Magnetic stimulation allows focal activation of the mouse cochlea
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, United States
- Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Harvard Medical School, United States
- Department of Otorhinolaryngology - Head and Neck Surgery, Paracelsus Medical University, Austria
- Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, United States
- Department of Otolaryngology – Head and Neck Surgery, Stanford University School of Medicine, United States
- Boston VA Medical Center, United States
Figures
Figure 1
Magnetic stimulation of spiral ganglion neurons (SGNs).
Conceptual diagram illustrating induced electric field generated by a micro-coil (A) and current spread from an electrode (B) positioned in the scala tympani. While high conductivity of the …
Figure 2 with 2 supplements
Response to acoustic stimulation measured in the inferior colliculus (IC).
(A–C) Typical spatial tuning curves (STCs) of the IC responses to acoustic stimulation (8, 16, and 32 kHz, respectively) recorded from the 16-channel probe positioned in the IC. Response magnitude …
Figure 2—figure supplement 1
IC responses to acoustic, magnetic, and electric stimulation.
(A) Representative raw recordings of single traces of the neural activity evoked by each stimulation modality were captured by the same recording electrode (positioned in IC). (B) Local field …
Figure 2—figure supplement 2
Cumulative d′ index with respect to dB levels above threshold.
The cumulative d′ index at BS plotted as a function of dB above threshold: (A) acoustic stimulation (32 kHz; n = 11 animals), (B) electric stimulation (basal turn; n = 6 animals), and (C) magnetic …
Figure 3 with 1 supplement
Magnetic stimulation evoked robust auditory brainstem responses (ABRs).
ABR responses to a 32-kHz monotone: (A) control, (B) after DI water was injected into the cochlear through the round window. ABRs from magnetic (C) and electric (D) stimulation (post-deafening). The …
Figure 3—figure supplement 1
Auditory brainstem responses (ABRs) in response to magnetic and electric stimulation.
(A-1, A-2) ABR responses to magnetic stimulation from two different animals (post-deafening). (B-1, B-2) ABR responses to electric stimulation from two different animals (post-deafening). The blue …
Figure 4 with 2 supplements
Spatial tuning curves (STCs) for magnetic stimulation are spatially more confined than STCs for electric stimulation.
(A, C) STCs in response to magnetic and electric stimulation delivered to the basal turn of the cochlea (aMUA signals quantified with d-prime analysis – see text). Dotted, dashed, and solid lines …
Figure 4—figure supplement 1
Spatial tuning curves (STCs) in response to magnetic and electric stimulation at the basal turn of the cochlea.
(A-1–A-6) STCs in response to magnetic stimulation delivered to the basal turn of the cochlea from different animals. Dotted, dashed, and solid lines are contours for cumulative d′ values of 1, 2, …
Figure 4—figure supplement 2
Spatial tuning curves (STCs) in response to apical magnetic and electric stimulation.
(A-1–A-3) STCs in response to magnetic stimulation delivered to the apical turn of the cochlea from different animals. Dotted, dashed, and solid lines are contours for cumulative d′ values of 1, 2, …
Figure 5
The spread of activation is narrower for magnetic vs. electric stimulation.
(A, B) The spatial spread of IC activation was measured by the width of activated channels at cumulative d′ levels of 2 and 4. (C, D) The spectral spread was estimated by converting the width of …
Figure 6
Dynamic range for magnetic stimulation is wider than that for electric stimulation.
Normalized responses rates as a function of stimulus intensity for magnetic (A) and electric (B) stimulation (basal turn). Each line is the averaged response curve from one animal. Insets show the …
Figure 7
Magnetic stimulation elicits responses in chronically deafened mice.
(A) Gentamicin caused complete loss of inner and outer hair cells (white, Myo7A). Supporting structures of the organ of Corti were stained with Phalloidin (red). Scale bar: 50 µm. (B) Quantification …
Tables
Table 1
Statistical analysis of spatial spread (Figure 5A, B) by two-way ANOVA and subsequent Tukey’s test for multiple comparisons; *p < 0.05, ***p < 0.001.
| Predicted (LS) mean diff. | 95.00% CI of diff. | Summary | Adjusted p value | |||
|---|---|---|---|---|---|---|
| Base | d' = 2 | Acoustic vs. magnetic | −0.08433 | −0.2383 to 0.06961 | ns | 0.3863 |
| Acoustic vs. electric | −0.3076 | −0.4615 to −0.1536 | *** | <0.0001 | ||
| Magnetic vs. electric | −0.2233 | −0.4010 to −0.04549 | * | 0.0108 | ||
| d' = 4 | Acoustic vs. magnetic | −0.07223 | −0.2262 to 0.08171 | ns | 0.4953 | |
| Acoustic vs. electric | −0.4324 | −0.5863 to −0.2785 | *** | <0.0001 | ||
| Magnetic vs. electric | −0.3602 | −0.5379 to −0.1824 | *** | <0.0001 | ||
| Apex | d' = 2 | Acoustic vs. magnetic | −0.03936 | −0.1635 to 0.08482 | ns | 0.7172 |
| Acoustic vs. electric | −0.07669 | −0.2009 to 0.04749 | ns | 0.2949 | ||
| Magnetic vs. electric | −0.03733 | −0.1944 to 0.1197 | ns | 0.8287 | ||
| d' = 4 | Acoustic vs. magnetic | −0.05788 | −0.1821 to 0.06630 | ns | 0.4922 | |
| Acoustic vs. electric | −0.4130 | −0.5372 to −0.2889 | *** | <0.0001 | ||
| Magnetic vs. electric | −0.3552 | −0.5122 to −0.1981 | *** | <0.0001 |
Key resources table
| Reagent type (species) or resource | Designation | Source or reference | Identifiers | Additional information |
|---|---|---|---|---|
| Strain, strain background (Mus musculus) | CBA/CaJ | The Jackson Laboratory, Bar Harbor, ME | 000654 | |
| Antibody | Anti-myosin 7A (rabbit polyclonal) | Proteus Biosciences, Ramona, CA | 25-6790 | 1:200 |
| Antibody | Anti-Rabbit IgG (H + L) Cross-Adsorbed Secondary Antibody, Alexa Fluor 488 (goat polyclonal) | Invitrogen, Carlsbad, CA | A-11008 | 1:500 |
| Chemical compound, drug | Gentamicin Sulfate | Sigma-Aldrich, St. Louis, MO | G-4918 | 200 µg |
| Software, algorithm | MATLAB | MathWorks | RRID:SCR_001622 | |
| Software, algorithm | GraphPad Prism | GraphPad | RRID:SCR_ 002798 | |
| Other | Alexa Fluor 647 Phalloidin | Invitrogen, Carlsbad, CA | A22287 | 1:200 |
