Publications (3)4.95 Total impact
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ABSTRACT: Studies combining electrophysiological and behavioral laterality measures hold great potential to illuminate hemispheric relations in attention. However, data from evoked or event related potentials (ERP) as well as spectral analyses (QEEG and band power) are conflicting, and do not support a coherent theory of the electrophysiology of hemispheric attention. At the same time, a definitive behavioral measure of attention does not currently exist. In order to remedy these lacunae, we carried out the following experiment. Four groups of learning disabled young adults received the same EEG biofeedback (EEGBF) protocol, consisting of training theta (4-8 Hz) down and training SMR (12-15 Hz) up at 4 different electrode sites: C3 (7 subjects), C4 (10 subjects), Cz (9 subjects), and Fz (8 subjects). The C3 site is over left sensory motor cortex, C4 is over right sensory motor cortex, and Fz and Cz are over the front and middle regions of the central strip, respectively. Attention in each hemisphere was measured before and after EEGBF training using the computerized Lateralized Attention Network Test (LANT). The LANT estimates four separate networks of attention: executive-frontal Conflict resolution (C), the benefit and cost of spatial Orienting (OB and OC, respectively), and Alerting, or sustained attention (A). EEGBF affected different networks maximally at different sites: Training at C3 reduced C in the right hemisphere, training at C4 improved A bilaterally and training at Cz increased OB bilaterally. Generally, C3 training improved attention in the right hemisphere and C4 training improved attention in the left hemisphere. This suggests that training at C3 and C4 activates a meta-cognitive control system which is contralaterally organized. We concluded that EEGBF has site-specific and function-specific effects on attention. Further, unilateral training can have bilateral effects or even predominantly contralateral ones. This procedure suggests a new way to probe discrete physiological correlates of discrete behavioral changes following EEG biofeedback. Such data inform functional theories of attention and clinical interventions in disorders of attention.
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ABSTRACT: The attention network test (ANT) is a brief computerized battery measuring three independent behavioral components of attention: Conflict resolution (ability to overcome distracting stimuli), spatial Orienting (the benefit of valid spatial pre-cues), and Alerting (the benefit of temporal pre-cues). Imaging, clinical, and behavioral evidence demonstrate hemispheric asymmetries in these attentional networks. We constructed a lateralized version of the ANT (LANT), with brief targets flashed in one or the other visual hemifield. We also modified the tests by including invalid spatial cues in order to measure the cost component of Orienting. In a series of experiments, we investigated the efficiency of the attention networks separately in each hemisphere. Participants exhibited significant estimates of all networks measured by the LANT, comparable to the ANT. The three networks were represented in each hemisphere separately and were largely comparable across the two hemispheres. We suggest that the LANT is an informative extension of the original ANT, allowing for measurement of the three attention networks in each hemisphere separately.
University of California, Los Angeles
Los Angeles, California, United States
- Department of Psychology