Objective: To investigate functional coupling between brain networks using spectral changes induced by single-pulse electric stimulation (SPES).
Method: We analyzed 20 patients with focal epilepsy, implanted with depth electrodes. SPES was applied to each pair of adjacent contacts, and responses were recorded from all other contacts. The mean response amplitude value was quantified in three time-periods after stimulation (10-60, 60-255, 255-500ms) for three frequency-ranges (Gamma, Ripples, Fast-Ripples), and compared to baseline. A total of 30,755 responses were analyzed, taking into consideration three dichotomous pairs: stimulating in primary sensory areas (S1-V1) vs. outside them, to test the interaction in physiologic networks; stimulating in seizure onset zone (SOZ) vs. non-SOZ, to test pathologic interactions; recording in default mode network (DMN) vs. non-DMN.
Results: Overall, we observed an early excitation (10-60ms) and a delayed inhibition (60-500ms). More specifically, in the delayed period, stimulation in S1-V1 produced a higher gamma-inhibition in the DMN, while stimulation in the SOZ induced a higher inhibition in the epilepsy-related higher frequencies (Ripples and Fast-Ripples).
Conclusion: Physiologic and pathologic interactions can be assessed using spectral changes induced by SPES.
Significance: This is a promising method for connectivity studies in patients with drug-resistant focal epilepsy.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.clinph.2016.12.016 | DOI Listing |
J Am Chem Soc
January 2025
Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
Switching electric polarization by external stimuli constitutes a technical foundation for various applications. Here, we reported the observation of polarization-switching behavior in an oxo-bridged mixed-valence complex [FeO(piv)(py)] (piv = pivalate, py = pyridine). Detailed variable-temperature Mössbauer spectral analyses unambiguously confirm the occurrence of an electron localization-delocalization transition between two inequivalent Fe sites.
View Article and Find Full Text PDFJ Microsc
January 2025
School of Chemical and Process Engineering, University of Leeds, Leeds, UK.
Transmission electron microscopy can be used for the characterisation of a wide range of thin specimens, but soft matter and aqueous samples such as gels, nanoparticle dispersions, and emulsions will dry out and collapse under the microscope vacuum, therefore losing information on their native state and ultimately limiting the understanding of the sample. This study examines commonly used techniques in transmission electron microscopy when applied to the characterisation of cryogenically frozen Pickering emulsion samples. Oil-in-water Pickering emulsions stabilised by 3 to 5 nm platinum nanoparticles were cryogenically frozen by plunge-freezing into liquid ethane to retain the native structure of the system without inducing crystallisation of the droplet oil cores.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX, 78249, USA.
The inherently stochastic nature of radiation emissions makes modeling background radiation structure a particularly challenging research area. In source identification scenarios, which are critical to nuclear security, the complexity of background radiation modeling is intensified by dynamically changing factors that influence radiation measurements. Consequently, accurately modeling and estimating background radiation can significantly improve our nuclear security capabilities by enhancing the detection of anomalies within radiation data.
View Article and Find Full Text PDFCell Stress Chaperones
January 2025
Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy. Electronic address:
To carry out their functions in cells, proteins are required to fold into well-defined three-dimensional conformations. The stability of the folded state dictates several aspects of protein life, such as their evolution, interactions, and selection of structures that are ultimately linked to activity. Sequence mutations may change the stability profile and consequently impact structure and function.
View Article and Find Full Text PDFFood Chem
January 2025
Department of Food Science, University of Otago, Dunedin 9016, New Zealand; Riddet Institute, Private Bag 11 222, Palmerston North 4442, New Zealand.
Near-infrared (NIR) spectroscopy with chemometrics was used to evaluate semi-refined flaxseed protein extract (SRFPE) and predict its protein content. The effect of extraction medium (water vs. alkaline) employed after pulsed electric field (PEF) treatment on protein yield was also studied.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!