The sensorimotor cortex is somatotopically organized to represent the vocal tract articulators, such as lips, tongue, larynx, and jaw. How speech and articulatory features are encoded at the subcortical level, however, remains largely unknown. We analyzed local field potential (LFP) recordings from the subthalamic nucleus (STN) and simultaneous electrocorticography recordings from the sensorimotor cortex of 11 human subjects (1 female) with Parkinson’s disease during implantation of deep brain stimulation (DBS) electrodes, while they read aloud three-phoneme words. The initial phonemes involved either articulation primarily with the tongue (coronal consonants) or the lips (labial consonants). We observed significant increases in high gamma (60–150 Hz) power in both the STN and the sensorimotor cortex that began before speech onset and persisted for the duration of speech articulation. As expected from previous reports, in the sensorimotor cortex, the primary articulators involved in the production of the initial consonants were topographically represented by high gamma activity. We found that STN high gamma activity also demonstrated specificity for the primary articulator, although no clear topography was observed. In general, subthalamic high gamma activity varied along the ventral-dorsal trajectory of the electrodes, with greater high gamma power recorded in the dorsal locations of the STN. Interestingly, the majority of significant articulator-discriminative activity in the STN occurred prior to that in sensorimotor cortex. These results demonstrate that articulator-specific speech information is contained within high gamma activity of the STN, but with different spatial and temporal organization compared to similar information encoded in the sensorimotor cortex.
There is a need for modern neurolinguisitcstandardized test for language assessment in aphasia and related neurogenic language disorders in Russian. Our research group is currently working on the development of the Russian Aphasia Test (RAT)that is based on contemporary models of language processing and principles of psychometrics.Language production subtests assess oral speech at each of the linguistic levels. The material for each task was selected and balanced considering modern theoretical models of language and takes into account important psycholinguistic factors. For many tasks, there is no standardized analogues in Russian with extensive, theoretically justified and carefully selected linguistic material. The subtests were piloted in a group of neurologically healthy individuals (n=20) and patients with different types of aphasia (n=20). As expected patients with aphasia performed worse compared to age-matched healthy controls across all tasks. Items demonstrating high sensitivity and reliability were selected to be included in the final version of the test.
Attentional control of referential information is an important contributor to the structure of discourse (Sanford, 2001; Sanford & Garrod, 1981). We investigated how attention and memory interplay during visually situated sentence production. We manipulated speakers’ attention to the agent or the patient of a described event by means of a referential or a dot visual cue (Posner, 1980). We also manipulated whether the cue was implicit or explicit by varying its duration (70 ms versus 700 ms). Participants used passive voice more often when their attention was directed to the patient’s location, regardless of whether the cue duration. This effect was stronger when the cue was explicit rather than implicit, especially for passive-voice sentences. Analysis of sentence onset latencies showed a divergent pattern: Latencies were shorter (1) when the agent was cued, (2) when the cue was explicit and (3) when the (explicit) cue was referential; (1) and (2) indicate facilitated sentence planning when the cue supports a canonical (active voice) sentence frame and when speakers had more time to plan their sentences; (3) suggests that sentence planning was sensitive to whether the cue was informative with regard to the cued referent. We propose that differences between production likelihoods and production latencies indicate distinct contributions from attentional focus and memorial activation to sentence planning: While the former partly predicts syntactic choice, the latter facilitates syntactic assembly (i.e., initiating overt sentence generation).
Institutions affect investment decisions, including investments in human capital. Hence institutions are relevant for the allocation of talent. Good market-supporting institutions attract talent to productive value-creating activities, whereas poor ones raise the appeal of rent-seeking. We propose a theoretical model that predicts that more talented individuals are particularly sensitive in their career choices to the quality of institutions, and test these predictions on a sample of around 95 countries of the world. We find a strong positive association between the quality of institutions and graduation of college and university students in science, and an even stronger negative correlation with graduation in law. Our findings are robust to various specifications of empirical models, including smaller samples of former colonies and transition countries. The quality of human capital makes the distinction between educational choices under strong and weak institutions particularly sharp. We show that the allocation of talent is an important link between institutions and growth.