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ObjectivesThe study aimed at determining the EEG correlates of concentration on either low or high-distressed tinnitus.MethodsSixty-seven patients (36 women, mean age = 50.34 ± 12.94 years) with chronic tinnitus were assigned to either a high (HD) or low (LD) tinnitus-related distress group based on THI results. All participants took part in the EEG study comprising two 3-4 min blocks of focusing on either tinnitus (Tinnitus Focus Condition, TFC) or the sensations from one's own body (Body Focus Condition, BFC). The absolute power and current density of 8 frequency bands in 7 clusters were compared between conditions and groups.ResultsThe most pronounced differences were found in the HD patients in the TFC, relative to the BFC, i.e. reduced power of frontally distributed low alpha (8-10 Hz) and posterior high alpha (10-12 Hz) as well as lower current density of 8-10 Hz rhythm over the right frontal/anterior cingulate cortex and higher middle beta (15-18 Hz) density in the precuneus. The HD, relative to LD patients, in both conditions, exhibited increased low beta (12-15 Hz) power over the left middle area and greater higher beta (15-25 Hz) power in the left posterior region.ConclusionsThe present study contrasted bioelectrical activity, acquired when concentrating on tinnitus with EEG data collected whilst patients focused on their body. Decreased alpha power and current density in the frontal/cingulate cortex when listening to bothersome tinnitus might reflect greater cortical arousal whereas increased beta power and density in the precuneus/posterior cingulate activity in this condition could be indicative for elevated tension or augmented cognitive/emotional processing of tinnitus sound. Enhanced beta rhythm in patients with high versus low tinnitus distress, observed independently of the study condition, may be due to greater self-focused attention or more active processing of sensations derived from the own body.

The knotweed taxa Fallopia japonica, F. sachalinensis and their interspecific hybrid F. × bohemica are some of the most aggressive invaders in Europe and North America and they are serious threats to native biodiversity. At the same time, they constitute a unique model system for the creation of hybrids and studies of the initiation of evolutionary processes. In the presented study, we focused on (i) examining genetic diversity in selected populations of three Fallopia taxa in the invaded (Poland) and native ranges (Japan), (ii) establishing genome size and ploidy levels and (iii) identifying ribosomal DNA (rDNA)-bearing chromosomes in all of the taxa from the invaded range. We found that the genetic diversity within particular taxa was generally low regardless of their geographical origin. A higher level of clonality was observed for the Polish populations compared to the Japanese populations. Our study suggests that the co-occurrence of F. sachalinensis together with the other two taxa in the same stand may be the source of the higher genetic variation within the F. × bohemica hybrid. Some shift towards the contribution of F. japonica alleles was also observed for selected F. × bohemica individuals, which indicates the possibility of producing more advanced generations of F. × bohemica hybrids. All of the F. sachalinensis individuals were hexaploid (2n = 6x = 66; 2C = 6.01 pg), while those of F. japonica were mostly octoploid (2n = 8x = 88; 2C = 8.87 pg) and all of the F. × bohemica plants except one were hexaploid (2n = 6x = 66; 2C = 6.46 pg). Within the chromosome complement of F. japonica, F. sachalinensis and F. × bohemica, the physical mapping of the rDNA loci provided markers for 16, 13 and 10 chromosomes, respectively. In F. × bohemica, a loss of some of rDNA loci was observed, which indicates the occurrence of genome changes in the hybrid.