Disentangling beat perception from sequential learning and examining the influence of attention and musical abilities on ERP responses to rhythm

AbstractBeat perception is the ability to perceive temporal regularity in musical rhythm. When a beat is perceived, predictions about upcoming events can be generated. These predictions can influence processing of subsequent rhythmic events. However, statistical learning of the order of sounds in a sequence can also affect processing of rhythmic events and must be differentiated from beat perception. In the current study, using EEG, we examined the effects of attention and musical abilities on beat perception. To ensure we measured beat perception and not absolute perception of temporal intervals, we used alternating loud and soft tones to create a rhythm with two hierarchical metrical levels. To control for sequential learning of the order of the different sounds, we used temporally regular (isochronous) and jittered rhythmic sequences. The order of sounds was identical in both conditions, but only the regular condition allowed for the perception of a beat. Unexpected intensity decrements were introduced on the beat and offbeat. In the regular condition, both beat perception and sequential learning were expected to enhance detection of these deviants on the beat. In the jittered condition, only sequential learning was expected to affect processing of the deviants. ERP responses to deviants were larger on the beat than offbeat in both conditions. Importantly, this difference was larger in the regular condition than in the jittered condition, suggesting that beat perception influenced responses to rhythmic events in addition to sequential learning. The influence of beat perception was present both with and without attention directed at the rhythm. Moreover, beat perception as measured with ERPs correlated with musical abilities, but only when attention was directed at the stimuli. Our study shows that beat perception is possible when attention is not directed at a rhythm. In addition, our results suggest that attention may mediate the influence of musical abilities on beat perception

Can Birds Perceive Rhythmic Patterns? A Review and Experiments on a Songbird and a Parrot Species

Article / Letter to editorInstituut Biologie Leide

Phosphatidylinositol-(4,5)-bisphosphate regulates sorting signal recognition by the clathrin-associated adaptor complex AP2

The alpha,beta2,mu2,sigma2 heterotetrameric AP2 complex is recruited exclusively to the phosphatidylinositol-4,5-bisphosphate (PtdIns4,5P(2))-rich plasma membrane where, amongst other roles, it selects motif-containing cargo proteins for incorporation into clathrin-coated vesicles. Unphosphorylated and mu2Thr156-monophosphorylated AP2 mutated in their alphaPtdIns4,5P(2), mu2PtdIns4,5P(2), and mu2Yxxvarphi binding sites were produced, and their interactions with membranes of different phospholipid and cargo composition were measured by surface plasmon resonance. We demonstrate that recognition of Yxxvarphi and acidic dileucine motifs is dependent on corecognition with PtdIns4,5P(2), explaining the selective recruitment of AP2 to the plasma membrane. The interaction of AP2 with PtdIns4,5P(2)/Yxxvarphi-containing membranes is two step: initial recruitment via the alphaPtdIns4,5P(2) site and then stabilization through the binding of mu2Yxxvarphi and mu2PtdIns4,5P(2) sites to their ligands. The second step is facilitated by a conformational change favored by mu2Thr156 phosphorylation. The binding of AP2 to acidic-dileucine motifs occurs at a different site from Yxxvarphi binding and is not enhanced by mu2Thr156 phosphorylation

A Critical Appraisal of Circumferential Resection Margins in Esophageal Carcinoma

In esophageal cancer, circumferential resection margins (CRMs) are considered to be of relevant prognostic value, but a reliable definition of tumor-free CRM is still unclear. The aim of this study was to appraise the clinical prognostic value of microscopic CRM involvement and to determine the optimal limit of CRM.To define the optimal tumor-free CRM we included 98 consecutive patients who underwent extended esophagectomy with microscopic tumor-free resection margins (R0) between 1997 and 2006. CRMs were measured in tenths of millimeters with inked lateral margins. Outcome of patients with CRM involvement was compared with a statistically comparable control group of 21 patients with microscopic positive resection margins (R1).A cutoff point of CRM at a parts per thousand currency sign1.0 mm and &gt; 1.0 mm appeared to be an adequate marker for survival and prognosis (both P &lt;0.001). The outcome in patients with CRMs a parts per thousand currency sign1.0 and &gt; 0 mm was equal to that in patients with CRM of 0 mm (P = 0.43). CRM involvement was an independent prognostic factor for both recurrent disease (P = 0.001) and survival (P &lt;0.001). Survival of patients with positive CRMs (a parts per thousand currency sign1 mm) did not significantly differ from patients with an R1 resection (P = 0.12).Involvement of the circumferential resection margins is an independent prognostic factor for recurrent disease and survival in esophageal cancer. The optimal limit for a positive CRM is a parts per thousand currency sign1 mm and for a free CRM is &gt; 1.0 mm. Patients with unfavorable CRM should be approached as patients with R1 resection with corresponding outcome.</p

Cholinergic chemotransmission and anesthetic drug effects at the carotid bodies

Perioperative Medicine: Efficacy, Safety and Outcome (Anesthesiology/Intensive Care

Microtiming patterns and interactions with musical properties in Samba music

In this study, we focus on the interaction between microtiming patterns and several musical properties: intensity, meter and spectral characteristics. The data-set of 106 musical audio excerpts is processed by means of an auditory model and then divided into several spectral regions and metric levels. The resulting segments are described in terms of their musical properties, over which patterns of peak positions and their intensities are sought. A clustering algorithm is used to systematize the process of pattern detection. The results confirm previously reported anticipations of the third and fourth semiquavers in a beat. We also argue that these patterns of microtiming deviations interact with different profiles of intensities that change according to the metrical structure and spectral characteristics. In particular, we suggest two new findings: (i) a small delay of microtiming positions at the lower end of the spectrum on the first semiquaver of each beat and (ii) systematic forms of accelerando and ritardando at a microtiming level covering two-beat and four-beat phrases. The results demonstrate the importance of multidimensional interactions with timing aspects of music. However, more research is needed in order to find proper representations for rhythm and microtiming aspects in such contexts