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It is generally held that noun processing is specifically sub-served by temporal areas, while the neural underpinnings of verb processing are located in the frontal lobe. However, this view is now challenged by a significant body of evidence accumulated over the years. Moreover, the results obtained so far on the neural implementation of noun and verb processing appear to be quite inconsistent. The present review briefly describes and critically re-considers the anatomo-correlative, neuroimaging, MEG, TMS and cortical stimulation studies on nouns and verbs with the aim of assessing the consistency of their results, particularly within techniques. The paper also addresses the question as to whether the inconsistency of the data could be due to the variety of the tasks used. However, it emerged that neither the different investigation techniques used nor the different cognitive tasks employed fully explain the variability of the data. In the final section we thus suggest that the main reason for the emergence of inconsistent data in this field is that the cerebral circuits underlying noun and verb processing are not spatially segregated, at least for the spatial resolution currently used in most neuroimaging studies.

Acupuncture is largely used for pain control in several pathological conditions. Its effects on the central nervous system are not well defined. We investigated the effect of the application of acupuncture to 13 normal subjects (males, 21-32 years). (H2O)-O-15 bolus PET scans were read before the application of the needles (Rest, R) and after 25 min of needle insertion. Data were acquired by scanning in 3-D mode. The acupuncture application, true acupuncture (TA), was alternated to a placebo needle application (PA) in two:different sequences (seven and six subjects, respectively), either R,PA,R, TA or R,TA,R,PA, a period of 15 min being left after every first TA or PA to allow for the recovery of basal conditions. Here we show that classic acupuncture activates the left Anterior Cingulus, the Insulae bilaterally, the Cerebellum bilaterally, the left Superior Frontal Gyrus, and the right Medial and Inferior Frontal Gyri. Most of the activated areas are shared with areas activated in acute and chronic pain states as described in the literature. Thus acupuncture appears to act by activating areas also involved in pain. This indicates that acupuncture could relief pain by unbalancing the equilibrium of distributed pain-related central networks

Poeppel (1996) raises a number of criticisms about the methods and reported results for eight studies of phonological processing from six different neuroimaging laboratories. We would freely admit that valid criticisms of PET methodology can be made and that, like any method, it has limitations; in fact, we and others have engaged in such critical commentary (Steinmetz & Seitz, 1991; Sergent et al., 1992; Demonet, 1995; Fiez et al., 1996a; Zatorre et al., 1996). Poeppel's analysis, though, falls far short of providing new insights into the limitations of PET methodology or the means by which future functional imaging studies could be improved. Many of Poeppel's criticisms derive from a failure to understand some of the fundamental issues which motivate functional imaging studies, including those he reviews. However, we are grateful to our critic inasmuch as he offers us the challenge to clarify our positions on important aspects of our experimental design, analysis, and interpretation. In our discussion of these issues, we begin with a general commentary, followed by specific comments from individual authors.