space and time resolved diagnostics of the enea euv discharge produced plasma source used for metrology and other applications

A discharge-produced-plasma (DPP) source emitting in the extreme ultraviolet (EUV) spectral region is running at the ENEA Frascati Research Centre. The plasma is generated in low-pressure xenon gas and efficiently emits 100-ns duration radiation pulses in the 10–20-nm wavelength range, with an energy of $20~\text{mJ}/\text{shot}/\text{sr}$ at a 10-Hz repetition rate. The complex discharge evolution is constantly examined and controlled with electrical measurements, while a ns-gated CCD camera allowed observation of the discharge development in the visible, detection of time-resolved plasma-column pinching, and optimization of the pre-ionization timing. Accurately calibrated Zr-filtered PIN diodes are used to monitor the temporal behaviour and energy emission of the EUV pulses, while the calibration of a dosimetric film allows quantitative imaging of the emitted radiation. This comprehensive plasma diagnostics has demonstrated its effectiveness in suitably adjusting the source configuration for several applications, such as exposures of photonic materials and innovative photoresists

Huntington disease-like phenotype in a patient with ANO3 mutation

A 71-year-old previously well white British female developed progressive involuntary tongue movements over one year, resulting in eating difficulty and 10 kg weight loss. She had also noted involuntary perioral, facial and distal limb movements beginning 18 months earlier. These had progressively worsened. In the 3 years prior to presentation, she reported subjective memory decline, word finding difficulty and depressed mood, which improved with mirtazapine 30 mg once daily. She had no history of neuroleptic exposure. Her brother had died aged 40 years, following years of mental illness and substance abuse. She was estranged from her father, who was said to have had ‘behavioural problems’. Her paternal grandmother and maternal aunt had Parkinson's disease

Disentangling EEG responses to TMS due to cortical and peripheral activations

Background: the use of combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG) for the functional evaluation of the cerebral cortex in health and disease is becoming increasingly common. However, there is still some ambiguity regarding the extent to which brain responses to auditory and somatosensory stimulation contribute to the TMS-evoked potential (TEP). Objective/Hypothesis: to measure separately the contribution of auditory and somatosensory stimulation caused by TMS, and to assess their contribution to the TEP waveform, when stimulating the motor cortex (M1). Methods: 19 healthy volunteers underwent 7 blocks of EEG recording. To assess the impact of auditory stimulation on the TEP waveform, we used a standard figure of eight coil, with or without masking with a continuous noise reproducing the specific time-varying frequencies of the TMS click, stimulating at 90% of resting motor threshold. To further characterise auditory responses due to the TMS click, we used either a standard or a sham figure of eight coil placed on a pasteboard cylinder that rested on the scalp, with or without masking. Lastly, we used electrical stimulation of the scalp to investigate the possible contribution of somatosensory activation. Results: auditory stimulation induced a known pattern of responses in electrodes located around the vertex, which could be suppressed by appropriate noise masking. Electrical stimulation of the scalp alone only induced similar, non-specific scalp responses in the in the central electrodes. TMS, coupled with appropriate masking of sensory input, resulted in specific, lateralized responses at the stimulation site, lasting around 300 ms. Conclusions: if careful control of confounding sources is applied, TMS over M1 can generate genuine, lateralized EEG activity. By contrast, sensory evoked responses, if present, are represented by non-specific, late (100–200 ms) components, located at the vertex, possibly due to saliency of the stimuli. Notably, the latter can confound the TEP if masking procedures are not properly used

Disentangling EEG responses to TMS due to cortical and peripheral activations

BACKGROUND: the use of combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG) for the functional evaluation of the cerebral cortex in health and disease is becoming increasingly common. However, there is still some ambiguity regarding the extent to which brain responses to auditory and somatosensory stimulation contribute to the TMS-evoked potential (TEP). OBJECTIVE/HYPOTHESIS: to measure separately the contribution of auditory and somatosensory stimulation caused by TMS, and to assess their contribution to the TEP waveform, when stimulating the motor cortex (M1). METHODS: 19 healthy volunteers underwent 7 blocks of EEG recording. To assess the impact of auditory stimulation on the TEP waveform, we used a standard figure of eight coil, with or without masking with a continuous noise reproducing the specific time-varying frequencies of the TMS click, stimulating at 90% of resting motor threshold. To further characterise auditory responses due to the TMS click, we used either a standard or a sham figure of eight coil placed on a pasteboard cylinder that rested on the scalp, with or without masking. Lastly, we used electrical stimulation of the scalp to investigate the possible contribution of somatosensory activation. RESULTS: auditory stimulation induced a known pattern of responses in electrodes located around the vertex, which could be suppressed by appropriate noise masking. Electrical stimulation of the scalp alone only induced similar, non-specific scalp responses in the in the central electrodes. TMS, coupled with appropriate masking of sensory input, resulted in specific, lateralized responses at the stimulation site, lasting around 300 ms. CONCLUSIONS: if careful control of confounding sources is applied, TMS over M1 can generate genuine, lateralized EEG activity. By contrast, sensory evoked responses, if present, are represented by non-specific, late (100-200 ms) components, located at the vertex, possibly due to saliency of the stimuli. Notably, the latter can confound the TEP if masking procedures are not properly used

