Prenatal Alcohol Exposure: Neuropathology and cognition

Integrating Behavioral & NeuralApproaches in Rats and Humans

Rob SutherlandCanadian Centre for Behavioural NeuroscienceThe University of Lethbridge

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Project DirectorsRobert Sutherland

Dan SavageDerek Hamilton

Subject RecruitmentCarol ClericuzioLuther Robinson

Julia PowersJorge Ganem

Hannah OlivetsMRI, MRS & fMRI

Roland Lee Allison LindsayWilliam Brooks

Helen Petropoulos

Neuropsychological Assessment

P.W. KodituwakkuBarbara WilsonPaula Wilbourne

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MEGClaudia Tesche

Kim PaulsonSandra Moses

Rat ModelRob McDonald

Linda Beyer-Smith

Rafael Galindo

Janice Hoesing

Michael Thomas

Ying Wu

Patti Sorensen

Moderate Ethanol Exposure Paradigm

• 5% EtOH diet throughout gestation.

• Pair-Fed 0% EtOH and Ad Lib controls

• 16 Hour feeding / 8 hour water schedule.

• No significant effects of the ethanol diet on:- Litter size or Neonatal mortality.- Offspring birthweight or growth curves.- Brain weight or gross anatomy after

sacrifice.

Morris water task

4030201000

20

40

60

80

100Ad lib

Pair-fed

5% ethanol

Fixed, hidden platform task

Trial

Tim

e t

o fi

nd

pla

tform

(s)

Simple, constant learning tasks are unaffected

Ad lib Pair-fed 5% alcohol0

10

20 Trial 1Trial 2

Group

Late

ncy t

o fi

nd

pla

tform

(s)

One-trial learning tasks that tax hippocampus are affected

Synaptic plasticity in hippocampus

Time ( minutes )0 20 40 60 80 100

fEP

SP

( F

ract

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l Cha

nge

)

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0.8Ad LibPair-Fed5% EtOH

Synaptic plasticity is impaired

Liquid Diet Ethanol Concentration

Mat

erna

l Blo

od E

than

ol

Con

cent

rati

on (

mg/

dL)

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2% 3% 5%

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enti

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n of

D-A

SP

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ease

(S

2 / S

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1.2

1.4

B.Fraction Intervals (minutes)

0 6 12 18 24 84 90 96 102 108

Fra

ctio

nal R

elea

seof

D-A

SP

(%

)

1.5

2.0

2.5

S1 S2TET

A.

AdLib

2%EtOH

PF-2 PF-3 3%EtOH

PF-5 5%EtOH

Pair-fed to 3% EtOH3% EtOH Diet

Threshold for adult synaptic effect

is .03 BAL

TRIAL 1

TRIAL 2

A.PAIR-FED CONTROL 3% EtOH DIET

Impr

ovem

ent i

nE

scap

e L

aten

cy (

Sec

)

0

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B.

AdLib

2%EtOH

PF-2 PF-3 3%EtOH

PF-5 5%EtOH

3% maternal alcohol affects adult learning

Green = neuronRed = new cellGold = new neuron

Adult hippocampus has thousands of new cells each day.

Alcohol exposed rats have many fewer new neurons in adult hippocampus

Correct Response Incorrect ResponseVisual Water Task

Monitors

Platform

Divider

Pool

Choice Plane

Visual acuity

0

0.1

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0.56

4

0.59

37

0.62

33

Spatial frequency

Corr

ect

Ad lib

Pair-fed

5%EtOH

Visual accuity not affected.

Fetal Alcohol - Induced Deficits

Hippocampus-sensitive memory tasks

Hippocampal synaptic plasticity

Neurochemical mechanisms associated with synaptic plasticity

Threshold is around .03 BAL for adult synaptic and learning deficits

Adult neurogenesis is decreased

Neuroimaging in FAS

What about people?

A virtual Morris water task

Phase I: Place learning(Twenty trials)

Phase II: Probe trial

Phase III: Cued-navigation(Eight trials)

A virtual Morris water task

VMWT Results

Virtual navigation is impaired. Examples of swim paths to hidden platform

VMWT Results

Searching in correct region on probe is impaired. Dwell time in regions of the pool

VMWT Results

Virtual navigation to a cue is unaffected. Examples of swim paths to visible platform

VMWT and Neuroimaging

Day 1 Neuropsychological test batteryTrain subjects on the VMWTMEG/EEG recording while performing

VMWT

Day 2 sMRI Proton MRS (right HPC & right DLPFC) fMRI recording while performing VMWT.

Virtual navigation with beacons. On different trial blocks participants must learn which cue is correct

or which location is correct

Magnetoencephalography

Magnetoencephalography

Front

Magnetoencephalography

Magnetoencephalography

MEG Results

Right hippocampal activation during place learning was observed in 2/7 children with FAS

Right hippocampal activation during place learning was observed in 6/7 controls

MEG Results and Behavior

0

10

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30

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80

+ -

Right Hippocampal ECD

Init

ial

Hea

din

g E

rro

r (d

eg)

Structural MRI

An automated procedure separates white and grey matter from sMRIs and calculates volume of

hippocampal grey matter.

Structural MRI

Total hippocampal volume is unaffected.

Magnetic Resonance Spectroscopy

MRS permits quantification of several neurochemicals from regions of prefrontal cortex

and hippocampus.

Magnetic Resonance Spectroscopy1H-Magnetic Resonance SpectroscopyN

AA

/ C

reati

ne

0.0

0.5

1.0

1.5

2.0

2.5

3.0

CONTROLFAS

HippocampalFormation

DL PrefrontalCortex

No significant differences in neurochemistry**

Human SummaryPlace learning in the VMWT

Participants with FAS were impaired at hippocampal- dependent place learning in the VMWT

Morphometrics/Volumetrics (sMRI)No evidence for alcohol-related differences in hippocampal volume/structure

Neurometabolites (1H-MRS)No evidence for alcohol-related differences in hippocampal neurometabolite profiles

Functional Neuroimaging (MEG)Participants with FAS were less-likely to display task-related activity in right hippocampus.Task-related activity in HPC was highly correlated with behavior in the VMWT

Conclusions

• Alcohol-related differences in brain function can be detected using technology that is currently available

• Alcohol-related differences in brain function may not correspond with neuroanatomical differences detected using structural MRI or MRS

• Functional techniques may be particularly useful and sensitive for identifying the neural bases of cognitive dysfunction in FASD

• Functional neuroimaging may help provide unique diagnostic information and may be helpful in assessing treatment

• It will be important to relate functional brain activation with behaviorally-relevant paradigms – Linking basic human and animal research on FASD with clinical research