Linguistic categories have been shown to influence perceptual discrimination, to do so preferentially in the right visual field, to fail to do so when competing demands are made on verbal memory, and to vary with the color-term boundaries of different languages. However, because there are strong commonalities across languages in the placement of color-term boundaries, the question remains open whether observed categorical perception for color can be entirely a result of learned categories or may rely to some degree on innate ones. We show here that lateralized color categorical perception can be entirely the result of learned categories. In a visual search task, reaction times to targets were faster in the right than the left visual field when the target and distractor colors, initially sharing the same linguistic term (e.g., "blue"), became between-category colors after training (i.e., when two different shades of blue had each acquired a new name). A control group, whose conditions exactly matched those of the experimental group except that no new categories were introduced, did not show this effect, establishing that the effect was not dependent on increased familiarity with either the color stimuli or the task. The present results show beyond question that lateralized categorical perception of color can reflect strictly learned color categories, even artificially learned categories that violate both universal tendencies in color naming and the categorization pattern of the language of the subject.category learning | Whorf hypothesis | nature versus nurture | linguistic relativity A long-standing "Whorfian" debate over the relation between language and thought has gained momentum in recent years with an increasing number of studies demonstrating the involvement of linguistic information in categorical perception of color (1-18).* For example, speakers of English judge colors that straddle the English category boundary between green and blue to be less similar than do speakers of Tarahumara, a UtoAztecan language of Mexico that uses a single word for these colors (1). Unlike English, Russian makes a distinction between lighter blues (goluboy) and darker blues (siniy), and Russian speakers are faster, compared with English speakers, in discriminating two colors when they fall into different categories, one goluboy and the other siniy, than when they belong to the same category (6). More recent findings provide a different perspective, suggesting that language is disproportionately engaged in the discrimination of colors presented in the right visual field (RVF) as compared with the left visual field (LVF) (5,7,8,10,11). Specifically, discrimination of colors from two different lexical categories (e.g., a green among blues) is faster than discrimination of colors from the same lexical category (e.g., one green among tokens of a different green), but only (or predominantly) when the between-category colors are presented in the RVF. [Significant color categorical perception (CP) has also been found in the LFV (7, ...

The human brain has been shown to exhibit changes in the volume and density of gray matter as a result of training over periods of several weeks or longer. We show that these changes can be induced much faster by using a training method that is claimed to simulate the rapid learning of word meanings by children. Using whole-brain magnetic resonance imaging (MRI) we show that learning newly defined and named subcategories of the universal categories green and blue in a period of 2 h increases the volume of gray matter in V2/3 of the left visual cortex, a region known to mediate color vision. This pattern of findings demonstrates that the anatomical structure of the adult human brain can change very quickly, specifically during the acquisition of new, named categories. Also, prior behavioral and neuroimaging research has shown that differences between languages in the boundaries of named color categories influence the categorical perception of color, as assessed by judgments of relative similarity, by response time in alternative forced-choice tasks, and by visual search. Moreover, further behavioral studies (visual search) and brain imaging studies have suggested strongly that the categorical effect of language on color processing is left-lateralized, i.e., mediated by activity in the left cerebral hemisphere in adults (hence "lateralized Whorfian" effects). The present results appear to provide a structural basis in the brain for the behavioral and neurophysiologically observed indices of these Whorfian effects on color processing.neuro-plasticity | brain development | Whorf hypothesis | anatomy R esearch on the adult animal brain has demonstrated experience-induced cortical structural changes and the relevant time scales at the cellular and synaptic level (1-11). In normal human adults, neuroimaging studies have shown structural plasticity (indexed by gray matter changes) in response to the acquisition of a new skill obtained by training over periods ranging from weeks (12) to years (13-17). Although these findings in themselves constitute a challenge to the traditional view that the anatomical structure of the intact adult human cortex cannot be altered, the degree of structural plasticity at this macroscopic level remains unknown.In this study, we show that learning artificially defined and named subcategories of the universal color names green and blue (18, 19) for 2 h increases the volume of gray matter in V2/3 of the visual cortex. We used an intensive training method to teach subjects (n = 19, females = 10, mean age = 20.1 y) to map new nonsense terms onto newly created color categories (two shades of blue and two shades of green). A similar training procedure was used by Markson and Bloom (20) to simulate the "fastmapping" phenomenon, in which children (and adults) learn new word-object associations after just a few exposures. Four visibly but not lexically distinguishable colors, which we originally designated green 1 (G1), green 2 (G2), blue 1 (B1), and blue 2 (B2) were taught to subjects to exemplify...

Postpartum depression (PPD) is the most common psychological health issue among women, which often comorbid with anxiety (PPD-A). PPD and PPD-A showed highly overlapping clinical symptoms. Identifying disorder-specific neurophysiological markers of PDD and PPD-A is important for better clinical diagnosis and treatments. Here, we performed functional connectivity density (FCD) and resting-state functional connectivity (rsFC) analyses in 138 participants (45 unmedicated patients with first-episode PPD, 31 PDD-A patients and 62 healthy postnatal women, respectively). FCD mapping revealed specifically weaker long-range FCD in right lingual gyrus (LG.R) for PPD patients and significantly stronger long-range FCD in left ventral striatum (VS.L) for PPD-A patients. The follow-up rsFC analyses further revealed reduced functional connectivity between dorsomedial prefrontal cortex (dmPFC) and left ventral striatum (VS.L) in both PPD and PPD-A. PPD showed specific changes of rsFC between LG.R and dmPFC, right angular gyrus, left precentral gyrus while PPD-A represented specifically abnormal rsFC between VS.L and left ventrolateral prefrontal cortex. Moreover, the altered FCD and rsFC were closely associated with depression and anxiety symptoms load. Taken together, our study is the first to identify common and disorder-specific neural circuit disruptions in PPD and PPD-A, which may facilitate more effective diagnosis and treatments.

The neural systems of lexical tone processing have been studied for many years. However, previous findings have been mixed with regard to the hemispheric specialization for the perception of linguistic pitch patterns in native speakers of tonal language. In this study, we performed two activation likelihood estimation (ALE) meta-analyses, one on neuroimaging studies of auditory processing of lexical tones in tonal languages (17 studies), and the other on auditory processing of lexical information in non-tonal languages as a control analysis for comparison (15 studies). The lexical tone ALE analysis showed significant brain activations in bilateral inferior prefrontal regions, bilateral superior temporal regions and the right caudate, while the control ALE analysis showed significant cortical activity in the left inferior frontal gyrus and left temporo-parietal regions. However, we failed to obtain significant differences from the contrast analysis between two auditory conditions, which might be caused by the limited number of studies available for comparison. Although the current study lacks evidence to argue for a lexical tone specific activation pattern, our results provide clues and directions for future investigations on this topic, more sophisticated methods are needed to explore this question in more depth as well.