Brainhack: a collaborative workshop for the open neuroscience community

Brainhack events offer a novel workshop format with participant-generated content that caters to the rapidly growing open neuroscience community. Including components from hackathons and unconferences, as well as parallel educational sessions, Brainhack fosters novel collaborations around the interests of its attendees. Here we provide an overview of its structure, past events, and example projects. Additionally, we outline current innovations such as regional events and post-conference publications. Through introducing Brainhack to the wider neuroscience community, we hope to provide a unique conference format that promotes the features of collaborative, open science.

at unconferences is dynamically determined by attendees, while hackathons feature unstructured time during which teams of participants collaborate intensively on various projects. These meeting formats have enabled rapid advances in computing technologies since the late 1990s, but they have yet to be widely adopted in academic research. Now in their fourth year, international and regional Brainhack events bring together brain enthusiasts from a variety of backgrounds to build relationships, learn from one another, and collaborate on projects related to the neurosciences. Unlike traditional hackathons that tend to focus on computer programming, projects at Brainhacks can be completed using a much broader array of methods. Time is set aside for periodic unconference sessions whose content is determined on-site by the participants. The unconference sessions can feature different styles of presentations, including but not limited to: updates on ongoing projects, ideas that could seed future collaborations, panel discussions, or tutorials. In consideration of the ever expanding interest in the tools of open science, Brainhack has developed an educational component that runs in parallel with the hacking sessions in order to introduce the basic tools of open collaboration. This combined model encourages active participation and interaction between attendees, while also maximizing the topical relevance of the more formally presented content (see Fig. 1).
There is no ideal background, skill set, or experience level required for Brainhack attendees. Fully translating neuroscience data to knowledge requires expertise that spans biology, computer science, engineering, informatics, mathematics, neuroanatomy, philosophy, physics, psychiatry, psychology, statistics, art, and many others. The goal of a Brainhack event is to facilitate the crosspollination of ideas and knowledge across these various disciplines and communities to accelerate the development of a richer understanding of the brain. In addition to sharing data and tools, attendees can contribute in a variety of ways. Philosophical debates about the meanings of cognition, coordinated efforts to manually segment brain images from different species, curating neuroscience literature, or helping others to understand the subtleties of diagnosing a developmental disorder are all examples of valuable contributions that have emerged at Brainhacks in the past (for further examples, see Table 1).

Hackathons based on collaboration, not competition
The hackathon format gained prominence in the technology sector by providing a meeting model that targets specific project goals during intense time-limited collaborations. The competitive aspect of the traditional hackathon, while catalyzing rapid advances toward specific technology ends, is contrary to the founding principle of Brainhack, which is to encourage open, crossinstitutional, and inter-disciplinary collaboration. Rather than subdividing attendees into competitive factions, Brainhack attendees are encouraged to work together in collaborative teams to solve problems of their choosing. In this way, rather than obtaining many solutions to a single problem, we aim to produce various solutions to many problems. Most importantly, we encourage the building of new relationships that continue to be productive beyond the end of the event.

Brainhack projects
Rather than focusing on a specific problem or toolset, which is common in traditional hackathons, attendees are encouraged to generate their own project ideas around which they can self-assemble into teams. As a consequence, some projects may receive more limited interest, whereas one might attract the majority of attendees. In this way, the projects developed at Brainhacks are elected by participation, rather than being pre-specified by the event organizers. This model is more conducive to collaboration than the alternative of organizing a hackathon around a challenge or competition. There are many different models between these two extremes; we are currently working on building thematic Brainhack events that bring researchers together to focus on specific questions of neuroscientific interest.
To date, projects completed at Brainhack events have included students interacting with more experienced researchers to learn about a new data modality or analysis method, inter-disciplinary collaborations to improve data collection, the development or optimization of data analysis tools, and testing hypotheses about brain structure using openly shared data. See Table 1 for selected examples of projects that have previously been initiated at Brainhack events, and www.brainhack.org [1] for a full list of projects.

Event organization
Brainhack events span 1 to 4 days and include a variety of content to make them both accessible and fruitful for a wide range of attendees. The format of the events is not fixed, but varies based on the needs determined by the local organizing committee. At past events, the schedule has included various components aiming to quickly integrate the attendees and generate an environment conducive to productive collaboration. We have found the Table 1 Selected examples of Brainhack projects • A child psychiatrist and a 3D video artist initiated a collaboration at the 2012 Brainhack to develop a movie to be shown to participants during resting-state fMRI scans to reduce head motion in hyperkinetic populations [5,6].
• A collaboration started at the 2012 Brainhack performed an analysis to identify differences in cortical thickness and structural covariance between individuals with autism spectrum disorder and neurotypical controls [24].
• A project team at Brainhack 2013 amassed a dataset of 14,781 structural MRI scans to estimate the distribution of brain sizes across individuals for optimizing scan acquisition parameters [25].
• The development team of LORIS, an open source database system for neuroimaging and phenotypic data, have repeatedly used Brainhack as an opportunity to meet and collaborate on new features [26].
• An early version of the Daydreaming app [27], an Android application for real-time assessment of users' mind-wandering, was developed at Brainhack 2013.
• The Clubs of Science [28] project, founded at Brainhack MTL 2015, has built a web-based visualization of the social web underlying neuroimaging research.
• The linkRbrain [29] tool for integrating and querying neuroimaging data with activation peaks from the literature and gene expression data was partially developed and first tested at Brainhack 2013 in Paris [30].
Further projects can be found at www.brainhack.org [1] activity categories included in Table 2 to be valuable elements of creating a productive environment.

