scholarly journals Temporo-Frontal Coherences and High-Frequency iEEG Responses during Spatial Navigation in Patients with Drug-Resistant Epilepsy

2021 ◽  
Vol 11 (2) ◽  
pp. 162
Author(s):  
Aljoscha Thomschewski ◽  
Eugen Trinka ◽  
Julia Jacobs
Keyword(s):  
Cognitive Processes ◽  
Spatial Navigation ◽  
General Effect ◽  
Permutation Testing ◽  
Intracranial Eeg ◽  
Epileptic Spikes ◽  
Drug Resistant Epilepsy ◽  
Task Conditions ◽  
Hippocampal Theta ◽  
Patients With Epilepsy

The prefrontal cortex and hippocampus function in tight coordination during multiple cognitive processes. During spatial navigation, prefrontal neurons are linked to hippocampal theta oscillations, presumably in order to enhance communication. Hippocampal ripples have been suggested to reflect spatial memory processes. Whether prefrontal-hippocampal-interaction also takes place within the ripple band is unknown. This intracranial EEG study aimed to investigate whether ripple band coherences can also be used to show this communication. Twelve patients with epilepsy and intracranial EEG evaluation completed a virtual spatial navigation task. We calculated ordinary coherence between prefrontal and temporal electrodes during retrieval, re-encoding, and pre-task rest. Coherences were compared between the conditions via permutation testing. Additionally, ripples events were automatically detected and changes in occurrence rates were investigated excluding ripples on epileptic spikes. Ripple-band coherences yielded no general effect of the task on coherences across all patients. Furthermore, we did not find significant effects of task conditions on ripple rates. Subsequent analyses pointed to rather short periods of synchrony as opposed to general task-related changes in ripple-band coherence. Specifically designed tasks and adopted measures might be necessary in order to map these interactions in future studies.

scholarly journals Functionally distinct high and low theta oscillations in the human hippocampus

2018 ◽  
Author(s):  
Abhinav Goyal ◽  
Jonathan Miller ◽  
Salman E. Qasim ◽  
Andrew J. Watrous ◽  
Joel M. Stein ◽  
...  
Keyword(s):  
Cognitive Processes ◽  
Spatial Navigation ◽  
Theta Oscillations ◽  
Movement Speed ◽  
General Role ◽  
Theta Oscillation ◽  
Human Hippocampus ◽  
Multiple Frequencies ◽  
Hippocampal Theta ◽  
Anterior Posterior

AbstractBased on rodent models, researchers have theorized that the hippocampus supports episodic memory and navigation via the theta oscillation, a ~4–10-Hz rhythm that coordinates brain-wide neural activity. However, recordings from humans have indicated that hippocampal theta oscillations are lower in frequency and less prevalent than in rodents, suggesting interspecies differences in theta’s function. To characterize human hippocampal theta, we examined the properties of theta oscillations throughout the anterior–posterior length of the hippocampus as neurosurgical subjects performed a virtual spatial navigation task. During virtual movement, we observed hippocampal oscillations at multiple frequencies from 2 to 14 Hz. The posterior hippocampus prominently displayed oscillations at ~8-Hz and the precise frequency of these oscillations correlated with the speed of movement, implicating these signals in spatial navigation. We also observed slower ~3-Hz oscillations, but these signals were more prevalent in the anterior hippocampus and their frequency did not vary with movement speed. Our results converge with recent findings to suggest an updated view of human hippocampal electrophysiology. Rather than one hippocampal theta oscillation with a single general role, high-and low-theta oscillations, respectively, may reflect spatial and non-spatial cognitive processes.

scholarly journals Zero-crossing patterns reveal subtle epileptiform discharges in the scalp EEG

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jan Pyrzowski ◽  
Jean- Eudes Le Douget ◽  
Amal Fouad ◽  
Mariusz Siemiński ◽  
Joanna Jędrzejczak ◽  
...  
Keyword(s):  
Normal Subjects ◽  
Intracranial Eeg ◽  
Zero Crossing ◽  
Temporal Precision ◽  
Scalp Eeg ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
Eeg Recordings ◽  
Patients With Epilepsy ◽  
Low Amplitude

