Scientific Title IN VITRO NEUROPHYSIOLOGY OF …...AGENDA 1) The generation of brain electricity...
Transcript of Scientific Title IN VITRO NEUROPHYSIOLOGY OF …...AGENDA 1) The generation of brain electricity...
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Plain English Title
EPILEPSY STUDIED IN A TEST TUBE
Scientific Title
IN VITRO NEUROPHYSIOLOGY OF EPILEPSY
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Spikes
Slow waves
Typical epileptic EEG wave: spike-and-slow-waves
EPILEPSY ABNORMAL EEG Epilepsy patient
undergoing EEG EEG of epilepsy patient
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Typical epileptic EEG wave: spike-and-slow-wave.
Spikes
Slow waves
Cells composing the brain
Neuronal cells
Neurons
Electrodes
Neurons isolated
and alive
Epileptic electric waves
of isolated neurons
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STUDYING EPILEPSY IN SINGLE CELLS
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AGENDA 1) The generation of brain electricity Neurons as batteries 2) What happens in single neurons in epilepsy? 3) How do neurons synchronize? The role of MAP-
kinase CREB pathway. 6) Recording micro-EEGs. The gradual coupling of
microscopic discharges 7) Can chronic epilepsy be studied in a test tube? Yes!
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AGENDA
1) The generation of brain electricity
Neurons as batteries
2) What happens in single neurons in epilepsy?
3) How do neurons synchronize? The role of MAP-kinase CREB pathway.
6) Recording micro-EEGs. The gradual coupling of microscopic discharges
7) Can chronic epilepsy be studied in a test tube?
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PHYSICAL AND BIOLOGICAL BATTERIES Biological systems Ionic transporters
Physical systems Volta battery
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+ + + +
Flow of current
through wire
Flow of current
through ion channels
Intracellular
electrode
Extracellular
Field electrode
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AGENDA
1) The generation of brain electricity
Neurons as batteries
2) What happens in single neurons in a seizure?
3) How do neurons synchronize? The role of MAP-kinase CREB pathway.
6) Recording micro-EEGs. The gradual coupling of microscopic discharges
7) Can chronic epilepsy be studied in vitro?
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From Ayala et al. Brain Research, 1973
ELECTRICAL WAVEFORM
OF AN EPILEPTIC SINGLE NEURON
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Going into recordings
on brain slices
and isolated neurons
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Single cell intracellular
Field extracellular
EPILEPTIC DISCHARGES IN BRAIN SLICES
EPILEPTIC DISCHARGES IN ISOLATED NEURONS
EPILEPSY IN A TEST TUBE (IN VITRO)
STUDIES IN THE 1970s (Traub, Miles and Wong)
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Studying interconnections
between neurons
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Spontaneous bursting Pacemaker (like in the heart)
Propagation
Synchronized bursting
Microscopic discharges
Large discharges detected by scalp EEG
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AGENDA
1) The generation of brain electricity
Neurons as batteries
2) What happens in single neurons in epilepsy?
3) How do neurons synchronize? The role of MAP-kinase CREB pathway.
6) Recording micro-EEGs. The gradual coupling of microscopic discharges
7) Can chronic epilepsy be studied in vitro?
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KEY MECHANISM OF NEURONAL SYNHRONY
The MAP-kinase CREB pathway
CREB CAMP responsive element binding protein
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Normal brain Epileptic brain
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Epileptic rat untreated
Epileptic rat treated bySL327
From Barkmeier, Senador, Leclerq, Pai, Hua, Boutros, Kaminski and Loeb, (2012)
Neurobiology of disease
MAP kinase-CREB activation
in brain of epileptic rats
MAP kinase-CREB block
cures epileptic rats
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AGENDA
1) Basic principles of neurophysiology
Neurons as batteries
2) What happens in single neurons in epilepsy?
3) How do neurons synchronize? The role of MAP-kinase CREB pathway.
6) Recording micro-EEGs. The gradual coupling of microscopic discharges
7) Can chronic epilepsy be studied in vitro?
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1. Placing brain
in a glass container
2. Cool up the brain
on ice bucket
3. Cut slices
PREPARING VIABLE BRAIN SLICES
Brain slices
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0.3 mM 4-AP
1 mM 4-AP
1 mM 4-AP
3 mM 4-AP
A B
C D
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Brain slices generate epileptic discharges
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Common types
of brain waveform patterns
in people with epilepsy
recorded also in the test tube
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C. Ictal rhythmic sharp waves
EPILEPTIC WAVEFORMS IN THE TEST TUBE
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PERSISTENT SEIZURES IN THE TEST TUBE
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Sy
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Discharge sequence
Microscopic epileptic waveforms
gradually synchronize
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Spontaneous bursting Pacemaker (like in the heart)
Propagation
Synchronized bursting
Microscopic discharges
Large discharges detected by scalp EEG
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AGENDA 1) Basic principles of neurophysiology Neurons as batteries 2) What happens in single neurons in epilepsy? 3) How do neurons synchronize? The role of MAP-
kinase CREB pathway. 6) Recording micro-EEGs. The gradual coupling of
microscopic discharges 7) Can chronic epilepsy be studied in a test tube? Yes!!
![Page 27: Scientific Title IN VITRO NEUROPHYSIOLOGY OF …...AGENDA 1) The generation of brain electricity Neurons as batteries 2) What happens in single neurons in epilepsy? 3) How do neurons](https://reader033.fdocuments.in/reader033/viewer/2022041905/5e63306685b0fc1a9d5e36f9/html5/thumbnails/27.jpg)
Brain slice from normal rat
Brain slice from an epileptic rat
Smaller
and
shorter
seizures
Larger
and
longer
seizures
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NORMAL RAT EPILEPTIC RAT
Slice 1
Slice 2
Slice 3 Slice 4
Slice 5 Slice 6 Slice 7
Slice 1
Slice 2 Slice 3 Slice 4
Slice 5 Slice 7 Slice 8
Slice 9 Slice 10 Slice 11
Slice 6
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Syn
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dis
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%)
Discharge sequence
SUMMARY AND CONCLUSIONS
1. Single cell seizures
Synchronization of neurons
2. MAPkinase activated
In chronic foci
3. MAPkinase inhibitor
Cures seizures
4. Acute seizures: coupling of microfoci 5. Chronic epilepsy
in test tube
Phase I
Independent microfoci
Phase II
Synchronous
microfoci
Flip-flop
Normal brain Epileptic brain
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1 2 3 Week
Dis
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ou
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Epileptic rat untreated
Epileptic rat treated
Larger and longer
seizures