当代生物(CURRENT BIOLOGY)2013-09-05 2:57 AM

Current Biology - Asynchronous Broadband Signals Are the Principal Source of the BOLD Response in Human Visual Cortex

Background Activity in the living human brain can be studied using multiple methods, spanning a wide range of spatial and temporal resolutions. We investigated the relationship between electric field potentials measured with electrocorticography (ECoG) and the blood oxygen level-dependent (BOLD) response measured with functional magnetic resonance imaging (fMRI). We set out to explain the full set of measurements by modeling the underlying neural circuits. Results ECoG responses in visual cortex can be separated into two visually driven components. One component is a specific temporal response that follows each stimulus contrast reversal (“stimulus locked”); the other component is an increase in the response variance (“asynchronous”). For electrodes in visual cortex (V1, V2, V3), the two measures respond to stimuli in the same region of visual space, but they have different spatial summation properties. The stimulus-locked ECoG component sums contrast approximately linearly across space; spatial summation in the asynchronous ECoG component is subadditive. Spatial summation measured using BOLD closely matches the asynchronous component. We created a neural simulation that accurately captures the main features of the ECoG time series; in the simulation, the stimulus-locked and asynchronous components arise from different neural circuits. Conclusions These observations suggest that the two ECoG components arise from different neural sources within the same cortical region. The spatial summation measurements and simulations suggest that the BOLD response arises primarily from neural sources that generate the asynchronous broadband ECoG component.

KEYWORDS

SHARE & LIKE

COMMENTS

ABOUT THE AUTHOR

当代生物(CURRENT BIOLOGY)

0 Following 0 Fans 0 Projects 13 Articles

SIMILAR ARTICLES

Background Actin-based cell motility is fundamental for development, function, and malignant events in eukaryotic organisms. During neural development

Read More

Background Dedicated storage organs in the form of tubers are evolutionary novelties that share a common function but originate in diverse species fro

Read More

Background Yeast cells depend on Arp2/3 complex to assemble actin filaments at sites of endocytosis, but the source of the initial filaments required

Read More

Background In the intracellular environment, motor-driven cargo must navigate a dense cytoskeletal network among abundant organelles. Results We i

Read More

Background In preimplantation mouse embryos, the first cell fate specification to the trophectoderm or inner cell mass occurs by the early blastocyst

Read More

Background Branched actin filament networks driving cell motility, endocytosis, and intracellular transport are assembled in seconds by the Arp2/3 com

Read More

Background During cell division, chromosomes must clear the path of the cleavage furrow before the onset of cytokinesis. The abscission checkpoint in

Read More

Background The juxtaposition of newly formed primordia in the root and shoot differs greatly, but their formation in both contexts depends on local ac

Read More

Listeners exploit small interindividual variations around a generic acoustical structure to discriminate and identify individuals from their voice—a ke

Read More

Background The ability to distinguish sensory signals that register unexpected events (exafference) from those generated by voluntary actions (reaffer

Read More