Transcript - Neuroscience Journal Club

Fundamental CNS Arousal;
Moods, Molecules, Maths.
Donald Pfaff
The Rockefeller University
Laboratory of Neurobiology and Behavior
[email protected]
I. Looking backward: It is possible to explain
mechanisms for a mammalian behavior.
II. Looking forward:
Sex Behavior
Sexual Arousal
Arousal.
III. Primitive, elementary arousal mechanisms:
BBURP Theory
IV. Can we do the maths of arousal mechanisms?
(Information Theory)
MECHANISMS ESTABLISHED FOR A SIMPLE
HORMONE – DEPENDENT SOCIAL
BEHAVIOR
• Pinpoint cellular targets for estrogens (cells express ERa, ERb). P
• Determine neural circuit for lordosis behavior.
P
• Establish which neurons accomplish E/ERs g Lordosis facilitation. P
• Show requirements for new mRNA, protein synthesis.
P
• Discover certain E gr gene transcription inductions.
P
• Test certain gene/lordosis behavior relations.
MODULAR SYSTEMS DOWNSTREAM FROM
HORMONE-FACILITATED TRANSCRIPTION
RESPONSIBLE FOR A MAMMALIAN SOCIAL
BEHAVIOR: “GAPPS” .
• Growth (rRNA, cell body, synapses).
• Amplify (pgst/PR  downstream genes).
• Prepare (indirect behavioral means;
analgesia (ENK gene) and anxiolysis (OT
gene).
• Permit (NE alpha-1b; muscarinic receptors).
• Synchronize (GnRH gene, GnRH Rcptr gene
synchronizes with ovulation).
Construction of Cassette for an
AAV Vector
Western blot: ER is Knocked Down
in Hypothalamus
In Hypothalamus, VMN Neurons
Do Not Have ER, and PR is Not
Induced Following AAV Injection
Musatov, S., et al.
2005
A 4-gene micronet controls social
recognition and thus affiliation & aggression.
Individual-specific
olfactory cues
Non volatile
volatile
Hypothalamus
PVN and SON
Vomeronasal
Organ
Main
Olfactory
Bulb/System
OT
ER b
OT
Accessory
Olfactory
Bulb/System
E
OT
Blood Stream
OTR
Amygdala
ER a
E
E
Social Recognition
Ovaries:
Estrogen (E)
production
Question answered:
“Is it possible to explain mechanisms for any mammalian
behavior?”
YES.
(II.)
New Question:
“Can we approach mechanisms for the fundamental force
in the CNS, which underlies all mammalian behaviors?”
YES
Literature Review:
COGNITIVE FUNCTION
DECISION MAKING
SUSTAINED ATTENTION
ATTENTION
EMOTIONAL FUNCTION
FEELINGS
(minutes)
MOODS
(hours)
TEMPERAMENT
ALERTNESS
(lifetime)
AROUSAL
AROUSAL
Fundamental Arousal of Brain and Behavior:
Applications
• Stupor, vegetative,
coma
• Aging
• Alzheimer’s
• ADHD
• Autism
• Anesthesia
• Sleep Disorders
• Mood Disorders
(Depression,
Bipolar Disorders)
• Vigilance/Military
• Vigilance/Shift Work
• Vigilance/Dangerous
Occupations
• Toxicology (e.g., Lead in
water)
• Fatigue states (CFIDS,
FMS, Gulf War)
Operational Definition of Arousal
A more aroused animal or human is:
i.
More alert to sensory stimuli in all
modalities.
ii. Emitting more voluntary motor activity.
iii. More reactive emotionally.
Re Inputs:
Re Operations:
Re Outputs:
A = Arousal, as a function of generalized arousal (Ag) and specific forms
of arousal (As). A is thought to be an increasing function of the variables
Ag and As (1 to n) , sometimes additive, sometimes multiplicative or
exponential and therefore potentially complex. While the constants (Kg
and Ks 1 - n) reflect traits of the individual, arousal components (Ag, As)
are determined by the immediate environment.
(III.) How does
generalized
arousal of the
CNS work?
