@article {188, title = {Static sound timing alters sensitivity to low-level visual motion.}, journal = {J Vis}, volume = {12}, year = {2012}, month = {2012}, abstract = {

Visual motion processing is essential to survival in a dynamic world and is probably the best-studied facet of visual perception. It has been recently discovered that the timing of brief static sounds can bias visual motion perception, an effect attributed to "temporal ventriloquism" whereby the timing of the sounds "captures" the timing of the visual events. To determine whether this cross-modal interaction is dependent on the involvement of higher-order attentive tracking mechanisms, we used near-threshold motion stimuli that isolated low-level pre-attentive visual motion processing. We found that the timing of brief sounds altered sensitivity to these visual motion stimuli in a manner that paralleled changes in the timing of the visual stimuli. Our findings indicate that auditory timing impacts visual motion processing very early in the processing hierarchy and without the involvement of higher-order attentional and/or position tracking mechanisms.

}, keywords = {Acoustic Stimulation, Attention, Auditory Perception, Humans, Motion Perception, Photic Stimulation, Sound, Time Perception}, issn = {1534-7362}, doi = {10.1167/12.11.2}, author = {Kafaligonul, Hulusi and Stoner, Gene R} } @article {212, title = {Neural substrates of time perception and impulsivity.}, journal = {Brain Res}, volume = {1406}, year = {2011}, month = {2011 Aug 11}, pages = {43-58}, abstract = {

Several studies provide empirical evidence for the association between impulsivity and time perception. However, little is known about the neural substrates underlying this function. This investigation examined the influence of impulsivity on neural activation patterns during the encoding and reproduction of intervals with durations of 3, 9 and 18s using event-related functional magnetic resonance imaging (fMRI). Twenty-seven subjects participated in this study, including 15 high impulsive subjects that were classified based on their self-rating. FMRI activation during the duration reproduction task was correlated with measures of two self-report questionnaires related to the concept of impulsivity (Barratt Impulsiveness Scale, BIS; Zimbardo Time Perspective Inventory, ZTPI). Behaviorally, those individuals who under-reproduced temporal intervals also showed lower scores on the ZTPI future perspective subscale and higher scores on the BIS. FMRI activation revealed an accumulating pattern of neural activity peaking at the end of the 9- and 18-s intervals within right posterior insula. Activations of brain regions during the reproduction phase of the timing task, such as those related to motor execution as well as to the {\textquoteright}core control network{\textquoteright} - encompassing the inferior frontal and medial frontal cortices, the anterior insula as well as the inferior parietal cortex - were significantly correlated with reproduced duration, as well as with BIS and ZTPI subscales. In particular, the greater activation in these regions the shorter were the reproduced intervals, the more impulsive was an individual and the less pronounced the future perspective. Activation in the core control network, thus, may form a biological marker for cognitive time management and for impulsiveness.

}, keywords = {Adolescent, Brain, Brain Mapping, Female, Humans, Image Processing, Computer-Assisted, Impulsive Behavior, Magnetic Resonance Imaging, Male, Neuropsychological Tests, Oxygen, Personality Inventory, Reaction Time, Self Report, Surveys and Questionnaires, Time Factors, Time Perception, Young Adult}, issn = {1872-6240}, doi = {10.1016/j.brainres.2011.06.048}, author = {Wittmann, Marc and Simmons, Alan N and Flagan, Taru and Lane, Scott D and Wackermann, Ji{\v r}{\'\i} and Paulus, Martin P} } @article {211, title = {Accumulation of neural activity in the posterior insula encodes the passage of time.}, journal = {Neuropsychologia}, volume = {48}, year = {2010}, month = {2010 Aug}, pages = {3110-20}, abstract = {

A number of studies have examined the perception of time with durations ranging from milliseconds to a few seconds, however the neural basis of these processes are still poorly understood and the neural substrates underlying the perception of multiple-second intervals are unknown. Here we present evidence of neural systems activity in circumscribed areas of the human brain involved in the encoding of intervals with durations of 9 and 18s in a temporal reproduction task using event-related functional magnetic resonance imaging (fMRI). During the encoding there was greater activation in more posterior parts of the medial frontal and insular cortex whereas the reproduction phase involved more anterior parts of these brain structures. Intriguingly, activation curves over time show an accumulating pattern of neural activity, which peaks at the end of the interval within bilateral posterior insula and superior temporal cortex when individuals are presented with 9- and 18-s tone intervals. This is consistent with an accumulator-type activity, which encodes duration in the multiple seconds range. Given the close connection between the dorsal posterior insula and ascending internal body signals, we suggest that the accumulation of physiological changes in body states constitutes our experience of time. This is the first time that an accumulation function in the posterior insula is detected that might be correlated with the encoding of time intervals.

