Dissecting the causal role of early inferior frontal activation in reading.

Cognitive models of reading assume that speech production occurs after visual and phonological processing of written words. This traditional view is at odds with more recent magnetoencephalography studies showing that the left posterior inferior frontal cortex (pIFC) classically associated with spoken production responds to print at 100-150 ms after word-onset, almost simultaneously with posterior brain regions for visual and phonological processing. Yet the theoretical significance of this fast neural response remains open to date.

Phonology facilitates deeply opaque logographic writing.

Phonological knowledge plays a pivotal role in many aspects of language processing, but it remains controversial whether it is required for writing. In the present study, we examined the issue by focusing on written production in an opaque logographic script (kanji) with highly irregular pronunciation rules, which allowed for a rigorous test of whether or not phonology contributes to writing. Using a phonological priming paradigm in two experiments, we measured response latency while participants orally named target pictures or wrote down their names in kanji.

Graphomotor memory in Exner's area enhances word learning in the blind.

Handwriting is thought to impede vocabulary learning in sighted adults because the motor execution of writing interferes with efficient audiovisual processing during encoding. However, the motor memory of writing may facilitate adult word learning when visual sensory inputs are severely restricted. Using functional MRI, we show that late-blind participants, but not sighted participants, learned novel words by recruiting the left dorsal premotor cortex known as Exner's writing area and its functional coupling with the left hippocampus.

On-Surface Synthesis of a π-Extended Diaza[8]circulene.

Heterocyclic [8]circulenes are an important class of polycyclic aromatic hydrocarbon molecules because of their unique structural properties and promising applications. However, the synthesis of heterocyclic [8]circulenes is still limited and thus is an important synthetic challenge. Here we describe the first example of a π-extended diaza[8]circulene surrounded by and fused with six hexagons and two pentagons, which was successfully synthesized only by a combined in-solution and on-surface synthetic strategy.

Left Amygdala Regulates the Cerebral Reading Network During Fast Emotion Word Processing.

Emotion words constitute a special class of verbal stimuli which can quickly activate the limbic system outside the left-hemisphere language network. Such fast response to emotion words may arise independently of the left occipitotemporal area involved in visual word-form analysis and rely on a distinct amygdala-dependent emotion circuit involved in fearful face processing. Using a hemifield priming paradigm with fMRI, we explored how the left and right amygdala systems interact with the reading network during emotion word processing.

Synthesis of carbonyl-bridged dibenzofulvalenes and related compounds by rhodium-catalyzed stitching reaction.

Various carbonyl-bridged dibenzofulvalenes were synthesized by a sequence of rhodium-catalyzed stitching reaction and post-functionalization, and their optical and electronic properties could be tuned by changing the terminal substituents. The present stitching reaction also allowed for facile synthesis of dibenzofulvalenes having C, Si, Ge, S, and P as the bridging elements.

Functionalization of Azapentabenzocorannulenes by Fivefold C-H Borylation and Cross-Coupling Arylation: Application to Columnar Liquid-Crystalline Materials.

Herein, the one-shot fivefold functionalization of azapentabenzocorannulenes by an iridium-catalyzed fivefold C-H borylation reaction that exhibits excellent regioselectivity is reported. The borylated product can be used as a versatile synthetic intermediate for further derivatization via Suzuki-Miyaura cross-coupling reactions. This fivefold borylation/arylation sequence was employed to synthesize liquid-crystalline azapentabenzocorannulenes with five 3,4,5-trialkoxyphenyl groups, which assemble into 1D hexagonal columnar structures over a wide temperature range.

Neural capacity limits during unconscious semantic processing.

A growing body of neuroimaging data suggests that direct measurements of brain activity can reveal subliminal effects that remain invisible with behavior measures alone. We examined whether sentence comprehension processes could be triggered by a sequence of masked words. On each trial, participants viewed a rapid sequence of masked or unmasked words, including a subject noun, three adverbs and followed by a visible target verb.

Phonological memory in sign language relies on the visuomotor neural system outside the left hemisphere language network.

Sign language is an essential medium for everyday social interaction for deaf people and plays a critical role in verbal learning. In particular, language development in those people should heavily rely on the verbal short-term memory (STM) via sign language. Most previous studies compared neural activations during signed language processing in deaf signers and those during spoken language processing in hearing speakers.

Remembering my friends: Medial prefrontal and hippocampal contributions to the self-reference effect on face memories in a social context.

Memories associated with the self are remembered more accurately than those associated with others. The memory enhancement related to the self is known as the self-reference effect (SRE). However, little is known regarding the neural mechanisms underlying the SRE in a social context modulated by social relationships.

Adaptation of the human visual system to the statistics of letters and line configurations.

By adulthood, literate humans have been exposed to millions of visual scenes and pages of text. Does the human visual system become attuned to the statistics of its inputs? Using functional magnetic resonance imaging, we examined whether the brain responses to line configurations are proportional to their natural-scene frequency. To further distinguish prior cortical competence from adaptation induced by learning to read, we manipulated whether the selected configurations formed letters and whether they were presented on the horizontal meridian, the familiar location where words usually appear, or on the vertical meridian.

