Multisensory perceptual interactions between higher-order temporal frequency signals

2018 ◽  
Author(s):  
Lexi E. Crommett ◽  
Deeksha Madala ◽  
Jeffrey M Yau
Keyword(s):  
Sensory Processing ◽  
Temporal Frequency ◽  
Temporal Variations ◽  
Higher Order ◽  
Frequency Sweep ◽  
Auditory Cues ◽  
Naturally Occurring ◽  
Multisensory Interactions ◽  
Sweep Direction ◽  
Frequency Sweeps

Naturally occurring signals in audition and touch can be complex and marked by temporal variations in frequency and amplitude. Auditory frequency sweep processing has been studied extensively; however, much less is known about sweep processing in touch since studies have primarily focused on the perception of simple sinusoidal vibrations. Given the extensive interactions between audition and touch in the frequency processing of pure tone signals, we reasoned that these senses might also interact in the processing of higher-order frequency representations like sweeps. In a series of psychophysical experiments, we characterized the influence of auditory distractors on the ability of participants to discriminate tactile frequency sweeps. Auditory frequency sweeps systematically biased the tactile perception of sweep direction. Importantly, auditory cues exerted little influence on tactile sweep direction perception when the sounds and vibrations occupied different absolute frequency ranges or when the sounds consisted of intensity sweeps. Thus, audition and touch interact in frequency sweep perception in a frequency- and feature-specific manner. Our results demonstrate that audio-tactile interactions are not constrained to the processing of simple sinusoids. Because higher-order frequency representations may be synthesized from simpler representations, our findings imply that multisensory interactions in the temporal frequency domain span multiple hierarchical levels in sensory processing.

scholarly journals Selective attention gates the interactive crossmodal coupling between perceptual systems

2017 ◽  
Author(s):  
Silvia Convento ◽  
Md. Shoaibur Rahman ◽  
Jeffrey M. Yau
Keyword(s):  
Selective Attention ◽  
Sensory Processing ◽  
Functional Relationship ◽  
Temporal Frequency ◽  
Sensory Modality ◽  
Sensory Modalities ◽  
Multisensory Interactions ◽  
Auditory Systems ◽  
Behavioural Experiments ◽  
Perceptual Systems

SummaryCortical sensory systems often activate in parallel, even when stimulation is experienced through a single sensory modality [1–3]. Critically, the functional relationship between co-activated cortical systems is unclear: Co-activations may reflect the interactive coupling between information-linked cortical systems or merely parallel but independent sensory processing. Here, we report causal evidence consistent with the hypothesis that human somatosensory cortex (S1), which co-activates with auditory cortex during the processing of vibrations and textures [4–9], interactively couples to cortical systems that support auditory perception. In a series of behavioural experiments, we used transcranial magnetic stimulation (TMS) to probe interactions between the somatosensory and auditory perceptual systems as we manipulated attention state. Acute manipulation of S1 activity using TMS impairs auditory frequency perception when subjects simultaneously attend to auditory and tactile frequency, but not when attention is directed to audition alone. Auditory frequency perception is unaffected by TMS over visual cortex thus confirming the privileged interactions between the somatosensory and auditory systems in temporal frequency processing [10–13]. Our results provide a key demonstration that selective attention can modulate the functional properties of cortical systems thought to support specific sensory modalities. The gating of crossmodal coupling by selective attention may critically support multisensory interactions and feature-specific perception.

Epilogue

2018 ◽  
Author(s):  
Bruno and
Keyword(s):  
Sensory Processing ◽  
Multisensory Processing ◽  
Multisensory Perception ◽  
Future Directions ◽  
Life Problems ◽  
Multisensory Interactions ◽  
Contemporary Work ◽  
New Perspective

Multisensory interactions in perception are pervasive and fundamental, as we have documented throughout this book. In this final chapter, we propose that contemporary work on multisensory processing is a paradigm shift in perception science, calling for a radical reconsideration of empirical and theoretical questions within an entirely new perspective. In making our case, we emphasize that multisensory perception is the norm, not the exception, and we remark that multisensory interactions can occur early in sensory processing. We reiterate the key notions that multisensory interactions come in different kinds and that principles of multisensory processing must be considered when tackling multisensory daily-life problems. We discuss the role of unisensory processing in a multisensory world, and we conclude by suggesting future directions for the multisensory field.

scholarly journals Structural and Functional Basis for an EBNA1 Hexameric Ring in Epstein-Barr Virus Episome Maintenance

