Journal: The Journal of Neuroscience

Article Title: Optogenetic Stimulation of the M2 Cortex Reverts Motor Dysfunction in a Mouse Model of Parkinson's Disease

doi: 10.1523/JNEUROSCI.2277-18.2019

Figure Lengend Snippet: Optogenetic activation of M2 neurons induces locomotion. a, Experimental scheme of the labeling approach to express either ChR2 (dmST:ChR2) or eYFP alone (dmST:eYFP) into the M2 area and to implant optical fiber over the dmST (n = 8/group). b, Representative coronal image represents M2 axons and optical fiber placement (fiber track) in dmST. Green represents eYFP from AAV. lv, Lateral ventricle. c, Illustration of the photostimulation setup used in the optogenetic sessions. Optogenetic testing consisted of five 3 min epochs with alternating light manipulation (OFF-ON-OFF-ON-OFF). d–h, Photostimulation (465 nm, 71 mW/mm2, 10 ms square pulses at 20 Hz) of dmST:ChR2 mice evoked transient increases in the (d) contralateral (contra) rotations (expressed as percentage of ipsilateral [ipsi] rotations relative to the total number of rotations), (e) changes of speed (relative to the first light-OFF epoch; lines indicate data for individual mice), (f) average speed (light colored lines represent data for individual mice, data from light-OFF epochs are pooled), (g) mobility time (as a percentage of the epoch duration), and (h) distance traveled during the light-ON periods, relative to the dmST:eYFP or the dmST:ChR2 group during the OFF epochs. i, Experimental scheme of the labeling approach to express either ChR2 (M2:ChR2) or eYFP alone (M2:eYFP) and to implant optical fiber into the M2 area (n = 6/group). j, Representative coronal image represents expression of ChR2-eYFP and optical fiber placement (fiber track) in M2. Green represents eYFP from AAV. k–o, Photostimulation of M2:ChR2 (465 nm, 37.4 mW/mm2,10 ms square pulses at 20 Hz) also increased (k) contralateral rotations, (l) changes in mean speed, (m) average speed, (n) mobility time, and (o) distance traveled during the light-ON periods, relative to the M2:eYFP and the M2:ChR2 group during the OFF epochs. p, Illustration of the photostimulation setup using a head-mounted wireless optogenetic device inside the mice's home cage. q, Representative images of M2 neurons expressing c-Fos after photostimulation in ChR2 (top) and eYFP (bottom) mice. Red represents c-Fos. Green represents eYFP (both from immunoreactivity). r, Photostimulation increased the number of c-Fos-positive neurons within M2 in ChR2 animals compared with eYFP controls (n = 6/group). d, e, k, l, Dashed line indicates chance performance. Summary data are indicated as mean ± SEM. ***p < 0.001. **p < 0.01. *p < 0.05.

Article Snippet: Photostimulation for c-Fos induction and quantification of catecholamines were performed using a head-mounted wireless optogenetic device (HELIOS, Plexon) in each mouse inside its home cage (to minimize the unspecific neuronal activity due to exposition to the new context).

Techniques: Activation Assay, Labeling, Expressing

Journal: The Journal of Neuroscience

Article Title: Optogenetic Stimulation of the M2 Cortex Reverts Motor Dysfunction in a Mouse Model of Parkinson's Disease

doi: 10.1523/JNEUROSCI.2277-18.2019

Figure Lengend Snippet: Chronic optogenetic stimulation supplemented with l-DOPA administration ameliorates motor and nonmotor symptoms of bilaterally dopamine-depleted mice. a, Experimental scheme to transfect eYFP or ChR2 in the M2 cortex, and produce the bilateral dopamine-depleted mice (n = 16) through injection of 6-OHDA into the dmST. Dopamine-intact mice (n = 8) received bilateral injections of PBS in dmST. On day 21, when nigrostriatal degeneration was confirmed (postlesion evaluation), only dopamine-depleted mice received optical fibers positioned into the dmST. These mice underwent an acute photostimulation on days 30–33. Then, l-DOPA and photostimulation were applied in all mice for 7 consecutive days, and another photostimulation trial (chronic) was performed to score the behavior. b, c, In a separate group of animals, we observed that bilateral depleted mice displayed decreases in TH immunoreactivity concentration of dopamine in striatum. d–g, Locomotor behavior and percentage of spontaneous alternation in the Y-maze in DA-intact and DA-depleted mice. h–k, Behavioral effects of acute photostimulation in dopamine-depleted mice expressing either ChR2 or eYFP. Light was delivered for 3 min during the ON epoch. l–o, Behavioral effects of chronic photostimulation supplemented with l-DOPA treatment in dopamine-depleted mice. In all figures, summary data are indicated as mean ± SEM. ***p < 0.001. **p < 0.01. *p < 0.05.

Article Snippet: Photostimulation for c-Fos induction and quantification of catecholamines were performed using a head-mounted wireless optogenetic device (HELIOS, Plexon) in each mouse inside its home cage (to minimize the unspecific neuronal activity due to exposition to the new context).

