**Author details**

related difference in the effects of brain lesions in men and women. While in men, subcortical lesions of the right hemisphere may be associated with severe color deficits because of impaired SLTP processes for wavelength-differencing, in women, cortical lesions of the left hemisphere could result in more severe deficits due to inability to form CLTP processes for frequency-differencing. The onset of memory deficits may be characterized by loss of the capability to perform 'exponential expansion' in the memory area of the left hemisphere in men, or 'logarithmic compression' in the selective memory area of the left hemisphere in women. The latter may open the possibility of use of *f*TCD and *f*TCDS to determine early onset of memory deficits in patients with neurodegenerative disorders. Another practical clinical implication of the findings is that, in the structuring of tests of color vision, one eye has to be tested at a time, since binocular interaction may inhibit the responses from color processing neurons due to multiplexing responses in ocular dominance hypercolumns, rather than

In conclusion, gender differences in color processing implicated right hemisphere wavelengthdifferencing in men, but left hemisphere frequency-differencing in women. Future research using *f*TCDS technique should explore clinical applications of color processing in stroke rehabilitation, and monitoring of drug effects. Genetic and comparative animal experiments, as well as brain lesion studies are needed to further elucidate mechanisms of gender differences

Facial perception occurred in the cortical region of the right hemisphere in men, but in the left in women. Similar observations have been made using transcranial Doppler [27], and electro‐ physiological techniques [28]. Similar gender-related hemisphere differences have been observed at the amygdale for emotionally related stimuli [29], and for performance-related processing [30-32]. Men showed a right lateralization during object processing, but women showed a right tendency or bilateral activation. The observed category-specific face effect was consistent with the concept of category-specific model, which posits a neural module for face category as distinct from non-face [59, 75, 76, 77]. However, others have advocated the

The *f*TCD technique presumes that, the neuronal assemblies processing light information share analogous topological organization as their blood flow supply, then dark would elicit the least effect, followed by Paradigm 1, Paradigm 2, and Paradigm 3. This type of summation of responses related to stimulus complexity could be presumed as evidence for topological organization of these cortical areas in men. It has been posited that the latter extends from the area implicated in object perception to a much greater area involved in facial perception [26]. This agrees with the object form topology hypothesis proposed by Ishai and colleagues [33]. However, the relatedness of object and facial perception was process-based, and appears to be associated with their common holistic processing strategy in the right hemisphere. Moreover, when the same men were presented with facial Paradigm 3 requiring analytic processing, the left hemisphere was activated. This agrees in principle with the suggestion made by Gauthier that the extrastriate cortex contains areas that are best suited for different computations, and

responses evoked from ocular dominance columns (blobs) [15].

160 Advancements and Breakthroughs in Ultrasound Imaging

**4.2. Gender-related asymmetry during facial processing**

existence of alternative models [33, 34].

in color processing.

Philip C. Njemanze

Address all correspondence to: info@chidicon.com

International Institutes of Advanced Research and Training, Chidicon Medical Center, Owerri, Imo State, Nigeria
