Measuring event-related potentials (ERPs) has been fundamental to our understanding of how language is encoded in the brain. One particular ERP response, the N400 response, has been especially influential as an index of lexical and semantic processing. However, there remains a lack of consensus on the interpretation of this component. Resolving this issue has important consequences for neural models of language comprehension. Here we show that evidence bearing on where the N400 response is generated provides key insights into what it reflects. A neuroanatomical model of semantic processing is used as a guide to interpret the pattern of activated regions in functional MRI, magnetoencephalography and intracranial recordings that are associated with contextual semantic manipulations that lead to N400 effects.

/pdf/a-cortical-network-for-semantics-de-constructing-the-n400-2mkch9vs5v.pdf

A cortical network for semantics: (de)constructing the N400.

This paper summarizes the experimental frontier of ultracold fermionic gases. It is based on three lectures which one of the authors gave at the Varenna Summer School describing the experimental techniques used to study ultracold fermionic gases, and some of the results obtained so far. In many ways, the area of ultracold fermionic gases has grown out of the study of Bose-Einstein condensates. After their first experimental realizations in 1995 [1,2], the field of BEC has grown explosively. Most of the explored physics was governed by mean-field interactions, conveniently described by the Gross-Pitaevskii equation. One novel feature of trapped inhomogeneous gases was the spatially varying density, that allowed for the direct observation of the condensate, but also led to new concepts of surface effects and collective excitations which depended on the shape of the cloud. The experimental and theoretical explorations of these and other features have been a frontier area for a whole decade!

Making, probing and understanding ultracold Fermi gases

https://pure.mpg.de/pubman/item/item_3314332_3/component/file_3324953/1-s2.0-S0370157320300363-main.pdf

A perspective on conventional high-temperature superconductors at high pressure: Methods and materials

A tour-de-force study finds that as the pressure of lithium is increased to 50 GPa, its melting point drops to 190 K—the lowest yet observed of any elemental metal. The results suggest lithium could be a promising candidate for exploring exotic states of matter similar to that predicted for metallic hydrogen.

/pdf/cold-melting-and-solid-structures-of-dense-lithium-344mmrjdvy.pdf

Cold melting and solid structures of dense lithium

https://www.mrc-cbu.cam.ac.uk/people/matt.davis/pubs/gagnepain_current_biology2012.pdf/

Temporal Predictive Codes for Spoken Words in Auditory Cortex

Elements in the alkali metal series are regarded as unlikely superconductors because of their monovalent character. A superconducting transition temperature as high as 20 K, recently found in compressed lithium (the lightest alkali element), probably arises from pressure-induced changes in the conduction-electron band structure. Superconductivity at ambient pressure in lithium has hitherto remained unresolved, both theoretically and experimentally. Here we demonstrate that lithium is a superconductor at ambient pressure with a transition temperature of 0.4 mK. As lithium has a particularly simple conduction electron system, it represents an important case for any attempts to classify superconductors and transition temperatures, especially to determine if any non-magnetic configuration can exclude superconductivity down to zero temperature. Furthermore, the combination of extremely weak superconductivity and relatively strong nuclear magnetism in lithium would clearly lead to mutual competition between these two ordering phenomena under suitably prepared conditions.

/pdf/superconductivity-in-lithium-below-0-4-millikelvin-at-2rrstti2ub.pdf

Superconductivity in lithium below 0.4 millikelvin at ambient pressure

Cortical dynamics of spoken word perception is not well understood. The possible interplay between analysis of sound form and meaning, in particular, remains elusive. We used magnetoencephalography to study cortical manifestation of phonological and semantic priming. Ten subjects listened to lists of 4 words. The first 3 words set a semantic or phonological context, and the list-final word was congruent or incongruent with this context. Attenuation of activation by priming during the first 3 words and increase of activation to semantic or phonological mismatch in the list-final word provided converging evidence: The superior temporal cortex bilaterally was involved in both analysis of sound form and meaning but the role of each hemisphere varied over time. Sensitivity to sound form was observed at ~100 ms after word onset, followed by sensitivity to semantic aspects from ~250 ms onwards, in the left hemisphere. From ~450 ms onwards, the picture was changed, with semantic effects now present bilaterally, accompanied by a subtle late effect of sound form in the right hemisphere. Present MEG data provide a detailed spatiotemporal account of neural mechanisms during speech perception that may underlie characterizations obtained with other neuroimaging methods less sensitive in temporal or spatial domain.

/pdf/spatiotemporal-interaction-between-sound-form-and-meaning-4ivdp1unts.pdf

Spatiotemporal Interaction between Sound Form and Meaning during Spoken Word Perception

http://lib.tkk.fi/Diss/2010/isbn9789526031422/article5.pdf

Parafoveal-on-foveal and foveal word priming are different processes: Behavioral and neurophysiological evidence

Experiments at ultra-low temperatures require very low thermal contact resistances, a serious issue even for metallic specimens below 1 mK . Customary practices include pressed contacts or welding by some means, e.g. diffusion welding. When dissimilar metals are joined, one must avoid excess formation of an alloy, usually a poor thermal conductor. The most firm contact with possibly deep alloying does not always have the best thermal conductivity. We have studied this problem when pressing lithium metal to contact with copper, silver and gold. The results are surprisingly different—good contacts could be produced only between Li and Cu, not with Li and Ag or Au. This is obviously due to easy alloying of Ag and Au with Li even at room temperature. This information is essential for proper materials choice in our planned experiment on superconductivity and nuclear magnetism on lithium metal.

/pdf/thermal-contact-to-lithium-metal-1vczljp209.pdf

Johanna Uusvuori

Papers

Superconductivity in lithium below 0.4 millikelvin at ambient pressure

Spatiotemporal Interaction between Sound Form and Meaning during Spoken Word Perception

Parafoveal-on-foveal and foveal word priming are different processes: Behavioral and neurophysiological evidence

Thermal contact to lithium metal