Situating language register across the ages, languages, modalities, and cultural aspects: Evidence from complementary methods.

In the present review paper by members of the collaborative research center "Register: Language Users' Knowledge of Situational-Functional Variation" (CRC 1412), we assess the pervasiveness of register phenomena across different time periods, languages, modalities, and cultures. We define "register" as recurring variation in language use depending on the function of language and on the social situation. Informed by rich data, we aim to better understand and model the knowledge involved in situation- and function-based use of language register. In order to achieve this goal, we are using complementary methods and measures. In the review, we start by clarifying the concept of "register", by reviewing the state of the art, and by setting out our methods and modeling goals. Against this background, we discuss three key challenges, two at the methodological level and one at the theoretical level: (1) To better uncover registers in text and spoken corpora, we propose changes to established analytical approaches. (2) To tease apart between-subject variability from the linguistic variability at issue (intra-individual situation-based register variability), we use within-subject designs and the modeling of individuals' social, language, and educational background. (3) We highlight a gap in cognitive modeling, viz. modeling the mental representations of register (processing), and present our first attempts at filling this gap. We argue that the targeted use of multiple complementary methods and measures supports investigating the pervasiveness of register phenomena and yields comprehensive insights into the cross-methodological robustness of register-related language variability. These comprehensive insights in turn provide a solid foundation for associated cognitive modeling.

Adaptive gain modulation in V1 explains contextual modifications during bisection learning.

The neuronal processing of visual stimuli in primary visual cortex (V1) can be modified by perceptual training. Training in bisection discrimination, for instance, changes the contextual interactions in V1 elicited by parallel lines. Before training, two parallel lines inhibit their individual V1-responses. After bisection training, inhibition turns into non-symmetric excitation while performing the bisection task. Yet, the receptive field of the V1 neurons evaluated by a single line does not change during task performance. We present a model of recurrent processing in V1 where the neuronal gain can be modulated by a global attentional signal. Perceptual learning mainly consists in strengthening this attentional signal, leading to a more effective gain modulation. The model reproduces both the psychophysical results on bisection learning and the modified contextual interactions observed in V1 during task performance. It makes several predictions, for instance that imagery training should improve the performance, or that a slight stimulus wiggling can strongly affect the representation in V1 while performing the task. We conclude that strengthening a top-down induced gain increase can explain perceptual learning, and that this top-down signal can modify lateral interactions within V1, without significantly changing the classical receptive field of V1 neurons.

Mass-screening for early detection of renal disease: benefits and limitations of self-testing for proteinuria.

INTRODUCTION: Chronic kidney diseases are of growing importance for our health system. With regard to the high number of undetected cases, screening programs provide opportunities for an early to detect and treat patients. METHODS: With the support of local newspapers, we performed a mass screening of the citizens of Würzburg, Germany. One hundred thousand dipsticks for proteinuria were distributed. Citizens were invited to self-test their urine and to report the results to the organizing centre. RESULTS: We received information for approximately 22% of the distributed dipsticks. Positive tests results numbered 2,458 after removal of 309 positive results for pre-diagnosed renal diseases. From family doctors, we obtained data for control investigations of 856 dipstick-positive subjects. In 104 of them, chronic proteinuria could be confirmed, due to essential hypertension (n=47), pyelo/interstitial nephritis (n=26), diabetic nephropathy (n=20), glomerulonephritis (n=4), nephrolithiasis (n=4), hypernephroma (n=2) and polycystic kidney disease (n=1). DISCUSSION: The benefit of self-testing was an unexpectedly high compliance, even in males. However, a great number of abnormal tests could not be confirmed by family doctors, possibly owing to the time variation in urine testing (early-morning urine in the self-test vs. daytime testing by the physician), the high variability of urinary protein excretion and a large number of false-positive tests in the inexperienced participants. CONCLUSION: Mass screening for proteinuria with self-testing enhances the awareness of renal diseases and improves the chances for an early diagnosis and therapy. Limitations are the frequent overdiagnosis of proteinuria due to minimal colour changes in the dipsticks.

Perceptual learning via modification of cortical top-down signals.

The primary visual cortex (V1) is pre-wired to facilitate the extraction of behaviorally important visual features. Collinear edge detectors in V1, for instance, mutually enhance each other to improve the perception of lines against a noisy background. The same pre-wiring that facilitates line extraction, however, is detrimental when subjects have to discriminate the brightness of different line segments. How is it possible to improve in one task by unsupervised practicing, without getting worse in the other task? The classical view of perceptual learning is that practicing modulates the feedforward input stream through synaptic modifications onto or within V1. However, any rewiring of V1 would deteriorate other perceptual abilities different from the trained one. We propose a general neuronal model showing that perceptual learning can modulate top-down input to V1 in a task-specific way while feedforward and lateral pathways remain intact. Consistent with biological data, the model explains how context-dependent brightness discrimination is improved by a top-down recruitment of recurrent inhibition and a top-down induced increase of the neuronal gain within V1. Both the top-down modulation of inhibition and of neuronal gain are suggested to be universal features of cortical microcircuits which enable perceptual learning.