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techniques are appropriate, and how the end results should be interpreted, depend a
great deal on the nature of the underlying data. Thus, in the next section we de-
scribe the database that we have been working with and how other researchers
can get access to it for their own use. Then, in the final section, we will describe
some of the projects to which we have applied this resource and some of the future
possibilities.
2.3 A Database of Imaging Experiments
Over the last year or so we have compiled a database containing 665 experiments
in 18 cognitive domains. The database currently consists of every qualifying imag-
ing study in the
Journal of Cognitive Neuroscience
from 1996 to 2006, as well as
the 135 experiments from [11] that were used in previous studies [4, 6]. To qual-
ify for inclusion in the database, the study had to be conducted on healthy adults
and to use a subtraction-based methodology for analyzing results. The database
contains only post-subtraction activations. The data recorded for each experiment
include the publication citation, the domain and sub-domain, the imaging method,
the Talairach coordinates of each reported activation, the Brodmann area of each
reported activation, the relative placement of the activation in the Brodmann area
(e.g., frontal, caudal, ventral, dorsal), and the comparison used to generate the re-
sults. The domain labels are consistent with those used by the BrainMap database
[22]. For experiments where coordinates were reported in MNI coordinates, a soft-
ware package called GingerALE was used to translate these into Talairach co-
ordinates [21]. When the authors of the study reported the Brodmann areas of
their activations, these were recorded as reported. Where the authors did not re-
port Brodmann areas, a software package called the Talairach demon [24] was
used to provide Brodmann area labels for the coordinates. This program reports
a distance in millimeters from the coordinate to the reported Brodmann area; this
is the range, and it is recorded in cases where the BA label was generated us-
ing the software. The range is useful for excluding from analysis Brodmann area
labels for coordinates that are further than desired from the reported area. Our
plans are to continue to add to the database and analysis, and to publish ver-
sions at 1 year intervals beginning in the fall of 2008. The published versions of
the database will contain the base data detailed above, as well as co-activation
graphs, and will be prepared according to the following procedure: first, we will
only include in the co-activation analysis sample domains containing some mini-
mum number of experiments (e.g., 50 or 100, to be determined by what is feasi-
ble given the state of the database at that time). Having identified these domains,
we will generate a concordance of authors to be sure that no individual labs are
overrepresented in any given domain. The samples will be balanced by lab by
randomly excluding experiments from overrepresented authors. At this point we
will choose a target
n
based on the number of experiments in the domain contain-
ing the fewest number of experiments. An equal number of experiments will be
