Visual cortex and auditory cortex activation in early binocularly blind macaques: A BOLD-fMRI study using auditory stimuli

The linearity of BOLD responses is a fundamental presumption in most analysis procedures for BOLD fMRI studies. Previous studies have examined the linearity of BOLD signal increments, but less is known about the linearity of BOLD signal decrements. The present study assessed the linearity of both BOLD signal increments and decrements in the human primary visual cortex using a contrast adaptation paradigm. Results showed that both BOLD signal increments and decrements kept linearity to long stimuli (e.g., 3 s, 6 s), yet, deviated from linearity to transient stimuli (e.g., 1 s). Furthermore, a voxel-wise analysis showed that the deviation patterns were different for BOLD signal increments and decrements: while the BOLD signal increments demonstrated a consistent overestimation pattern, the patterns for BOLD signal decrements varied from overestimation to underestimation. Our results suggested that corrections to deviations from linearity of transient responses should consider the different effects of BOLD signal increments and decrements.

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Differential effects of aquaporin-4 channel inhibition on BOLD fMRI and diffusion fMRI responses in mouse visual cortex

PLoS ONE ◽

10.1371/journal.pone.0228759 ◽

2020 ◽

Vol 15 (5) ◽

pp. e0228759 ◽

Cited By ~ 2

Author(s):

Yuji Komaki ◽

Clement Debacker ◽

Boucif Djemai ◽

Luisa Ciobanu ◽

Tomokazu Tsurugizawa ◽

...

Keyword(s):

Visual Cortex ◽

Aquaporin 4 ◽

Bold Fmri ◽

Differential Effects ◽

Channel Inhibition ◽

Mouse Visual Cortex ◽

And Diffusion

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Temporal Nonlinearity During Recovery From Sequential Inhibition by Neurons in the Cat Primary Auditory Cortex

Journal of Neurophysiology ◽

10.1152/jn.00625.2005 ◽

2006 ◽

Vol 95 (3) ◽

pp. 1897-1907 ◽

Cited By ~ 20

Author(s):

Kyle T. Nakamoto ◽

Jiping Zhang ◽

Leonard M. Kitzes

Keyword(s):

Auditory Cortex ◽

Recovery Rate ◽

Primary Auditory Cortex ◽

Auditory Stimuli ◽

Time Interval ◽

Large Set ◽

Strong Response ◽

Preceding Stimulus ◽

Sequential Inhibition ◽

Response Area

Auditory stimuli occur most often in sequences rather than in isolation. It is therefore necessary to understand how responses to sounds occurring in sequences differ from responses to isolated sounds. Cells in primary auditory cortex (AI) respond to a large set of binaural stimuli when presented in isolation. The set of responses to such stimuli presented at one frequency comprises a level response area. A preceding binaural stimulus can reduce the size and magnitude of level response areas of AI cells. The present study focuses on the effects of the time interval between a preceding stimulus and the stimuli of a level response area in pentobarbital-anesthetized cats. After the offset of a preceding stimulus, the ability of AI cells to respond to succeeding stimuli varies dynamically in time. At short interstimulus intervals (ISI), a preceding stimulus can completely inhibit responses to succeeding stimuli. With increasing ISIs, AI cells respond first to binaural stimuli that evoke the largest responses in the control condition, i.e., not preceded by a stimulus. Recovery rate is nonlinear across the level response area; responses to these most-effective stimuli recover to 70% of control on average 187 ms before responses to other stimuli recover to 70% of their control sizes. During the tens to hundreds of milliseconds that a level response area is reduced in size and magnitude, the selectivity of AI cells is increased for stimuli that evoke the largest responses. This increased selectivity results from a temporal nonlinearity in the recovery of the level response area which protects responses to the most effective binaural stimuli. Thus in a sequence of effective stimuli, a given cell will respond selectively to only those stimuli that evoke a strong response when presented alone.

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