Behavioral Time Course of Microstimulation in Cortical Area MT

Masse, Nicolas Y.; Cook, Erik P.

doi:10.1152/jn.91022.2008

Cited by 15 publications

(16 citation statements)

References 64 publications

(108 reference statements)

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“…However, it is far less obvious why such effects would last for as long as they do-in our MT recordings, direction-selective responses to a stationary grating could be observed several hundred milliseconds after 67 ms of motion adaptation. The observed effect is similar to that of brief electrical stimulation, which has been shown to cause transient excitation followed by a prolonged period of suppression (32), likely caused by slow inhibitory postsynaptic potentials (54).…”

Section: Discussionsupporting

confidence: 65%

“…Specifically, the spike trains were represented as sums of δ functions and convolved with an exponential kernel with a time constant of 50 ms. The choice of this time constant was based on results demonstrating that leaky integration with time constants between 30 and 70 ms adequately explains both neural and behavioral responses to brief motion signals (32,34). Additional analysis conducted without leaky integration is shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The integrator time constant was set to 50 ms. The use of the leaky integrator and its duration were motivated by previous results demonstrating that behavioral and neural responses to very brief motion signals (31,32,34) have an obligatorily low-pass character, possibly imposed by structures downstream from MT (31).…”

Section: Rapid Motion Adaptation Reflects Early Visual Motion Processmentioning

confidence: 99%

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Perceptual and neural consequences of rapid motion adaptation

Glasser

Tsui²,

Pack³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Nervous systems adapt to the prevailing sensory environment, and the consequences of this adaptation can be observed in the responses of single neurons and in perception. Given the variety of timescales underlying events in the natural world, determining the temporal characteristics of adaptation is important to understanding how perception adjusts to its sensory environment. Previous work has shown that neural adaptation can occur on a timescale of milliseconds, but perceptual adaptation has generally been studied over relatively long timescales, typically on the order of seconds. This disparity raises important questions. Can perceptual adaptation be observed at brief, functionally relevant timescales? And if so, how do its properties relate to the rapid adaptation seen in cortical neurons? We address these questions in the context of visual motion processing, a perceptual modality characterized by rapid temporal dynamics. We demonstrate objectively that 25 ms of motion adaptation is sufficient to generate a motion aftereffect, an illusory sensation of movement experienced when a moving stimulus is replaced by a stationary pattern. This rapid adaptation occurs regardless of whether the adapting motion is perceived. In neurophysiological recordings from the middle temporal area of primate visual cortex, we find that brief motion adaptation evokes directionselective responses to subsequently presented stationary stimuli. A simple model shows that these neural responses can explain the consequences of rapid perceptual adaptation. Overall, we show that the motion aftereffect is not merely an intriguing perceptual illusion, but rather a reflection of rapid neural and perceptual processes that can occur essentially every time we experience motion.T he nervous system constantly adapts to the statistics of its sensory inputs, and such adaptation has important perceptual consequences (1, 2). Examples include the desensitization of the somatosensory system to constant stimuli (e.g., clothing) and the visual system's adjustments to prevailing light levels. Adaptation affects both neural activity during constant stimulation and neural responses to subsequent stimuli (1). Given the variety of timescales underlying events in the natural world, determining the temporal characteristics of adaptation is a key step in understanding sensory perception. Traditionally, perceptual adaptation is thought to occur over long time periods, with the adapting stimuli being presented for seconds or longer. Neurophysiological work, however, has shown that adaptation occurs at a variety of timescales and can be observed following stimulus exposures as brief as tens of milliseconds (1, 3-7). This rapid adaptation has strong implications for neural coding of sensory stimuli (5,6,8), which renders the relative lack of evidence about brief perceptual adaptation puzzling. Here we consider this question in the context of visual motion processing. Because of the highly dynamic nature of moving stimuli, rapid adaptation is potentially of great relev...

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Section: Discussionsupporting

confidence: 65%

Section: Methodsmentioning

confidence: 99%

Section: Rapid Motion Adaptation Reflects Early Visual Motion Processmentioning

confidence: 99%

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Perceptual and neural consequences of rapid motion adaptation

Glasser

Tsui²,

Pack³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…The sum of model neurons from the same detector channel was integrated in time using a leaky integrator with a time constant of 60 ms and exponential decay. The integration time constant was based on past estimates of integration in a temporal summation task using random dot motion (Masse and Cook, 2010). The integrated signal from each pool was fed to a detector that triggered a response if the signal reached a fixed threshold (Fig.…”

Section: A Feedforward Model Reproduces Neural-behavioral Correlationsmentioning

confidence: 99%

The Functional Link between Area MT Neural Fluctuations and Detection of a Brief Motion Stimulus

Smith

Zhan²,

Cook³

2011

J. Neurosci.

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Fluctuations of neural firing rates in visual cortex are known to be correlated with variations in perceptual performance. It is important to know whether these fluctuations are functionally linked to perception in a causal manner or instead reflect non-causal processes that arise after the perceptual decision is made. We recorded from middle temporal (MT) neurons from monkey subjects while they detected the random occurrence of a brief 50 ms motion pulse that occurred in either of two (or simultaneously in both) random dot patches located in the same hemisphere. The receptive field parameters of the motion pulse were matched to that preferred by each MT neuron under study. This task contained uncertainty in both space and time because, on any given trial, the subjects did not know which patch would contain the motion pulse or when the motion pulse would occur. Covariations between MT activity and behavior began just before the motion pulse onset and peaked at the maximum neural response. These neural-behavioral covariations were strongest when only one patch contained the motion pulse and were still weakly present when a patch did not contain a motion pulse. A feedforward temporal integration model with two independent detector channels captured both the detection performance and evolution of the neuralbehavior covariations over time and stimulus condition. The results suggest that, when detecting a brief visual stimulus, there is a causal relationship between fluctuations in neural activity and variations in behavior across trials.

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“…Similarly, sustained electrical stimulation of neuronal tissue results in a desensitization of neurons to electrical stimulation (McCreery et al, 1997). In addition, direct stimulation of cortical neurons (Logothetis et al, 2010;Masse and Cook, 2010) activates both excitatory and inhibitory circuits and can lead to long-lasting depression. As a result, a perceptible stimulus can rapidly become indiscernible as a result of adaptation and the perceived magnitude of a constant electrical stimulus decreases over time.…”

Section: Adaptationmentioning

confidence: 99%