HOW-TO #5
		   	    Experiment Background


				--------------
			        THE EXPERIMENT
				--------------

This experiment used FMRI to examine the organization of brain responses to 
different types of complex visual motion.  Participants were presented with 
visual displays depicting the movement of humans (e.g., doing jumping jacks) or 
tools (e.g., a hammer swinging).  The displays were either movies of real people
and tools engaged in motion, or point-light displays mimicking the movement of 
people and tools.  The point-light displays were created by identifying specific
points on the human body and tools, which moved with motion vectors equivalent 
to the movie stimuli.

Design:
------
	Event-related

Stimulus Conditions:
-------------------
	1. Human Movie
	2. Tool Movie
	3. Human Point Light
	4. Tool Point Light

Participants:
------------
	The original sample size (n) for this study was 9 participants.  
	However, due to the tremendous amount of data collected for each 
	subject, we have included the data of only 3 participants that can be 
	downloaded from this how-to on the AFNI website.  Participants are 
	identified by their two-letter ID codes ED, EE, and EF.  Likewise, data 
	for each subject can be found in directories ED/, EE/, and EF/.  Each 
	subject directory contains one anatomical volume, and 10 time-series 
	datasets (i.e., 10 runs).

				--------
				THE DATA
				--------

Anatomical Data Collected:
-------------------------
	The SPGR anatomical data consists of 124 sagittal slices, spanning from 
	67.6 mm Left to 80.0 mm Right.  Each slice is a 256 x 256 voxel image, 
	with each voxel being a 0.938 mm square.  The slice thickness is 1.2 mm 
	and the axis orientation is ASL.  

	The dataset was created using the AFNI program 'to3d', which has been 
	described in earlier how-to's (also see 'to3d -help').  Each subject's 
	anatomical volume is stored in their respective data directory:

	ED/			EE/			EF/
	ED_spgr+orig.HEAD	EE_spgr+orig.HEAD  	EF_spgr+orig.HEAD
	ED_spgr+orig.BRIK	EE_spgr+orig.BRIK  	EF_spgr+orig.BRIK


Time-Series Data Collected:
--------------------------
	Each EPI run consists of 138 volumes, 23 axial slices each.  These 
	slices were taken from 68.3 mm Superior to 41.7 mm Inferior.  Each slice
	is a 64 x 64 voxel image, with a resolution of 3.75 mm on each side.  
	The thickness of each of the 23 slices is 5.0 mm, the axis orientation 
	is RAS, and the TR = 2 seconds. 

	The data were saved in a sequence of directories generated by the GE 
	scanner (003/, 023/, 043/... 623/).  The AFNI program 'Imon' was used to
	verify the integrity of the I-files (i.e., Are any files missing? Out of
	sequence?).  The '-GERT_Reco2' option was included on the command line 
	to create AFNI datasets for our 10 runs of data (this 'GERT_Reco2' 
	script is similar to the 'GERT_Reco' script found in the AFNI 'Ifile' 
	program.  The 'Imon' command is shown below:

		Imon -start_dir 003  -GERT_Reco2 -quit

	An excellent description of the 'Imon' program can be found by typing 
	'Imon -help' on the command line.  

	The 10 AFNI datasets are stored in each subject's data 	directory:

	ED/		EE/	     	EF/
	ED_r1+orig	EE_r1+orig	EF_r1+orig
	ED_r2+orig	EE_r2+orig	EF_r2+orig
	.		.		.
	.		.		.
	ED_r10+orig	EE_r10+orig	EF_r10+orig


				--------------
				STUDY FINDINGS
				--------------

Lateral Temporal Cortex:
-----------------------
	The lateral temporal cortex showed strong responses to movement overall.
	As such, this area of the brain seems to be the cortical locus for 
	processing complex visual motion.  

     	Within the lateral temporal cortex:
	----------------------------------
		The superior temporal sulcus (STS) responded strongly to both 
		human movies and human point-light displays.

		The middle temporal gyrus (MTG) and the inferior temporal sulcus
		responded strongly to tool movies and tool point-light displays.
		
Ventral Temporal Cortex:
-----------------------
	This area tends to respond better to movie displays than point-light 
	displays, suggesting that form, color, and texture (present in movies 
	but not point-light displays) are main contributors to ventral temporal 
	activity.

	Within the Ventral Temporal Cortex:
	----------------------------------
		The lateral fusiform responded more to human movies than to any 
		other stimulus category, while the medial fusiform preferred 
		tool movies.

				---------
				REFERENCE
				---------

The data used for this how-to was kindly donated by Michael Beauchamp.  For a 
full review of the experiment described in this how-to, see:

	Beauchamp, M. S., Lee, K. E., Haxby, J. V., & Martin, A. (2003).  FMRI 
	     responses to video and point-light displays of moving humans and 
	     manipulable objects.  Journal of Cognitive Neuroscience, 15:7, 
	     991-1001.

The data reported in this experiment have also been deposited with the fMRI Data
Center archive (http://www.fmridc.org).  The ascension number is 2-2003-113QA.