scholarly journals Task-specific sensory coding strategies are matched to detection and discrimination performance

2018 ◽  
Vol 221 (6) ◽  
pp. jeb170563 ◽  
Author(s):  
Kathryne M. Allen ◽  
Gary Marsat
2017 ◽  
Author(s):  
K.M. Allen ◽  
G. Marsat

ABSTRACTAll sensory systems must reliably translate information about the environment into a neural code, mediating perception. The most relevant aspects of stimuli may change as behavioral context changes, making efficient encoding of information more challenging. Sensory systems must balance rapid detection of a stimulus with perception of fine details that enable discrimination between similar stimuli. We show that in a species of weakly electric fish, Apteronotus leptorhynchus, two coding strategies are employed for these separate behavioral tasks. Using communication signals produced in different contexts, we demonstrate a strong correlation between neural coding strategies and behavioral performance on a discrimination task. Extracellular recordings of pyramidal cells within the electrosensory lateral line lobe of alert fish show two distinct response patterns, either burst discharges with little variation between different signals of the same category, or a graded, heterogeneous response that contains enough information to discriminate between signals with slight variations. When faced with a discrimination-based task, the behavioral performance of the fish closely matches predictions based on coding strategy. Comparisons of these results with neural and behavioral responses observed in other model systems suggest that our study highlights a general principle in the way different neural codes are utilized in the sensory system.SIGNIFICANCE STATEMENTResearch relating the structure of stimuli to the response of sensory neurons has left us with a detailed understanding of how different neural codes can represent information. Although various aspects of neural responses have been related to perceptual abilities, general principles relating behavioral tasks to sensory coding strategies are lacking. A major distinction can be made between signals that must simply be detected versus stimuli that must also be finely discriminated and evaluated. We show that these two different perceptual tasks are systematically matched by distinct neural coding strategies and we argue that our study identifies a general principle that is observed in various sensory systems.Conflict of interest statementThe authors declare no competing financial interests.


2020 ◽  
Vol 103 (6) ◽  
pp. 548-552

Objective: To predict the quality of anticoagulation control in patients with atrial fibrillation (AF) receiving warfarin in Thailand. Materials and Methods: The present study retrospectively recruited Thai AF patients receiving warfarin for three months or longer between June 2012 and December 2017 in Central Chest Institute of Thailand. The patients were classified into those with SAMe-TT₂R₂ of 2 or less, and 3 or more. The Chi-square test or Fisher’s exact test was used to compare the proportion of the patients with poor time in therapeutic range (TTR) between the two groups of SAMe-TT₂R₂ score. The discrimination performance of SAMe-TT₂R₂ score was demonstrated with c-statistics. Results: Ninety AF patients were enrolled. An average age was 69.89±10.04 years. Most patients were persistent AF. An average CHA₂DS₂-VASc, SAMe-TT₂R₂, and HAS-BLED score were 3.68±1.51, 3.26±0.88, and 1.98±0.85, respectively. The present study showed the increased proportion of AF patients with poor TTR with higher SAMe-TT₂R₂ score. The AF patients with SAMe-TT₂R₂ score of 3 or more had a larger proportion of patients with poor TTR than those with SAMe-TT₂R₂ score of 2 or less with statistical significance when TTR was below 70% (p=0.03) and 65% (p=0.04), respectively. The discrimination performance of SAMe-TT₂R₂ score was demonstrated with c-statistics of 0.60, 0.59, and 0.55 when TTR was below 70%, 65% and 60%, respectively. Conclusion: Thai AF patients receiving warfarin had a larger proportion of patients with poor TTR when the SAMe-TT₂R₂ score was higher. The score of 3 or more could predict poor quality of anticoagulation control in those patients. Keywords: Time in therapeutic range, Poor quality of anticoagulation control, Warfarin, SAMe-TT₂R₂, Labile INR


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yuan Fu ◽  
Yuxia Pan ◽  
Yuanfeng Gao ◽  
Xinchun Yang ◽  
Mulei Chen

Abstract Background New-onset atrial fibrillation (NOAF) is common during acute myocardial infarction (AMI) and independently associated with worse prognosis. We aimed to validate the discrimination performance of CHA2DS2-VASc score combined with hs-CRP in the prediction of NOAF after AMI in elderly Chinese population. Methods 311 consecutive elderly patients (age ≥ 65 years old) with AMI from 1 January 2018 to 1 January 2019 without atrial fibrillation history were enrolled in our study. Univariable and multivariable logistic regression analyses were used to identify risk factors of NOAF. The discrimination performance of different score models were evaluated using ROC curve analysis and AUCs were compared using the Z test. Results 30 (9.65%) patients developed NOAF during hospitalization. The NOAF group were older and had higher hs-CRP, initial Killip class, BNP, LAD, CHADS2 score, CHA2DS2-VASc score, in-hospital mortality and lower LVEF and ACEI/ARB use (P < 0.05 vs group without NOAF for all measures). In multivariate regression analyses, age (OR = 1.127, 95% CI 1.063–1.196, P < 0.001) and hs-CRP (OR = 1.034, 95% CI 1.018–1.05, P < 0.001) were independent predictors of NOAF. In ROC curve analyses, both CHADS2 score (AUC = 0.624, 95% CI 0.516–0.733, P = 0.026) and CHA2DS2-VASc score (AUC = 0.687, 95% CI 0.584–0.79, P = 0.001) had acceptable but unsatisfactory discrimination performance in predicting NOAF after AMI. The combined model with CHA2DS2-VASc score and hs-CRP showed a significant better predictive value (AUC = 0.791, 95% CI 0.692–0.891, P < 0.001) compared to that of the CHA2DS2-VASc score alone (Z test, P = 0.008). Conclusion The combined model with CHA2DS2-VASc score and hs-CRP had high accuracy in predicting post-AMI NOAF.


2021 ◽  
Vol 207 (3) ◽  
pp. 303-319
Author(s):  
Heiner Römer

AbstractTo perform adaptive behaviours, animals have to establish a representation of the physical “outside” world. How these representations are created by sensory systems is a central issue in sensory physiology. This review addresses the history of experimental approaches toward ideas about sensory coding, using the relatively simple auditory system of acoustic insects. I will discuss the empirical evidence in support of Barlow’s “efficient coding hypothesis”, which argues that the coding properties of neurons undergo specific adaptations that allow insects to detect biologically important acoustic stimuli. This hypothesis opposes the view that the sensory systems of receivers are biased as a result of their phylogeny, which finally determine whether a sound stimulus elicits a behavioural response. Acoustic signals are often transmitted over considerable distances in complex physical environments with high noise levels, resulting in degradation of the temporal pattern of stimuli, unpredictable attenuation, reduced signal-to-noise levels, and degradation of cues used for sound localisation. Thus, a more naturalistic view of sensory coding must be taken, since the signals as broadcast by signallers are rarely equivalent to the effective stimuli encoded by the sensory system of receivers. The consequences of the environmental conditions for sensory coding are discussed.


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