Recurrent Subarachnoid Bleeding and Superficial Siderosis in a Patient with Histopathologically Proven Cerebral Amyloid Angiopathy

A 68-year-old man with a history of hypertension presented with recurrent subarachnoid bleeding. Brain MRI showed superficial siderosis, and diagnostic cerebral angiograms did not show any intracranial vascular malformation or arterial aneurism. Post mortem neuropathological examination of the brain was consistent with a diagnosis of cerebral amyloid angiopathy. Clinicians should be aware that cerebral amyloid angiopathy should be considered in patients with unexplained recurrent subarachnoid bleeding, even in cases without familial clustering or transthyretin variant

The TMS Map Scales with Increased Stimulation Intensity and Muscle Activation

One way to study cortical organisation, or its reorganisation, is to use transcranial magnetic stimulation (TMS) to construct a map of corticospinal excitability. TMS maps are reported to be acquired with a wide variety of stimulation intensities and levels of muscle activation. Whilst MEPs are known to increase both with stimulation intensity and muscle activation, it remains to be established what the effect of these factors is on the map's centre of gravity (COG), area, volume and shape. Therefore, the objective of this study was to systematically examine the effect of stimulation intensity and muscle activation on these four key map outcome measures. In a first experiment, maps were acquired with a stimulation intensity of 110, 120 and 130% of resting threshold. In a second experiment, maps were acquired at rest and at 5, 10, 20 and 40% of maximum voluntary contraction. Map area and map volume increased with both stimulation intensity (P 0.09 in all cases). This result indicates the map simply scales with stimulation intensity and muscle activation

Somatosensory input in the context of transcranial magnetic stimulation coupled with electroencephalography: An evidence-based overview

The transcranial evoked potential (TEP) is a powerful technique to investigate brain dynamics, but some methodological issues limit its interpretation. A possible contamination of the TEP by electroencephalographic (EEG) responses evoked by the somatosensory input generated by transcranial magnetic stimulation (TMS) has been postulated; nonetheless, a characterization of these responses is lacking. The aim of this work was to review current evidence about possible somatosensory evoked potentials (SEP) induced by sources of somatosensory input in the craniofacial region. Among these, only contraction of craniofacial muscle and stimulation of free cutaneous nerve endings may be able to induce EEG responses, but direct evidence is lacking due to experimental difficulties in isolating these inputs. Notably, EEG evoked activity in this context is represented by a N100/P200 complex, reflecting a saliency-related multimodal response, rather than specific activation of the primary somatosensory cortex. Strategies to minimize or remove these responses by EEG processing still yield uncertain results; therefore, data inspection is of paramount importance to judge a possible contamination of the TEP by multimodal potentials caused by somatosensory input

A consensus panel review of central nervous system effects of the exposure to low-intensity extremely low-frequency magnetic fields

BACKGROUND: A large number of studies explored the biological effects of extremely low-frequency (0-300 Hz) magnetic fields (ELF-MFs) on nervous system both at cellular and at system level in the intact human brain reporting several functional changes. However, the results of different studies are quite variable and the mechanisms of action of ELF-MFs are still poorly defined. The aim of this paper is to provide a comprehensive review of the effects of ELF-MFs on nervous system. METHODS: We convened a workgroup of researchers in the field to review and discuss the available data about the nervous system effects produced by the exposure to ELF-MFs. MAIN FINDINGS/DISCUSSION: We reviewed several methodological, experimental and clinical studies and discussed the findings in five sections. The first section analyses the devices used for ELF-MF exposure. The second section reviews the contribution of the computational methods and models for investigating the interaction between ELF-MFs and neuronal systems. The third section analyses the experimental data at cellular and tissue level showing the effects on cell membrane receptors and intracellular signaling and their correlation with neural stem cell proliferation and differentiation. The fourth section reviews the studies performed in the intact human brain evaluating the changes produced by ELF-MFs using neurophysiological and neuropsychological methods. The last section shows the limits and shortcomings of the available data, evidences the key challenges in the field and tracks directions for future research