Exploring the physiology and function of high-frequency oscillations (HFOs) from the somatosensory cortex

Ozaki, Isamu; Hashimoto, Isao

doi:10.1016/j.clinph.2011.05.023

Cited by 78 publications

(62 citation statements)

References 76 publications

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“…Alternatively, it has also been proposed that S1 pyramidal chattering cells participate in the generation of l-HFO (Restuccia et al , 2003), so an increase in excitability of these neural elements should also be considered. In contrast with l-HFO, e-HFO are supposed to originate from activity of thalamocortical fibers directed to areas 3b and 1 within S1 (Ozaki et al , 2011). As such, the increase in e-HFO area produced by HF-RSS might be interpreted as an increase in excitability of thalamo-cortical relay cells.…”

Section: Electrophysiological Resultsmentioning

confidence: 97%

“…HFOs are small wavelets with a frequency around 600 Hz superimposed on the N20 component of SEP. l-HFO are thought to depend on the activity of S1 inhibitory interneurons (Hashimoto et al , 1996, Curio, 2000, Jones et al , 2000, Klostermann et al , 2001, Ozaki et al , 2001, Ikeda et al , 2002, Gobbele et al , 2004, Ozaki et al , 2011 possibly producing feedforward inhibition of cortical pyramidal neurons (Ozaki et al , 2011). Since HF-RSS produced an increase in l-HFO, it is likely that excitability of S1 inhibitory interneurons was increased.…”

Section: Electrophysiological Resultsmentioning

confidence: 99%

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High frequency somatosensory stimulation increases sensori-motor inhibition and leads to perceptual improvement in healthy subjects

Rocchi

Erro

Antelmi

et al. 2017

Clinical Neurophysiology

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Objective: high frequency repetitive somatosensory stimulation (HF-RSS), which is a patterned electric stimulation applied to the skin through surface electrodes, improves two-point discrimination, somatosensory temporal discrimination threshold (STDT) and motor performance in humans.However, the mechanisms which underlie this changes are still unknown. In particular, we hypothesize that refinement of inhibition might be responsible for the improvement in spatial and temporal perception. Methods: fifteen healthy subjects underwent 45 minutes of HF-RSS. Before and after the intervention several measures of inhibition in the primary somatosensory area (S1), such as paired-pulse somatosensory evoked potentials (pp-SEP), high-frequency oscillations (HFO), and STDT were tested, as well as tactile spatial acuity and short intracortical inhibition (SICI). Results:HF-RSS increased inhibition in S1 tested by pp-SEP and HFO; these changes were correlated with improvement in STDT. HF-RSS also enhanced bumps detection, while there was no change in grating orientation test. Finally there was an increase in SICI, suggesting widespread changes in cortical sensorimotor interactions. Conclusions: these findings suggest that HF-RSS can improve spatial and temporal tactile abilities by increasing the effectiveness of inhibitory interactions in the somatosensory system. Moreover, HF-RSS induces changes in cortical sensorimotor interaction.Significance: HF-RSS is a repetitive electric stimulation technique able to modify the effectiveness of inhibitory circuitry in the somatosensory system and primary motor cortex. 4

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Section: Electrophysiological Resultsmentioning

confidence: 97%

Section: Electrophysiological Resultsmentioning

confidence: 99%

High frequency somatosensory stimulation increases sensori-motor inhibition and leads to perceptual improvement in healthy subjects

Rocchi

Erro

Antelmi

et al. 2017

Clinical Neurophysiology

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“…Physiological HFOs occur also in normal neocortex. They can be evoked by various stimuli, as HFOs emerging from the somatosensory areas overlying the cortical response of the somatosensory evoked potential (Hashimoto, 2000;Ozaki and Hashimoto, 2011) or HFOs recorded from the nonepileptic occipital cortex and driven by visual tasks . A high frequency (80-120 Hz) gamma oscillation partially overlapping the frequency band of the continuous HFA has been previously reported in patients studied with large-scale microelectrode recordings in all investigated cortical areas during slow-wave sleep, in the form of short bursts, and speculated to briefly restore "microwake" activity important for memory traces consolidation (Le Van Quyen et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

