Spared cognitive processing of visual oddballs despite delayed visual evoked potentials in patient with partial recovery of vision after 53years of blindness

AbstractWe examined the visual and cognitive functions of a 72-year-old subject, KP, who recovered his sight after 53years of visual deprivation. We used visual evoked potentials (VEPs) to pattern-reversal and motion-onset stimuli and cognitive responses (ERPs) during the oddball paradigm to assess the effect of long-term deprivation on a mature visual system. KP lost his sight at the age of 17years, and light projection onto his right retina was restored at 71years by a corneal implant. Nine months after sight recovery we recorded reproducible responses to all examined stimuli. The response to pattern reversal contained two P100-like peaks with the later peak being dominant and significantly delayed (260ms) when compared to the P100s of two control subjects, to whom the stimuli were adjusted in size and contrast to mimic KP’s vision. KP’s motion-onset VEPs to full-field and peripheral stimuli had a characteristic shape with a well-defined N2 peak; however, both peaks were significantly delayed (262 and 272ms) compared to control responses. Unlike the P100 and N2 peaks, which represent sensory detection, the P3b/P300 component of the ERP to a target event in the oddball paradigm was not further delayed. In spite of degraded vision and sensory deprivation lasting 53years, KP displayed reproducible responses to all reported stimuli. Long-term visual deprivation and retinal detachment degraded KP’s visual sensory processing, assessed by pattern-reversal and motion-onset VEPs, whereas the cognitive processing of appropriate visual stimuli was not compromised

C,N-chelated Organoarsenic(I) Compounds - Synthesis, Structure and Coordination of Transition Metals

Fakulta chemicko-technologickáDokončená práce s úspěšnou obhajobo

The reactivity of latent heterocyclic dienes containing phosphorus and arsenic

Tato práce se věnuje převážně studiu reaktivity C,N a N,C,N chelatovaných fosfinidenů a arsinidenů. Připravené produkty jsou následně také charakterizovány. Teoretická část je pojata jako rešerše přípravy a reaktivity pniktinidenů a některých heteropniktolů. Diskuze je věnována nejprve unikátnímu nejednoznačnému chování N,C,N chelatovaných fosfinidenů a arsinidenů, díky čemuž mohou vystupovat jako čtyřelektronové donory, ale i jako heterodieny v hetero-Diels-Alderově [4+2] cykloadici.This thesis is focused mainly on the study of the reactivity of C,N and N,C,N chelated fosfinidenes and arsinidenes. Prepared compounds were subsequently also characterized. The theoretical part is drafted as a literary search dealing with the preparation and reactivity of pnictinidenes and several heteropnictoles. The discussion is dedicated in the first part toward the unique ambiguous behaviour of the N,C,N chelated phosphinidenes and arsinidenes, which allows them to act as either four-electron donors, or heterodienes in hetero-Diels-Alder [4+2] cycloaddition.Fakulta chemicko-technologickáDokončená práce s úspěšnou obhajobo

N,N,N-chelating Ligands for the Coordination of Heavier Group 14 and 15 Elements

V první části se práce věnuje literární rešerši na téma obecné vlastnosti N,C,N a N,N,N ligandů, dále popisuje sloučeniny N,C,N a N,N,N ligandů obsahující kovy 14. a 15. skupiny v nízkém oxidačním stavu. Experimentální část přináší popis syntézy N,N,N chelatujícího ligandu odvozeného od pyrrolového skeletu. Dále je prezentován popis syntéz odvozených sloučenin s centrálním atomem Ge a Sn v oxidačním stavu +II a Sb a Bi v oxidačním stavu +III.First part of the thesis focuses on a literary research on general properties of N,C,N and N,N,N ligands followed by description of compounds stabilized by N,C,N and N,N,N ligands containing group 14 and 15 metals in a low oxidation state. Experimental section delivers synthesis description of N,N,N ligand derived from pyrrole backbone. Next, syntheses of compounds thereof with Ge, Sn in oxidation state +II and Sb and Bi in oxidation state +III are described.Ústav organické chemie a technologieStudent prezentoval svoji bakalářskou práci a vyjádřil se k dotazům