Horst M. Müller

Theta synchronization predicts efficient memory encoding of concrete and abstract nouns.

Functional and topographical differences between processing of spoken nouns which were remembered or which were forgotten were shown by means of EEG coherence analysis. Later recalled nouns were related with increased neuronal synchronization (= cooperation) between anterior and posterior brain regions regardless of presented word category (either concrete or abstract nouns). However, theta coherence exhibited topographical differences during encoding of concrete and abstract nouns whereby former were related with higher short-range (mainly intrahemispheric), later with higher long-range (mainly interhemispheric) coherence. Thus, theta synchronization possibly is a general phenomenon always occurring if task demand increases and more efficient information processing is required. Measurement of EEG coherence yields new information about the neuronal interaction of involved brain regions during memory encoding of different word classes.

What's in a name? Electrophysiological differences between spoken nouns, proper names and one's own name.

TO investigate the neural processing of different word categories, we recorded event-related potentials (ERPs) from 32 individuals listening to sentences, beginning either with a proper name (first name), the subjects own name, or a common noun. Names and nouns both elicited ERP waveforms with the same early componentry, but the N1 and P2 components were larger for proper names than common nouns. The ERPs to the subjects own name also had a large N1/P2 plus a prominent negativity at parieto-central site peaking around 400 ms and a late positivity between 500–800 ms over left lateral-frontal sites. These findings are consistent with differential processing of peoples first names within the category of nouns.

The responses of central octavolateralis cells to moving sources

Mechanosensory lateral line units recorded from the medulla (medial octavolateralis nucleus) and midbrain (torus semicircularis) of the bottom dwelling catfish Ancistrus sp. responded to water movements caused by an object that passed the fish laterally. In terms of peak spike rate or total number of spikes elicited responses increased with object speed and sometimes showed saturation (Figs. 7, 14). At sequentially greater distances the responses of most medullary lateral line units decayed with object distance (Fig. 11). Units tuned to a certain object speed or distance were not found. The signed directionality index of most lateral line units was between −50 and +50, i.e. these units were not or only slightly sensitive to the direction of object motion (Figs. 10, 17). However, some units were highly directionally sensitive in that the main features of the response histograms and/or peak spike rates clearly depended on the direction of object movement (e.g. Fig. 9C, D and Fig. 16). Midbrain lateral line units of Ancistrus may receive input from more than one sensory modality. All bimodal lateral line units were OR units, i.e., the units were reliably driven by a unimodal stimulus of either modality. Units which receive bimodal input may show an extended speed range (e.g. Fig. 18).

Indications for feature detection with the lateral line organ in fish

Abstract 1. Stimulated by a moving object or two stationary, oscillating spheres at different positions to the fish, extracellular recordings were obtained from 77 units in the torus semicircularis of a catfish ( Ancistrus spp.). 2. Five mechanosensory units showed complex filter properties, e.g. they responded exclusively to complex hydrodynamic stimuli caused by the moving object, but not to oscillating spheres independent of location, amplitude and phase. 3. Particular midbrain units reacted only to certain stimulus features and responded I) only to the visible vortices following the moving object with a latency of about 300, 900 or 2800 ms depending on the speed of the moving object (n = 8); II) only to a preferred direction of object motion (n = 12); III) only to an exclusively contralateral sphere stimulus, not to a simultaneously bilateral stimulation (n = 3). 4. Seven units have shown a long-lasting response to the moving object (2.3, 10 and 20 cm/sec) with one or two zones of inhibition, which reminds one of OFF- or ON-center units in the visual system. 5. The present findings let us assume the existence of filter properties of toral neurons in lateral line processing, which calls to mind “feature detectors” reported in other sensory systems. It can be regarded as evidence for complex perception of the hydrodynamic environment in fish.

Processing Concepts and Scenarios: Electrophysiological Findings on Language Representation

Studying the underlying neuronal substrate of language processing with electrophysiological techniques, we could provide evidence for a physiological reality of linguistic categories. The processing of abstract concepts (Nouns) activates a less complicated network in the brain, thus showing different functional representation than concrete concepts. As we have demonstrated earlier this is only true with respect to those frequency bands of the EEG, which reflect higher cognitive processes. In other frequency bands the processing of both abstract and concrete nouns activates similar networks. This can be explained by the fact that mere acoustical and visual word perception does not differ between concrete and abstract nouns. The comprehension of complex sentences requires analysis of whole scenarios depending on phonological, syntactic and semantic entities across time. This can also be monitored by EEG-analysis. Even working memory demands can be observed in frontal cortical regions during sentence processing. EEG coherence analysis seems to be an important tool for the investigation of the physiology of language representation and supports theoretical findings in linguistics and philosophy of language.

