An fMRI study of the numerical Stroop task in individuals with and without minimal cognitive impairment

Kaufmann, Liane; Ischebeck, Anja; Weiss, Elisabeth; Koppelstaetter, Florian; Siedentopf, Christian; Vogel, Stephan E.; Gotwald, Thaddaeus; Marksteiner, Josef; Wood, Guilherme

doi:10.1016/j.cortex.2007.11.009

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Volume 44, Issue 9 , Pages 1248-1255, October 2008

An fMRI study of the numerical Stroop task in individuals with and without minimal cognitive impairment

Liane Kaufmann
- Innsbruck Medical University, Clinical Department of Paediatrics IV, Division of Neuropediatrics, Austria
- University of Tuebingen, Department of Psychology, Germany
- Corresponding author. Innsbruck Medical University, Clinical Department of Paediatrics IV, Division of Neuropediatrics, Anichstrasse 35, A-6020 Innsbruck, Austria.
Anja Ischebeck
- Innsbruck Medical University, Clinical Department of Neurology, Austria
Elisabeth Weiss
- Innsbruck Medical University, Clinical Department of Psychiatry, Austria
Florian Koppelstaetter
- Innsbruck Medical University, Clinical Department of Radiology II, Austria
Christian Siedentopf
- Innsbruck Medical University, Clinical Department of Radiology II, Austria
Stephan E. Vogel
- Innsbruck Medical University, Clinical Department of Paediatrics IV, Division of Neuropediatrics, Austria
Thaddaeus Gotwald
- Innsbruck Medical University, Clinical Department of Radiology II, Austria
Josef Marksteiner
- Innsbruck Medical University, Clinical Department of Psychiatry, Austria
Guilherme Wood
- University of Salzburg, Department of Psychology, Austria
- University of Salzburg, Center for Neurocognitive Research, Austria

Received 8 January 2007; received in revised form 28 February 2007 and 30 April 2007; accepted 29 November 2007. published online 29 February 2008.

Action editor Yves von Cramon

Abstract

Aim of this functional magnetic resonance imaging (fMRI) study was to dissociate normal aging and minimal cognitive impairment (MCI) concerning magnitude processing and interference control. We examined the neural correlates of a numerical Stroop task in elderly individuals with and without MCI. Fifteen elderly participants (six patients with MCI and nine controls) were subjected to a numerical Stroop task requiring numerical/physical magnitude classifications while inhibiting task-irrelevant stimulus dimensions. Effects of distance and congruity were examined.

Behaviourally, robust distance and congruity effects were observed in both groups and tasks. Imaging baseline conditions revealed stronger and more distributed activations in MCI patients relative to controls which could not be explained by the higher error rates committed by patients. Across tasks, conjunction analysis revealed highly significant activations in intra-parietal and prefrontal regions suggesting that both groups recruit comparable brain regions upon processing magnitude and interference, respectively. MCI patients exhibited stronger pre-/postcentral and thalamic activations, possibly reflecting more effortful response-selection processes or alternatively, deficient inhibitory control. Moreover, MCI patients exhibited additional activations in fronto-parietal (magnitude) and occipital/cerebellar (congruity) regions. To summarize, though MCI patients needed to recruit more distributed activation patterns conjunction analysis revealed common activation sites in response to magnitude processing and interference control.

Keywords: fMRI study, Numerical Stroop task, Intra-parietal sulcus, Prefrontal regions, Cerebellum, Minimal cognitive impairment