AbstractClinical diagnosis of epilepsy depends heavily on the detection of interictal epileptiform discharges (IEDs) from scalp electroencephalographic (EEG) signals, which by purely visual means is far from straightforward. Here, we introduce a simple signal analysis procedure based on scalp EEG zero-crossing patterns which can extract the spatiotemporal structure of scalp voltage fluctuations. We analyzed simultaneous scalp and intracranial EEG recordings from patients with pharmacoresistant temporal lobe epilepsy. Our data show that a large proportion of intracranial IEDs manifest only as subtle, low-amplitude waveforms below scalp EEG background and could, therefore, not be detected visually. We found that scalp zero-crossing patterns allow detection of these intracranial IEDs on a single-trial level with millisecond temporal precision and including some mesial temporal discharges that do not propagate to the neocortex. Applied to an independent dataset, our method discriminated accurately between patients with epilepsy and normal subjects, confirming its practical applicability.

Detection of Intracranial Signatures of Interictal Epileptiform Discharges from Concurrent Scalp EEG

2016 ◽  
Vol 26 (04) ◽  
pp. 1650016 ◽  
Author(s):  
Loukianos Spyrou ◽  
David Martín-Lopez ◽  
Antonio Valentín ◽  
Gonzalo Alarcón ◽  
Saeid Sanei
Keyword(s):  
Detection Algorithm ◽  
The Other ◽  
Intracranial Eeg ◽  
Scalp Eeg ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
Scalp Electroencephalogram ◽  
Patients With Epilepsy ◽  
Electrical Activities ◽  
The Brain

Interictal epileptiform discharges (IEDs) are transient neural electrical activities that occur in the brain of patients with epilepsy. A problem with the inspection of IEDs from the scalp electroencephalogram (sEEG) is that for a subset of epileptic patients, there are no visually discernible IEDs on the scalp, rendering the above procedures ineffective, both for detection purposes and algorithm evaluation. On the other hand, intracranially placed electrodes yield a much higher incidence of visible IEDs as compared to concurrent scalp electrodes. In this work, we utilize concurrent scalp and intracranial EEG (iEEG) from a group of temporal lobe epilepsy (TLE) patients with low number of scalp-visible IEDs. The aim is to determine whether by considering the timing information of the IEDs from iEEG, the resulting concurrent sEEG contains enough information for the IEDs to be reliably distinguished from non-IED segments. We develop an automatic detection algorithm which is tested in a leave-subject-out fashion, where each test subject’s detection algorithm is based on the other patients’ data. The algorithm obtained a [Formula: see text] accuracy in recognizing scalp IED from non-IED segments with [Formula: see text] accuracy when trained and tested on the same subject. Also, it was able to identify nonscalp-visible IED events for most patients with a low number of false positive detections. Our results represent a proof of concept that IED information for TLE patients is contained in scalp EEG even if they are not visually identifiable and also that between subject differences in the IED topology and shape are small enough such that a generic algorithm can be used.

scholarly journals Effect and Safety of Shihogyejitang for Drug Resistant Childhood Epilepsy

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Jinsoo Lee ◽  
Kwanghyun Son ◽  
Gwiseo Hwang ◽  
Moonju Kim
Keyword(s):  
Adverse Events ◽  
Antiepileptic Drugs ◽  
Retention Rate ◽  
Seizure Type ◽  
Drug Resistant ◽  
Exact Test ◽  
Alternative Treatment Option ◽  
Drug Resistant Epilepsy ◽  
Intent To Treat ◽  
Patients With Epilepsy

Objective. Herbal medicine has been widely used to treat drug resistant epilepsy. Shihogyejitang (SGT) has been commonly used to treat epilepsy. We investigated the effect and safety of SGT in children with drug resistant epilepsy.Design. We reviewed medical records of 54 patients with epilepsy, who failed to respond to at least two antiepileptic drugs and have been treated with SGT between April 2006 and June 2014 at the Department of Pediatric Neurology, I-Tomato Hospital, Korea. Effect was measured by the response rate, seizure-free rate, and retention rate at six months. We also checked adverse events, change in antiepileptic drugs use, and the variables related to the outcome.Results. Intent-to-treat analysis showed that, after six months, 44.4% showed a >50% seizure reduction, 24.1% including seizure-free, respectively, and 53.7% remained on SGT. Two adverse events were reported, mild skin rash and fever. Focal seizure type presented significantly more positive responses when compared with other seizure types at six months (p=0.0284, Fisher’s exact test).Conclusion. SGT is an effective treatment with excellent tolerability for drug resistant epilepsy patients. Our data provide evidence that SGT may be used as alternative treatment option when antiepileptic drug does not work in epilepsy children.

Vicariance, Complexity, Space

2018 ◽  
pp. 53-68
Keyword(s):  
Cognitive Processes ◽  
Spatial Navigation ◽  
Sport Activity ◽  
Point Of View ◽  
Special Educational Needs ◽  
National Guidelines ◽  
Research Perspective ◽  
Orientation Course ◽  
Space Navigation ◽  
Action Process

The peculiar topic of this research - perspective taking and spatial navigation - has naturally led to cross over the course of the journey other spatial navigation comprehensions. Specifically, during prototype testing, there were several comparisons with another game, Catching Features1, an orienteering game that tackles the theme of space navigation from a different point of view. The point of view is that of Orienteering, a sports orientation course that consists in making a predefined path with the exclusive help of a compass and a topographic map that represents the details of the territory to be covered. The experimental path of this research has shown that cognitive processes involved in peculiar orienteering activities (map reading, spatial thinking) are also involved in the management of intersubjective relations, and make orienteering a sporting practice with considerable educational potential. This chapter develops by introducing the concept of vicariance, quickly describing orienteering as a sport activity, emphasizing links with Italian national guidelines for the first cycle of education, and, basing on revision of the scientific literature on cognitive processes involved in space navigation and the management of spatial reference systems, provides a proposal for the spread of orientation as an effective didactic practice in a training context aimed at inclusion of pupils Present Special Educational Needs. Paragraph 6.6 discusses the link between autism, empathy and perception – action process, according to neuroscientific evidences.

scholarly journals Adult Hippocampal Neurogenesis in Different Taxonomic Groups: Possible Functional Similarities and Striking Controversies

Cells ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 125 ◽  
Author(s):  
Marcus Augusto-Oliveira ◽  
Gabriela Arrifano ◽  
João Malva ◽  
Maria Crespo-Lopez
Keyword(s):  
Cognitive Processes ◽  
Adult Neurogenesis ◽  
Spatial Navigation ◽  
Absolute Number ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Consolidation Process ◽  
Apparent Reduction ◽  
Taxonomic Groups ◽  
Intense Debate

Adult neurogenesis occurs in many species, from fish to mammals, with an apparent reduction in the number of both neurogenic zones and new neurons inserted into established circuits with increasing brain complexity. Although the absolute number of new neurons is high in some species, the ratio of these cells to those already existing in the circuit is low. Continuous replacement/addition plays a role in spatial navigation (migration) and other cognitive processes in birds and rodents, but none of the literature relates adult neurogenesis to spatial navigation and memory in primates and humans. Some models developed by computational neuroscience attribute a high weight to hippocampal adult neurogenesis in learning and memory processes, with greater relevance to pattern separation. In contrast to theories involving neurogenesis in cognitive processes, absence/rarity of neurogenesis in the hippocampus of primates and adult humans was recently suggested and is under intense debate. Although the learning process is supported by plasticity, the retention of memories requires a certain degree of consolidated circuitry structures, otherwise the consolidation process would be hampered. Here, we compare and discuss hippocampal adult neurogenesis in different species and the inherent paradoxical aspects.

scholarly journals Efficacy of Vagal Nerve Stimulation for Drug-Resistant Epilepsy: Is it the Stimulation or Medication?

