting site may cause selective interareal synchronization with the receiving site if combined with a slow-rhythm gamma phase reset. We also demonstrate the relevance of a slightly lower intrinsic frequency of the receiving site for this scenario. Moreover, we discuss conditions for a transition from bottom-up to top-down driven phase locking.

Slow Dorsal-Ventral Rhythm Generator in the Lamprey Spinal Cord

2001 ◽  
Vol 85 (1) ◽  
pp. 211-218 ◽  
Author(s):  
Fumi Aoki ◽  
Thierry Wannier ◽  
Sten Grillner
Keyword(s):  
Spinal Cord ◽  
Metabotropic Glutamate Receptor ◽  
Motor Pattern ◽  
Ventral Root ◽  
Locomotor Rhythm ◽  
Metabotropic Glutamate ◽  
The Neural Network ◽  
The Right ◽  
Glutamate Receptor Agonist ◽  
Slow Rhythm

In the isolated lamprey spinal cord, a very slow rhythm (0.03–0.11 Hz), superimposed on fast N-methyl-d-aspartate (NMDA)-induced locomotor activity (0.26–2.98 Hz), could be induced by a blockade of GABAA or glycine receptors or by administration of (1 s, 3 s)-l-aminocyclopentane-1,3-dicarboxylic acid a metabotropic glutamate receptor agonist. Ventral root branches supplying dorsal and ventral myotomes were exposed bilaterally to study the motor pattern in detail. The slow rhythm was expressed in two main forms: 1) a dorsal-ventral reciprocal pattern was the most common (18 of 24 preparations), in which bilateral dorsal branches were synchronous and alternated with the ventral branches, in two additional cases a diagonal dorsal-ventral reciprocal pattern with alternation between the left (or right) dorsal and the right (or left) ventral branches was observed; 2) synchronous bursting in all branches was encountered in four cases. In contrast, the fast locomotor rhythm occurred always in a left-right reciprocal pattern. Thus when the slow rhythm appeared in a dorsal-ventral reciprocal pattern, fast rhythms would simultaneously display left-right alternation. A longitudinal midline section of the spinal cord during ongoing slow bursting abolished the reciprocal pattern between ipsilateral dorsal and ventral branches but a synchronous burst activity could still remain. The fast swimming rhythm did not recover after the midline section. These results suggest that in addition to the network generating the swimming rhythm in the lamprey spinal cord, there is also a network providing slow reciprocal alternation between dorsal and ventral parts of the myotome. During steering, a selective activation of dorsal and ventral myotomes is required and the neural network generating the slow rhythm may represent activity in the spinal machinery used for steering.

scholarly journals Processing and model design of the gamma oscillation activity based on FitzHugh-Nagumo model and its interaction with slow rhythms in the brain

2021 ◽  
pp. 265-272
Author(s):  
Evgeniia S. Sevasteeva ◽  
Sergei A. Plotnikov ◽  
Volodymyr Lynnyk
Keyword(s):  
Signal Processing ◽  
Correlation Coefficient ◽  
Model Design ◽  
Gamma Rhythm ◽  
Phase Type ◽  
Processing Information ◽  
Delta Rhythm ◽  
Envelope Extraction ◽  
Slow Rhythm ◽  
The Brain

The brain is processing information 24 hours a day. There are millions of processes proceeding in it accompanied by various spectra of rhythms. This paper tests the hypothesis that the slow delta rhythm excites the gamma rhythm oscillations. Unlike other papers, we determine the slow rhythm spectrum not at the hypothesis stage but during the experiment. We design algorithms of filtering, envelope extraction, and correlation coefficient calculation for signal processing. Moreover, we examine the data on all electroencephalogram channels, which allows us to make a more reasonable conclusion. We confirm that a slow delta rhythm excites a fast gamma rhythm with an amplitude-phase type of interaction and calculate a delay between these two signals equal to about half a second.

scholarly journals Frequency Regulation of a Slow Rhythm by a Fast Periodic Input

1998 ◽  
Vol 18 (13) ◽  
pp. 5053-5067 ◽  
Author(s):  
Farzan Nadim ◽  
Yair Manor ◽  
Michael P. Nusbaum ◽  
Eve Marder
Keyword(s):  
Frequency Regulation ◽  
Periodic Input ◽  
Slow Rhythm

Coupled oscillators account for the slow rhythms in sympathetic nerve discharge and phrenic nerve activity

