skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: What computations can be done with traveling waves in visual cortex?
Abstract Recent analyses have found waves of neural activity traveling across entire visual cortical areas in awake animals. These traveling waves modulate excitability of local networks and perceptual sensitivity. The general computational role for these spatiotemporal patterns in the visual system, however, remains unclear. Here, we hypothesize that traveling waves endow the brain with the capacity to predict complex and naturalistic visual inputs. We present a new network model whose connections can be rapidly and efficiently trained to predict natural movies. After training, a few input frames from a movie trigger complex wave patterns that drive accurate predictions many frames into the future, solely from the network’s connections. When the recurrent connections that drive waves are randomly shuffled, both traveling waves and the ability to predict are eliminated. These results show traveling waves could play an essential computational role in the visual system by embedding continuous spatiotemporal structures over spatial maps.  more » « less
Award ID(s):
2015276
PAR ID:
10529738
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
Research Square
Date Published:
Format(s):
Medium: X
Institution:
Research Square
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; (, Nature Communications)
    Abstract Recent analyses have found waves of neural activity traveling across entire visual cortical areas in awake animals. These traveling waves modulate the excitability of local networks and perceptual sensitivity. The general computational role of these spatiotemporal patterns in the visual system, however, remains unclear. Here, we hypothesize that traveling waves endow the visual system with the capacity to predict complex and naturalistic inputs. We present a network model whose connections can be rapidly and efficiently trained to predict individual natural movies. After training, a few input frames from a movie trigger complex wave patterns that drive accurate predictions many frames into the future solely from the network’s connections. When the recurrent connections that drive waves are randomly shuffled, both traveling waves and the ability to predict are eliminated. These results suggest traveling waves may play an essential computational role in the visual system by embedding continuous spatiotemporal structures over spatial maps. 
    more » « less
  2. ; ; (, Soft Matter)
    null (Ed.)
    Autonomous active, elastic filaments that interact with each other to achieve cooperation and synchrony underlie many critical functions in biology. The mechanisms underlying this collective response and the essential ingredients for stable synchronization remain a mystery. Inspired by how these biological entities integrate elasticity with molecular motor activity to generate sustained oscillations, a number of synthetic active filament systems have been developed that mimic oscillations of these biological active filaments. Here, we describe the collective dynamics and stable spatiotemporal patterns that emerge in such biomimetic multi-filament arrays, under conditions where steric interactions may impact or dominate the collective dynamics. To focus on the role of steric interactions, we study the system using Brownian dynamics, without considering long-ranged hydrodynamic interactions. The simulations treat each filament as a connected chain of self-propelling colloids. We demonstrate that short-range steric inter-filament interactions and filament roughness are sufficient – even in the absence of inter-filament hydrodynamic interactions – to generate a rich variety of collective spatiotemporal oscillatory, traveling and static patterns. We first analyze the collective dynamics of two- and three-filament clusters and identify parameter ranges in which steric interactions lead to synchronized oscillations and strongly occluded states. Generalizing these results to large one-dimensional arrays, we find rich emergent behaviors, including traveling metachronal waves, and modulated wavetrains that are controlled by the interplay between the array geometry, filament activity, and filament elasticity. Interestingly, the existence of metachronal waves is non-monotonic with respect to the inter-filament spacing. We also find that the degree of filament roughness significantly affects the dynamics – specifically, filament roughness generates a locking-mechanism that transforms traveling wave patterns into statically stuck and jammed configurations. Taken together, simulations suggest that short-ranged steric inter-filament interactions could combine with complementary hydrodynamic interactions to control the development and regulation of oscillatory collective patterns. Furthermore, roughness and steric interactions may be critical to the development of jammed spatially periodic states; a spatiotemporal feature not observed in purely hydrodynamically interacting systems. 
    more » « less
  3. ; (, American Society of Mechanical Engineers)
    Abstract The Basilar Membrane (BM) is the structural component of the mammalian cochlea that transmits auditory information as traveling structural waves, and inner hair cells transduce acoustic waves into electrical impulses in the inner ear. These waves go up towards the cochlea’s apex from its base. The primary structure at the apex of the cochlea that keeps waves from returning to the base is the helicotrema. People can hear continuous sound waves without acoustic reflection or overlap because of this property of the BM. Our research is motivated by this biological phenomenon and aims to comprehend and passively reproduce it in engineering structures. By studying the dynamics of a uniform beam linked to a spring-damper system as a passive absorber, we can use this characteristic of the inner ear to explain some of the observed phenomenological behaviors of the basilar membrane. The spring-damper system’s position separates the beam into two dynamic regions: one with standing waves and the other with non-reflecting traveling waves. This study presents the computational realization of traveling waves co-existing with standing waves in the two different zones of the structure. Moreover, this study aims to establish a correlation between two approaches to analyze the characteristics of the wave profiles: (i) the absorption coefficient approach and (ii) the cost function based on the wave envelope. The Basilar Membrane (BM) serves as the crucial structural conduit for transmitting auditory information through traveling structural waves, with inner hair cells in the inner ear transducing these waves into electrical impulses. These waves ascend from the cochlea’s base towards its apex, and the helicotrema, positioned at the cochlear apex, plays a pivotal role in preventing wave reflection and overlap, thereby facilitating the perception of continuous sound waves. The intrinsic characteristics of the Basilar Membrane (BM) inspire our research as we seek to comprehend and passively replicate this phenomenon in simplified forms. The investigation involves the exploration of the dynamics exhibited by a uniform beam connected to a spring-damper system acting as a passive absorber. This chosen system allows us to take advantage of the unique property of the inner ear, shedding light on some of the observed phenomenological behaviors of the basilar membrane. The positioning of the spring-damper system engenders two distinct dynamic regions within the beam: one characterized by standing waves and the other by non-reflecting traveling waves. The comprehensive analysis incorporates analytical and computational aspects, providing a holistic understanding of the coexistence of traveling and standing waves within these two dynamic zones. 
    more » « less
  4. ; ; ; (, Chaos: An Interdisciplinary Journal of Nonlinear Science)
    Propagating precipitation waves are a remarkable form of spatiotemporal behavior that arise through the coupling of reaction, diffusion, and precipitation. We study a system with a sodium hydroxide outer electrolyte and an aluminum hydroxide inner electrolyte. In a redissolution Liesegang system, a single propagating precipitation band moves down through the gel, with precipitate formed at the band front and precipitate dissolved at the band back. Complex spatiotemporal waves occur within the propagating precipitation band, including counter-rotating spiral waves, target patterns, and annihilation of waves on collision. We have also carried out experiments in thin slices of gel, which have revealed propagating waves of a diagonal precipitation feature within the primary precipitation band. These waves display a wave merging phenomenon in which two horizontally propagating waves merge into a single wave. Computational modeling permits the development of a detailed understanding of the complex dynamical behavior. 
    more » « less
  5. ; ; ; (, Geophysical Research Letters)
    Abstract Satellite observations reveal short pulses in the second time derivative of the geomagnetic field. We seek to interpret these signals using complex empirical orthogonal functions (CEOFs). This methodology decomposes the signal into traveling waves, permitting estimates for the period, angular wave number, and phase velocity. We recover CEOFs from the CHAOS‐6 model, focusing on three geographic regions with strong secular acceleration. Two regions are confined to the equator, while the third is located under Alaska. We find evidence for both eastward and westward traveling waves with periods between 7 and 20 years. There is also evidence for weaker standing waves with complex spatial patterns. Two of the three regions have waves that are compatible with predictions for waves in a stratified fluid. Our results yield estimates for the structure of fluid stratification at the top of the core. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email