Biomedical Engineering Reference
In-Depth Information
(a)
(d)
No AO
AO
No AO
AO
9851
7388
4926
2463
0
lateral
lateral
lateral
lateral
13,900
10,425
7360
5520
6,950
3680
3,475
0
1840
axial
axial
axial
axial
0
16,000
1800
No AO
AO correction
(e)
No AO
AO correction
(f)
1600
14,000
1400
12,000
1200
10,000
1000
2541
8,000
800
1906
6,000
600
1270
4,000
400
2,000
635
200
axial
axial
0
0
0
0
5 10 15 20 25 30 35 40
0
2
4
6
8
10
12
(
µ
m)
(
µ
m)
2800
(g)
(c)
No AO
(b)
7
6
5
4
3
2
1
0
2600
8
7
6
5
4
3
2
1
0
AO correction
2400
2200
2000
1800
1600
1400
1200
1000
800
600
400
200
0
0 2 4 6 8 10 12 14 16 18 20
(
µ
m)
FIGuRE 13.12 (See color insert.)
AO. improves. imaging. quality. for. in. vivo. mouse-brain. imaging:. (a). Lateral.
and.axial.images.of.GFP-expressing.dendritic.processes.170.μm.below.the.surface.of.the.brain.before.and.ater.AO.
correction;.(b) Axial.signal.proiles.along.the.white.line.in.(a);.(c).Measured.aberrated.wavefront.in.units.of.excita-
tion.wavelength;.(d).Lateral.and.axial.images.of.GFP-expressing.neurons.110.μm.below.the.surface.of.the.brain.
with.and.without.AO.correction;.(e,.f ).Axial.signal.proiles.along.the.white.dashed.lines.in.(d).(let.dashed.line.goes.
through.a.soma.and.the.right.dashed.line.goes.through.a.dendrite);.(g).Aberrated.wavefront.measured.in.units.of.
excitation.wavelength..Scale.bars:.10.μm..(Ji,.N.,.et.al.,.
Proc. Natl. Acad. Sci
..
USA
,.109,.22-27,.2012.)
13.5 Discussion
13.5.1 Pupil Segmentation Strategy
Since.we.approximate.the.local.wavefront.of.each.pupil.segment.as.a.plane,.the.greater.the.number.of.
subregions.into.which.we.segment.the.pupil,.the.more.accurate.the.wavefront.can.be.described..
Figure.
13.13
.
demonstrates,.for.a.1.μm.luorescent.bead.below.a.250-μm-thick.ixed.brain.slice,.how.the.lateral.
resolution,.axial.resolution,.and.signal.vary.as.a.function.of.the.number.of.pupil.subregions..For.this.
luorescent.bead,.slight.improvement.in.lateral.resolution.is.seen.for.all.subregion.numbers,.consistent.
with.the.above-mentioned.fact.that.lateral.resolution.is.more.resistant.to.aberration..However,.even.by.
segmenting.the.pupil.into.12.subregions,.we.improved.both.the.axial.resolution.and.the.signal.signii-
cantly..With.increasing.number.of.subregions.thereater,.the.improvement.in.the.axial.resolution.rap-
idly.saturated,.indicating.that.even.with.modest.numbers.of.subregions,.most.rays.already.intersect.near.
