منابع مشابه
The Negative BOLD Signal Unmasked
Many fMRI experiments show regions of cortex that seem to respond in antiphase with the primary stimulus. In this issue of Neuron, Shmuel et al. show that this "negative BOLD response" is spatially and temporally linked to reductions in blood flow. By combining BOLD and blood flow data to model the energy consumption in cortex, they conclude that the NBR is primarily due to active neuronal inhi...
متن کاملInterpreting the BOLD signal.
The development of functional magnetic resonance imaging (fMRI) has brought together a broad community of scientists interested in measuring the neural basis of the human mind. Because fMRI signals are an indirect measure of neural activity, interpreting these signals to make deductions about the nervous system requires some understanding of the signaling mechanisms. We describe our current und...
متن کاملDetectability of the BOLD signal
Introduction The BOLD signal is a weak signal, and hence if no BOLD signal is found in an area this does not automatically mean there is no neural activity in that area. Signal dropout, artifacts, instability, physiological noise, RF-coil inhomogeneity etc. can all reduce the SNR locally leading to decreased detectability of the BOLD signal. Here we illustrate that calculation of the spatial di...
متن کاملLong-latency reductions in gamma power predict hemodynamic changes that underlie the negative BOLD signal.
Studies that use prolonged periods of sensory stimulation report associations between regional reductions in neural activity and negative blood oxygenation level-dependent (BOLD) signaling. However, the neural generators of the negative BOLD response remain to be characterized. Here, we use single-impulse electrical stimulation of the whisker pad in the anesthetized rat to identify components o...
متن کاملBehavioral correlates of negative BOLD signal changes in the primary somatosensory cortex
Functional magnetic resonance imaging (fMRI) hypothesis testing based on the blood oxygenation level dependent (BOLD) contrast mechanism typically involves a search for a positive effect during a specific task relative to a control state. However, aside from positive BOLD signal changes there is converging evidence that neuronal responses within various cortical areas also induce negative BOLD ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Neuron
سال: 2002
ISSN: 0896-6273
DOI: 10.1016/s0896-6273(02)01138-8