Neuroscience 2003 Functional Brain Imaging · 1. Functional Magnetic Resonance Imaging, fMRI 2. Somatasensory Evoked Potential, SSEP 3. Direct Cortical Stimulation 4. Positron Emission

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Joy Hirsch, Ph.D., ProfessorDirector, fMRI Research Center

Columbia University Health Sciences NI Basement

www.fmri.org

Neuroscience 2003Functional Brain Imaging

Hirsch, J., et alColumbia fMRI

A. Hypothesis of functional specificity


B. Brain Mapping Techniques1. Functional Magnetic Resonance Imaging, fMRI2. Somatasensory Evoked Potential, SSEP3. Direct Cortical Stimulation4. Positron Emission Tomography, PET5. Magnetoencephalography, MEG6. Electroencephalography, EEG

C. Integration of Brain Mapping Techniques

A Brief Outline



1. Specializations of single brain areas

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PrimaryVisual Cortex

FlashingLED Display

7 7

66

5

4 4

5

Calcarine Sulcus

PreviousSurgicallesion

BINOCULARFLASHING

LIGHTS

Left Eye Right Eye

Visual Field

Harrington, 1964

lesion

R


HISTORICAL MILESTONES

1841

Aphasia and lesions in GFi

BROCA

1874

WERNICKE

Aphasia and lesions in GTs

1890

ROY & SHERRINGTONRelationship between neural activity and vascular changes

1909

BRODMANN

Cytoarchitectonic regions of cortex

1950

PENFIELDIntraoperative cortical maps

1845

FARADAYMagnetic properties of blood

1936

PAULINGMagnetic state of hemoglobin changes with oxygenationRABIDiscovery of Magnetic Resonance

1945

PURCELL BLOCK

Demonstrated NMR in condensed

matter

1971

HOUNSFIELD CORMACKInvention of Computed Tomography


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Damasio, H., et al; Science 264: 1102-1105, 20 May 1994


HISTORICAL MILESTONES

1977

TER-POGOSSIAN SOKOLOFF

First PET studies of brain metabolism, blood flow, and correlates of human behavior

MANSFIELD

1976

First MRI of a body part

Invented EPI (scans whole brain in secs.)

1972

LAUTERBUR

First MR image

OGAWA

Blood Oxygen dependent signal

EPI / MRI Behavior

BELLIVEAUCortical Map:human visual

system

1990

1992

fMRI1971

DAMADIAN

Discovered that biological tissues have different relaxation rates




1. Specializations of single brain areas2. Specializations of multiple brain areas

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Functional Organization of Visual Cortex


B. Brain Mapping Techniques


1. Functional Magnetic Resonance Imaging, fMRI

Sadek K. Hilal, M.D., Ph.D.Department of RadiologyColumbia University

Early Developments in MR Solved the Occluded-Structure Problem


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R L


2 minutes 24 seconds 2 minutes 24 seconds

- 40 s - - 40 s - - 40 s - - 40 s - - 40 s - - 40 s -

TIME

MR

I Sig

nal I

nten

sity

REST REST REST RESTTASK TASK

R L

From Hirsch, J., et al; An Integrated Functional Magnetic Resonance Imaging Procedure for Preoperative Mapping of Cortical Areas Associated with Tactile, Motor, Language, and Visual Functions, Neurosurgery 47: 711-722, 2000.

Current Developments in MR are focused on the structure/function problem

Left Hand - Touch




1. Functional Magnetic Resonance Imaging, fMRI

a. Source of signal

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PHYSIOLOGY PHYSICSNEURAL ACTIVATIONIS ASSOCIATED WITH ANINCREASE IN BLOOD FLOW

O2 EXTRACTION ISRELATIVELY UNCHANGED

RESULT:REDUCTION IN THEPROPORTION OF DEOXY HGBIN THE LOCAL VASCULATURE

DEOXY HGBIS PARAMAGNETIC

AND DISTORTS THE LOCALMAGNETIC FIELD CAUSINGSIGNAL LOSS

RESULT:LESS DISTORTION OF THEMAGNETIC FIELD RESULTS IN LOCAL SIGNAL INCREASE




1. Functional Magnetic Resonance Imaging, fMRIa. Source of signalb. Measuremnet techniques

Imaging While Naming Objects


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Block Design


Event-Related Design



1. Functional Magnetic Resonance Imaging, fMRIa. Source of signalb. Measuremnet techniquesc. Computation for analysis

COMPUTATIONS FOR fUNCTIONAL IMAGE PROCESSING

RECONSTRUCTIONALIGNMENT

VOXEL BY VOXEL ANALYSIS

GRAPHICALREPRESENTATION

ScannerFunctionalBrain Map

PrimaryAuditory Cortex

Language


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Penfield’sMotor

Homonculus

Left Hand: Finger Thumb Tapping

MULTI-STAGE ANALYSISWITH COINCIDENCE

Run 1(90 secs)

