CNL would also like to congratulate Dr.
Ian C. Fiebelkorn on the successful defense of his doctoral thesis
"RULES ARE MADE TO BE BROKEN:MULTISENSORY INTERACTIONS AT TWO STAGES OF
CORTICAL PROCESSING" on Monday, February 7th, 2011!
Abstract:
Research over the past few decades has illuminated the multisensory
brain.
While information from the various senses is first processed in
segregated channels, this segregation is more the exception than the norm. It
has now been convincingly demonstrated that the senses can begin to interact at
the onset of processing in early sensory cortices (e.g., Foxe et al., 2000;
Foxe & Schroeder, 2005; Lakatos, Chen, O’Connell, Mills & Schroeder,
2007; Lakatos, Karmos, Mehta, Ulbert & Schroeder, 2008; Lakatos et al., 2009;
Molholm et al., 2002; Murray et al., 2005). These multisensory interactions
continue as environmental stimuli proceed to be processed in higher-order
cortical areas, but the rules and outcomes change. The following experiments
were designed to investigate the neuroanatomic and neurophysiologic
underpinnings of multisensory interactions at two stages of processing: (1) an
earlier stage at the onset of cortical processing, where multisensory
interactions contribute to detection and selection, and (2) a later stage of cortical
processing, where multisensory features are combined into a coherent object. We
also focus on the rules that govern these interactions. Basic rules for
multisensory integration were first established in the cat superior colliculus
(Meredith & Stein, 1983; Meredith & Stein, 1986; Meredith, Nemitz &
Stein, 1987). These rules state that multisensory integration is more likely
when (1) the unisensory components arise from approximately the same location
(i.e., the spatial rule), (2) the unisensory components occur at approximately
the same time (i.e., the temporal rule), and (3) the unisensory components
elicit weak responses when they are presented in isolation (i.e., the rule of
inverse effectiveness). While these seminal rules have provided useful guidelines,
more recent research has shown that they are not applicable to all multisensory
interactions (e.g., Murray et al., 2005; Stein, London, Wilkonson & Price,
1996; Teder-Sälejärvi, Di Russo, McDonald & Hillyard, 2005; Van der Burg et
al., 2008a). Here we provide further evidence that the rules for multisensory
integration, as well as its outcomes, depend on several factors, including the
stage of cortical processing and the observer’s strategic goals.