  In the context of the increasing number of works on multisensory and
cross-modal effects in cerebral processing, a review is made on the functional
model of human brain proposed by Justo Gonzalo (1910-1986), in relation to what
he called central syndrome (caused by unilateral lesion in the
parieto-occipital cortex, equidistant from the visual, tactile and auditory
projection areas). The syndrome is featured by a bilateral, symmetric and
multisensory involvement, and by a functional depression with dynamic effects
dependent on the neural mass lost and related to physiological laws of nervous
excitability. Inverted or tilted vision as well as tactile and auditive
inversion, under minimum stimulus, appears as a stage of incomplete
integration, being almost corrected under higher stimulus or facilitation by
multisensory integration. The syndrome reveals aspects of the brain dynamics
that suggest a functional continuity and unity of the cortex. A functional
gradients scheme was proposed in which the specificity of the cortex is
distributed with a continuous variation. This syndrome is interpreted as a
scale reduction in the nervous excitability of the system, the different
sensory qualities being affected allometricaly according to scaling laws. A
continuity from lower to higher sensory functions was proposed. The sensory
growth by an increase of the stimulus or by multisensory facilitation is found
to follow approximately power laws, that would reflect basic laws of biological
neural networks. We restrict the analysis to the visual system.