Run 2(90 secs)

Stage 1

Stage 2

1 and 2

COINCIDENCERun 1 AND Run 2


R

Kim, Relkin, Lee, & Hirsch

+ +

+ +

0

“LATE” BILINGUAL(Separate Language Areas)

Native (English)Second (French)

+ Center-of-Mass

from Nature 388, 171-174 (1997)

Broca’s Area

R

++

++

0

Native 1 (Turkish)Native 2 (English)

Common Region+ Center-of-Mass

“EARLY” BILINGUAL(Overlapping Language Areas)




1. Functional Magnetic Resonance Imaging, fMRIa. Source of signalb. Measuremnet techniquesc. Computation for analysisd. Individual brain maps

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Before Surgery

R

Tumor

ConventionalImaging

Functional Imaging

CC 23 (AB)

Left Hand: Sensory/Motor

Tumor


R

Tumor

ConventionalImaging

CC 23 (AB)


Left HandMovement

Before Surgery After Surgery

R

Tumor

ConventionalImaging

Functional Imaging

CC 23 (AB)

Left Hand: Sensory/Motor

Tumor


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SENSORYTouch

MOTORFinger Thumb

Tapping(active)

Standard Brain Mapping Tasks

PictureNaming

Listeningto Words

(passive)

GPoC GPrC GOi GTs

LANGUAGE

GFiGTT

(active)(passive)

From Hirsch, J., et al; Neurosurgery 47: 711-722, 2000


Functional Organization of Visual Cortex


QuickTime™ and a Video decompressor are needed to see this picture.



1. Functional Magnetic Resonance Imaging, fMRI2. Somatasensory Evoked Potential, SSEP3. Direct Cortical Stimulation

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SSEP - SomatoSensory Evoked PotentialsCortical Stimulation

Conventional functional mapping in the OR

Based on Electrical Activity of Neurons Induced by External Stimulation


Tag 3

Tag 5

Localization fMRISSEP

“Twitching in 1st three digits”

“Twitching of hand,

focal seizure involving arm ”

Direct Cortical StimulationCraniotomy

Sensory Motor Mapping


Tag 3

Tag 5



Homonculus

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Language Mapping


fMRIIntraoperative

Stimulation Response

Speech ArrestDuring Counting

Broca’s Area

Literal paraphasic

speech error during picture

naming

Wernicke’s Area




1. Functional Magnetic Resonance Imaging, fMRI2. Somatasensory Evoked Potential, SSEP3. Direct Cortical Stimulation4. Positron Emission Tomography, PET

a. Source of signal

Positron Emission TomographyRadionuclides that emit positrons such as 15O and 18F are introduced into the brain.

H215O behaves like H2

16O and indicates blood flow (rCBF) (half life = 123 seconds) integration time ≈ 60 seconds.

18F – deoxyglucose behaves like deoxyglucose and indicates metabolic activity (half-life = 110 minutes) integration time ≈ 20 minutes

From: www.epub.org.br/cm/n011pet/pet.htm

PET SCANNER


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Principle of PET

From: Principles of Neural Science (4th. Ed.) Kandel, Schwartz, & Jessell, p. 377.

A2 Positron and electron annihilationand emission of gamma raysPET is based on the radioactive

decay of positrons from the nucleus of the unstable atoms (15O has 8 protons and 7 neutrons)

resolutionlimit

Electron

PositronUnstableradionuclide

0-9mm

Gamma ray

Site of positron annihilation (imaged point)

Gamma rayphoton

A1 Positron emissionin the brain





a. Source of signalb. Measurement techniques

Gamma Ray Detections to Location of Function

From: Principles of Neural Science (4th. Ed.) Kandel,Schwartz, & Jessell, p. 377.


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Injection of radioactive-labeled water for PET scanning





a. Source of signalb. Measurement techniquesc. Computation for analysis

From: Images of Mind by Posner, M. and Raichle, M. Scientific American Library, 1994, p. 24

Fixation

Flashing Checkerboard

Stimulation Fixation Difference

Individual difference images

Mean difference image

Analysis of PET Results


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1. Functional Magnetic Resonance Imaging, fMRI2. Somatasensory Evoked Potential, SSEP3. Direct Cortical Stimulation4. Positron Emission Tomography, PET5. Magnetoencephalography, MEG6. Electroencephalography, EEG

MEG: MagnetoEncephaloGraphyEEG: ElectroEncephaloGraphy

Measurement of Electromagnetic Activity

Provides Information of temporal interactions




1. Functional Magnetic Resonance Imaging, fMRI2. Somatasensory Evoked Potential, SSEP3. Direct Cortical Stimulation4. Positron Emission Tomography, PET5. Magnetoencephalography, MEG

a. Source of signal

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Relationship between currents in the brain and the magnetic field outside the head.

