Cited by 779Functional Brain Connectivity StudiesAdvanced Neuroimaging Techniques and ApplicationsNeural dynamics and brain function

The elusive concept of brain connectivity

Horwitz, Barry·2003·NeuroImage

Abstract

Neurons and neural populations do not function as islands onto themselves. Rather, they interact with other such elements through their afferent and efferent connections in an orchestrated manner so as to enable different sensorimotor and cognitive tasks to be performed. The concept of functional connectivity and the allied notion of effective connectivity were introduced to designate the functional strengths of such interactions. Functional neuroimaging methods, especially PET and fMRI, have been used extensively to evaluate the functional connectivity between different brain regions. After providing a brief historical review of these notions of brain connectivity, I argue that the conceptual formulations of functional and effective connectivity are far from clear. Specifically, the terms functional and effective connectivity are applied to quantities computed on types of functional imaging data (e.g., PET, fMRI, EEG) that vary in spatial, temporal, and other features, using different definitions (even for data of the same modality) and employing different computational algorithms. Until it is understood what each definition means in terms of an underlying neural substrate, comparisons of functional and/or effective connectivity across studies may appear inconsistent and should be performed with great caution.

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Crossref · 10.1016/s1053-8119(03)00112-5

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Authors
Horwitz, B.
Affiliations
National Institutes of Health (US)
Corresponding author
Horwitz, Barry
Venue
NeuroImage
Publisher
Elsevier BV
Published
2003-06
Volume
19
Issue
2
Pages
466-470
ISSN
1053-8119 (ISSN-L)
OpenAlex
W2168396492
Cited by
779
References
47
Citations by year
2026: 5 · 2025: 13 · 2024: 20 · 2023: 28 · 2022: 24 · 2021: 61 · 2020: 37 · 2019: 38 · 2018: 27 · 2017: 34 · 2016: 45 · 2015: 28 · 2014: 45 · 2013: 59 · 2012: 34
FWCI
12.56
Type
journal article
Language
en
Open access
closed
Locations
  • NeuroImage (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Functional Brain Connectivity Studies
  • Health Sciences › Medicine › Radiology, Nuclear Medicine and Imaging › Advanced Neuroimaging Techniques and Applications
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Neural dynamics and brain function
Keywords
brain connectivity, functional connectivity, effective connectivity, afferent and efferent connections, neuronal populations, functional neuroimaging, PET, functional MRI, EEG, conceptual definitions, inter-study comparability
MeSH terms
Brain, Brain Mapping, Electroencephalography, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Mathematical Computing, Nerve Net, Neural Pathways, Neurons, Tomography, Emission-Computed, Neural Networks, Computer

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