Subtype-specific plasticity of inhibitory circuits in motor cortex during motor learning.

Motor skill learning induces long-lasting reorganization of dendritic spines, principal sites of excitatory synapses, in the motor cortex. However, mechanisms that regulate these excitatory synaptic changes remain poorly understood. Here, using in vivo two-photon imaging in awake mice, we found that learning-induced spine reorganization of layer (L) 2/3 excitatory neurons occurs in the distal branches of their apical dendrites in L1 but not in the perisomatic dendrites. This compartment-specific spine reorganization coincided with subtype-specific plasticity of local inhibitory circuits. Somatostatin-expressing inhibitory neurons (SOM-INs), which mainly inhibit distal dendrites of excitatory neurons, showed a decrease in axonal boutons immediately after the training began, whereas parvalbumin-expressing inhibitory neurons (PV-INs), which mainly inhibit perisomatic regions of excitatory neurons, exhibited a gradual increase in axonal boutons during training. Optogenetic enhancement and suppression of SOM-IN activity during training destabilized and hyperstabilized spines, respectively, and both manipulations impaired the learning of stereotyped movements. Our results identify SOM inhibition of distal dendrites as a key regulator of learning-related changes in excitatory synapses and the acquisition of motor skills

Deterministic, Stash-Free Write-Only ORAM

Write-Only Oblivious RAM (WoORAM) protocols provide privacy by encrypting the contents of data and also hiding the pattern of write operations over that data. WoORAMs provide better privacy than plain encryption and better performance than more general ORAM schemes (which hide both writing and reading access patterns), and the write-oblivious setting has been applied to important applications of cloud storage synchronization and encrypted hidden volumes. In this paper, we introduce an entirely new technique for Write-Only ORAM, called DetWoORAM. Unlike previous solutions, DetWoORAM uses a deterministic, sequential writing pattern without the need for any "stashing" of blocks in local state when writes fail. Our protocol, while conceptually simple, provides substantial improvement over prior solutions, both asymptotically and experimentally. In particular, under typical settings the DetWoORAM writes only 2 blocks (sequentially) to backend memory for each block written to the device, which is optimal. We have implemented our solution using the BUSE (block device in user-space) module and tested DetWoORAM against both an encryption only baseline of dm-crypt and prior, randomized WoORAM solutions, measuring only a 3x-14x slowdown compared to an encryption-only baseline and around 6x-19x speedup compared to prior work

Contagion and learning in business networks

The purpose of this study is to examine network learning through the application of contagion theories. The transmission of knowledge, sharing of resources, and facilitation of learning through contagion has interested both business-to-business and economic geography researchers. This study responds to calls in both research traditions for research into knowledge and learning at the level of an interfirm network. More specifically, it focuses on developing an understanding of how the contagion of knowledge and ideas and the co-ordination of activities within a network tales place. We achieve this by drawing upon research in both network relationships dynamics and learning processes to investigate the causal mechanisms that drive contagion. We focus on two types of contagion: contagion by cohesion (i.e. the presences and closeness of direct contact with others in the network), and contagion by structural equivalence (i.e. where influence is related to the structural patterns of relationships in the network). We also identify two key mechanisms that act as a barrier to such contagion: isolation and immunity. We explore the implications of these findings for network learning opportunities, specifically learning-by-doing, learning-by-using, and learning-by-interacting

Contingent factors affecting network learning

To increase understanding of the impact of individuals on organizational learning processes, this paper explores the impact of individual cognition and action on the absorptive capacity process of the wider network. In particular this study shows how contingent factors such as social integration mechanisms and power relationships influence how network members engage in, and benefit from, learning. The use of cognitive consistency and sensemaking theory enables examination of how these contingent factors influence the learning processes of two construction industry design teams embedded within more permanent home-organizational structures. A number of practical ways arise by which firms can facilitate organizational learning through their interactions with network partners. Enhancement of learning in and between organizations occurs when members are cognizant of the means by which they connect within a network to create shared meanings, and the way in which they forge ties and share expertise in the learning process they engage in

Involving customers in innovation: knowledgeability and agency as process variables

Purpose: Recent research places an increased emphasis on the inclusion of the customer in value creation, learning, and innovation processes yet there remains a gap in our understanding of just how such customer involvement may work. This paper seeks to address this gap by examining two aspects of customer involvement; their knowledgeability and their agency. In addition, we explore three boundaries (semantic, syntactic, and pragmatic) across which relationship development occurs and which mayfacilitate and/or inhibit value co-creation, collaborative learning, and innovation processes. Design/methodology/approach: We utilised three case studies. Two were large scale construction projects in the UK, and one was a global professional accounting firm in the USA. Findings: Customers may become frustrated if not allowed to exercise their agency. However, their involvement can create tensions for suppliers who may have to become more tolerant of divergent goals. In respect of knowledgeability, we found that constraint satisfaction is important in allowing customers to reconcile their personal knowledge schema with that of the collective schema. However, we also noted that customer knowledgeability brings with it challenges for suppliers, who must find ways to add value for such customers. Research implications: We pose a number of further questions relating to the agency and knowledgeability of customers and their inclusion in value co-creation, collaborative learning, and innovation processes. We also highlight the need for guidance in identifying and minimising the barriers to crossing semantic, syntactic and pragmatic boundaries between customers and suppliers. Originality/value: We make an important contribution to research in the field in that we investigate how the inclusion of the customer in business networksalters current assumptions and practices