1997 ◽  
Vol 272 (4) ◽  
pp. R1314-R1324 ◽  
Author(s):  
S. Zhong ◽  
S. Y. Zhou ◽  
G. L. Gebber ◽  
S. M. Barman
Keyword(s):  
Phrenic Nerve ◽  
Sympathetic Nerve ◽  
Coupled Oscillators ◽  
Sympathetic Nerves ◽  
Partial Coherence ◽  
Coherence Analysis ◽  
Nerve Activity ◽  
Phrenic Nerve Activity ◽  
Slow Rhythm ◽  
Nerve Discharge

Phase-locked slow rhythms in sympathetic nerve discharge (SND) and phrenic nerve activity (PNA) are generally thought to arise from a common brain stem "cardiorespiratory" oscillator. The results obtained in vagotomized and baroreceptor-denervated cats anesthetized with pentobarbital sodium do not support this view. First, partial coherence analysis revealed that the discharges of pairs of sympathetic nerves remained correlated at the frequency of the central respiratory cycle after mathematical removal of the portion of these signals common to PNA. The residual coherence suggests that the slow rhythm in SND is dependent on central mechanisms in addition to those responsible for rhythmic PNA. Second, the rhythms in SND and PNA became coupled in a 2:1 relationship during either moderate systemic hypocapnia or hypercapnia. Third, the slow rhythm in SND was maintained when rhythmic PNA was eliminated during extreme hypocapnia. Fourth, during extreme hypercapnia, coherence of the rhythms in SND and PNA was drastically reduced. These results suggest that the slow rhythms in SND and PNA arise from separate oscillators that are normally coupled.

scholarly journals Cortical silencing results in paradoxical fMRI overconnectivity

2020 ◽  
Author(s):  
Carola Canella ◽  
Federico Rocchi ◽  
Shahryar Noei ◽  
Daniel Gutierrez-Barragan ◽  
Ludovico Coletta ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Functional Connectivity ◽  
Resting State ◽  
Resting State Fmri ◽  
Gamma Activity ◽  
Functional Coupling ◽  
Cortical Region ◽  
Delta Band ◽  
Slow Rhythm

ABSTRACTfMRI-based measurements of functional connectivity are commonly interpreted as an index of anatomical coupling and direct interareal communication. However, causal testing of this hypothesis has been lacking. Here we combine neural silencing, resting-state fMRI and in vivo electrophysiology to causally probe how inactivation of a cortical region affects brain-wide functional coupling. We find that chronic silencing of the prefrontal cortex (PFC) via overexpression of a potassium channel paradoxically increases rsfMRI connectivity between the silenced area and its thalamo-cortical terminals. Acute chemogenetic silencing of the PFC reproduces analogous patterns of overconnectivity, an effect associated with over-synchronous fMRI coupling between polymodal thalamic regions and widespread cortical districts. Notably, multielectrode recordings revealed that chemogenetic inactivation of the PFC attenuates gamma activity and increases delta power in the silenced area, resulting in robustly increased delta band coherence between functionally overconnected regions. The observation of enhanced rsfMRI coupling between chemogenetically silenced areas challenges prevailing interpretations of functional connectivity as a monotonic index of direct axonal communication, and points at a critical contribution of slow rhythm generators to the establishment of brain-wide functional coupling.

scholarly journals Attentional brain rhythms during prolonged cognitive activity

2021 ◽  
Author(s):  
Corentin Gaillard ◽  
Carine De Sousa ◽  
Julian Amengual ◽  
Célia Loriette ◽  
Camilla Ziane ◽  
...  
Keyword(s):  
Cognitive Activity ◽  
Cognitive Demand ◽  
Processing Load ◽  
Neuronal Populations ◽  
Human Operators ◽  
Assistive Systems ◽  
High Cognitive Demand ◽  
Slow Rhythm ◽  
Field Coherence

As routine and lower demand cognitive tasks are taken over by automated assistive systems, human operators are increasingly required to sustain cognitive demand over long periods of time. This has been reported to have long term adverse effects on cardiovascular and mental health. However, it remains unclear whether prolonged cognitive activity results in a monotonic decrease in the efficiency of the recruited brain processes, or whether the brain is able to sustain functions over time spans of one hour and more. Here, we show that during working sessions of one hour or more, contrary to the prediction of a monotonic decline, behavioral performance in both humans and non-human primates consistently fluctuates between periods of optimal and suboptimal performance at a very slow rhythm of circa 5 cycles per hour. These fluctuations are observed in both high attentional (in non-human primates) and low attentional (in humans) demand conditions. They coincide with fluctuations in pupil diameter, indicating underlying changes in arousal and information-processing load. Accordingly, we show that these rhythmic behavioral fluctuations correlate, at the neurophysiological level, with fluctuations in the informational attention orientation and perception processing capacity of prefrontal neuronal populations. We further identify specific markers of these fluctuations in LFP power, LFP coherence and spike-field coherence, pointing towards long-range rhythmic modulatory inputs to the prefrontal cortex rather than a local prefrontal origin. These results shed light on the resilience of brain mechanisms to sustained effort and have direct implications on how to optimize high cognitive demand working and learning environments.

