Semantic memory refers to knowledge about people, objects, actions, relations, self,

Semantic memory refers to knowledge about people, objects, actions, relations, self, and culture acquired through experience. of actions, manipulable artifacts, abstract ideas, and concrete ideas. The cortical areas involved in semantic processing can be grouped into 3 broad groups: posterior multimodal and heteromodal association cortex, heteromodal prefrontal cortex, and medial limbic areas. The expansion of these regions in the human relative to the nonhuman primate mind may explain uniquely human capacities to utilize language productively, strategy, solve problems, and create social and technological artifacts, all of which depend on the fluid and efficient retrieval and manipulation of semantic knowledge. values HMN-214 supplier associated with each HMN-214 supplier Rabbit polyclonal to NSE maximum (if obtainable), and the published table from which the coordinates were copied. All coordinates were converted to a single common stereotaxic space. The studies were evenly divided between those that reported coordinates in the standard space of Talairach and Tournoux (1988) and those that used a variance of MNI space (Evans et al. 1993). We converted all MNI coordinates to the Talairach and Tournoux (1988) system using the icbm2tal transform (Lancaster et al. 2007). This transform reduces the HMN-214 supplier bias associated with research framework and level in MNICTalairach conversion. Probabilistic maps of the producing units of coordinates were constructed using the Activation Probability Estimate (ALE) method (Turkeltaub et al. 2002), implemented in the GingerALE software package (Laird et al. 2005) (available at, using an 8-mm FWHM 3D Gaussian point spread function and a spatial grid composed of 2 2 2 mm voxels. This method treats each reported focus as the center of a Gaussian probability distribution. The 3D Gaussian distributions corresponding to all foci included in a given analysis are summed to create a whole-brain map that represents the overlap of activation peaks at each voxel, referred to as the ALE statistic. Subsequent analysis is restricted to a mind volume face mask (Kochunov et al. 2002) distributed with the GingerALE software. To determine the null distribution of the ALE statistic for each analysis, a Monte Carlo simulation with 10?000 iterations was performed, in which each iteration consisted of a set of foci equal in number to the observed data, placed at random locations within the analysis volume and convolved with the same point spread function (Laird et al. 2005). Based on these null distributions, the ALE statistic maps for each analysis are converted to voxelwise probability maps. The probability of opportunity formation of suprathreshold clusters was then determined by Monte Carlo simulation using in-house software, with 1000 iterations. Each iteration contained randomly located foci the same in number to the observed data and convolved with the same point spread function. The ALE map was then computed for each iteration, and the number and size of HMN-214 supplier voxel clusters were recorded after thresholding each simulated data arranged at numerous voxelwise ALE thresholds. ALE maps from each of the observed data sets were then thresholded at an ALE value that yielded a corrected mapwise < 0.05 after removing clusters smaller than 1000 L. For visualization of probability ideals at each voxel, these corrected ALE maps HMN-214 supplier were applied as masks within the probability maps generated from the GingerALE software. These thresholded probability maps are demonstrated in Figs. 3C6. Physique 3. ALE map of all semantic foci, thresholded at whole-brain corrected < 0.05. Activations are displayed on serial sagittal sections through the stereotaxic space of Talairach and Tournoux (1988) at 4-mm intervals, with slice locations given at ... Physique 6. ALE maps derived from contrasts comparing perceptual (i.e., pertaining to sensory characteristics of concrete objects) with verbal (i.e., abstract or encyclopedic) knowledge. The 113 foci representing perceptual knowledge are demonstrated in warm colours, and the ... Results The initial search and testing methods recognized 520 content articles, which were consequently examined in detail. A total of 120 content articles met inclusion criteria and offered 187 semantic contrasts. Physique 1 shows a breakdown of these.