Age-related declines in motion perception have been well documented. We investigated the impact of age on electrophysiological correlates of motion perception, namely the P1 and N2 components of motion onset visual evoked potentials (MO-VEPs). Additionally, we used a model of response times based on the diffusion model to pinpoint the cognitive processes affected by aging. Twelve healthy adults (age (55years) and 19 elderly (age )55years) performed a motion direction discrimination task during EEG recording. Behaviorally, younger and older participants had similar, high accuracy rates - 98% correct, but older adults exhibited 85ms longer response times. Fitting behavioral results with a diffusion model revealed differences between young adults and elderly in non-decision time, which we argue reflects an early perceptual stage. Electrophysiologically, aging effects were present at MO-VEPs P1 and N2 components at the posterior sites. For the P1 component, older as compared to younger adults showed greater topographical voltage distribution. For the N2 component of elderly as compared to young adults we found delayed onsets and diminished amplitudes. We did not find any significant correlations between behavioral and MO-VEP measures. However, regression analysis showed that N2 amplitude and latency were significant age predictors. Overall, our results indicate that in motion perception, age-related changes occur in early stages of visual processing, most likely in striate and extrastriate visual cortices.
COBISS.SI-ID: 30760921
This study investigated the associations between single nucleotide polymorphisms in the neurodevelopmental Disrupted In Schizophrenia 1 ( DISC1 ), neuregulin 1 ( NRG1 ), brain-derived neurotrophic factor ( BDNF )and NOTCH4 genes and the clinical symptoms and the occur- rence of treatment-resistant schizophrenia in the Slovenian population. We included 138 schizophrenia patients, divid- ed into treatment-responsive a nd treatment-resistant group and 94 healthy blood donors. All subjects were genotyped for eight polymorphisms ( DISC1 rs6675281, DISC1 rs821616, NRG1 rs3735781, NRG1 rs3735782, NRG1 rs10503929, NRG1 rs3924999, BDNF rs6265, NOTCH rs367398) and investigated for associations with clinical variables. NOTCH4 rs367398 AA/AG was significantly associated with worse Positive and Negative Syndrome Scale (PANSS) and Clinical Global Impression (CGI) score. NOTCH4 rs367398 was not statistically significant- ly associated with the occurrence of treatment-resistant schizophrenia after the correction for multiple testing. Our data indicate that NOTCH4 polymorphism can influ- ence clinical symptoms in Slovenian patients with schizophrenia
COBISS.SI-ID: 31770585
Heritability plays an important role in the development and expression of alcohol dependence. The present genetic association study explored the role of TPH2 polymorphisms and their haplotypes to investigate its role in alcohol dependence and comorbid psychopathological symptoms. The sample included 101 subjects currently diagnosed as alcohol abusers, 100 abstinent alcohol-dependent subjects and 97 healthy controls. Subjects were genotyped for TPH2 rs4570625, rs1843809, rs7305115, rs4290270. TPH2 genotypes were not associated with alcohol dependence, but GGAA haplotype was less common (p = 0.038) and GTAA and GGGT were more common (p = 0.011 and p = 0.021, respectively), in currently dependent patients compared to controls. Exploratory analysis of genotypes in currently dependent patients showed that rs1843809 was associated with depressive and aggressive traits (p = 0.045 and p = 0.001, respectively), rs4290270 with depressive and anxiety traits (p = 0.040 and p = 0.025, respectively) and rs4570625 with aggressive traits (p = 0.011). In abstinent subjects rs1843809 genotype was associated with traits of social anxiety (p = 0.003). Only association between rs1843809 and the BDHI score (p = 0.001) and associations between GTAA haplotype and Zung Anxiety Scale and BDHI score (p = 0.001 and p ( 0.001, respectively), in currently dependent patients remained significant after applying the Bonferroni’s correction. Our findings support a potential role of TPH2 in alcohol dependence. TPH2 genetic variability may be also associated with anxiety and aggression traits in alcohol dependent subjects.
COBISS.SI-ID: 5518655
The slowing of information processing, a hallmark of cognitive aging, has several origins. Previously we reported that in a motion direction discrimination task, older as compared to younger participants showed prolonged non-decision time, an index of an early perceptual stage, while in motion onset visual evoked potentials (MO-VEPs) the P1 component was enhanced and N2 was diminished. We did not find any significant correlations between behavioral and MO-VEP measures. Here, we investigated the role of age in encoding and perceptual processing of stimulus onset visually evoked potentials (SO-VEPs). Twelve healthy adults (age ( 55 years) and 19 elderly (age ) 55 years) performed a motion direction discrimination task during EEG recording. Prior to motion, the stimulus consisted of a static cloud of white dots on a black background. As expected, SO-VEPs evoked well defined P1, N1, and P2 components. Elderly participants as compared to young participants showed increased P1 amplitude while their P2 amplitude was reduced. In addition elderly participants showed increased latencies for P1 and N1 components. Contrary to the findings with MO-VEPs, SO-VEP parameters were significant predictors of average response times and diffusion model parameters. Our electrophysiological results support the notion that slowing of information processing in older adults starts at the very beginning of encoding in visual cortical processing, most likely in striate and extrastriate visual cortices. More importantly, the earliest SO-VEP components, possibly reflecting configuration of visual cortices and encoding processes, predict subsequent prolonging and tardiness of perceptual and higher-level cognitive processes.
COBISS.SI-ID: 31947225