Socioeconomic status and the developing brain

Abstract

Childhood socioeconomic status (SES) is associated with cognitive achievement throughout life. How does SES relate to brain development, and what are the mechanisms by which SES might exert its influence? We review studies in which behavioral, electrophysiological and neuroimaging methods have been used to characterize SES disparities in neurocognitive function. These studies indicate that SES is an important predictor of neurocognitive performance, particularly of language and executive function, and that SES differences are found in neural processing even when performance levels are equal. Implications for basic cognitive neuroscience and for understanding and ameliorating the problems related to childhood poverty are discussed.

Figure 1

Heuristic illustrating a lateral view of the localization of five basic neurocognitive systems, defined anatomically based on the cognitive performance of patients with lesions in specific regions and activation in brain regions during specific cognitive tasks in healthy subjects (for further description of the rationale see Refs [16–18]). The five systems are: (1) the `Left perisylvian/Language' system, a complex, distributed system predominantly located in the temporal and frontal areas of the left hemisphere that surround the Sylvian fissure, which encompasses semantic, syntactic and phonological aspects of language; (2) the `Prefrontal/Executive' system, including the Lateral prefrontal/Working memory system that enables us to hold information `on line' to maintain it over an interval and manipulate it, the Anterior cingulate/Cognitive control system that is required when we must resist the most routine or easily available response in favor of a more task-appropriate response and the Ventromedial prefrontal/Reward processing system, which is responsible for regulating our responses in the face of rewarding stimuli; (3) the `Medial temporal/Memory' system (towards the interior of the brain from the visible surface of the temporal lobe depicted here), responsible for one-trial learning, the ability to retain a representation of a stimulus after a single exposure; (4) the `Parietal/Spatial cognition' system, underlying our ability to mentally represent and manipulate the spatial relations among objects and (5) the `Occipitotemporal/Visual cognition' system, responsible for pattern recognition and visual mental imagery, translating image format visual representations into more abstract representations of object shape and identity, and reciprocally translating visual memory knowledge into image format representations.

Figure 2

In first-graders, SES accounts for variance in neurocognitive composite measures of (a) `language' performance on vocabulary and phonological processing tasks; (b) `cognitive control' measures of the ability to inhibit a prepotent response and (c) `working memory', based on tasks assessing working memory of spatial location and figural stimuli. SES accounts for statistically more variance in the language composite than in all other composites, which do not statistically differ from each other. Figure adapted, with permission, from Ref. [18].

Figure 3

Event-related potentials (ERPs) in response to auditory probes in attended and unattended stimuli during a selective spatial auditory attention task. Children age 3–8 years were presented with two simultaneous narrative stories, one in each ear, along with a visual cue directing attention to one ear. (a) Electrode configuration for ERP recording. The 16 electrodes included in analysis are enclosed in boxes. (b) Mean amplitude response (in μV) to probe stimuli in the attended and unattended channel, separately for children in the higher and lower maternal education groups; children with lower maternal education exhibited a higher amplitude response to the probes in the unattended channel, indicative of difficulty suppressing distracting stimuli early in the processing stream. (c) Grand average evoked potentials for attended and unattended stimuli in children in the higher maternal education group (upper panel) and lower maternal education group (lower panel). Figure adapted, with permission, from Ref [40].