Fluid intelligence and the locus coeruleus–norepinephrine system

Abstract

The last decade has seen significant progress identifying genetic and brain differences related to intelligence. However, there remain considerable gaps in our understanding of how cognitive mechanisms that underpin intelligence map onto various brain functions. In this article, we argue that the locus coeruleus–norepinephrine system is essential for understanding the biological basis of intelligence. We review evidence suggesting that the locus coeruleus–norepinephrine system plays a central role at all levels of brain function, from metabolic processes to the organization of large-scale brain networks. We connect this evidence with our executive attention view of working-memory capacity and fluid intelligence and present analyses on baseline pupil size, an indicator of locus coeruleus activity. Using a latent variable approach, our analyses showed that a common executive attention factor predicted baseline pupil size. Additionally, the executive attention function of disengagement––not maintenance––uniquely predicted baseline pupil size. These findings suggest that the ability to control attention may be important for understanding how cognitive mechanisms of fluid intelligence map onto the locus coeruleus–norepinephrine system. We discuss how further research is needed to better understand the relationships between fluid intelligence, the locus coeruleus–norepinephrine system, and functionally organized brain networks.

Spatiotemporal dissociation of brain network connectivity in salience processing: A simultaneous pupillometry-EEG-fMRI study

“…The DMN has been implicated in future planning [14], task switching [24], attention shifts [2], as well as other functions [14], and the LC-NE system has been proposed to modulate the DMN as a neural modulator of mind wandering [65]. Our results are consistent with hypothesis that the LC-NE system modulates the connectivity between the DMN and DAN [94], and also the proposed role as a 7/23 'master switch' [75]. Potential candidate mechanisms of the LC-NE modulation on the DMN and DAN are: 1) The LC-NE system modulates them through the heterogeneous spatial distribution of NE receptor types and densities across the cortex [101,103]; 2) The heterogeneity in LC cell populations might be responsible for the targeted modulations of specific cortex areas [82,93], for example, a modular organization in the LC with distinct efferent neural projection patterns has been reported [73,100]; 3) The LC-NE system might interact with other subcortical nuclei in the modulation [102], such as thalamus, which has been associated with the LC activity [55,57], SN activity [83], and the modulation of cortical networks connectivity [15,40,43,69].…”

Sex differences in developmental pathways to mathematical competence.

“…These factors are often called general intelligence, but the underlying brain and cognitive mechanisms are debated and likely result from a combination of processes from cognition to brain systems to cellular functions (Geary, 2018; Jung & Haier, 2007; Tsukahara & Engle, 2021). At the cognitive level and given the overlap with in-class attention, one plausible explanation is the General Ability factor is capturing, at least in part, individual differences in top-down attentional control, that is the ability to explicitly maintain focused attention on the task at hand (Engle et al, 1999; Kane & Engle, 2002).…”

Publication guidelines and recommendations for pupillary measurement in psychophysiological studies

“…Despite evidence of multiple contributions to pupillary dilation, there has been a recent tendency to interpret pupil dilation as reflecting only the activity of the locus coeruleus (LC; e.g., Elman et al, 2017;Tsukahara & Engle, 2021;van der Linden et al, 2021;Yeung et al, 2021). The LC is a complex of neurons in the rostral pons of the brain, which is the primary site for the synthesis of noradrenaline (norepinephrine) and is closely associated with sympathetic arousal, having wide ranging effects throughout the brain and body.…”