We have proposed that haptic activation of the shape-selective lateral occipital
complex (LOC) reflects a model of multisensory object representation in which the role of
visual imagery is modulated by object familiarity. Supporting this, a previous functional
magnetic resonance imaging (fMRI) study from our laboratory used inter-task correlations
of blood oxygenation level-dependent (BOLD) signal magnitude and effective connectivity
(EC) patterns based on the BOLD signals to show that the neural processes underlying
visual object imagery (objIMG) are more similar to those mediating haptic perception of
familiar (fHS) than unfamiliar (uHS) shapes. Here we employed fMRI to test a further
hypothesis derived from our model, that spatial imagery (spIMG) would evoke activation and
effective connectivity patterns more related to uHS than fHS. We found that few of the
regions conjointly activated by spIMG and either fHS or uHS showed inter-task correlations
of BOLD signal magnitudes, with parietal foci featuring in both sets of correlations. This
may indicate some involvement of spIMG in HS regardless of object familiarity, contrary to
our hypothesis, although we cannot rule out alternative explanations for the commonalities
between the networks, such as generic imagery or spatial processes. EC analyses, based on
inferred neuronal time series obtained by deconvolution of the hemodynamic response
function from the measured BOLD time series, showed that spIMG shared more common paths
with uHS than fHS. Re-analysis of our previous data, using the same EC methods as those
used here, showed that, by contrast, objIMG shared more common paths with fHS than uHS.
Thus, although our model requires some refinement, its basic architecture is supported: a
stronger relationship between spIMG and uHS compared to fHS, and a stronger relationship
between objIMG and fHS compared to uHS.