Journal: Science Advances

Article Title: Integration of reconfigurable microchannels into aligned three-dimensional neural networks for spatially controllable neuromodulation

doi: 10.1126/sciadv.adf0925

Figure Lengend Snippet: ( A ) Schematic illustration depicting microfluidic neuromodulation with KCl via the center channel to an aligned 3D neural network. ( B ) Computational simulation of 3D transient diffusion of K + (39.0983 Da) into a collagen scaffold at 239.7 s. ( C ) Color-mapped differential confocal fluorescence images (left images in each panel) of Fluo-4 AM (Ca 2+ signal) between two adjacent time frames [ I Fluo-4 AM, t ( i ) − I Fluo-4 AM, t ( i −1) ] and snapshots of the computational calculation (right images in each panel) from the solutions in (B) at 0 ( t 0 ), 28.2 ( t 1 ), 51.7 ( t 2 ), and 239.7 ( t 3 ) s. Scale bar, 500 μm. ( D ) y -Mean concentration of K + along the x axis at t i . ( E ) [ I Fluo-4 AM, t ( i ) − I Fluo-4 AM, t ( i −1) ] along the x axis. Light and bold colors represent y -mean intensities and fitted curves generated by a smoothing option of LOWESS in Prism.

Article Snippet: We generated fitted curves using a smoothing option of LOWESS in Prism (GraphPad).

Techniques: Diffusion-based Assay, Fluorescence, Concentration Assay, Generated

Journal: Science Advances

Article Title: Integration of reconfigurable microchannels into aligned three-dimensional neural networks for spatially controllable neuromodulation

doi: 10.1126/sciadv.adf0925

Figure Lengend Snippet: ( A ) Schematic illustration depicting spatiotemporally resolved microfluidic neuromodulation by two consecutive pulsatile deliveries of KCl via the left microchannel to an aligned 3D neural network. ( B ) Color-mapped differential confocal fluorescence images of Fluo-4 AM (Ca 2+ signal) between two adjacent representative time frames [ I Fluo-4 AM, t ( i ) − I Fluo-4 AM, t ( i -1) ] (a) and [ I Fluo-4 AM, t ( i ) − I Fluo-4 AM, t ( i −1) ] along the x axis after the first pulse: −18 ( t 0 ), 0 ( t 1 ), 6 ( t 2 ), and 66 ( t 3 ) s and the second pulse: 522 ( t 0 ), 525 ( t 1 ), 570 ( t 2 ), and 603 ( t 3 ) s (b). Scale bars, 500 μm. Curve profiles represent y -mean intensities generated by a smoothing option of LOWESS in Prism.

Article Snippet: We generated fitted curves using a smoothing option of LOWESS in Prism (GraphPad).

Techniques: Fluorescence, Generated

Journal: Science Advances

Article Title: Integration of reconfigurable microchannels into aligned three-dimensional neural networks for spatially controllable neuromodulation

doi: 10.1126/sciadv.adf0925

Figure Lengend Snippet: ( A and B ) Schematic illustrations depicting spatially resolved microfluidic neuromodulation with KCl via the right microchannel and TTX, nifedipine, mibefradil via the center microchannel to an aligned 3D neural network. ( C ) Color-mapped differential confocal fluorescence images of Fluo-4 AM (Ca 2+ signal) between two adjacent representative time frames [ I Fluo-4 AM, t ( i ) − I Fluo-4 AM, t ( i −1) ] (a) and [ I Fluo-4 AM, t ( i ) − I Fluo-4 AM, t ( i −1) ] along the x axis upon simultaneous treatments of TTX: −6 ( t 0 ), 0 ( t 1 ), 78 ( t 2 ), and 210 ( t 3 ) s; nifedipine: −3 ( t 0 ), 0 ( t 1 ), 39 ( t 2 ), and 72 ( t 3 ) s; and mibefradil: −6 ( t 0 ), 0 ( t 1 ), 21 ( t 2 ), and 54 ( t 3 ) s (b). Scale bars, 500 μm. Curve profiles represent y -mean intensities generated by a smoothing option of LOWESS in Prism.

