# Presentation: 877644

## Peter A. Bandettini, Ph.D.

Section on Functional Imaging Methods
http://fim.nimh.nih.gov 
Laboratory of Brain and Cognition
&
Functional MRI Facility
http://fmrif.nimh.nih.gov

- Section on Functional Imaging Methods
- http://fim.nimh.nih.gov
- Laboratory of Brain and Cognition
- &
- Functional MRI Facility
- http://fmrif.nimh.nih.gov

**Functional MRI **

**Notes:**
50 minutes

## How does fMRI Work?

- Temporal, spatial, interpretive, practical limitations.
- Costs/Benefits in Security Evaluation?
- Necessary improvements - what needs to be known?

## fMRI Setup

## MRI vs. fMRI

- MRI

- fMRI

**one image**

**many images**
- (e.g., every 2 sec for 5 mins)

- high resolution
- (1 mm or less)

- low resolution
- (1.5 to 4 mm)

- ...

- Time

## blood flow

**blood flow**
**oxygenated-blood**
**MR signal**

## Basis of BOLD Contrast

- red blood cells

- L. Pauling, C. D. Coryell, *Proc.Natl. Acad. Sci. USA 22, 210-216*, **1936**.
- K.R. Thulborn, J. C. Waterton, et al.,  *Biochim. Biophys. Acta. 714: 265-270*, **1982**.
- S. Ogawa, T. M. Lee, A. R. Kay, D. W. Tank, *Proc. Natl. Acad. Sci. USA 87, 9868-9872*, **1990**.

- oxygenated

- deoxygenated

*Oxygenated and deoxygenated red blood cells have different magnetic properties*

## BOLD Contrast Imaging

**K. K. Kwong, et al, (1992) “Dynamic magnetic resonance imaging of human brain activity during primary sensory stimulation.” Proc. Natl. Acad. Sci. USA. 89, 5675-5679.**
**S. Ogawa, et al., (1992) “Intrinsic signal changes accompanying sensory stimulation: functional brain mapping with magnetic resonance imaging. Proc. Natl. Acad. Sci. USA.” 89, 5951-5955.**
**P. A. Bandettini, et al., (1992) “Time course EPI of human brain function during task activation.”  Magn. Reson. Med 25, 390-397.**
**Blamire, A. M., et al. (1992). “Dynamic mapping of the human visual cortex by high-speed magnetic resonance imaging.” Proc. Natl. Acad. Sci. USA 89: 11069-11073.**

**BOLD Contrast Imaging**

## Slide 8

## Activation Statistics

- <date/time>

- Statistical Map
- superimposed on anatomical MRI image

- ~2s

- Functional images

- Time

- Condition 1

- Condition 2

- ...

- ~ 5 min

- Time

- fMRI
- Signal
- (% change)

- ROI Time Course

- Condition

**Activation Statistics**

- Region of interest (ROI)

## 3

**Log Size (mm)**

- 2
- 1
- 0
- -1

- Brain
- Map
- Column
- Layer

**Log Time (sec)**

- -3 -2 -1 0 1 2 3 4 5 6 7

- NIRS NIRS

- Millisecond   Second   Minute  Hour  Day

**MEG, EEG**

**NIRS**

**fMRI**

**MRI**

**PET**

**Notes:**
Might include other scales for ease of implementation, as well as robustness

## Spatial and Temporal Resolution

- P. A. Bandettini*, *(1999) "Functional MRI" 205-220.

**Latency Variation...**

**Spatial and Temporal Resolution**

- Cheng, et al. (2001) Neuron,32:359-374

- Spatial

- Temporal

## ?

**Hemodynamics**

**?**

**?**

**?**

**Measured Signal**

**Noise**

**?**

**Interpretation**

## Slide 13

## Motor 

**J. Illes, M. P. Kirschen, J. D. E. Gabrielli, Nature Neuroscience, 6 (3) p.205, 2001**

**Motor **
**Primary Sensory**
**Integrative Sensory**
**Basic Cognition**
**High-Order Cognition**
**Emotion**

**Type of fMRI research performed**

## Slide 15

## Clinical Applications

**Comparison of two groups of *****normal***** individuals with differences in the Serotonin Transporter Gene**

**Clinical Applications**

## NEUROIMAGE 19 (2): 261-270 Part 1 JUN 2003

## Extensive Individual Differences in Brain Activations During Episodic Retrieval

**Extensive Individual Differences in Brain Activations During Episodic Retrieval**
**Miller et al., 2002**** **

**Courtesy, Mike Miler, UC Santa Barbara and Jack Van Horn, fMRI Data Center, Dartmouth University**

**Notes:**
I’ve become interested in the extensive and extreme individual differences in brain activations that occur during episodic retrieval. This is a group analysis of 9 subjects that we did a while back. The subjects were engaged in a word recognition task contrasted with a non-retrieval baseline. These activations are thresholded at .001 uncorrected using a random effects model. By looking at the group map, one would say the the predominant activation for this task is in the left inferior frontal gyrus. Yet, here are the individual maps from the nine subjects that made up that group. In very few of these subjects would you make that same generalization. And, as you can see, the differences go way beyond any differences due to spatial warping or gyral location. Some subjects have mostly superior activations, while others have mostly ventral. Some subjects have a lot of parietal activations, others none. Some subjects like JL have very little activation in the left hemisphere, but much more in the right.

## These individual patterns of activations are stable over time 

**These individual patterns of activations are stable over time **

**Courtesy, Mike Miler, UC Santa Barbara and Jack Van Horn, fMRI Data Center, Dartmouth University**

**Notes:**
One critical point is that these unique and extensive individual activations are stable over time. Here is one subject who deviated greatly from the group. Here is the same subject 6 months later in the same task. Another words, these unique activations are not just random noise. And they could be critical to the task that is not be accounted for by the group maps alone.

## When comparing two groups, if one group shows a difference in activation, it does not imply that an individual that shows a similar difference is in that group.

**The problem of drawing individual inferences from fMRI data: **

## 2

- 3

- 4

- 5

- 6

- 7

- 8

- 9

- 10

- 11

- 12

- 13

- Overt Word Production

- Motion sensitivity

## Concluding thoughts..

- Very difficult to draw individual inferences.
- Needs individual calibration.
- 	(example: face recognition..)
- Practically, very difficult to implement.
- 	(requires considerable subject cooperation)

## Uses

**Future Uses**

- Understanding normal brain organization and changes
- 	-networks involved with specific tasks (low to high level processing)
- 	-changes over time (seconds to years)
- 	-correlates of behavior (response accuracy, performance changes...)
- Clinical research
- 	-correlates of specifically activated networks to clinical populations
- 	-presurgical mapping

- Complementary use for clinical diagnosis
- 	-utilization of clinical research results
- 	-prediction of pathology
- Clinical treatment and assessment
- 	-drug, therapy, rehabilitation, biofeedback
- 	-epileptic foci mapping
- 	-drug effects
- Non clinical uses
- 	-complementary use with behavioral, anatomical, other modality results
- 	-lie detection
- 	-prediction of behavior tendencies
- 	-brain/computer interface