Fundamental CNS Arousal; Moods, Molecules, Maths.

Donald Pfaff

The Rockefeller University

Laboratory of Neurobiology and Behavior

pfaff@rockefeller.edu

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 ER, ER). • Determine neural circuit for lordosis behavior. • Establish which neurons accomplish E/ERs Lordosis facilitation. • Show requirements for new mRNA, protein synthesis. • Discover certain E gene transcription inductions. • 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.

Ovaries:Estrogen (E)productionSocial Recognition

OTER

OT

Individual-specificolfactory cues

Non volatile

volatile

Amygdala ER

MainOlfactory

Bulb/System

HypothalamusPVN and SON

VomeronasalOrgan

OTR

E

E

OTE

Blood Stream

AccessoryOlfactory

Bulb/System

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:

(minutes)

(hours)

(lifetime)

FEELINGS

EMOTIONAL FUNCTION

MOODS

TEMPERAMENT

AROUSAL

COGNITIVE FUNCTION

SUSTAINED ATTENTION

ATTENTION

ALERTNESS

AROUSAL

DECISION MAKING

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.

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.

Re Inputs:

Re Operations:

Re Outputs:

(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

– ER, Nuclear receptor

– PGDS, Enzyme

– Histamine Receptor, Type 1

• 3 Methods in Mouse CNS Functional Genomics– Null Mutation

– Anti-sense Oligos

– Mol. Pharmacology

a) Running Wheel, ERKO(Older Mice)

0 1 2 3 4 5 6 7 8 9 10 11 12 13 140

25000

50000

75000

100000WTERKO

Day #

# o

f R

evo

luti

on

sWT ERKO

100%

% o

f W

T

b) Running Wheel, ERKO(Younger Mice)

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evo

luti

on

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WT ERKO

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% o

f W

T

1

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10000

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1000000

1 10 100 1000 10000 100000 1000000

24 hr Estradiol

24 h

r V

ehic

le

Gene Expression (N=11,669) of MBH following 24 hours Estradiol vs Vehicle Treatment in OVX Female Mice

PresentAbsent

Chip: Affymetrix Mu11 A,B

Microarray Confirmation

Northern Blot

V E2 V E2 V E2 V E2

OBMBHCTX POA

Blotted total RNA was probed with a P32-labeled DNA probefor PGDS.

The same blot was re-probed with a DNA probe for 18s ribosomal RNA as a measure of RNA quantity per lane

PGD2S

18s

Poly-[D,L-lactide-co-glycolide] Microspheres (PLGA)

RESOMER® RG 502 H

With Steven Little and Robert Langer at MIT

Average size Ø = 5 m

inside view

Encapsulation Release

0

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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Time (Days)

% R

elea

sePoly-[D,L-lactide-co-glycolide] Microspheres (PLGA)

Antisense

Scrambled

Duration of Activity Vestibular Stimulus

0

10

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30

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60

SAL SALSCRM SCRM AS AS

OIL E2

** *

*

n=6 n=5 n=6 n=5 n=5 n=7

MIN

MALES

FEMALES

time (minutes)

HA

CT

EFFECT OF AN H1 RECEPTOR ANTAGONIST ON SENSORY RESPONSIVENESS

TACTILE

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200

b1 b2 1 2 3 4 5 6 7 8

OLFACTORY

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b1 b2 1 2 3 4 5 6 7 8

OLFACTORY

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TACTILE

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b1 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

Gi/Go

H3

HVACC

Ca2+AC ATP

cAMP

PLA2

AA

H2

GsAC

ATP

cAMP

PKA

CREB

H2

Gq

PLC

IP3

Ca2+

HVACC

Kca

K+

Ca2+

Ca2+

Gq/11

AA

IP3

PKCgK+

leak

PLA2

PLC

cGMP

DAG

NMDA

H1

Gs

ACATP

cAMP

+

K+

H2/A2

NO

Generalized Arousal Transmitters on VMN Neurons

800000600000400000200000

T im e (m s)

IN 2 (mV)

-100

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-40

800000400000Time (m s)

IN 2 (mV)

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IN 2 (mV)

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-40

Sodium channel blocker, TTX, had no effect on histamine-induced depolarization

Pre-TTX During TTX Post-TTX

Pataky et al.

Histamine depolarization was abolished by potassium channel blocker TEA

HA on

600000400000200000Tim e (m s)

IN 2 (mV)

-80

-60

-40

-20

TEA off

HA on

16000001400000Tim e (m s)

IN 2

(mV)

-80

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-40

-20

Pataky et al.

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

)(1log)()( 2 xpxpxH

Where H is the total amount of “Shannon” information and p(x) is the probability of event x.

•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:

Arousal / Information theorythinking naturally yields a universal

phenomenon: HABITUATION.

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., Ribary, U., Plum, F., and Llinas, R. (1999) Words without mind. Journal of Cognitive Neuroscience 1(6) 650-656.

Schiff, N.D., and Purpura, K.P. (2002) Towards a neurophysiological basis for cognitive neuromodulation. Thalamus and Related Systems 2(1): 55-69.

Papers on impaired consciousness

Nicholas Schiff, MD

Department of Neurology

Weill Medical College of Cornell University

MCS

Cognitive function

Motorfunction

Normal

Total functional loss

PVS

Coma

Full CognitiveRecovery

Severe to

Moderate Cognitive Disability

LIS*

Conceptualizing global disorders of consciousness

Total functional loss

Functional Communication

( Schiff, ND, The Neurology of Impaired Consciousness, Cognitive Neurosciences III, MIT Press)

Penfield, WG, Jasper, HH, (1954) Epilepsy and the functional anatomy of the human brain

Vegetative state EEG patterns are typicallysimilar to coma

Minimally conscious stateEEG patterns may be similar to normal wakefulness

Minimally Conscious State Patient Normal Subject

Forward Speech

Reversed Speech

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?