Co-ordinating interneurones of the locust which convey two patterns of motor commands: their connexions with flight motoneurones

1975 ◽  
Vol 63 (3) ◽  
pp. 713-733
Author(s):  
M. Burrows
Keyword(s):  
Expiratory Phase ◽  
Sensory Inputs ◽  
Thoracic Ganglia ◽  
Synaptic Potentials ◽  
Motor Commands ◽  
Metathoracic Ganglion ◽  
Lower Amplitude ◽  
Left And Right ◽  
Slow Rhythm ◽  
Fast Rhythm

1. Some flight motoneurones receive two superimposed rhythms of depolarizing synaptic potentials when the locust is not flying; a slow rhythm which is invariably linked to the expiratory phase of ventilation, and a fast rhythm with a period of about 50 ms which is similar to the wingbeat period in flight. 2. By recording simultaneously from groups of motoneurones, the synaptic potentials which underly these rhythms have been revealed in 30 flight motoneurones in the three thoracic ganglia. The inputs occur in elevator motoneurones and some depressors but are of lower amplitude in the latter. The inputs have not been found in leg motoneurones. 3. The rhythmic depolarizations are usually subthreshold but sum with sensory inputs to evoke spikes in flight motoneurones at intervals equal to or multiples of the wingbeat period in flight. 4. Both rhythms originate in the metathoracic ganglion and are mediated by the same interneurones. They can be adequately explained by supposing that there are two symmetrical interneurones which each make widespread connexions with left and right flight motoneurones in the three ganglia. 5. The slow rhythm is coded in the overall burst of interneurone spikes during expiration and the fast rhythm in the interval between the spikes of a burst.

Fictive motor patterns in chronic spinal cats

1991 ◽  
Vol 66 (6) ◽  
pp. 1874-1887 ◽  
Author(s):  
K. G. Pearson ◽  
S. Rossignol
Keyword(s):  
Rhythmic Activity ◽  
Cycle Period ◽  
Motor Patterns ◽  
Locomotor Pattern ◽  
Leg Flexion ◽  
Perineal Region ◽  
Short Time ◽  
Slow Rhythm ◽  
Leg Position ◽  
Stimulation Of

1. Fictive motor patterns were recorded in hind leg nerves of 10 adult chronic spinal cats (spinalized at T13). Four of these animals had been trained to step with their hind legs on a treadmill (late-spinal animals), whereas the remainder received no training and were examined a short time after spinalization (early-spinal animals). 2. A fictive pattern resembling the locomotor pattern for stepping was evoked in all animals in response to stimulation of the skin of the perineal region. (2-[2,6-Dichloroaniline]-2-imidazoline) hydrochloride (Clonidine) at doses ranging from 100 to 500 micrograms/kg iv facilitated the production of this pattern, particularly in early-spinal animals. 3. The fictive locomotor pattern in late-spinal animals was more complex than that occurring in early-spinal animals. In the latter the pattern consisted of an alternation of activity in flexor and extensor nerves, and changing leg position did not qualitatively alter the pattern, whereas in late-spinal animals the relative durations of the bursts in different flexors were usually not the same, and the pattern of flexor activity was dependent on leg position. 4. Moving the legs from extension to flexion progressively decreased the duration of flexor bursts, increased the cycle period, and decreased the ease with which the pattern could be evoked in both early- and late-spinal animals. 5. 1-beta-3,4-Dihydroxyphenylalanine (DOPA)/Isonocotinic acid 2-[(2-benzylcarbamoyl)ethyl]hydrazide (Nialamide) treatment following Clonidine in early-spinal animals increased the complexity of flexor burst activity. This, and other observations, indicates that DOPA and Clonidine do not have strictly identical actions on the locomotor pattern generator. 6. Stimulation of the paws in late-spinal animals produced two patterns of activity distinctly different from the locomotor pattern. of activity distinctly different from the locomotor pattern. One was a short sequence of high-frequency rhythmic activity (at approximately 8 c/s) in response to gently stimulating one paw with a water jet, and the other was a slow rhythm in flexor nerves in response to squeezing the paw. 7. The main conclusion of this investigation is that three distinctly different fictive motor patterns can be generated in chronic spinal cats depending on the method and site of stimulation. These patterns correspond to three different behaviors (locomotion, paw shake, and rhythmic leg flexion) that can be elicited in behaving chronic spinal cats in response to the same stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)

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