Pattern-information fMRI: New questions which it opens up and challenges which face it

Recent years have seen a strong growth of interest in multivariate approaches for analysing brain activity patterns. The primary goal of these approaches is to reveal the information represented in neuronal population codes. Here, we review how these methods have been used to relate neural activity patterns both to stimulus input and to behavioural output and how they might help to explain individual differences in behavioural performance. We examine the neuroscientific interpretation of different types of pattern-information analysis and highlight current challenges and promising future directions for this emerging field. The open challenges that we discuss are as follows: inferring the causal role of pattern information, seeking diagnostic power for functional Magnetic Resonance Imaging (fMRI) at the level of individuals, determining whether observed patterns have real functional significance, finding the structure underlying high-dimensional activation spaces and relating one person’s neural patterns to another’s. VC 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 31–41, 2010; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/ima.20225