Biology subjects

Damasio, H.

Publications and source records attributed to Damasio, H..

2 recordsLinked to original sources

bioRxiv2020

A Hybrid High-Resolution Anatomical MRI Atlas with Sub-parcellation of Cortical Gyri using Resting fMRI

We present a new high-quality, single-subject atlas with sub-millimeter voxel resolution, high SNR, and excellent grey-white tissue contrast to resolve fine anatomical details. The atlas is labeled into two parcellation schemes: 1) the anatomical BCI-DNI atlas, which is manually labeled based on known morphological and anatomical features, and 2) the hybrid USCBrain atlas, which incorporates functional information to guide the sub-parcellation of cerebral cortex. In both cases, we provide consistent volumetric and cortical surface-based parcellation and labeling. The intended use of the atlas is as a reference template for structural coregistration and labeling of individual brains. A single-subject T1-weighted image was acquired at a resolution of 0.547mm x 0.547mm x 0.800mm five times and averaged. Images were processed by an expert neuroanatomist using semi-automated methods in BrainSuite to extract the brain, classify tissue-types, and render anatomical surfaces. Sixty-six cortical and 29 noncortical regions were manually labeled to generate the BCI-DNI atlas. The cortical regions were further sub-parcellated into 130 cortical regions based on multi-subject connectivity analysis using resting fMRI (rfMRI) data from the Human Connectome Project (HCP) database to produce the USCBrain atlas. In addition, we provide a delineation between sulcal valleys and gyral crowns, which offer an additional set of 26 sulcal subregions per hemisphere. Lastly, a probabilistic map is provided to give users a quantitative measure of reliability for each gyral subdivision. Utility of the atlas was assessed by computing adjusted Rand indices between individual sub-parcellations obtained through structural-only coregistration to the USCBrain atlas and sub-parcellations obtained directly from each subjects resting fMRI data. Both atlas parcellations can be used with the BrainSuite, FreeSurfer, and FSL software packages.

bioinformatics↗

bioRxiv2017

The neurobiology of agrammatic sentence comprehension: a lesion study

Brocas area has long been implicated in sentence comprehension. Damage to this region is thought to be the central source of \"agrammatic comprehension\" in which performance is substantially worse (and near chance) on sentences with noncanonical word orders compared to canonical word order sentences (in English). This claim is supported by functional neuroimaging studies demonstrating greater activation in Brocas area for noncanonical versus canonical sentences. However, functional neuroimaging studies also have frequently implicated the anterior temporal lobe (ATL) in sentence processing more broadly, and recent lesion-symptom mapping studies have implicated the ATL and mid temporal regions in agrammatic comprehension. The present study investigates these seemingly conflicting findings in 66 left hemisphere patients with chronic focal cerebral damage. Patients completed two sentence comprehension measures, sentence-picture matching and plausibility judgments. Patients with damage including Brocas area (but excluding the temporal lobe; n=11) on average did not exhibit the expected agrammatic comprehension pattern, e.g. their performance was > 80% on noncanonical sentences in the sentence-picture matching task. Patients with ATL damage (n=18) also did not exhibit an agrammatic comprehension pattern. Across our entire patient sample, the lesions of patients with agrammatic comprehension patterns in either task had maximal overlap in posterior superior temporal and inferior parietal regions. Using voxel-based lesion symptom mapping (VLSM), we find that lower performances on canonical and noncanonical sentences in each task are both associated with damage to a large left superior temporal-inferior parietal network including portions of the ATL, but not Brocas area. Notably however, response bias in plausibility judgments was significantly associated with damage to inferior frontal cortex, including gray and white matter in Brocas area, suggesting that the contribution of Brocas area to sentence comprehension may be related to task-related cognitive demands.

neuroscience↗