Continuous High Frequency Activity: A peculiar SEEG pattern related to specific brain regions

Melani

Zelmann

Mari

et al. 2013

Clinical Neurophysiology

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Objective-While visually marking the high frequency oscillations in the stereo-EEG of epileptic patients, we observed a continuous/semicontinuous activity in the ripple band (80-250 Hz), which we defined continuous High Frequency Activity (HFA). We aim to analyze in all brain regions the occurrence and significance of this particular pattern.Methods-Twenty patients implanted in mesial temporal and neocortical areas were studied. One minute of slow-wave sleep was reviewed. The background was classified as continuous/ semicontinuous, irregular, or sporadic based on the duration of the fast oscillations. Each channel was classified as inside/outside the seizure onset zone (SOZ) or a lesion.Results-The continuous/semicontinuous HFA occurred in 54 of the 790 channels analyzed, with a clearly higher prevalence in hippocampus and occipital lobe. No correlation was found with the SOZ or lesions. In the occipital lobe the continuous/semicontinuous HFA was present independently of whether eyes were open or closed. Conclusions-We describe what appears to be a new physiological High Frequency Activity, independent of epileptogenicity, present almost exclusively in the hippocampus and occipital cortex but independent of the alpha rhythm.Significance-The continuous HFA may be an intrinsic characteristic of specific brain regions, reflecting a particular type of physiological neuronal activity.

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“…Pyramidal “chattering” cells (Gray and McCormick, 1996), cortical fast-spiking inhibitory interneurons (Hashimoto et al, 1996) and thalamocortical relay cells (Curio, 2000) have been proposed as possible cell populations generating HFO. Supporters of the interneuron hypothesis propose that the late HFO represent the activities of combined vertically and horizontally oriented GABAergic inhibitory interneurons in somatosensory cortex (Hashimoto et al, 1996; Ozaki et al, 2001; Ozaki and Hashimoto, 2005, 2011). They rely on the divergence in the orientation of the dipoles between HFO source and underlying N20 source (Ozaki et al, 2001; Ozaki and Hashimoto, 2011).…”

Section: Introductionmentioning

confidence: 99%

Early somatosensory processing in individuals at risk for developing psychoses

Hagenmuller

Theodoridou

Walitza

et al. 2014

Front. Behav. Neurosci.

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Human cortical somatosensory evoked potentials (SEPs) allow an accurate investigation of thalamocortical and early cortical processing. SEPs reveal a burst of superimposed early (N20) high-frequency oscillations around 600 Hz. Previous studies reported alterations of SEPs in patients with schizophrenia. This study addresses the question whether those alterations are also observable in populations at risk for developing schizophrenia or bipolar disorders. To our knowledge to date, this is the first study investigating SEPs in a population at risk for developing psychoses. Median nerve SEPs were investigated using multichannel EEG in individuals at risk for developing bipolar disorders (n = 25), individuals with high-risk status (n = 59) and ultra-high-risk status for schizophrenia (n = 73) and a gender and age-matched control group (n = 45). Strengths and latencies of low- and high-frequency components as estimated by dipole source analysis were compared between groups. Low- and high-frequency source activity was reduced in both groups at risk for schizophrenia, in comparison to the group at risk for bipolar disorders. HFO amplitudes were also significant reduced in subjects with high-risk status for schizophrenia compared to healthy controls. These differences were accentuated among cannabis non-users. Reduced N20 source strengths were related to higher positive symptom load. These results suggest that the risk for schizophrenia, in contrast to bipolar disorders, may involve an impairment of early cerebral somatosensory processing. Neurophysiologic alterations in schizophrenia precede the onset of initial psychotic episode and may serve as indicator of vulnerability for developing schizophrenia.

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Exploring the physiology and function of high-frequency oscillations (HFOs) from the somatosensory cortex

Cited by 78 publications

References 76 publications

High frequency somatosensory stimulation increases sensori-motor inhibition and leads to perceptual improvement in healthy subjects

High frequency somatosensory stimulation increases sensori-motor inhibition and leads to perceptual improvement in healthy subjects

Continuous High Frequency Activity: A peculiar SEEG pattern related to specific brain regions

Early somatosensory processing in individuals at risk for developing psychoses

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