Kazuki Iijima

The cortical dynamics in building syntactic structures of sentences: an MEG study in a minimal-pair paradigm.

The importance of abstract syntactic structures and their crucial role in analyzing sentences have long been emphasized in contemporary linguistics, whereas the linear order model, in which next-coming words in a sentence are claimed to be predictable based on lexico-semantic association or statistics alone, has also been proposed and widely assumed. We examined these possibilities with magnetoencephalography (MEG) and measured cortical responses to a verb with either object-verb (OV) or subject-verb (SV) sentence structures, which were tested in a minimal-pair paradigm to compare syntactic and semantic decision tasks. Significant responses to the normal OV sentences were found in the triangular part of the left inferior frontal gyrus (F3t) at 120-140 ms from the verb onset, which were selective for explicit syntactic processing. The earliest left F3t responses can thus be regarded as predictive effects for the syntactic information of the next-coming verb, which cannot be explained by associative memory or statistical factors. Moreover, subsequent responses in the left insula at 150-170 ms were selective for the processing of the OV sentence structure. On the other hand, responses in the left mediofrontal and inferior parietal regions at 240-280 ms were related to syntactic anomaly and verb transitivity, respectively. These results revealed the dynamics of the multiple cortical regions that work in concert to analyze hierarchical syntactic structures and task-related information, further elucidating the top-down syntactic processing that is crucial during on-line sentence processing.

Left Inferior Frontal Activations Depending on the Canonicity Determined by the Argument Structures of Ditransitive Sentences: An MEG Study

To elucidate the relationships between syntactic and semantic processes, one interesting question is how syntactic structures are constructed by the argument structure of a verb, where each argument corresponds to a semantic role of each noun phrase (NP). Here we examined the effects of possessivity [sentences with or without a possessor] and canonicity [canonical or noncanonical word orders] using Japanese ditransitive sentences. During a syntactic decision task, the syntactic structure of each sentence would be constructed in an incremental manner based on the predicted argument structure of the ditransitive verb in a verb-final construction. Using magnetoencephalography, we found a significant canonicity effect on the current density in the left inferior frontal gyrus (IFG) at 530–550 ms after the verb onset. This effect was selective to canonical sentences, and significant even when the precedent NP was physically identical. We suggest that the predictive effects associated with syntactic processing became larger for canonical sentences, where the NPs and verb were merged with a minimum structural distance, leading to the left IFG activations. For monotransitive and intransitive verbs, in which structural computation of the sentences was simpler than that of ditransitive sentences, we observed a significant effect selective to noncanonical sentences in the temporoparietal regions during 480–670 ms. This effect probably reflects difficulty in semantic processing of noncanonical sentences. These results demonstrate that the left IFG plays a predictive role in syntactic processing, which depends on the canonicity determined by argument structures, whereas other temporoparietal regions would subserve more semantic aspects of sentence processing.

Subliminal enhancement of predictive effects during syntactic processing in the left inferior frontal gyrus: an MEG study

Predictive syntactic processing plays an essential role in language comprehension. In our previous study using Japanese object-verb (OV) sentences, we showed that the left inferior frontal gyrus (IFG) responses to a verb increased at 120–140 ms after the verb onset, indicating predictive effects caused by a preceding object. To further elucidate the automaticity of the predictive effects in the present magnetoencephalography study, we examined whether a subliminally presented verb (“subliminal verb”) enhanced the predictive effects on the sentence-final verb (“target verb”) unconsciously, i.e., without awareness. By presenting a subliminal verb after the object, enhanced predictive effects on the target verb would be detected in the OV sentences when the transitivity of the target verb matched with that of the subliminal verb (“congruent condition”), because the subliminal verb just after the object could determine the grammaticality of the sentence. For the OV sentences under the congruent condition, we observed significantly increased left IFG responses at 140–160 ms after the target verb onset. In contrast, responses in the precuneus and midcingulate cortex (MCC) were significantly reduced for the OV sentences under the congruent condition at 110–140 and 280–300 ms, respectively. By using partial Granger causality analyses for the OV sentences under the congruent condition, we revealed a bidirectional interaction between the left IFG and MCC at 60–160 ms, as well as a significant influence from the MCC to the precuneus. These results indicate that a top-down influence from the left IFG to the MCC, and then to the precuneus, is critical in syntactic decisions, whereas the MCC shares its task-set information with the left IFG to achieve automatic and predictive processes of syntax.

How (not) to draw philosophical implications from the cognitive nature of concepts: the case of intentionality.

Philosophers have often appealed to intuitive judgments in various thought experiments to support or reject particular theses. Experimental philosophy is an emerging discipline that examines the cognitive nature of such intuitive judgments. In this paper, we assess the methodological and epistemological status of experimental philosophy. We focus on the Knobe effect, in which our intuitive judgment of the intentionality of an action seems to depend on the perceived moral status of that action. The debate on the philosophical implications of the Knobe effect has been framed in terms of the distinction between the competence and performance of the concept of intentionality. Some scholars seem to suggest that the Knobe effect reflects the competence (or otherwise, the performance error) of the concept of intentionality. However, we argue that these notions are purely functional and thus do not have philosophical implications, without assuming normativism, which we see as problematic in a psychological methodology. Finally, focusing on the gap between competence and rationality, we suggest future directions for experimental philosophy.

