Search results for "field potential"
showing 10 items of 37 documents
Local field potential activity dynamics in response to deep brain stimulation of the subthalamic nucleus in Parkinson's disease
2020
Abstract Local field potentials (LFPs) may afford insight into the mechanisms of action of deep brain stimulation (DBS) and potential feedback signals for adaptive DBS. In Parkinson's disease (PD) DBS of the subthalamic nucleus (STN) suppresses spontaneous activity in the beta band and drives evoked resonant neural activity (ERNA). Here, we investigate how STN LFP activities change over time following the onset and offset of DBS. To this end we recorded LFPs from the STN in 14 PD patients during long (mean: 181.2 s) and short (14.2 s) blocks of continuous stimulation at 130 Hz. LFP activities were evaluated in the temporal and spectral domains. During long stimulation blocks, the frequency …
Biophysics of high density nanometer regions extracted from super-resolution single particle trajectories: application to voltage-gated calcium chann…
2019
AbstractThe cellular membrane is very heterogenous and enriched with high-density regions forming microdomains, as revealed by single particle tracking experiments. However the organization of these regions remain unexplained. We determine here the biophysical properties of these regions, when described as a basin of attraction. We develop two methods to recover the dynamics and local potential wells (field of force and boundary). The first method is based on the local density of points distribution of trajectories, which differs inside and outside the wells. The second method focuses on recovering the drift field that is convergent inside wells and uses the transient field to determine the…
The Cumulative Effect of Transient Synchrony States on Motor Performance in Parkinson's Disease.
2020
Bursts of beta frequency band activity in the basal ganglia of patients with Parkinson's disease (PD) are associated with impaired motor performance. Here we test in human adults whether small variations in the timing of movement relative to beta bursts have a critical effect on movement velocity and whether the cumulative effects of multiple beta bursts, both locally and across networks, matter.
Deviance sensitivity in the auditory cortex of freely moving rats.
2018
Deviance sensitivity is the specific response to a surprising stimulus, one that violates expectations set by the past stimulation stream. In audition, deviance sensitivity is often conflated with stimulus-specific adaptation (SSA), the decrease in responses to a common stimulus that only partially generalizes to other, rare stimuli. SSA is usually measured using oddball sequences, where a common (standard) tone and a rare (deviant) tone are randomly intermixed. However, the larger responses to a tone when deviant does not necessarily represent deviance sensitivity. Deviance sensitivity is commonly tested using a control sequence in which many different tones serve as the standard, eliminat…
Spike-wave discharges in absence epilepsy: segregation of electrographic components reveals distinct pathways of seizure activity.
2020
Key points The major electrophysiological hallmarks of absence seizures are spike and wave discharges (SWDs), consisting of a sharp spike component and a slow wave component. In a widely accepted scheme, these components are functionally coupled and reflect an iterative progression of neuronal excitation during the spike and post-excitatory silence during the wave. In a genetic rat model of absence epilepsy, local pharmacological inhibition of the centromedian thalamus (CM) selectively suppressed the spike component, leaving self-contained waves in epidural recordings. Thalamic inputs induced activity in cortical microcircuits underlying the spike component, while intracortical oscillations…
Neural oscillations in the infralimbic cortex after electrical stimulation of the amygdala. Relevance to acute stress processing
2017
The stress system coordinates the adaptive reactions of the organism to stressors. Therefore, dysfunctions in this circuit may correlate to anxiety-related disorders, including depression. Comprehending the dynamics of this network may lead to a better understanding of the mechanisms that underlie these diseases. The central nucleus of the amygdala (CeA) activates the hypothalamic–pituitary–adrenal axis and brainstem nodes by triggering endocrine, autonomic and behavioral stress responses. The medial prefrontal cortex plays a significant role in regulating reactions to stressors, and is specifically important for limiting fear responses. Brain oscillations reflect neural systems activity. S…
Reduced firing rates of pyramidal cells in frontal cortex of APP/PS1 can be restored by acute treatment with levetiracetam
2019
AbstractIn recent years aberrant neural oscillations in various cortical areas have emerged as a common physiological hallmark across mouse models of amyloid pathology and patients with Alzheimer’s disease. However, much less is known about the underlying effect of amyloid pathology on single cell activity. Here, we used high density silicon probe recordings from frontal cortex area of 9 months old APP/PS1 mice to show that resting state Local Field Potential (LFP) power in the theta and beta band is increased in transgenic animals, while single cell firing rates, specifically of putative pyramidal cells, are significantly reduced. At the same time, these sparsely firing pyramidal cells pha…
Brain Activity Characterization Induced by Alcoholic Addiction: Spectral and Causality Analysis of Brain Areas Related to Control and Reinforcement o…
2014
Addiction to drugs generates modifications in the brain structure and its functions. In this work, an experimental model is described, using rats to characterize the brain activity induced by alcohol addiction. Four records were obtained using electrodes located in brain areas related to impulsivity control and reinforcement, i.e. the prelimbic (PL) and infralimbic (IL) cortex, together with the hippocampus (HPC). In the records, three main events related to the drinking action were selected: in the previous minute (T1), the first minute while drinking (T2) and the first minute after stopping drinking (T3).
Somatosensory evoked potentials aiding the diagnosis of brain death.
1988
SEP were recorded in 14 patients, who fulfilled the clinical and electroencephalographic criteria of brain death. The results are compared with the respective ones in healthy subjects. Beside the absence of cortical N 20 in each brain dead patient, reduction of amplitude or absence of near field negativity (N 13b) from upper neck regardless of the position of the reference electrode represents the predominant result. The near field potential from the lower neck (N 13a) was unaffected. The counterpart in the far field potential recorded from F z was amplitude reduction of P 13. These results suggest that the dissociation of N 13a and N 13b can confirm the diagnosis of brain death. Moreover t…
Rapid categorization of sound objects in anesthetized rats as indexed by the electrophysiological mismatch response
2014
It is not known whether animals can, similarly to humans, categorize auditory objects based on an abstract rule in combining their physical features. We recorded local-field potentials from the dura above the primary auditory cortex in urethane-anesthetized rats presented with sound series occasionally violating a rule (e.g., "the higher the frequency, the weaker the intensity"). In a separate control condition, the same frequency and intensity levels were applied in the sound objects, but they obeyed no rule. Responses found selectively to the violations of the rule suggest that an abstract rule was represented in the rat brain, enabling auditory categorization.