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Posts tagged “review

Day 239: Review – Burst-modulated waveforms optimize electrical stimuli for charge efficiency and fiber selectivity

Example processed nerve responses during stimulation trials.
Example processed nerve responses during stimulation trials.

Example processed nerve responses during stimulation trials. The individual CNAP responses for each stimulus (thin traces) were averaged (thick trace, n=20 stimuli). All traces are shown from time 0 to 6ms. The top trace corresponds to an amplitude of 0, the bottom 1mA, and the traces in between are arranged in increments of 0.2mA. Peak latencies and heights (o’s) and widths at half peak height (x’s) were extracted from the averaged signal. The peaks labeled for the 0mA trial are due to noise and baseline activity. These peaks are not actual response peaks from the nerve and are ignored.

Another two weeks, another critical review and as always since my PI gets a copy, so do you. Technically this should’ve come yesterday, but I really wanted to follow up with the Roosevelt mess going on. In any case today we are looking at something not quite spinal cord stimulation, but has applications in the spinal cord stimulation field. Let’s take a look!

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Day 224: Review – Cortical and Subcortical Effects of Transcutaneous Spinal Cord Stimulation

Figure 1 of the paper showing the experimental set-up and the type of pulse used for stimulation
Figure 1 of the paper showing the experimental set-up and the type of pulse used for stimulation

Experimental set-up. (A) Participants were comfortably seated in a customized chair during transcutaneous electrical spinal stimulation (TESS) or sham-TESS for 20 min. TESS was delivered using a surface electrode on the back of the neck between C5–C6 spinous processes segments (cathode) and a surface electrode in each anterior crest of the hip bone (anode) using a custom made 5 channel stimulator (BioStim5, Cozyma). Electrophysiological and behavioral outcomes were tested before (Pre) and immediately after, 15, 30, 45, 60 and 75 min after the end of the stimulation or sham stimulation period. (B) Schematic representation of the type of current used during TESS. We used 5 biphasic pulses at 5kHz with each biphasic pulse lasting for 200us. The middle scheme shows the blocks of 5 biphasic pulses passed at a 30Hz frequency. Lower part of the schematic shows the number of pulses delivered in one second.

Well it’s been two weeks since the last critical review so it’s that time again. As usual, my PI gets a copy and so do all of you. Since I’ve done several of these now (this is number six) I have a category just for these reviews called critical reviews. This is a really new study which tries to help tease apart what we are actually stimulating when we apply transcutaneous spinal stimulation. I think it’s a super interesting paper and I hope you do as well.

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Day 210: Review – Cervical trans-spinal direct current stimulation: a modelling-experimental approach

Cervical trans-spinal direct current stimulation - Fig. 3
Cervical trans-spinal direct current stimulation - Fig. 3

Average magnitude of the E-field and average amplitude of its components in the spinal-WM in all montages along the z axis. Position of spinal segments is marked on the grey vertical bar, electrodes are represented by vertical bars and active connectors are marked with letter “A”. Volume plots of the E-field magnitude in cervico-thoracic spinal-WM, brainstem and cerebellum are represented at the right of the average distribution in each montage, with the corresponding colour scales

I lied! I did know what today was going to be on, it’s the fifth critical review paper. Since my PI gets a copy, so do you! To be honest, I need to create a category for these reviews (Update: I did make a category, Critical reviews), but for now, my first looking at elbow spinal stretch reflexes is here. My second where I review modulating spinal cord excitability with a static magnetic field here. The third where I review modulating the H-reflex while walking in spinal cord injury populations. Lastly, my fourth on Motoneuron excitability during voluntary muscle activity in a spinal cord injury population  can be found here. That said, let’s take a look at my latest review.

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Day 196: Review – Changes in Motoneuron Excitability during Voluntary Muscle Activity in Humans with Spinal Cord Injury

Figure 1
Figure 1

Figure 1. Experimental setup. A, Schematic representation of the hand showing the ulnar nerve and F-waves recorded from the first dorsal interosseous (FDI) muscle. B, On the left side, schematic representation of the head showing the electrodes placed at the cervicomedullary junction and on the right side a raw trace showing a cervicomedullary motor evoked potential (CMEP). C, A cartoon showing the concept of the visual feedback. Individuals were tested at rest (left single horizontal line) and during 5% (middle double horizontal lines) and 30% (right double horizontal lines) of maximal voluntary contraction (MVC).

A little detour from our spinal cord series for my fourth critical review paper. As usual, my PI get a copy and so do all of you! You can read my first looking at elbow spinal stretch reflexes here. My second where I review modulating spinal cord excitability with a static magnetic field here. Or the third where I review modulating the H-reflex while walking in spinal cord injury populations. Today is an interesting paper on motoneuron excitability while walking in spinal cord injury populations. It’s a really cool paper, so here’s my review.

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Day 182: Review – Modulation of soleus stretch reflexes during walking in people with chronic incomplete spinal cord injury

Fig2

Figure 2 of the paper showing examples of the soleus H-reflex (labeled H) during standing  and during different phases of walking in a participant without known neurological injuries (top) and in a participant with chronic incomplete SCI (bottom).

Today is my third attempt at a critical review paper. Since my PI gets a copy, so do all of you! You can read my first looking at elbow spinal stretch reflexes here. Or my second where I review modulating spinal cord excitability with a static magnetic field here. Today is an interesting paper on soleus stretch reflex and H-reflex. I really appreciate the methodology the researchers used and they did an excellent job of highlighting the limitations to the study, which is always important. Per the usual disclaimer, this is my third critical review, so you can take my opinion n the methodology and findings how you will. (more…)