Operation of Micro Gas Turbine System Employing Two Stage Combustion of Biomass Gas

A two-axis, recuperated cycle micro-gas turbine (MGT) system for biomass gas is developed. The rated specifications of the MGT are as follows, pressure ratio of 2.7, turbine inlet temperature of 1120K, and output power of 5kW. The system consists of three components: the MGT power-generating system, control system and mock biomass gas supply system. The original two-stage combustor and H infinity system controller used in this system are discriminative. Since the gaseous fuel converted from biomass has a low heat quantity, the combustor is designed to achieve both high combustion efficiency and low NOx emission for lower calorific fuel. In the combustor, a stable tubular flame combustion of city gas in the first stage supplies burned gas, which has enthalpy and activated radicals, to the second stage and enables stable ignition and combustion of biomass gas and air premixture. In addition, because the gas composition of biomass gas is also affected by the sources, the gasification method, and the gasifying condition, the system controller is required to absorb fuel fluctuation while meeting the demanded output. Hence, the H infinity algorithm is employed as a system controller because of its robustness against disturbances from the unpredictable fuel component fluctuation. Using this MGT system, an operation test was carried out with mock biomass gases. The rotational speed of the power turbine could be kept almost constant with both mock fermentation gas and pyrolysis gas as the second-stage fuel, and NOx emission was 50ppm when load was increased to a rated power of 5kW. When the second-stage fuel composition changed from 100% methane to 50% methane and 50% CO2 at a certain speed, the power turbine speed could also be kept constant. The H infinity controller is compared with the 2-DOF PID controller for secondary fuel concerning the response to varying load. The former shows slightly better performance than the 2-DOF PID controller.Copyright

The effect of canonical word orders on the neural processing of double object sentences: An MEG study

Previous studies showed deficits in the anterior cingulate cortex (ACC) in various psychiatric disorders such as autism and schizophrenia. In the present study, 2 monkeys were paired and placed in a cage where we monitored their behavior and neuronal activity of one monkey. Then we analyzed correlation between their behavior and ACC neuronal activity while the 2 monkeys socially interacted. The results indicated that the activity of some neurons was significantly correlated with one or more measures of social behavior. Activity of the leavingand approaching-related neurons changed in response to leaving and approaching behaviors of recording and/or partner monkeys, respectively. Activity of the communication-related neurons changed while the 2 monkeys engaged in social behavior such as grooming together, lip smacking, facing, etc. These results provide neurophysiological bases for ACC involvement in psychiatric disorders with social disturbance.

Subliminal priming for the syntactic judgment: An MEG study

The embedding depth in the tree structure of a sentence is a key factor for sentence processing, and we examined whether cortical activations are modulated by this factor or syntactic operations (e.g., Merge and Agree). To eliminate any semantic factors, we used the nonsense Jabberwocky sentences formed from pseudonouns (N; e.g., rara), pseudoverbs (V; e.g., hihiru), and real Japanese particles (e.g., -ga). To ensure the formation of sentence structures based on Ns and Vs, we introduced a rule of the subject-verb agreement, such that the last vowel of the verb root is caused to harmonize with the vowel of the subject (e.g., rara-ga hiharu). The participants judged this agreement under three distinct conditions: a conjoined sentence condition (CS; e.g., N1V1N2V2, where the subscripts denote different vowels of Ns) with multiple sentences conjoined, a single sentence condition (SS; e.g., N1N2V3V2) with a single subject-verb pair, and a nested sentence condition (NS; e.g., N1N2V2V1) with center-embedded sentences. Each condition had short and long stimuli (embedding depth: NS > SS > CS). We treated CS as the control for agreement, because CS and NS had the same numbers of agreement. An ANCOVA with the difference in accuracy as a nuisance variable showed significant main effects of conditions ((NS – CS) > (SS – CS)) and length (long > short) in the left inferior frontal gyrus (L. F3op/F3t) and lateral premotor cortex (LPMC) (p < 0.05, FWE corrected). We also used a backward matching condition (BM) with the same memory load as NS (embedding depth: NS > BM = SS). An ANCOVA showed significant main effects of conditions ((NS – CS) > (BM – CS)) and length (long > short) in the L. LPMC/F3op. These results suggest that the embedding depth is a crucial factor for the syntax-selective frontal activations.

Early hierarchical syntactic processing in Broca's area for merging words

The prefrontal cortex (PFC) is one of areas involved in time perception; however, roles of this area remains unclear. We recorded single neuronal activity from the PFC of two monkeys while they performed a durationdiscrimination task. In the task, two visual cues (squares in blue or red) in different durations were presented consecutively followed by delay periods and the subjects then chose one of the cues presented longer in duration. We focused analysis on the first cue (C1) activity, because the neuronal activity of the second cue period (C2) may carry temporal information of both the C1 and C2. We found that prefrontal neurons showed activity that was related to temporal processing. For instance, a group of neurons exhibited phasic responses after constant intervals from the C1 onset. Our results suggest that the PFC contributes to compare current C1 durations with template duration that is learned after repeated trials, due to sort the C1s into possibly long or short cues in the present task.