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Neurophysiological investigation of the basis of the fMRI signal
These findings suggest that the BOLD contrast mechanism reflects the input and intracortical processing of a given area rather than its spiking output, and that LFPs yield a better estimate of BOLD responses than the multi-unit responses.
What we can do and what we cannot do with fMRI
- N. Logothetis
- 12 June 2008
An overview of the current state of fMRI is given, and the current understanding of the haemodynamic signals and the constraints they impose on neuroimaging data interpretation are presented.
Decorrelated Neuronal Firing in Cortical Microcircuits
- Alexander S. Ecker, Philipp Berens, Georgios A. Keliris, M. Bethge, N. Logothetis, A. Tolias
The findings suggest a refinement of current models of cortical microcircuit architecture and function: Either adjacent neurons share only a few percent of their inputs or, alternatively, their activity is actively decorrelated.
The Underpinnings of the BOLD Functional Magnetic Resonance Imaging Signal
- N. Logothetis
- BiologyThe Journal of Neuroscience
- 15 May 2003
The good coverage and high resolution afforded by functional magnetic resonance imaging make it an excellent tool for the noninvasive imaging of the human brain and the use of this technique in animal studies using high magnetic fields is interesting.
Interpreting the BOLD signal.
The current understanding of the causal relationships between neural activity and the blood-oxygen-level-dependent (BOLD) signal is described, and how these analyses have challenged some basic assumptions that have guided neuroscience are reviewed.
Modelling and analysis of local field potentials for studying the function of cortical circuits
Careful mathematical modelling and analysis are needed to take full advantage of the opportunities that this signal offers in understanding signal processing in cortical circuits and, ultimately, the neural basis of perception and cognition.
Shape representation in the inferior temporal cortex of monkeys
Multistable phenomena: changing views in perception
Very slow activity fluctuations in monkey visual cortex: implications for functional brain imaging.
The existence of widespread coherent activity fluctuations in the brain of the awake monkey over very long time-scales is demonstrated and it is proposed that such signals may make a significant contribution to the high variability observed in the time course of physiological signals, including those measured with functional imaging techniques.
Evidence from imaging and electrophysiological techniques supports a view of rivalry as a series of processes, each of which is implemented by neural mechanisms at different levels of the visual hierarchy.