Annals of the New York Academy of Sciences
-
Ann. N. Y. Acad. Sci. · Dec 2005
Case ReportsEffects of prior exposure on music liking and recognition in patients with temporal lobe lesions.
Prior exposure to music typically increases liking. This manifestation of implicit memory can be dissociated from explicit memory recognition. To examine the contribution of the medial temporal lobe to musical preference and recognition, we tested patients with either left (LTL) or right (RTL) temporal lobe lesions as well as normal control (NC) participants using the procedure of Peretz et al. ⋯ In this case, the exposure effect on liking was also absent. However, repeated exposure to melodies was found to enhance both liking and recognition judgments. This remarkable sparing of memory observed through melody repetition suggests that extensive exposure may assist both implicit and explicit memory in the presence of global amnesia.
-
The spinal cord is an important part of the nervous system and provides the connection of the brain with the periphery. It consists not only of a large number of longitudinal fibers, but also contains collateral fibers and a central gray matter structure, which are part of autonomous circuits. ⋯ This report summarizes the normal findings for ADC, diffusion anisotropy, and diffusion eigenvector directions in the spinal cord. Sagittal and axial diffusion-weighted images of the spinal cord were obtained with line scan diffusion imaging (LSDI) in adults, children, infants, and a spinal cord specimen.
-
Ann. N. Y. Acad. Sci. · Dec 2005
White matter tractography by means of Turboprop diffusion tensor imaging.
White matter fiber-tractography by means of diffusion tensor imaging (DTI) is a noninvasive technique that provides estimates of the structural connectivity of the brain. However, conventional fiber-tracking methods using DTI are based on echo-planar image acquisitions (EPI), which suffer from image distortions and artifacts due to magnetic susceptibility variations and eddy currents. Thus, a large percentage of white matter fiber bundles that are mapped using EPI-based DTI data are distorted, and/or terminated early, while others are completely undetected. ⋯ There were no visible distortions in any of the traced fiber bundles, even when these were located in the vicinity of significant magnetic field inhomogeneities. Additionally, the Turboprop-DTI data used in this research were acquired in less than 19 min of scan time. Thus, Turboprop appears to be a promising DTI data acquisition technique for tracing white matter fibers.
-
Ann. N. Y. Acad. Sci. · Nov 2005
Endo-Porter: a novel reagent for safe, effective delivery of substances into cells.
Delivering large molecules into the cytosol of animal cells without damaging the cells has been one of the toughest challenges in biology. Endo-Porter is a weak-base amphiphilic peptide that was designed to deliver morpholino antisense oligomers and other non-ionic substances into the cytosol/nuclear compartment of cells by an endocytosis-mediated process that avoids damaging the plasma membrane of the cell. This prevents the loss of vital cell contents and the attendant high cell toxicity typical of most delivery systems. ⋯ Upon subsequent acidification of the endosome (a natural process) the Endo-Porter contained within that endosome is converted to its poly-cationic form, which acts to permeabilize the endosomal membrane. This acid-induced permeabilization of the endosomal membrane allows any co-endocytosed cargo to pass from the endosome into the cytosol of the cell. This paper describes the basic design strategy used to develop Endo-Porter, test systems used to guide that development, and the effects of various structural parameters, including size and composition of the lipophilic face, size and composition of the weak-base face, and the relationship between peptide length and delivery efficiency in the presence of serum.
-
Ann. N. Y. Acad. Sci. · Aug 2005
ReviewPotentially neuroprotective and therapeutic properties of nitrous oxide and xenon.
Despite the beneficial effects of prototypical glutamatergic receptor antagonists in animal models, the pharmacological attempts by the use of such agents have met with very limited clinical success because these compounds produce adverse side effects and possess an intrinsic neurotoxicity at neuroprotective and therapeutic concentrations. Interestingly, nitrous oxide and xenon, which are anesthetic gases with a remarkably safe clinical profile, have been shown to be effective inhibitors of the NMDA receptor. We briefly review accumulating evidence that nitrous oxide and xenon at subanesthetic concentrations may have potentially neuroprotective and therapeutic properties, with a particular focus on their beneficial effects on ischemia-induced neuronal death and amphetamine-induced sensitization. ⋯ However, at a higher concentration of 75-vol%, xenon shows potentially neurotoxic properties and adverse side effects. Because both agents are rapidly eliminated from the body, it is plausible that their administration at appropriate subanesthetic neuroprotective and therapeutic concentrations may not be associated, in contrast with prototypical NMDA receptor antagonists, with adverse side effects and potentially neurotoxicity. Finally, the possible therapeutic implications in humans are discussed.