Tinnitus Intensity Dependent Gamma Oscillations of the Contralateral Auditory Cortex

Non-pulsatile tinnitus is considered a subjective auditory phantom phenomenon present in 10 to 15% of the population. Tinnitus as a phantom phenomenon is related to hyperactivity and reorganization of the auditory cortex. Magnetoencephalography studies demonstrate a correlation between gamma band activity in the contralateral auditory cortex and the presence of tinnitus. The present study aims to investigate the relation between objective gamma-band activity in the contralateral auditory cortex and subjective tinnitus loudness scores. In unilateral tinnitus patients (N = 15; 10 right, 5 left) source analysis of resting state electroencephalographic gamma band oscillations shows a strong positive correlation with Visual Analogue Scale loudness scores in the contralateral auditory cortex (max r = 0.73, p<0.05). Auditory phantom percepts thus show similar sound level dependent activation of the contralateral auditory cortex as observed in normal audition. In view of recent consciousness models and tinnitus network models these results suggest tinnitus loudness is coded by gamma band activity in the contralateral auditory cortex but might not, by itself, be responsible for tinnitus perception

Mechanisms of Acido-Tolerance and Characteristics of Photosystems in an Acidophilic and Thermophilic Red Alga, Cyanidium Caldarium

In this chapter, we describe the mechanisms of acido-tolerance in an acidophilic- and thermophilic red alga, Cyanidium caldarium. In spite of the extremely acidic environments it inhabits, the intracellular pH of Cyanidium cells is kept neutral by pumping out the protons previously leaked into the cells according to the steep pH gradient. The H+ pump is driven by the plasma membrane ATPase, utilizing intracellular ATP produced by both oxidative phosphorylation and cyclic photophosphorylation via photosystem I. We also describe the characteristics and function of the two photosystems, Photosystem I (PSI) and II (PSII), in Cyanidium caldarium in comparison with those of cyanobacteria, other eukaryotic algae, and higher plants, based on the crystal structures of the two complexes reported so far