Browsing by Subject "Time perception"
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Item Restricted Carpe Diem ya da zamanın başbakanı!(1998) Eren, Ali HikmetItem Open Access Dating the sea of Marmara sediments by a uniform mixing model(Elsevier, 1996) Gökmen, A.; Yıldız, M.; Erten, H. N.; Salihoğlu, İ.The sedimentation rates and ‘t”Pb fluxes on sediment surfaces were measured in the north, northwestern and southwestern parts of the Sea of Marmara. Each core had varying thickness of constant 2’0Pb activity regions followed by a decreasing part with sediment depth. The sedimentation rates of the samples collected from the Bosporus and the Dardanelles could not be analysed due to the homogenization of activity in the strong currents of these straits. A untform mixing model is proposed for the simultaneous analysis of sedimentation rates, “‘Pb fluxes and mixing depths from the experimental data. In this model, the parameters were obtained by minimizing the multi-dimensional parameter space using a grid search algorithm. The 2’0Pbfluxes were found to be about 0.048 Bqcm-’ year-t for all sampling sites. The mass sedimentation rates were 0.19 and 0.073gcm-2 year-’ at the shelves of the Bosporus and the Dardanelles and 0.055 and 0.064 g cm-’ year -’ in the northwestern and middle northern basins, respectively, of the Sea of Marmara.Item Open Access The involvement of centralized and distributed processes in sub-second time interval adaptation: an ERP investigation of apparent motion(Blackwell Publishing Ltd, 2017) Kaya, Utku; Yildirim, Fazilet Zeynep; Kafaligonul, HulusiAccumulating evidence suggests that the timing of brief stationary sounds affects visual motion perception. Recent studies have shown that auditory time interval can alter apparent motion perception not only through concurrent stimulation but also through brief adaptation. The adaptation after-effects for auditory time intervals was found to be similar to those for visual time intervals, suggesting the involvement of a central timing mechanism. To understand the nature of cortical processes underlying such after-effects, we adapted observers to different time intervals using either brief sounds or visual flashes and examined the evoked activity to the subsequently presented visual apparent motion. Both auditory and visual time interval adaptation led to significant changes in the ERPs elicited by the apparent motion. However, the changes induced by each modality were in the opposite direction. Also, they mainly occurred in different time windows and clustered over distinct scalp sites. The effects of auditory time interval adaptation were centred over parietal and parieto-central electrodes while the visual adaptation effects were mostly over occipital and parieto-occipital regions. Moreover, the changes were much more salient when sounds were used during the adaptation phase. Taken together, our findings within the context of visual motion point to auditory dominance in the temporal domain and highlight the distinct nature of the sensory processes involved in auditory and visual time interval adaptation. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons LtdItem Restricted Millennium sancısı ve zaman(2000) Yücel, ŞükranItem Open Access Pupil dilation in time perception(Bilkent University, 2023-07) İnan, CanselTime perception corresponds to how we perceive and understand the duration, sequence, and pacing of incidents in our surroundings and is the subjective expe- rience of the course of time. The integration of data from various sensory inputs as well as higher-order cognitive processes like attention, recall, and decision-making are all part of this intricate and multidimensional process. Pupil size is known to increase in response to all kinds of demands like attention, working memory, decision-making, difficult perception, memory recall, etc. In fact, studies show increased pupil size to any kind of task demands. A recent study suggested a dichotomy of task demands based on their distinct neural responses (Farooqui and Manly, 2018). The commonly recognized type of task demand (i.e., type I demand) pertains to issues like increased attention, working memory, the complexity of decisions, etc. For what is being done at that moment. This kind of demand increases activity in the control-related fronto- parietal regions and is well-known to increase pupil size. Farooqui and Manly suggested a different kind of demand (or type II demand) that is related to the length and complexity of the episode of cognition being organized as one unit. They argued that this demand comes about because we execute long tasks as one entity. We, e.g., write emails, shop and not individually execute their very- many component acts. Longer tasks require a longer period of cognition to be organized and controlled as one unit. They evidenced that this demand leads to a deactivation of the control-related fronto-parietal regions and suggested that this demand may psychophysiologically be the opposite of type I demands. The current study investigates this thesis. We used a time-interval replication task. Time-interval replication involves cre- ating an extended cognitive episode. Longer intervals will require creating longer episodes and hence involve higher type II cognitive demands. If type II demands indeed generate the opposite psychophysiological response compared to type I de- mands, we can expect longer time-interval replications to lead to a decreased pupil size. Participants were given various time intervals, e.g., 11 seconds, to replicate by pressing a button at the beginning and at the end of the interval. We used a set of short (8-12 seconds) intervals and a set of long (14-18 seconds) intervals. Long intervals were expectedly more demanding and led to a more erroneous performance. We tested 30 participants (22 females, ages 18-27). If, as is popularly thought, pupil size increases during any kind of demand, then it should be larger when participants replicated longer durations. In contrast, if type II demands of creating longer cognitive episodes were psychophysiologically opposite, then pupil size may be smaller during longer durations. We found this was indeed the case. We show that task demands related to organizing longer cognitive episodes may indeed be distinct from the commonly recognized task demands related to increased attention and working memory.Item Restricted Time and eternity in the thirteenth century(1988) Dales, Richard C.