Coordination and consensus: the role of compromisers in Tibetan macaques

Coordination and consensus in collective behavior have attracted a lot of research interest. Although previous studies have investigated the role of compromisers in group consensus, they provide little insight into why compromisers would allow such social arrangements to persist. In this study, the potential relationship between group movements and conflict management in Tibetan macaques in Anhui province, China, was investigated using hierarchical cluster analyses. Some members with higher social centrality or social rank often formed a front-runner cluster during group movements. They had higher leadership success than individuals outside the front-runner cluster. Other members with lower social centrality or social rank often followed the group movements initiated by the front-runner cluster, and thus formed the compromiser cluster. Compromisers’ proximity relations with front-runners increased with their following scores to front-runners. Compromisers had fewer events of being attacked when they followed group movements initiated by the front-runners. The compromising process made compromisers lose the choice of direction preference, but it could increase their individual safeties. This trade-off suggests that compromisers play a role of decision-maker in coordination and consensus scenarios among social animals.

Serotonergic neurons mediate operant conditioning in Drosophila larvae

Observed across species, operant conditioning facilitates learned associations between behaviours and outcomes, biasing future action selection to maximise reward and avoid punishment. To elucidate the underlying neural mechanisms, we built a high-throughput tracker for Drosophila melanogaster, combining real-time behaviour detection with closed-loop optogenetic and thermogenetic stimulation capabilities. We demonstrate operant conditioning in Drosophila larvae by inducing a bend direction preference through optogenetic activation of reward-encoding serotonergic neurons. Specifically, we establish that the ventral nerve cord is necessary for this memory formation. Our results extend the role of serotonergic neurons for learning in insects as well as the existence of learning circuits outside the mushroom body. This work supports future studies on the function of serotonin and the mechanisms underlying operant conditioning at both circuit and cellular levels.

Hydrogen bonding to carbonyl oxygen of nitrogen-pyramidalized amide – detection of pyramidalization direction preference by vibrational circular dichroism spectroscopy

Hydrogen-bonding to carbonyl of nitrogen-pyramidalized bicyclic β-proline amides can switch the preferred nitrogen-pyramidalization direction, as detected by VCD spectroscopy.

Directionality in ASL-English interpreting

Among spoken language interpreters, a long-standing question regarding directionality is whether interpretations are better when working into one’s native language (L1) or into one’s ‘active’ non-native language (L2). In contrast to studies that support working into L1, signed language interpreters report a preference for working into L2. Accordingly, we investigated whether signed language interpreters actually perform better when interpreting into their L2 (American Sign Language, ASL) or into their L1 (English). Interpretations by 30 interpreters (15 novice, 15 expert), delivered under experimental conditions, were assessed on accuracy (semantic content) and articulation quality (flow, speed, and prosody). For both measures, novices scored significantly better when interpreting into English (L1); experts were equally accurate, and showed similar articulation quality, in both directions. The results for the novice interpreters support the hypothesis that the difficulty of L2 production drives interpreting performance in relation to directionality. Findings also indicate a disconnect between direction preference and interpreting performance. Novices’ perception of their ASL production ability may be distorted because they can default to fingerspelling and transcoding. Weakness in self-monitoring of signing may also lead novices to overrate their ASL skills. Interpreter educators should stress misperceptions of signing proficiency that arise from available, but inappropriate, strategies.

Single-cell–initiated monosynaptic tracing reveals layer-specific cortical network modules

Individual cortical neurons can selectively respond to specific environmental features, such as visual motion or faces. How this relates to the selectivity of the presynaptic network across cortical layers remains unclear. We used single-cell–initiated, monosynaptically restricted retrograde transsynaptic tracing with rabies viruses expressing GCaMP6s to image, in vivo, the visual motion–evoked activity of individual layer 2/3 pyramidal neurons and their presynaptic networks across layers in mouse primary visual cortex. Neurons within each layer exhibited similar motion direction preferences, forming layer-specific functional modules. In one-third of the networks, the layer modules were locked to the direction preference of the postsynaptic neuron, whereas for other networks the direction preference varied by layer. Thus, there exist feature-locked and feature-variant cortical networks.

Direction asymmetries in spoken and signed language interpreting

Spoken language (unimodal) interpreters often prefer to interpret from their non-dominant language (L2) into their native language (L1). Anecdotally, signed language (bimodal) interpreters express the opposite bias, preferring to interpret from L1 (spoken language) into L2 (signed language). We conducted a large survey study (N = 1,359) of both unimodal and bimodal interpreters that confirmed these preferences. The L1 to L2 direction preference was stronger for novice than expert bimodal interpreters, while novice and expert unimodal interpreters did not differ from each other. The results indicated that the different direction preferences for bimodal and unimodal interpreters cannot be explained by language production–comprehension asymmetries or by work or training experiences. We suggest that modality and language-specific features of signed languages drive the directionality preferences of bimodal interpreters. Specifically, we propose that fingerspelling, transcoding (literal word-for-word translation), self-monitoring, and consumers’ linguistic variation influence the preference of bimodal interpreters for working into their L2.