Direct interhemispheric cortical communication via thalamic commissures: a new white matter pathway in the primate brain

Cortical neurons of eutherian mammals project to the contralateral hemisphere, crossing the midline primarily via the corpus callosum and the anterior, posterior, and hippocampal commissures. We recently reported and named the thalamic commissures (TCs) as an additional interhemispheric axonal fiber pathway connecting the cortex to the contralateral thalamus in the rodent brain. Here, we demonstrate that TCs also exist in primates and characterize the connectivity of these pathways with high-resolution diffusion-weighted MRI, viral axonal tracing, and fMRI. We present evidence of TCs in both New World (Callithrix jacchus and Cebus apella) and Old World primates (Macaca mulatta). Further, like rodents, we show that the TCs in primates develop during the embryonic period, forming anatomical and functionally active connections of the cortex with the contralateral thalamus. We also searched for TCs in the human brain, showing their presence in humans with brain malformations, although we could not identify TCs in healthy subjects. These results pose the TCs as a vital fiber pathway in the primate brain, allowing for more robust interhemispheric connectivity and synchrony and serving as an alternative commissural route in developmental brain malformations.

Direct interhemispheric cortical communication via thalamic commissures: a new white-matter pathway in the primate brain

Cortical neurons of eutherian mammals project to the contralateral hemisphere, crossing the midline primarily via the corpus callosum and the anterior, posterior, and hippocampal commissures. We recently reported an additional commissural pathway in rodents, termed the thalamic commissures (TCs), as another interhemispheric axonal fiber pathway that connects cortex to the contralateral thalamus. Here, we demonstrate that TCs also exist in primates and characterize the connectivity of these pathways with high-resolution diffusion-weighted magnetic resonance imaging, viral axonal tracing, and functional MRI. We present evidence of TCs in both New World (Callithrix jacchus and Cebus apella) and Old World primates (Macaca mulatta). Further, like rodents, we show that the TCs in primates develop during the embryonic period, forming anatomical and functionally active connections of the cortex with the contralateral thalamus. We also searched for TCs in the human brain, showing their presence in humans with brain malformations, although we could not identify TCs in healthy subjects. These results pose the TCs as an important fiber pathway in the primate brain, allowing for more robust interhemispheric connectivity and synchrony and serving as an alternative commissural route in developmental brain malformations.

Invasive Lobular Carcinoma of the Breast: Appearance on Digital Breast Tomosynthesis

BACKGROUND

The aim of this study was to characterize the signs of invasive lobular carcinoma of the breast on digital breast tomosynthesis (DBT) imaging.

PATIENTS AND METHODS

The study group included 23 women with pathologically proven invasive lobular carcinoma of the breast for whom both digital mammography (DM) and DBT images were available. The images were read jointly by 2 experienced breast radiologists. Findings were recorded according to the descriptors in the Breast Imaging and Reporting Data System lexicon and correlated with the detailed pathology results.

RESULTS

In 21 of the 23 patients, the combination of DM and DBT yielded pathologic findings (91%). Architectural distortions or spiculations were demonstrated in 87% of cases. The addition of DBT to DM improved lesion detection by more clearly depicting both the lesion margins and architectural distortions. Only 2 lesions were occult by both DM and DBT, including 1 lesion in a peripheral location that was not incorporated in the standard mediolateral oblique and craniocaudal views.

CONCLUSION

DBT improves the detection of invasive lobular carcinoma lesions by more clearly depicting architectural distortions and spiculations.

Covered stents safely utilized to prevent catastrophic hemorrhage in patients with advanced head and neck malignancy

PURPOSE

The purpose of this study was to review the use of covered stents in patients with squamous cell carcinoma of the head and neck threatening bilateral neurovascular structures.

METHODS

The radiology information system was searched for all patients with bilateral head and neck carcinoma treated with covered stents in the carotid vasculature from 2006 through 2009. Five patients (one woman) of mean age 60.5 years (range 45-69) were identified. All had carotid blowout syndrome after treatment for primary squamous cell carcinoma of the head and neck with subsequent tumor recurrence or metastases immediately threatening bilateral carotid vasculature. Covered stents were placed. Long-term follow-up included clinical progress, verification of stent patency and detection of tumor progression via ultrasound or contrast-enhanced CT after the first month and then every 3-6 months. All patients were maintained on antiplatelet medication after treatment.

RESULTS

Covered stents were safely deployed in all patients. Mean survival was 5 months with one outlier surviving for 3 years. There were no subsequent uncontrollable hemorrhages.

CONCLUSION

The use of covered stents for avoidance of catastrophic hemorrhage following treatment in patients with head and neck tumors with bilaterally threatened carotid arteries was successful.

Self-assembly of Au Nanoparticle-containing Peptide Nano-rings on Surfaces

The peptide nano-rings containing Au nanoparticles inside their cavities were self-assembled on dithiol SAMs patterned as an array by AFM-based nanolithography. The peptide nano-rings were aligned as a line on these SAMs, and Au formed lines with the spacing between these nanoparticles as the peptide nano-rings functioned as spacers. This type of array fabrication will provide improved tunability in their optical properties of resulting nanoparticle-assembled arrays. In addition, optimization of the inter-particle distance of nanoparticles in the array with various spacers may allow one to design new types of photonic crystals with desired optical properties.