Transcript oxy-Hb - University of Illinois Archives

Artificial Intelligence
Biological
Intelligence
Biological Sensors
Cognitive Neuroscience
Cognitive Science
Neuronal Pattern Analysis
Single Cell and Subcellular MALDI Mass Spectrometry
for the Direct Assay of the Neuropeptides
Physiological
Saline
MALDI Matrix
Solution
 1-9
Cell
Relative Intensity
Matrix

AP9-27
AP
ELH
ELH
30-36
AP8-27
1-7

1-8
ELH15-36
ELH1-14

AP
ELH
7-27
Sample Plate
1000
2000
1-29
3000
m/z
p
4000
pELH
p
5000
Neuropeptides and hormones can be directly detected from biological samples ranging in size
from femtoliter peptidergic vesicles to large invertebrate neurons. When combined with genetic
information, the complete processing of prohormones into biologically active peptides can be
measured in a single cell. Current work involves developing mass spectrometric imaging (to
determine the precise locations of the peptides) and the ability to measure peptide release from
single cells and brain slices.
Placenta vs. Brain – 3800 Placenta Array
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Center for Biomedical Computing
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Narendra Ahuja
Bill Greenough
William O'Brien
Mark Band
Steve Boppart
Sariel Har-Peled
Art Kramer
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Harris Lewin
Zhi-Pei Liang
Lei Liu
Greg Miller
Jean Ponce
Jim Zachary
Micro Patterned Neuronal Networks in Culture
Recent Progress
Robustness:
Neurons Stay in Patterns
for One Month
Designability:
Neurons Can Be Guided Over
Electrodes on a Microelectrode Array
Single fibers
superimposed on electrodes
Patterned fiber track
superimposed on electrodes
Bruce C. Wheeler, Member of the Neuronal Pattern Analysis and Biosensor
Research Groups, Faculty in the Electrical and Computer Engineering Department
Micro Patterned Neuronal Networks in Culture
Recent Progress
Input/Output:
Function: Are Neurons in Patterns More Active?
Multiple Channel Electrical
A. Patterned Networks Have Greater Activity
Recordings Can be
Without Patterns: 1% ± 3% active electrodes
Obtained Routinely
With Patterns: 16%  12% active electrodes
B. Activity Increases with Cell Density
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800
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% Active Electrodes
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Patterned
Neuron Cultures
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Local Cell Density (per mm2)
Bruce C. Wheeler, Member of the Neuronal Pattern Analysis and Biosensor
Research Groups, Faculty in the Electrical and Computer Engineering Department
Detection of weak signals in noisy spike trains
B) Signal superimposed on noisy spike train
A) Signal due to small prey
C) Signal superimposed
on regular afferent spike train
Model of electric fish with electroreceptors distributed over its body. (A) The
change in afferent firing activity due to a small prey. (B) the signal due to the
prey superimposed on fluctuations due to spontaneous activity, in the case of a
standard (binomial) model for afferent firing activity with the same firing rate as
the afferent and (C) the signal superimposed on the actual afferent baseline
activity. In contrast to (B), the afferent spike train exhibits long-term regularity
(memory). This limits the fluctuations in baseline firing rate, making weak
signals easier to detect.
number of spikes in a 10 ms window
with mean subtracted
Production of transgenic mice
using cre-loxP technology
• Create cell-type
specific knockout
mice
• Two lines of mice
required:
– cre mice which
express cre in
desired cells
– loxP mice with
loxP sites flanking
the gene of
interest
cre mice
loxP mice
Creation of NR1 loxP mice
Characterization of NR1 loxP mice
Dendritic Development in Barrel Cortex
Dendritic Development in Barrel Cortex
Chang and Greenough, 1988
Dendritic Development in Barrel Cortex
CTL
KO
Optical Coherence Tomography
A
Surgical Microscope
Aiming Beam
Sample Arm
Dichroic
Mirror
SLD Source
50/50
Optical
