Measuring Independent Attention Networks in the Two Hemispheres

1. Results IVA shows no difference between learning disabled & normal controls No effect of NF • Measuring Independent Attention Networks in the Two Hemispheres • Deanna J. Greene1, Anat Barnea2,, Amir Raz3, & Eran Zaidel1 • 1Department of Psychology, University of California at Los Angeles, CA, USA; 2Bio-Keshev Center, Kibutz Givat Chaim Ichud, Israel; • 3Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY, USA • Introduction • Attention can be viewed as a system of three separate and independent networks: Conflict resolution, spatial Orienting, and Alerting. • Posner and associates devised a test to measure the three attention networks: the Attention Network Test (ANT). • We developed an adaptation of the ANT to measure the networks separately within each hemisphere: the Lateralized Attention Network Test (LANT). • We ran five versions of the LANT on a population of normal young adults and found a version that is optimal for measuring the efficiency of the networks independently in each hemisphere. Independence: within each hemisphere • Definitions: • Conflict: C = Reaction time (RT) for trials with Incongruent flankers minus RT for trials with Congruent flankers • Orienting: divided into cost & benefit components • Orienting Benefit: OB = Center cues minus Valid cues Orienting Cost: OC = Invalid cues minus Center cues • Alerting: A = RT for trials with No cues minus RT for trials with Double cues Versions LANT: • Presented tachistoscopically for 170ms to the left visual field (LVF) or right visual field (RVF) • Target: middle arrow pointing up/down. (see figure) • Flanker arrows: Congruent= same direction as target Incongruent= opposite direction as target Neutral= straight lines Methods ‘+’ = independent ‘-’ = not independent Results Hemispheric Independence Estimates of attention networks  target Conclusions Version 2 (small target, rare invalid cues) yields the best estimates of attention networks, demonstrates the most independence among networks, and demonstrates the most independence for each network between hemispheres. 2.Orienting Cost and Conflict, though both inhibitory, are independent of each other, indicating that they operate under different mechanisms. 3. This version of the LANT is useful for profiling populations with attention deficits and abnormal cerebral asymmetry. Congruent flankers Incongruent flankers Neutral flankers in RVF in LVF in LVF NS • Target preceded by 1 of 5 possible cues: Center= asterisk at central fixation Double= asterisk on both sides of central fixation Valid= asterisk on the side in which the target will appear Invalid= asterisk on the opposite side of where target will appear No cue NS NS • References • Posner, M. I., & Raichle, M. E. (1994). Images of mind. New York: Scientific American Library. • Fan J., McCandliss B.D., Sommer T., Raz A., & Posner M.I. (2002). Testing the efficiency and independence of attentional networks. Journal of Cognitive Neuroscience, 3, 340-347. • Barnea A., Rassis A., Raz A., Neta Maital., & Zaidel Z., (in preparation) The Lateralized Attention Network Test (LANT). • Barnea A., Rassis A., Neta M., Raz A. and Zaidel, E. (2004). The Lateralized Attention Network Test (LANT) in Children and Adults. Abstract. TENNET, Montreal Canada. NS NS Center cue Double cue Valid/ Invalid cue Contact: Deanna J. Greene djgreene@ucla.edu