Based on the discoverythat electrical currents generate magnetic fields: Hans Christian Oersted, a Danish physicist (early 19th. century)

A current source with strength Q causes a current flow Jv within the brain.

The current flow produces a potential difference V on the scalp: (measured by EEG)

And a magnetic field B outside of the head: (measured by MEG)

from: www.Aston.ac.uk/psychology/meg/meg/intro/magfield.htm

B

JvQ

V






Magnetoencephalography, MEG

Tiny magnetic fields produced by brain activity (10-13 Teslas) can be measured using Superconducting Quantum Interference Devices (SQUIDs).

SQUIDS operate at superconducting temperatures (-269oC). Sensors are placed in a dewar containing liquid helium.

Stimulus – evoked neuromagnetic signals

are recorded by an array of detectors.

The spatial location of the source is inferred by mathematical modeling of the magnetic field pattern.


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Somatosensory evoked magnetic signals in response to tactile stimulation of the

contralateral index finger

Isofield contour maps at the time of maximal

response (50 msec) to the tactile stimulation

Neuro magnetic response occurs about 50 msec after

the stimulation.

The field pattern is dipolar with clearly defined regions of entering (solid lines) and

emerging (dashed lines) magnetic flux.






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Electroencephalography






Averaged Activity profiles during bilateral finger movement

Electrode Array for EEG

Electroencephalography


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1. Task of specificity and conjunctions


CONJUNCTION OF BOLD RESPONSES DURING OBJECT NAMING TASKS

VISUAL AUDITORY TACTILE

COMMONAREAS

R. Inferior Frontal GBA (45)

L. Cingulate GBA (24)

L. Inferior Frontal GBA (44)

L. Medial Frontal GBA (6)

L. Middle Frontal G BA (6)

L. Inferior Frontal GBA (45)

R

Hirsch, R-Moreno, Kim, Interconnected large-scale systems for three fundamental cognitive tasks revealed by functional MRI. Journal of Cognitive Neuroscience, 13(3), 389-405, 2001.



1. Task of specificity and conjunctions2. Labels of functional areas


a. Atlas-Based

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1. Task of specificity and conjunctions2. Labels of functional areas


a. Atlas-Basedb. Registration methods

Labeling of Active Brain AreasFunctional Brain Atlas Brain

transferactivity labels

GPrC 4GFs 6GFd 6GFs 6GRC 4LPs 7

c,Eb,Ea,E,60,-ab,E,60c,E,60b,G,60

Name BA Sector


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1. Task of specificity and conjunctions2. Labels of functional areas3. Connectivity computations


Hirsch, R-Moreno, Kim, Interconnected large-scale systems for three fundamental cognitive tasks revealed by functional MRI. Journal of Cognitive Neuroscience, 13(3), 389-405, 2001.

Map of Human Language System

Medial Frontal Gyrus Superior Temporal GyrusInferior Frontal GyrusInferior Frontal Gyrus

6224445

9574940

-6-261025

539

258

Anatomical Region BA zyx

Center of mass



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1. Task of specificity and conjunctions2. Labels of functional areas3. Connectivity computation4. Models of long-range connectivity


Lateral Pain System

Medial Pain System

M1

MedialThalamus

LateralThalamus

Hypothalamus

AMYGPB

PAG

Brain Areas Modified by Treatment of Pain

‘After-Sensation’ Related Areas Based on Vogt and Sikes, 2000

M

CG

PF


Cognitive Events are caused by Neural EventsThe Astonishing Hypothesis


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MissionTo establish a collaborative and multi-investigator

neuroimaging research environment focused on education, medical applications, and the study of

brain, behavior, and therapy-induced cortical effects aimed at the systems of the brain that underlie

cognition, perception, and action.

Columbia fMRI

Functional MRI Research CenterDepartment of Radiology

Center for Neurobiology and BehaviorColumbia University

College of Physicians and Surgeons


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Neuroscience 2003 Functional Brain Imaging · 1. Functional Magnetic Resonance Imaging, fMRI 2. Somatasensory Evoked Potential, SSEP 3. Direct Cortical Stimulation 4. Positron Emission