The Brain Basis of Positive and Negative Affect: Evidence from a Meta-Analysis of the Human Neuroimaging Literature.
Level 1 - systematic review of randomized trials
Meta-analysis of neuroimaging studies (graded by design analogy)
PubMed 25631056 · doi:10.1093/cercor/bhv001
What was done
Authors conducted a meta-analysis of 397 human functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) neuroimaging studies, comprising 914 experimental contrasts and 6,827 participants. They evaluated three models of hedonic valence: the bipolarity hypothesis (a single network scaling monotonically across valence), the bivalent hypothesis (separate, dedicated networks for positive and negative affect), and the affective workspace hypothesis (a flexible set of valence-general brain regions).
What was found
The authors found little evidence supporting either the bipolar or bivalent hypotheses. The data supported the affective workspace hypothesis, indicating that valence is implemented across instances by a shared set of valence-general limbic and paralimbic brain regions. The abstract reports no numerical effect sizes or quantitative test statistics.
Why it matters
This synthesis challenges classical models in affective neuroscience that separate positive and negative emotions into distinct anatomical brain systems, supporting a common, flexible neural architecture for valence processing.
Limits
The abstract provides no numerical effect estimates, statistical thresholds, or heterogeneity measures. Findings are constrained to the macroscopic spatial resolution of fMRI and PET, which cannot detect fine-grained, neuronal-level population coding that may distinguish positive from negative valence within shared brain regions.
Cited by
- contradicts More brain tissue in the limbic system is dedicated to negative emotions than to positive emotions.
- contradicts There is more brain space and tissue devoted in the limbic system to negative emotions than to positive emotions.