Article Snippet: We generated fitted curves using a smoothing option of LOWESS in Prism (GraphPad).

Techniques: Fluorescence, Generated

Journal: iScience

Article Title: Amplitude- and frequency-dependent activation of layer II/III neurons by intracortical microstimulation

doi: 10.1016/j.isci.2023.108140

Figure Lengend Snippet: Spatial characterization of neuronal responses to electrical stimulation (A) Heat maps of calcium signals from TPM evoked by different current amplitudes of stimulation (20, 40, and 100 μA) at different locations away from the stimulation electrode (outside of the field of view on the top). (B) Neurons’ maximal calcium responses in relation to their distance to the stimulating electrode. Note that the responses peak at ∼200 μm away from the stimulating electrode and remarkably decrease at ∼500 μm away. (C) Amplitudes of calcium signals evoked by various levels of stimulation in relation to the distance to the stimulating electrode. Data are shown as LOWESS fitting curves (GraphPad Prism 9). (D) Activation threshold versus neuronal location relative to the stimulating electrode. Note that the activation threshold increases fast over 400 μm away. (E) Ratio of activated neurons with buildup, sustained, and transient types of calcium responses in relation to the distance to the stimulating electrode. (F) Amplitude-dependent dynamics of responses of two examples cells located at different distances from the stimulation electrode. The orange insets show zoomed in review of responses to 20 μA stimulation. (G) Ratio of neurons with buildup, sustained, and transient types of calcium responses in relation to stimulation amplitude at different distances from the stimulation electrode. Data are shown as mean ± SEM of six animals with a total of 2275 activated neurons (379 ± 53 neurons in each animal) analyzed in B, D, and E. Gray lines in B and D represent individual animal.

Article Snippet: Solid lines are LOWESS fitting curves (GraphPad Prism 9). (G) Enlarged view of (F) to show that 4 out of 6 animals showed saturated calcium responses at around 400 V/m.

Techniques: Activation Assay

Journal: iScience

Article Title: Amplitude- and frequency-dependent activation of layer II/III neurons by intracortical microstimulation

doi: 10.1016/j.isci.2023.108140

Figure Lengend Snippet: Relationship between neuronal responses and local electrical field (E-field) (A) E-field simulation configuration. Electrode shank angle and stimulation electrode depth were determined by OCT image. E-field at the TPM imaging plane was simulated. (B) An example E-field map of 100 μA stimulation at the TPM imaging plane with the center directly at the stimulation electrode in x and y locations. (C) E-field map of a 100 μA stimulation in the ROIs of TPM imaging of an example animal. x and y axes show the relative distance to the stimulating electrode. (D) Calcium responses to the electrical stimulation corresponding to (C). Note the alignment of E-field strength in (C) and calcium response amplitude in (D). (E) Relationship between calcium response and E-field at different stimulation amplitudes extracted from the example animal in (C) and (D). Regardless of the stimulation amplitude, the relationship between calcium response and E-field remains the same. (F) Summary of the relationship between calcium response and E-field of 6 animals at a stimulation level of 100 μA. Each color represents one animal. Solid lines are LOWESS fitting curves (GraphPad Prism 9). (G) Enlarged view of (F) to show that 4 out of 6 animals showed saturated calcium responses at around 400 V/m. One animal started showing saturation at about 175 V/m. (H) Linear regression demonstrated that below 400 V/m, calcium responses are linearly correlated to the E-field with a narrow range of slope. Each line represents one animal, and the black line is the linear regression analysis of all neurons from 6 animals.

Article Snippet: Solid lines are LOWESS fitting curves (GraphPad Prism 9). (G) Enlarged view of (F) to show that 4 out of 6 animals showed saturated calcium responses at around 400 V/m.

Techniques: Imaging