(Neuroanat., Neurophys.,
Functional Genomics)
Descending Arousal-controlling Systems
Bilateral
Bidirectional
Universal
Response
Potentiation
High throughput assay of all three
components of CNS arousal
Starting a Proof of Principle: CNS
Arousal is Experimentally Tractable
• 3 Genes
• 3 Methods in Mouse CNS
Functional Genomics
– ER, Nuclear receptor
– Null Mutation
– PGDS, Enzyme
– Anti-sense Oligos
– Histamine Receptor,
Type 1
– Mol. Pharmacology
a)
Running Wheel, a ERKO
(Older Mice)
% of WT
# of Revolutions
100000
75000
aWT
aERKO
100%
a WT
50000
a ERKO
25000
0
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14
Day #
b)
Running Wheel, a ERKO
(Younger Mice)
% of WT
# of Revolutions
100000
75000
aWT
aERKO
100%
aWT
50000
aERKO
25000
0
0
1
2
3
4
5
6
7
8
Day #
9 10 11 12 13 14
Gene Expression (N=11,669) of MBH following 24 hours
Estradiol vs Vehicle Treatment in OVX Female Mice
1000000
Chip: Affymetrix Mu11 A,B
100000
24 hr Vehicle
10000
1000
Present
Absent
100
10
1
1
10
100
1000
24 hr Estradiol
10000
100000
1000000
Microarray Confirmation
Northern Blot
CTX MBH OB POA
V E2
PGD2S
Blotted total RNA was
probed with a P32labeled DNA probe
for PGDS.
The same blot was re- 18s
probed with a DNA
probe for 18s ribosomal
RNA as a measure of
RNA quantity per lane
V E2
V E2 V E2
Poly-[D,L-lactide-co-glycolide] Microspheres (PLGA)
With Steven Little and Robert Langer at MIT
inside view
Average size Ø = 5 m
RESOMER® RG 502 H
Poly-[D,L-lactide-co-glycolide] Microspheres (PLGA)
110
Encapsulation Release
100
90
% Release
80
70
60
Antisense
Scrambled
50
40
30
20
10
0
0
1
2
3
4
5
6
7
8
9
Time (Days)
10
11
12
13
14
15
MIN
n=6
n=5
n=6
n=5
n=5
n=7
EFFECT OF AN H1 RECEPTOR ANTAGONIST
ON SENSORY RESPONSIVENESS
OLFACTORY
TACTILE
160
200
120
150
80
100
40
50
0
0
HACT
MALES
b1
b2
1
2
3
4
5
6
7
8
b1
b2
1
2
3
4
5
6
7
8
TACTILE
OLFACTORY
160
200
120
150
80
100
40
50
0
0
FEMALES
b1
b2
1
2
3
4
5
6
7
8
b1
time (minutes)
b2
1
2
3
4
5
6
7
8
How do generalized
arousal mechanisms
influence particular
arousal states, thus to
facilitate specific
behaviors?
Histamine Receptor Signal Transduction Pathways
AA
cAMP
HVACC
PLA2
Ca2+
NMDA
K+
H1
DAG
IP3
ATP
Gi/Go
H3
gK+leak
PKC
AC
Gq/11
Gq
PLC
PLC
PLA2
Ca2+
Gs
AC
AA
HVACC
IP3
ATP
+
Gs
NO
ATP
cGMP
AC
Ca2+
Kca
cAMP
K+
PKA
CREB
cAMP
Ca2+
Generalized Arousal Transmitters on VMN Neurons
Sodium channel blocker, TTX, had no effect on
histamine-induced depolarization
Pataky et al.
Pre-TTX
-40
During TTX
Post-TTX
-40
-60
-80
-100
200000
400000
600000
800000
-60
IN 2
(m V )
IN 2
(m V )
IN 2
(m V )
-40
-60
-80
-80
-100
-100
400000
800000
200000
400000
600000
Histamine depolarization was abolished by potassium
channel blocker TEA
Pataky et al.
