NEURAL CORRELATES OF "ANALYTICAL-SPECIFIC VISUAL PERCEPTION" AND DEGREE OF TASK DIFFICULTY AS INVESTIGATED BY THE MANGINA-TEST: A FUNCTIONAL MAGNETIC RESONANCE IMAGING (FMRI) STUDY IN YOUNG HEALTHY ADULTS

The Mangina-Test is a neuropsychometric method for evaluating varying degrees of "analytical-specific perception" as they relate to learning abilities and disabilities. It consists of the identification of simple stimuli which are masked within a complex configuration according to their exact size, dimension, direction, spatial orientation, and shape within a limited span of time. This test has been successfully applied in clinical settings for the assessment of cognitive abilities and disorders in young and elderly populations. This investigation aimed to examine the neural correlates of analytical-specific visual perceptual processes as measured by the Mangina-Test. Functional Magnetic Resonance Imaging (fMRI) was recorded during the administration of a computer-adapted version of the Mangina-Test in twelve young healthy adults. Multiple linear regression analysis was applied to estimate the overall brain activation during task accomplishment. In addition, the fMRI response area was correlated with task difficulty, in order to explore the spatial distribution of brain regions modulated by increasing task demand. Results indicate that a widely distributed bilateral network of brain regions, including the ventral and dorsal occipital cortex, parietal lobule, frontal and supplementary eye field, dorsolateral prefrontal cortex, and supplementary motor area, was significantly activated during test performance. Moreover, increasing difficulty significantly enhanced the neural response of ventral and dorsal occipital regions, frontal eye field, and superior parietal sulcus bilaterally, as well as the right dorsolateral prefrontal cortex. Conversely, neural activity in the left temporo-parietal junction, inferior frontal gyrus, and bilateral middle-superior temporal cortex was inversely correlated with task difficulty. Results also indicate that performance in the Mangina-Test requires an optimal integration between the enhancement of activity in specific task-related cortical areas and suppression of interfering noise from unrelated brain regions

Modulation of specific brain activity by the perceptual analysis of very subtle geometrical relationships of the Mangina-Test stimuli: a functional magnetic resonance imaging (fMRI) investigation in young healthy adults

The Mangina-Test provides a neuropsychometric assessment of varying degrees of "Analytical-Specific Visual Perception", i.e., the ability to identify simple stimuli inserted into more complex ones according to their exact geometrical properties in a limited span of time. Perceptual analysis of stimuli dealing with the exact discrimination of size and dimension is related more to mathematical abilities (MATH), while perceptual analysis of direction and spatial orientation is related more to abilities in reading and reading comprehension (READ). Some stimuli are MIXED since they deal with both of the above features combined. We previously determined the distributed neuronal network of analytical-specific visual perceptual processes as measured by the Mangina-Test. Here, we aim at further assessing as to how brain activity is differentially modulated by the discrimination of very subtle category-specific perceptual relationships. Brain activity was measured by functional magnetic resonance imaging in 12 young healthy subjects while they performed a computer-adapted version of the Mangina-Test. Behavioral results of the present study indicate that performance was not different among stimulus categories. However, brain functional data show that analytical-specific perceptual processes for MATH, READ and MIXED stimuli rely on partially distinct brain circuits. Bilateral posterior parietal, premotor and prefrontal regions along with the anterior cingulate appeared to be more activated by MATH stimuli, while READ stimuli predominantly activated bilateral medial occipito-temporal, amygdala/parahippocampal and sensorimotor cortices, and the right inferior frontal cortex. Moreover, the posterior parahippocampal cortex showed a higher activity specifically for MIXED stimuli. Altogether, these findings demonstrate that in the Mangina-Test, the exact discrimination of very subtle perceptual relationships between geometrical stimuli distinctly modulates cerebral activity, so that category-specific brain responses can be related to identifiable cognitive abilities