}, keywords = {Adult, Analysis of Variance, Brain Mapping, Cerebral Cortex, Factor Analysis, Statistical, Female, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Male, Neuropsychological Tests, Oxygen, Reaction Time, Time Factors, Time Perception, Young Adult}, issn = {1873-3514}, doi = {10.1016/j.neuropsychologia.2010.06.023}, author = {Wittmann, Marc and Simmons, Alan N and Aron, Jennifer L and Paulus, Martin P} } @article {187, title = {Auditory modulation of visual apparent motion with short spatial and temporal intervals.}, journal = {J Vis}, volume = {10}, year = {2010}, month = {2010}, pages = {31}, abstract = {

Recently, E. Freeman and J. Driver (2008) reported a cross-modal temporal interaction in which brief sounds drive the perceived direction of visual apparent-motion, an effect they attributed to "temporal capture" of the visual stimuli by the sounds (S. Morein-Zamir, S. Soto-Faraco, \& A. Kingstone, 2003). Freeman and Driver used "long-range" visual motion stimuli, which travel over long spatial and temporal intervals and engage high-order cortical areas (K. G. Claeys, D. T. Lindsey, E. De Schutter, \& G. A. Orban, 2003; Y. Zhuo et al., 2003). We asked whether Freeman and Driver{\textquoteright}s temporal effects extended to the short-range apparent-motion stimuli that engage cortical area MT, a lower-order area with well-established spatiotemporal selectivity for visual motion (e.g. A. Mikami, 1991, 1992; A. Mikami, W. T. Newsome, \& R. H. Wurtz, 1986a, 1986b; W. T. Newsome, A. Mikami, \& R. H. Wurtz, 1986). Consistent with a temporal-capture account, we found that static sounds bias the perception of both the direction (Experiment 1) and the speed (Experiment 2) of short-range motion. Our results suggest that auditory timing may interact with visual spatiotemporal processing as early as cortical area MT. Examination of the neuronal responses of this well-studied area to the stimuli used in this study would provide a test and might provide insight into the neuronal representation of time.

}, keywords = {Acoustic Stimulation, Auditory Perception, Humans, Motion Perception, Photic Stimulation, Temporal Lobe, Time Perception, Visual Cortex}, issn = {1534-7362}, doi = {10.1167/10.12.31}, author = {Kafaligonul, Hulusi and Stoner, Gene R} } @article {175, title = {Computational influence of adult neurogenesis on memory encoding.}, journal = {Neuron}, volume = {61}, year = {2009}, month = {2009 Jan 29}, pages = {187-202}, abstract = {

Adult neurogenesis in the hippocampus leads to the incorporation of thousands of new granule cells into the dentate gyrus every month, but its function remains unclear. Here, we present computational evidence that indicates that adult neurogenesis may make three separate but related contributions to memory formation. First, immature neurons introduce a degree of similarity to memories learned at the same time, a process we refer to as pattern integration. Second, the extended maturation and change in excitability of these neurons make this added similarity a time-dependent effect, supporting the possibility that temporal information is included in new hippocampal memories. Finally, our model suggests that the experience-dependent addition of neurons results in a dentate gyrus network well suited for encoding new memories in familiar contexts while treating novel contexts differently. Taken together, these results indicate that new granule cells may affect hippocampal function in several unique and previously unpredicted ways.

}, keywords = {Age Factors, Algorithms, Animals, Cell Proliferation, Computer Simulation, Dentate Gyrus, Humans, Memory, Nerve Net, Neural Pathways, Neurogenesis, Neuronal Plasticity, Neurons, Stem Cells, Synapses, Time Perception}, issn = {1097-4199}, doi = {10.1016/j.neuron.2008.11.026}, author = {Aimone, James B and Wiles, Janet and Gage, Fred H} }