Human Auditory Cortical Activation during Self-Vocalization

During speaking, auditory feedback is used to adjust vocalizations. The brain systems mediating this integrative ability have been investigated using a wide range of experimental strategies. In this report we examined how vocalization alters speech-sound processing within auditory cortex by directly recording evoked responses to vocalizations and playback stimuli using intracranial electrodes implanted in neurosurgery patients. Several new findings resulted from these high-resolution invasive recordings in human subjects. Suppressive effects of vocalization were found to occur only within circumscribed areas of auditory cortex. In addition, at a smaller number of sites, the opposite pattern was seen; cortical responses were enhanced during vocalization. This increase in activity was reflected in high gamma power changes, but was not evident in the averaged evoked potential waveforms. These new findings support forward models for vocal control in which efference copies of premotor cortex activity modulate sub-regions of auditory cortex

Phylogenetic relationships within Tillandsia subgenus Diaphoranthema (Bromeliaceae, Tillandsioideae) based on a comprehensive morphological dataset

Tillandsia subgenus Diaphoranthema (Tillandsioideae, Bromeliaceae) includes 29 epiphytic species distributed widely from southern North America to central Argentina and Chile. The species of Diaphoranthema are characterized by few small flowers, and most species are differentiated by phyllotaxy, leaf shape, flower number, and by the morphology and number of bracts. In addition to the highly variable vegetative characters, most species of subgenus Diaphoranthema possesses polyembryonic seeds (rare in Bromeliaceae) and an autogamous breeding system with a few number of species having cleistogamous flowers. In order to clarify relationships within Diaphoranthema and to understand the evolution of polyembryony, the breeding system, and diagnostic characters, a cladistic analysis of all known species using 85 morphological characters was conducted. Phylogenetic results suggest that Diaphoranthema is monophyletic if some species from the closely related subgenus Phytarrhiza are included. These two subgenera can only be distinguished from each other by the shape and size of their petals. A complete sampling of Phytarrhiza is still needed to test these hypotheses. None of the six informal groups as previously recognized are monophyletic. Vegetative characters such as phyllotaxy and the shape, length, and width of leaves were the most useful for distinguishing four major clades within Diaphoranthema. Flower number, scape development, exocarp and endocarp fusion at fruit ripening, and absence of endosperm in mature seeds were also used to distinguish some clades. Evolutionary trends favour a distichous phyllotaxy, linear shape leaf blades, and a reduction in flower number and bracts per inflorescence. In addition, capsules with disaggregating exocarp and endocarp at ripening, and polyembryonic seeds are also derived states within subgenus Diaphoranthema.Fil: Donadío, Sabina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Pozner, Raul Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Giussani, Liliana Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentin