Download - Bioelectronics Laboratory The Yoshida Lab
Ch2Ch1
Bioelectronics Laboratory - The Yoshida Lab
In-silico Model Framework of the Neural Interface A realistic model to understand the biophysics and inform interface design
Biophysics & Modeling - Electrode Coupling Function - Electrode Sensitivity Function - Active Nerve Fiber Model - Neural Interface Design Tools - In-silico Model Framework
Instrumentation, System Control, Signal Processing - Spike Detection and Tracking - Closed Loop Control of FES - Kalman Filter System Identification - Universal Invertible Amplifier - Rapid Impedance Measurement
Neural Interfaces - thin film LIFE - TIME - microTIME - Multi-Contact Cuff
Biointegration & Biocompatibility - in-vivo Testing - Histology - Shaping of Glial Scarring - Softening Electrode Structures
Disruptive Technologies - GraFET Bioelectric Interface - Configurable Artificial Neural Net Chip - PS1 Light Activated Muscle - Low Frequency Alternating Current Nerve Block
Basic Science- Characterization of Tissue Properties- Biophysics of Membranes and Channels- Sensory Motor Electrophysiology
Sensory-Motor Bioelectronic Therapies - Operant Conditioning and Sensory Replacement Therapy for Phantom Limb Pain - Functional Electrical Stimulation - Bioelectronic Medicines
Neural engineering to translate neuroscience to therapies, develop bioelectronic medicines and improve the quality of life of those with sensory-motor injuries & diseases
Research Areas and Projects
Low Frequency Alternating Current BlockExperimental in-vivo measurement of % block
well formed
stites
25μm TungstenNeedle
μTIME
Intacttraces
The microTIME Electrode ArrayA gateway to the Autonomic Nervous System
Contact: Ken Yoshida Office: SL220F Ph: +1 (317) 274-9714 Email: [email protected]
The Team10.2019
A means to do the impossible: Access the information in small caliber nerve fibers
VR
VL
REF
Wagner
DP-311 Amp
RadnotiPressure
Transducer
Trac
hea
ECG
LFACb
BP
Digitimer
DS-3 Stimulator
VStim
Rigol DG-5072 Func Gen
SRS CS-580
Current Source
Experimental ParadigmTwo Pt-Ir bipolar hook electrode sets (800μm anode/cathode spacing, FHC, Bowdoin, ME) were positioned on the exposed left cervical vagus nerve. Standard rectangular pulse trains (1 ms PW, 25 Hz, 10 pulses, 1 Hz train rate) were applied to the vagus nerve to evoke bradycardia and hypotension. Adequate block amplitude was determined using a 1 Hz sinusoidal waveform and increasing the amplitude of the waveform until the effect of the vagal stimulation was blocked. To test the effect of LFACb, the vagal stimulus train and the LFACb waveform were presented in a regular continuous sequence as follows: (1) Pre: 20s baseline period of no stimulation(2) LFAC_only: 20s LFACb delivered to the caudal electrode(3) LFAC+VStim: 20s LFACb at the caudal electrode and vagal stimulation at the rostral electrode(4) VStim_only: Vagal stimulation at rostral electrode until BP falls below ~50mmHg(5) Post: No stimulation return to baseline
RR
Rat
e (H
z)
1
2
3
4
5
Time (s)0 10 20 30 40 50 60 70 80 90
Mea
n B
P (
mm
Hg)
0
20
40
60
80
100
120Pre LFAC only LFAC+VStim VStim Post
Time (s)
ECG vs LFAC and Vagal StimulationRat 56 Test Case
Filt
ered
EC
G (
mV
)
0 10 20 30 40 50 60 70 80 90-1
-0.5
0
0.5
Pre LFAC only LFAC+VStim VStim Post
21 22 36 37 51 52 60 61 91 92
Pre LFAC only LFAC+Stim Stim only Post
-0.6
-0.4
-0.2
0
0.2
0.4
Filt
ered
EC
G (
mV
)
Time (s)
In-silico Experiments of LFAC Block
Block
ConductingAction Potential
Blocking CuffIntracellularStimulation
Nerve Fascicle
Nerve Fiber
2μA
150
100
50
00 10 20 30 40 50
Position (mm)
Tim
e (m
s)
3μA
150
100
50
00 10 20 30 40 50
Position (mm)
Tim
e (m
s)
Action potential initiated
Conducting AP
Electrode Contacts
LFAC Block
AP Slowing
50
0
-50
-100
-150
Tra
nsm
embr
ane
Po
tent
ial (
mV
)
Subthreshold LFAC Block Threshold
30μA
150
100
50
00 10 20 30 40 50
Position (mm)
Tim
e (m
s)
100μA
150
100
50
00 10 20 30 40 50
Position (mm)
Tim
e (m
s)
LFAC BlockAP Slowing
Activation
AnodalBlock
Activation
LFAC Activation Threshold Anodal Block Threshold
Onset Activation
LFAC threshold predictions(1μm unmyelinated autonomic fiber, 1.3 mm fascicle, cuff electrode)
In-silico results using the Horn-Schild autonomic nerve model combined with the spatial-temporal potential distributions from a Comsol Multiphysics FEM model during application of a LFAC waveform through a bipolar cuff electrode to a nerve fascicle at different LFAC current amplitudes. The in-silico experiment predicts the slowing and block of seen in the in-vitro experiments. Inspection of the channel state variables suggests a closed state Na+ channel block as the mechanism for LFACb. Increasing the current amplitude, the model predicts activation and anodal block, which are both experimentally seen in-vivo