Techniques: Injection, Concentration Assay, Expressing

Journal: The Journal of Neuroscience

Article Title: Optogenetic Stimulation of the M2 Cortex Reverts Motor Dysfunction in a Mouse Model of Parkinson's Disease

doi: 10.1523/JNEUROSCI.2277-18.2019

Figure Lengend Snippet: M2-dmST projection relies on basal ganglia neurotransmission to promote locomotion. a–c, Optogenetic stimulation of dmST:ChR2 mice (n = 4) increased tissue concentrations of DA and DOPAC, relative to the eYFP group (n = 4). The changes were observed in the dorsal striatum and midbrain measured immediately after photostimulation session. d, e, Pretreatment with the D2R antagonist haloperidol (ChR2-HAL, n = 5) and D1R antagonist SCH23390 (ChR2-SCH23390, n = 5) equally attenuated the light-evoked increases in the contralateral (contra) rotations compared with saline-treated animal (ChR2-Sal, n = 5) (top, expressed as percentage of ipsilateral [ipsi] rotations relative to the total number of rotations) and blocked the changes of speed (bottom, relative to the first light-OFF epoch; lines indicate data for individual mice) and average speed (inset). f, Mice injected with l-DOPA (n = 4) displayed a 68% increase in the DA levels, relative to vehicle-treated animals (n = 4). g, h, Treatment with l-DOPA potentiated the locomotor behavior as it decreased the minimum light power intensity (18.8 mW/mm2 vs 71 mW/mm2 in Fig. 2d–h) necessary to elicit the contralateral rotations, changes of speed, and average speed (n = 5/group). i, A schematic diagram of the experimental approach to deliver ChR2 in the M2, place optical fiber in the dmST and inject glutamate antagonists into SNc. j, Representative coronal image represents M2 axons in the midbrain and guide cannula placement ∼1.0 mm above SNc. Green represents eYFP from AAV. Magenta represents TH immunoreactivity. k, l, Infusion of NBQX/AP5 (AMPA/NMDA receptor antagonists, respectively) into the SNc attenuated contralateral rotations and ablated changes of speed and average speed (inset) elicited by photostimulation (n = 5/group). m, Schematic diagram of the experimental approach to deliver Cre-dependent ChR2 or EYFP in the M2, and WGA-Cre in the SNc. Optical fiber was placed in M2. n, Representative sagittal image represents a subset of M2 neurons (green) in the cortical layer 5 (L5) that makes synaptic contact within SNc (M2-SNc circuit). o, p, Stimulation of M2-SNc neurons expressing ChR2 did not evoke rotational behavior but induced speed increments (n = 6–8/group). In all figures, summary data are indicated as mean ± SEM. d, e, g, h, k, l, o, p, Dashed line indicates chance performance. ***p < 0.001. **p < 0.01. *p < 0.05.

Article Snippet: Photostimulation for c-Fos induction and quantification of catecholamines were performed using a head-mounted wireless optogenetic device (HELIOS, Plexon) in each mouse inside its home cage (to minimize the unspecific neuronal activity due to exposition to the new context).

Techniques: Injection, Expressing

Journal: The Journal of Neuroscience

Article Title: Optogenetic Stimulation of the M2 Cortex Reverts Motor Dysfunction in a Mouse Model of Parkinson's Disease

doi: 10.1523/JNEUROSCI.2277-18.2019

Figure Lengend Snippet: Optogenetic stimulation of M2-dmST projection improves motor dysfunction of unilateral dopamine-depleted mice. a, Top, Experimental scheme to deliver either ChR2 or eYFP into the M2 cortex, and PBS (dopamine-intact) or 6-OHDA (dopamine-depleted) into dorsal striatum. On day 28, when nigrostriatal degeneration is completed, an optical fiber was positioned into the dorsal striatum. Bottom, Timeline of the nigrostriatal lesion, and optogenetics stimulation in the same hemisphere following stereotaxic injections. b, c, All unilateral dopamine-depleted mice exhibited forelimb use asymmetry (cylinder test) and circling motor abnormalities at the end of the postlesion phase: dopamine intact (eYFP): n = 6; dopamine intact (ChR2): n = 7; dopamine depleted (eYFP): n = 8; dopamine depleted (ChR2): n = 10. d–f, Unilateral dopamine depletion did not result in significant changes in mobility, speed, and total distance traveled over the analyzed period. g, Representative coronal sections of the dopamine-intact (top) and dopamine-depleted (bottom) mice showing immunoreactivity for TH in four striatal subregions along the AP axis (relative to bregma). lv, Lateral ventricle; cc, corpus callosum; aca, anterior commissure. Red represents TH from immunoreactivity. h, Overall, there was an 80% reduction of TH immunoreactivity in the DA-depleted hemispheres along the AP axis. Inset, Percentage of TH immunoreactivity in ipsilateral relative to the contralateral hemisphere (n = 4/group). i, Representative coronal section showing the SNc of the dopamine-intact (left) and the dopamine-depleted hemisphere (right). Green represents eYFP from AAV. Magenta represents TH from immunoreactivity. j, The number of TH-positive cells in the SNc was also significantly reduced in the dopamine-depleted hemisphere. Inset, Percentage of TH-positive cells in ipsilateral relative to the contralateral hemisphere. k, Reduction of striatal levels of DA, DOPAC, and HVA in the dopamine-depleted hemispheres, relative to the intact hemispheres. No significant differences were observed for NE (n = 4/group). l, m, Optogenetic stimulation improved the forelimb use asymmetry and circling motor abnormality at the light-ON epoch. b, c, l, m, Dashed line indicates chance performance. In all figures, summary data are indicated as mean ± SEM. ***p < 0.001. ###p < 0.001.

Article Snippet: Photostimulation for c-Fos induction and quantification of catecholamines were performed using a head-mounted wireless optogenetic device (HELIOS, Plexon) in each mouse inside its home cage (to minimize the unspecific neuronal activity due to exposition to the new context).

Techniques: Optogenetics