2017 ◽  
Vol 44 (5) ◽  
pp. 532-537 ◽  
Author(s):  
Jaylynn Arcand ◽  
Karen Waterhouse ◽  
Lizbeth Hernandez-Ronquillo ◽  
Aleksander Vitali ◽  
Jose F. Tellez-Zenteno
Keyword(s):  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Drug Resistant ◽  
Idiopathic Generalized Epilepsy ◽  
Drug Resistant Epilepsy ◽  
Generalized Epilepsy ◽  
Patients With Epilepsy ◽  
Seizure Classification

AbstractBackground: Vagus nerve stimulation (VNS) therapy has been widely recognized as an alternative for the treatment of drug-resistant epilepsy, although modification of antiepileptic drugs (AEDs) during VNS treatment could explain the improvement in patients. Methods: We retrospectively assessed the efficacy of VNS in 30 adult patients with epilepsy treated with >6 months of follow-up. The criteria for implantation were the following: (1) not a candidate for resective epilepsy surgery, (2) drug-resistant epilepsy, (3) impairment of quality of life, (4) no other option of treatment, and (5) patients with idiopathic generalized epilepsy who fail to be controlled with appropriate AEDs. We assessed sociodemographics, seizure etiology, seizure classification, and AEDs used during treatment with VNS. We assessed adverse effects and efficacy. Responder rate was defined as >50% seizure improvement from baseline. Results: Thirty patients (females, 18; males, 12; age, 35.1±13.3 years) were included. After 6, 12, 24, and 36 months of follow-up, the response rates were: 13/30 (43%), 13/27 (48%), 9/22 (41%), and 8/16 (50%), respectively; none was seizure free. Fifty-seven percent, 33%, 59%, and 81% of patients had changes of medication type or dose at 6, 12, 24, and 36 months respectively. In the majority of patients, the change of medication consisted of an increase in the dose of AEDs. Conclusions: Our study shows that VNS is an effective therapy, although significant changes in medications were done along with the therapy; therefore, the real effect of VNS could be controversial.

scholarly journals In vivo Interictal Neuronal Signatures of Human Periventricular Nodular Heterotopia

2019 ◽  
Author(s):  
Valerio Frazzini ◽  
Stephen Whitmarsh ◽  
Katia Lehongre ◽  
Pierre Yger ◽  
Jean-Didier Lemarechal ◽  
...  
Keyword(s):  
Epileptic Activity ◽  
Neuronal Firing ◽  
Periventricular Nodular Heterotopia ◽  
Firing Rates ◽  
Neuronal Populations ◽  
Malformation Of Cortical Development ◽  
Nodular Heterotopia ◽  
Epileptic Spikes ◽  
Drug Resistant Epilepsy

AbstractPeriventricular nodular heterotopia (PNH) is a common type of malformation of cortical development and a cause of drug-resistant epilepsy. In contrast with other cortical malformations, no consistent interictal patterns have yet been identified in PNH, and it remains controversial whether epileptic activity originates within nodules. The current study addresses the heterogeneity in LFP signatures, as well as the question of epileptogenicity of nodules, by means of microelectrode recordings implanted within PNH tissues in two epileptic patients. Microelectrodes also allowed the first in vivo recording of heterotopic neurons in humans, permitting the investigation of neuronal firing rates during patterns of interictal activity. Highly consistent interictal patterns (IPs) were identified within PNH: 1) trains of periodic slow waves and 2) isolated slow deflections, both with superimposed fast activity, and 3) epileptic spikes. Neuron firing rates were significantly modulated during all IPs, suggesting that different IPs were generated by the same local neuronal populations. To conclude, this study presents the first in vivo microscopic description of local PNH microcircuits in humans and their organization into multiple epileptic neurophysiological patterns, providing a first pathognomonic signature of human PNH.

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