Die Verarbeitung von Eigennamen und Gattungsbezeichnungen. Eine elektrophysiologische Studie

Bei Wortfindestorungen kann der Zugriff auf Namen von Personen und Objekten selektiv beeintrachtigt sein. Nach einer vergleichenden Darstellung der Diskussion um die Unterscheidung von Eigennamen und Gattungsbezeichnungen aus sprachwissenschaftlicher, biologischer und neuropsychologischer Sicht werden die Ergebnisse eines elektrophysiologischen Experimentes zu diesem Problem vorgestellt. Naturlichsprachliche Satze wurden 32 Versuchspersonen dargeboten, wahrend ein Elektroenzephalogramm (EEG) mit 23 Kanalen abgeleitet wurde. Die wahrend der Verarbeitung von Eigennamen und Gattungsbezeichnungen abgeleiteten ereigniskorrelierten Hirnpotentiale (event related potential, ERP) zeigten bei sonst ahnlicher Morphologie Amplitudenunterschiede in der N1- und der P2-Komponente, wobei Eigennamen hohere Amplituden auslosten. Der eigene Vorname bewirkte daruber hinaus eine langanhaltende Negativitat mit einem Hauptmaximum um 400 msec. Neben den bisherigen Hinweisen aus der Aphasiologie und der klinischen Neuropsychologie konnen die vorliegenden Ergebnisse als weitere Unterstutzung einer Sonderstellung der Eigennamen innerhalb der Nomina gelten. Die mehr als 2000 Jahre alte philosophische und sprachtheoretische Unterteilung der Konkreta in Nomina propria und Nomina appellativa konnte somit durchaus der “kognitiven Realitat” entsprechen.

Neurolinguistic Findings on the Language Lexicon: The Special Role of Proper Names

Cognitive linguistics proposes the existence of a human language lexicon as a necessary subsystem of language production and comprehension. While the inner structure of the lexicon remains speculative, measures of its function may distinguish separate processing paths for different types of lexical entries. Based upon the presented findings on nomina from reaction time measurements, event-related potentials (ERP) analysis, and functional magnetic resonance imaging (fMRI), the special role of proper names in language--in contrast to common nouns--appears to be grounded in a neurocognitive reality.

EEG beta-power changes reflect motor involvement in abstract action language processing

&NA; Brain oscillations in the &agr;‐ and &bgr;‐range become suppressed during motor processing and motor imagery. It has recently been discussed that such power changes also occur during action language processing. In our study, we compared &bgr;2‐oscillations (16–25 Hz) during the observation of prototypical arm movements (revealed via motion tracking) as well as during semantic processing of concrete and abstract sentences containing arm‐related action verbs. Whereas we did find a strong desynchronization in the &bgr;2‐range during action observation, the processing of action sentences evoked a rather weak desynchronization. However, this desynchronization occurred for action verbs in both concrete and abstract contexts. These results might indicate a tendency for abstract action language to be processed similar to concrete action language rather than abstract sentences. The oscillation patterns reflect the close relationship between language comprehension and motor functions – one of the core claims of current theories on embodied cognition. HighlightsAnalysis of &bgr;2‐power during prototypical movements and abstract action language.&bgr;2‐ERD during action observation vs. language processing is only partially similar.&bgr;2‐ERD during abstract vs. concrete action language processing is comparable.

Influences of semantic and syntactic incongruence on readiness potential in turn-end anticipation

Knowing when it is convenient to take a turn in a conversation is an important task for dialog partners. As it appears that this decision is made before the transition point has been reached, it seems to involve anticipation. There are a variety of studies in the literature that provide possible explanations for turn-end anticipation. This study particularly focuses on how turn-end anticipation relies on syntactic and/or semantic information during utterance processing, as tested with syntactically and semantically violated sentences. With a combination reaction time and EEG experiment, we used the onset latencies of the readiness potential (RP) to uncover possible differences in response preparation. Although the mean anticipation timing accuracy (ATA) values of the behavioral test were all within a similar time range (control sentences: 108 ms, syntactically violated sentences: 93 ms and semantically violated sentences: 116 ms), we found evidence that response preparation is indeed different for syntactically and semantically violated sentences in comparison with control sentences. Our preconscious EEG data, in the form of RP results, indicated a response preparation onset to sentence end interval of 1452 ms in normal sentences, 937 ms in sentences with syntactic violations and 944 ms in sentences with semantic violations. Compared with control sentences, these intervals resulted in a significant RP interruption for both sentence types and indicate an interruption of preconscious response preparation. However, the behavioral response to sentence types occurred at comparable time points.

IONIC CONCENTRATIONS, OSMOLARITY AND pH OF THE HAEMOLYMPH OF THE COMMON HOUSESPIDER TEGENARIA ATRICA C.L. KOCH (AGELENIDAE, ARACHNIDA)

Abstract 1. 1. In the haemolymph of adult female of Tegenaria atrica the concentrations of Na + , K + , Mg ++ , Ca ++ and Cl − ions as well as osmolarity and pH-values were measured. 2. 2. On the basis of these findings the following Ringer solution for T. atrica was developed: 10.25 g/l NaCl, 0.40 g/l NaHCO 3 , 0.83 g/l KC1,0.16 g/l MgCl 2 :6H 2 O,0.62 g/l CaCl 2 :2H 2 O and 13.3 g/l saccharose, if necessary. The pH is adjusted at 8.2. 3. 3. In the Ringer solution the semi-isolated heart of T. atrica, T. ferruginea and T. derhami beats for up to 169 hr at +8°C. 4. 4. The results of this investigation are discussed and compared with earlier data.