Functional magnetic resonance imaging was used to identify the neural correlates of Chinese character and word reading. The Chinese stimuli were presented visually, one at a time. Subjects covertly generated a word that was semantically related to each stimulus. Three sorts of Chinese items were used: single characters having precise meanings, single characters having vague meanings, and two-character Chinese words. The results indicated that reading Chinese is characterized by extensive activity of the neural systems, with strong left lateralization of frontal (BAs 9 and 47) and temporal (BA 37) cortices and right lateralization of visual systems (BAs 17-19), parietal lobe (BA 3), and cerebellum. The location of peak activation in the left frontal regions coincided nearly completely both for vague- and precise-meaning characters as well as for two-character words, without dissociation in laterality patterns. In addition, left frontal activations were modulated by the ease of semantic retrieval. The present results constitute a challenge to the deeply ingrained belief that activations in reading single characters are right lateralized, whereas activations in reading two-character words are left lateralized.

There are defined medullary, mesencephalic, hypothalamic, and thalamic functions in regulation of respiration, but knowledge of cortical control and the elements subserving the consciousness of breathlessness and air hunger is limited. In nine young adults, air hunger was produced acutely by CO 2 inhalation. Comparisons were made with inhalation of a N2͞O2 gas mixture with the same apparatus, and also with paced breathing, and with eyes closed rest. A network of activations in pons, midbrain (mesencephalic tegmentum, parabrachial nucleus, and periaqueductal gray), hypothalamus, limbic and paralimbic areas (amygdala and periamygdalar region) cingulate, parahippocampal and fusiform gyrus, and anterior insula were seen along with caudate nuclei and pulvinar activations. Strong deactivations were seen in dorsal cingulate, posterior cingulate, and prefrontal cortex. The striking response of limbic and paralimbic regions points to these structures having a singular role in the affective sequelae entrained by disturbance of basic respiratory control whereby a process of which we are normally unaware becomes a salient element of consciousness. These activations and deactivations include phylogenetically ancient areas of allocortex and transitional cortex that together with the amygdalar͞periamygdalar region may subserve functions of emotional representation and regulation of breathing. R egulatory physiologic processes occur continuously beyond the realm of consciousness, and only rarely do we volitionally attend to them or do they intrude and dominate conscious awareness. Feeling breathless or ''hunger for air'' is one process capable of making such an imperious intrusion. Intense breathlessness occurs in certain psychiatric states such as panic disorder (theorized to be due to a malfunction of the ''suffocation alarm'') (1), where no physiologic impairment accounts for the reaction. This fact indicates the involvement of higher brain centers, and that basic respiratory circuitry can be accessed and powerfully influenced by neural processes subserving emotion.Humans are extremely sensitive to carbon dioxide. The pathway for this effect involves pH changes (2) detected by the neurons of the ventral respiratory group. How this sensitivity leads to respiratory changes and the perception of air hunger has been explored in humans by elegant work by Banzett and colleagues (3, 4), and Gandevia and colleagues (5). Their work, including study of curarized subjects and quadriplegics, indicates that central neural processes are involved in the perception of air hunger and that peripheral afferents play a minor role.The CO 2 -sensitive neurons in the ventral respiratory group and Botzinger complexes, aligned along the ventrolateral medulla, are involved in generating respiratory rhythms. Studies in rats using anterograde and retrograde tracing of connections of the ventral respiratory group show widespread projections involving several cerebellar regions, brainstem, midbrain, hypothalamus, thalamus, amygdalohippocampal area, and i...

Using a categorized pictures paradigm, Koutstaal and Schacter (1997) reported high levels of false recognition of lures that were categorically related to presented items. Although also shown by younger adults, false recognition was markedly higher for older adults. To probe the factors underlying this age difference, these experiments required participants to engage in more careful scrutiny of the items at retrieval or to notice specific differentiating perceptual features of the objects during encoding. False recognition was reduced with each of these manipulations, but neither manipulation, either separately or together, eliminated the age difference in false recognition. Older adults can considerably reduce false recognition if encouraged to use more stringent decision criteria. Persistent difficulty in opposing familiarity-based responding and comparatively more generic encoding may contribute to residual deficits.

Functional magnetic resonance imaging was used to identify the neural correlates of Chinese character and word reading. The Chinese stimuli were presented visually, one at a time. Subjects covertly generated a word that was semantically related to each stimulus. Three sorts of Chinese items were used: single characters having precise meanings, single characters having vague meanings, and two-character Chinese words. The results indicated that reading Chinese is characterized by extensive activity of the neural systems, with strong left lateralization of frontal (BAs 9 and 47) and temporal (BA 37) cortices and right lateralization of visual systems (BAs 17-19), parietal lobe (BA 3), and cerebellum. The location of peak activation in the left frontal regions coincided nearly completely both for vague- and precise-meaning characters as well as for two-character words, without dissociation in laterality patterns. In addition, left frontal activations were modulated by the ease of semantic retrieval. The present results constitute a challenge to the deeply ingrained belief that activations in reading single characters are right lateralized, whereas activations in reading two-character words are left lateralized.