2017 ◽  
Vol 91 (19) ◽  
Author(s):  
Julianna S. Deakyne ◽  
Kimberly A. Malecka ◽  
Troy E. Messick ◽  
Paul M. Lieberman
Keyword(s):  
Crystal Structure ◽  
Dna Binding ◽  
Complex Formation ◽  
Epstein Barr Virus ◽  
Higher Order ◽  
Order Complex ◽  
Barr Virus ◽  
Naturally Occurring ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) establishes a stable latent infection that can persist for the life of the host. EBNA1 is required for the replication, maintenance, and segregation of the latent episome, but the structural features of EBNA1 that confer each of these functions are not completely understood. Here, we have solved the X-ray crystal structure of an EBNA1 DNA-binding domain (DBD) and discovered a novel hexameric ring oligomeric form. The oligomeric interface pivoted around residue T585 as a joint that links and stabilizes higher-order EBNA1 complexes. Substitution mutations around the interface destabilized higher-order complex formation and altered the cooperative DNA-binding properties of EBNA1. Mutations had both positive and negative effects on EBNA1-dependent DNA replication and episome maintenance with OriP. We found that one naturally occurring polymorphism in the oligomer interface (T585P) had greater cooperative DNA binding in vitro, minor defects in DNA replication, and pronounced defects in episome maintenance. The T585P mutant was compromised for binding to OriP in vivo as well as for assembling the origin recognition complex subunit 2 (ORC2) and trimethylated histone 3 lysine 4 (H3K4me3) at OriP. The T585P mutant was also compromised for forming stable subnuclear foci in living cells. These findings reveal a novel oligomeric structure of EBNA1 with an interface subject to naturally occurring polymorphisms that modulate EBNA1 functional properties. We propose that EBNA1 dimers can assemble into higher-order oligomeric structures important for diverse functions of EBNA1. IMPORTANCE Epstein-Barr virus is a human gammaherpesvirus that is causally associated with various cancers. Carcinogenic properties are linked to the ability of the virus to persist in the latent form for the lifetime of the host. EBNA1 is a sequence-specific DNA-binding protein that is consistently expressed in EBV tumors and is the only viral protein required to maintain the viral episome during latency. The structural and biochemical mechanisms by which EBNA1 allows the long-term persistence of the EBV genome are currently unclear. Here, we have solved the crystal structure of an EBNA1 hexameric ring and characterized key residues in the interface required for higher-order complex formation and long-term plasmid maintenance.

scholarly journals Higher order Rab programming in phagolysosome biogenesis

2006 ◽  
Vol 174 (7) ◽  
pp. 923-929 ◽  
Author(s):  
Esteban A. Roberts ◽  
Jennifer Chua ◽  
George B. Kyei ◽  
Vojo Deretic
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Higher Order ◽  
Intracellular Pathogen ◽  
Control Mechanisms ◽  
Rab Gtpases ◽  
Endosomal Compartment ◽  
Phagosomal Maturation ◽  
Naturally Occurring ◽  
Latex Beads

Phagosomes offer kinetically and morphologically tractable organelles to dissect the control of phagolysosome biogenesis by Rab GTPases. Model phagosomes harboring latex beads undergo a coordinated Rab5–Rab7 exchange, which is akin to the process of endosomal Rab conversion, the control mechanisms of which are unknown. In the process of blocking phagosomal maturation, the intracellular pathogen Mycobacterium tuberculosis prevents Rab7 acquisition, thus, providing a naturally occurring tool to study Rab conversion. We show that M. tuberculosis inhibition of Rab7 acquisition and arrest of phagosomal maturation depends on Rab22a. Four-dimensional microscopy revealed that phagosomes harboring live mycobacteria recruited and retained increasing amounts of Rab22a. Rab22a knockdown in macrophages via siRNA enhanced the maturation of phagosomes with live mycobacteria. Conversely, overexpression of the GTP-locked mutant Rab22aQ64L prevented maturation of phagosomes containing heat-killed mycobacteria, which normally progress into phagolysosomes. Moreover, Rab22a knockdown led to Rab7 acquisition by phagosomes harboring live mycobacteria. Our findings show that Rab22a defines the critical checkpoint for Rab7 conversion on phagosomes, allowing or disallowing organellar transition into a late endosomal compartment. M. tuberculosis parasitizes this process by actively recruiting and maintaining Rab22a on its phagosome, thus, preventing Rab7 acquisition and blocking phagolysosomal biogenesis.

scholarly journals Review: Higher Order Sensory Processing

Perception ◽  
1992 ◽  
Vol 21 (1) ◽  
pp. 141-142
Author(s):  
V Dobson
Keyword(s):  
Sensory Processing ◽  
Higher Order

scholarly journals Time Variation of Velocity Flows from Ring Diagrams: A First Approach

1998 ◽  
Vol 185 ◽  
pp. 175-176
Author(s):  
J. Patrón ◽  
I. González Hernández ◽  
D.-Y. Chou ◽  
Keyword(s):  
Temporal Frequency ◽  
Power Spectra ◽  
Temporal Variations ◽  
Three Dimensions ◽  
Wave Number ◽  
Local Analysis ◽  
The Sun ◽  
Ring Diagram ◽  
Analysis Technique ◽  
Horizontal Wave

The Ring Diagram analysis is a technique designed to infer the presence of horizontal velocity flows under the solar surface by the analysis of the power spectra of solar oscillations in three dimensions: the two components of the horizontal wave number and temporal frequency (Hill, 1988 and Patrón et al., 1995). This procedure is applied as a local analysis technique, performed for a region of the Sun of several heliographic degrees (typically around 15×15 degrees square). As the Sun is rotating, we must track a chosen region as long as it is present at the visible part of the solar disk, and we can continue the tracking after several solar rotations. The comparison of the estimated flow fields obtained at different times can give some ideas about the temporal variations of the flows.