Delay Line
Detector
B
Electronics
OCT Catheter
Sync
Computer
S-VHS Recorder
Fiber-Optic OCT Instrument
Rotating
Optical Coupling
Radial
Imaging
High-Resolution OCT of Cell Mitosis & Migration
rt
ey
h
g
v
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Real-Time Endoscopic Imaging
Non-Invasive Imaging of Developing Biology
Non-invasive optical imaging
• New group of procedures for measuring the
optical parameters of the cortex
– Scattering and absorption of near-infrared
(NIR) photons traveling through tissue
• These parameters can be inferred by
measuring:
– The degree of light attenuation (intensity)
– The degree of photon (phase) delay
Optical Methods
Assessment of exposed tissue
(UV and visible light)
Intrinsic
Contrast
Absorption
Fluorescence
Light
Scatter
[CytochromeC-Oxidase]
[NADH]
Brain Cell
Swelling
during
functional
activity?
[Oxy-Hb]
[Deoxy-Hb]
‘Intrinsic
Brain signals’?
[oxyFlaveoproteins]
‘Intrinsic
Brain signals’?
Contrast
Agents
Doppler Absorp- FluoresShift
tion
cence
Blood
Flow
Blood
Volume
Blood Cell
Velocity
LDF
Blood Flow Ion-Conc
(e.g.Indicator (Ca, K, Mg)
Dilution
with
Voltage
Cardiogreen) Sensitive
Dyes
Microcirculation
Assessment of deep tissue
(Near infrared light)
Contrast
Agents
Fluorescence
Principally
feasible,
depending
on tracer
development?
Intrinsic
Contrast
Absorp- Doppler
Shift
tion
Blood
Flow
(Indicator
dilution
with
Cardiogreen
oxygen)
NIRS
Modified from A. Villringer
Blood
Flow
Light
Scatter
Fluorescence
Absorption
Brain cell
swelling
during
functional
activity?
FAST
NIRS-Signals
?
[CytochromeC-Oxidase]
EROS
[Oxy-Hb]
[Deoxy-Hb]
NIRS
Optical effects
“Slow” effects
– develop over several seconds after stimulation
– correspond to effects observed with fMRI and PET
– are presumably due to hemodynamic changes
• “Fast” effects (EROS)
– develop within the first 500 ms after stimulation
– are most visible on the photon delay parameter
– are presumably due to neuronal changes
Hb oxygenation in visual cortex
Concentration changes / microM
0.6
[oxy-Hb]
0.4
0.2
0.0
-0.2
0.2
0.0
-0.2
-0.4
[deoxy-Hb]
-0.6
0
5 10 15 20 25 30 35 40 45 50 55 60
Modified from A. Villringer
Time / s
Comparison of PET and NIRS
 [oxy-Hb]
vs.
 CBF
 [deoxy-Hb]
vs.
 CBF
-14
 CBF (PET)
12
-20
 oxy-Hb (NIRS)
30
-14
 CBF (PET)
12
 CBF (PET)
12
 [total-Hb]
vs.
 CBF
-30
15
 deoxy-Hb (NIRS)
Modified from A. Villringer
-14
-15
 total-Hb (NIRS)
15
NIR Absorption Spectra
0.5
Water
Hb
0.4
0.3
0.2
0.1
0.0
600
HbO2
700
800
900 1000
Wavelength (nm)
In-vitro scattering effects
Scattering changes during
an action potential
voltage
scattering
Scattering changes during
tetanic activation of a
hippocampal slice
Phase
delay
measured
at 5 kHz
Synthesizer
Delays (ps)
EROS: Methods
1
2
3 Time (s)
Stimulus
Head
surface
LED
Cerebral cortex
PMT
Signal
Averaging
Optic
fiber
Volume described
by photons reaching fiber
Delays (ps)
112 MHz
200
400 Time (ms)
Average Evoked Response
Recording helmet
Slow/Fast Effects Relationship
D C
1.004
2 Hz
1.003
5 Hz
10 Hz
R e la tiv e
• The hemodynamic
(NIRS) effect is
proportional to the
size of the neuronal
(EROS) effect
integrated over time
• This supports the use of
hemodynamic brain
imaging methods to
quantify neuronal
activity
In te n s ity
Neuro-Vascular Relationship
1.002
1 Hz
Baseline
1.001
0.0
1.0
2.0
Fast Effect x Stimulation Frequency
Gratton, Goodman-Wood, & Fabiani,
HBM, in press
Upper-left visual stimulation
fMRI
RH
EROS
LH
Gratton et al., NeuroImage, 1997
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-0.12
-0.18
-0.24
0.24
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0.06
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pre-stimulus
baseline
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-0.12
-0.18
-0.24
0.24
0.18
0.12
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0.36
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0
100 ms
latency
-0.06
-0.12
-0.18
-0.24
0.24
0.18
0.12
0.06
-0.3
0.3
0
200 ms
latency
Right Visual Field Stimulation
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