Timing the impact of literacy on visual processing.

Learning to read requires the acquisition of an efficient visual procedure for quickly recognizing fine print. Thus, reading practice could induce a perceptual learning effect in early vision. Using functional magnetic resonance imaging (fMRI) in literate and illiterate adults, we previously demonstrated an impact of reading acquisition on both high- and low-level occipitotemporal visual areas, but could not resolve the time course of these effects.

Mirror-image discrimination in the literate brain: a causal role for the left occpitotemporal cortex.

Previous studies show that the primate and human visual system automatically generates a common and invariant representation from a visual object image and its mirror reflection. For humans, however, this mirror-image generalization seems to be partially suppressed through literacy acquisition, since literate adults have greater difficulty in recognizing mirror images of letters than those of other visual objects. At the neural level, such category-specific effect on mirror-image processing has been associated with the left occpitotemporal cortex (L-OTC), but it remains unclear whether the apparent "inhibition" on mirror letters is mediated by suppressing mirror-image representations covertly generated from normal letter stimuli.

Eating tools in hand activate the brain systems for eating action: a transcranial magnetic stimulation study.

There is increasing neuroimaging evidence suggesting that visually presented tools automatically activate the human sensorimotor system coding learned motor actions relevant to the visual stimuli. Such crossmodal activation may reflect a general functional property of the human motor memory and thus can be operating in other, non-limb effector organs, such as the orofacial system involved in eating. In the present study, we predicted that somatosensory signals produced by eating tools in hand covertly activate the neuromuscular systems involved in eating action.

Literacy breaks mirror invariance for visual stimuli: a behavioral study with adult illiterates.

The ability to recognize 2 mirror images as the same picture across left-right inversions exists early on in humans and other primates. In order to learn to read, however, one must discriminate the left-right orientation of letters and distinguish, for instance, b from d. We therefore reasoned that literacy may entail a loss of mirror invariance.

Universal brain systems for recognizing word shapes and handwriting gestures during reading.

Do the neural circuits for reading vary across culture? Reading of visually complex writing systems such as Chinese has been proposed to rely on areas outside the classical left-hemisphere network for alphabetic reading. Here, however, we show that, once potential confounds in cross-cultural comparisons are controlled for by presenting handwritten stimuli to both Chinese and French readers, the underlying network for visual word recognition may be more universal than previously suspected. Using functional magnetic resonance imaging in a semantic task with words written in cursive font, we demonstrate that two universal circuits, a shape recognition system (reading by eye) and a gesture recognition system (reading by hand), are similarly activated and show identical patterns of activation and repetition priming in the two language groups.

Task-sensitivity of unconscious word processing in spatial neglect.

Neuropsychological studies of spatial neglect have shown that ignored visual stimuli can produce measurable behavioral changes without eliciting subjective perceptual experience. However, such non-conscious, implicit cognitive processing may not be fully automatic but rather could be influenced by the patients' voluntary behavioral control. Using a hemifield priming paradigm with two different task instructions, we studied spatial neglect patients to assess whether non-conscious processing of ignored words is modulated by behavioral task requirements.

Symmetrical hemispheric priming in spatial neglect: a hyperactive left-hemisphere phenomenon?

Hemispheric rivalry models of spatial neglect suggest that the left hemisphere becomes hyperactive following right-hemisphere lesions since the two hemispheres normally exert an inhibitory influence on each other via callosal connections. Using a masked hemifield priming paradigm, we investigated whether the putative change in hemispheric balance involves other, higher-order abstract representational systems in spatial neglect. Participants consisted of 12 neglect patients with right-hemisphere damage and three groups of control participants, i.

Breaking the symmetry: mirror discrimination for single letters but not for pictures in the Visual Word Form Area.

Humans and primates can quickly recognize mirror images of previously exposed pictures. This spontaneous mirror invariance, though advantageous for visual recognition, makes it difficult to distinguish the orientation of letters (e.g.

Neural control of cross-language asymmetry in the bilingual brain.

Most bilinguals understand their second language more slowly than their first. This behavioral asymmetry may arise from the perceptual, phonological, lexicosemantic, or strategic components of bilingual word processing. However, little is known about the neural source of such language dominance and how it is regulated in the bilingual brain.

Why do children make mirror errors in reading? Neural correlates of mirror invariance in the visual word form area.

Young children often make mirror errors when learning to read and write, for instance writing their first name from right to left in English. This competence vanishes in most adult readers, who typically cannot read mirror words but retain a strong competence for mirror recognition of images. We used fast behavioral and fMRI repetition priming to probe the brain mechanisms underlying mirror generalization and its absence for words in adult readers.

Task-specific change of unconscious neural priming in the cerebral language network.

We explored the impact of task context on subliminal neural priming using functional magnetic resonance imaging. The repetition of words during semantic categorization produced activation reduction in the left middle temporal gyrus previously associated with semantic-level representation and dorsal premotor cortex. By contrast, reading aloud produced repetition enhancement in the left inferior parietal lobe associated with print-to-sound conversion and ventral premotor cortex.