-20
-40
-40
TEA
off
IN 2
(m V )
IN 2
(m V )
-20
-60
-60
HA on
HA on
-80
-80
200000
400000
Time (ms)
600000
1400000
1600000
Time (ms)
Jin Zhou et al: Potassium current blocker (TEA, 4-AP), but not sodium (TTX)
and/or calcium (Cd2+) current blocker abolished histamine-induced
depolarization in VMH neurons.
Calcium chelator (BAPTA) and Calcium-free ACSF
did not block histamine-induced depolarization.
Estrogen treatment increased both HA-induced depolarization and inward current in VMH
neurons. Significantly higher percentage of neurons showed action potential firing during
depolarization in E2-treated group compared with oil-treated group (Zhou et al).
(IV.) Idea: Information theory maths
shed light on CNS arousal
mechanisms
•Arousal-related neurons respond best to high-information
(salient, surprising, unpredictable) stimuli (Harvard Univ.
Press, 2005)
•Claude Shannon devised an intuitively pleasing,
mathematically precise definition of information as follows:
1
H ( x)   p( x) log 2
p ( x)
Where H is the total amount of “Shannon” information and p(x) is the probability of
event x.
Arousal / Information theory
thinking naturally yields a universal
phenomenon: HABITUATION.
Nicholas Schiff, MD
Department of Neurology
Weill Medical College of Cornell University
Papers on impaired consciousness
Laureys, S.L., Owen, A.M., and Schiff, N.D. (2004) Brain function in coma, vegetative state and related disorders. Lancet Neurology
3(9):537-46.
Schiff, N., Ribary, U., Moreno, D., Beattie, B., Kronberg, E., Blasberg, R., Giacino, J., McCagg, C., Fins, J.J., Llinas, R. and Plum, F.
(2002) Residual cerebral activity and behavioral fragments in the persistent vegetative state. Brain 125(6): 1210-1234.
Schiff, N.D., and Purpura, K.P. (2002) Towards a neurophysiological basis for cognitive neuromodulation. Thalamus and Related
Systems 2(1): 55-69.
Schiff, N.D., Ribary, U., Plum, F., and Llinas, R. (1999) Words without mind. Journal of Cognitive Neuroscience 1(6) 650-656.
Conceptualizing global disorders of consciousness
Total functional loss
Cognitive function
Normal
Functional
Communication
Severe
to
Moderate
Cognitive
Disability
Full
Cognitive
Recovery
Motor
function
MCS
PVS
Coma
LIS*
Total functional
loss
( Schiff, ND, The Neurology of Impaired Consciousness, Cognitive Neurosciences III, MIT Press)
Minimally conscious state
EEG patterns may be
similar to normal wakefulness
Vegetative state EEG
patterns are typically
similar to coma
Penfield, WG, Jasper, HH, (1954) Epilepsy and
the functional anatomy of the human brain
Minimally Conscious State Patient
Normal Subject
Forward Speech
Reversed Speech
hronic minimally conscious state in response to
passive language stimuli
Overlap
FORWARD
BACKWARD
OVERLAP
Schiff, N, Rodriguez-Moreno, D, Kamal, A, Petrovich, N, Giacino, J, Plum, F and Hirsch, J.
fMRI reveals large-scale network activation in minimally conscious patients. Neurology (in press)
Overall Summary
1) We understand neural, hormonal and
genetic mechanisms for a specific
hormone-driven behavior: VMN
Hypothalamic neurons expressing ERs
influence several genomic modules to
control a spinal-midbrain-spinal behavior
circuit.
2) Underlying all mammalian behaviors is
CNS arousal: Newly precise operational
definition features sensory alertness,
motor activity and emotional reactivity.
We have a high throughput assay.
Overall Summary, Continued
3) We understand how generalized arousal
forces impact specific arousal states:
e.g. HA, NE and ACh, themselves
hormone dependent, increase electrical
activity in behavior-controlling VMN
hypothalamic neurons.
4) Information theoretic treatments of
arousal mechanisms lead to new
questions: Shannon-Weaver equations
offer potential insight to arousal-related
neurons?