Temporal-frequency selectivity in monkey visual cortex

1996 ◽  
Vol 13 (3) ◽  
pp. 477-492 ◽  
Author(s):  
M. J. Hawken ◽  
R. M. Shapley ◽  
D. H. Grosof
Keyword(s):  
Frequency Tuning ◽  
Temporal Frequency ◽  
Higher Order ◽  
Primary Input ◽  
Simple Cells ◽  
Complex Cells ◽  
Lateral Geniculate ◽  
Low Pass ◽  
Band Pass ◽  
Visual Delay

AbstractWe investigated the dynamics of neurons in the striate cortex (V1) and the lateral geniculate nucleus (LGN) to study the transformation in temporal-frequency tuning between the LGN and V1. Furthermore, we compared the temporal-frequency tuning of simple with that of complex cells and direction-selective cells with nondirection-selective cells, in order to determine whether there are significant differences in temporal-frequency tuning among distinct functional classes of cells within V1. In addition, we compared the cells in the primary input layers of V1 (4a, 4cα, and 4cβ) with cells in the layers that are predominantly second and higher order (2, 3, 4b, 5, and 6). We measured temporal-frequency responses to drifting sinusoidal gratings. For LGN neurons and simple cells, we used the amplitude and phase of the fundamental response. For complex cells, the elevation of impulse rate (F0) to a drifting grating was the response measure. There is significant low-pass filtering between the LGN and the input layers of V1 accompanied by a small, 3-ms increase in visual delay. There is further low-pass filtering between V1 input layers and the second- and higher-order neurons in V1. This results in an average decrease in high cutoff temporal-frequency between the LGN and V1 output layers of about 20 Hz and an increase in average visual latency of about 12–14 ms. One of the most salient results is the increased diversity of the dynamic properties seen in V1 when compared to the cells of the lateral geniculate, possibly reflecting specialization of function among cells in V1. Simple and complex cells had distributions of temporal-frequency tuning properties that were similar to each other. Direction-selective and nondirection-selective cells had similar preferred and high cutoff temporal frequencies, but direction-selective cells were almost exclusively band-pass while nondirection-selective cells distributed equally between band-pass and low-pass categories. Integration time, a measure of visual delay, was about 10 ms longer for V1 than LGN. In V1 there was a relatively broad distribution of integration times from 40–80 ms for simple cells and 60–100 ms for complex cells while in the LGN the distribution was narrower.

Perception of Distress Calls in Mallard Ducklings (Anas Platyrhynchos)

Behaviour ◽  
1986 ◽  
Vol 99 (3-4) ◽  
pp. 250-274 ◽  
Author(s):  
Christopher S. Evans ◽  
Stephen J. Gaioni
Keyword(s):  
Auditory Perception ◽  
Selection Pressure ◽  
Anas Platyrhynchos ◽  
Acoustic Features ◽  
Acoustic Feature ◽  
Frequency Sweep ◽  
Significant Decrement ◽  
Distress Calls ◽  
Mallard Duckling ◽  
Frequency Sweeps

AbstractThree experiments examined mallard ducklings' perception of conspecific distress calls, as measured by their tendency to alternate their own vocalizations with tape-recorded test calls. This alternation response involved a duckling inhibiting its own calls during the tape-recorded stimuli, and then calling during the interstimulus intervals. 1. In Experiments 1 and 2, when ducklings were tested with calls having note periods that were substantially shorter or longer than the normal note period for distress calls, they showed a significant decrement in their call alternation response. The effects of shortening and lengthening note period, however, were not symmetrical: shortening note period by a given amount had a greater effect on responding than lengthening note period by that same amount. This response asymmetry may be due to a selection pressure operating to enable ducklings to discriminate between distress calls and another conspecific vocalization, contentment calls, which have shorter note periods than distress calls. 2. Experiment 3 examined the effect on ducklings of simultaneously manipulating two acoustic features known to be important for duckling recognition of distress calls: the temporal patterning of the notes within the call, and the frequency sweep found at the end of each distress note. Ducklings tested with a call having both a shortened note period, and the terminal frequency sweep removed from each note, displayed a significantly worse alternation response than ducklings tested with calls having either shortened note periods, or deleted frequency sweeps, but not both. The ducklings in the latter two treatments, in turn, had a significantly worse alternation response than ducklings tested with a normal call. Thus, the effects of manipulating these two acoustic features summated. 3. These results are consistent with a model of auditory perception in mallard ducklings in which recognition of a species-typical call depends on the summation of outputs from a set of perceptual filters each tuned to a specific acoustic feature of the call. Experiments are currently in progress to examine whether this model can be applied to mallard duckling perception of a second species-typical vocalization, the duckling contentment call.

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