Practical considerations
To enable broad attendance by researchers, regardless of their resources, fees are kept as low as possible and many of the events are free. This has been made possible through generous financial support and meeting space provided by hosting institutions and corporate sponsors. When possible, lunch and dinner have been provided to encourage continued interaction between attendees throughout the duration of the event. We have also Table 2 Programming components of Brainhack events • Meet and greet: Brainhack events begin with a welcome to the hosting facility by the local organizing committee, along with a briefing about the event schedule, procedures, or other information that might be important for the attendees.
• Ice breaker: Interaction between attendees is the key to a successful Brainhack event. The ice breaker is an activity to introduce attendees and their interests to one another. One strategy that has been successful is for each attendee to give their name, their institution, and three words that describe their interests. Such ice breakers could take various forms, including a speed-dating paradigm in which attendees pair up for a brief conversation, after which attendees swap partners, and this continues until every pair has met.
• Ignite talks: Brainhack's equivalent of keynote sessions, Ignite talks are inspirational talks on the big picture of open brain science that are intended to invigorate the audience for the day ahead. These are ideally brief (a 10-minute presentation followed by 10 minutes of questions), of general relevance, and are provided by a luminary in the field.
• Hacking: The core of Brainhack is 'open hacking' sessions during which attendees collaborate together on projects of their choosing. Attendees who have specific project ideas or data that they would like to explore are encouraged to advertise their project at www.brainhack.org [1] prior to the event. At the opening of the Brainhack event, typically after the ice breaker, attendees pitch their ideas and afterwards mingle with others to organize a project team. Teams work together throughout the remainder of Brainhack and are given the opportunity to present their progress during the wrap-up session at the end of the event.
• Brainhacking 101: The educational track enables less experienced attendees to learn basic software and data analysis skills. Occurring in parallel so as not to interfere with the ongoing hacking sessions, this track begins with 'Installfest' sessions during which attendees receive help installing any required software. Afterwards there are several hands-on tutorials that cover topics like: using Github, Python programming, using Python to load and visualize neuroimaging data, and performing meta-analyses of scientific literature. The resources for educational sessions are made freely available online (e.g., [31]).
• Unconference: Sessions for attendees to present their research or other topics of current interest. Immediately prior to these sessions, the agenda is determined on-site. Attendees who are willing to present add their name to a sign-up sheet and in the event that there are more interested presenters than time, the group is polled to determine which presentations are given time or to extend the amount of time allotted. Instead of unconference sessions, some sites have incorporated 'data blitzes,' consisting of a pre-organized session where attendees have the opportunity to present their research. Brainhack Miami has had success with this model and has secured funding to award monetary prizes to the best presentations.
• Wrap-up and feedback: Brainhack events typically finish with a wrap-up session during which project teams describe the progress that they made or give a demo of their results in a brief (∼1-2-minute) presentation. Afterwards, the local organizers lead a discussion about what worked well with the event, and how it could be improved in the future.

Regional events
Brainhack began as international events that drew attendees from all over the world to work together in open collaboration. Early interest in transferring this model to the local level was tempered by fears that local events would not be able to provide enough content to attract attendees. Brainhack Eastern Daylight Time (Brainhack EDT) was developed to address these concerns by organizing several simultaneous events that are virtually linked to enable the real-time sharing of content across sites. Events were limited to sites in time zones within 1 hour of EDT to simplify scheduling. This innovative distributed model drew 242 attendees across seven sites located in three different countries, and has since been followed by Brainhack Americas, which extended this model to the entirety of North, South, and Central America (see Tables 3 and 4).

Conclusions
Brainhack promotes open neuroscience by offering unique opportunities to researchers from a variety of backgrounds to build collaborations and develop new skills. It is particularly valuable to junior researchers and those from developing economies who have limited opportunities to interact with peers and senior scientists outside their home institutions. Despite these successes, Brainhack is a nascent concept for scientific meetings, and there remains substantial room for innovation. To this end, we are excited to announce the Brainhack Proceedings and Brainhack Thematic Series for providing researchers with tangible scientific credit for their contributions to Brainhack events and open science. For the future, we will be working to expand the global audience of Brainhack by hosting events throughout Asia.