42 results on '"Manley, Jason"'
Search Results
2. Commensal, Multi-user Observations with an Ethernet-based Jansky Very Large Array
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Hickish, Jack, Beasley, Tony, Bower, Geoff, Burke-Spolaor, Sarah, Croft, Steve, DeBoer, Dave, Demorest, Paul, Diamond, Bill, Gajjar, Vishal, Law, Casey, Lazio, Joseph, Manley, Jason, Paragi, Zsolt, Ransom, Scott, and Siemion, Andrew
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Over the last decade, the continuing decline in the cost of digital computing technology has brought about a dramatic transformation in how digital instrumentation for radio astronomy is developed and operated. In most cases, it is now possible to interface consumer computing hardware, e.g. inexpensive graphics processing units and storage devices, directly to the raw data streams produced by radio telescopes. Such systems bring with them myriad benefits: straightforward upgrade paths, cost savings through leveraging an economy of scale, and a lowered barrier to entry for scientists and engineers seeking to add new instrument capabilities. Additionally, the typical data-interconnect technology used with general-purpose computing hardware -- Ethernet -- naturally permits multiple subscribers to a single raw data stream. This allows multiple science programs to be conducted in parallel. When combined with broad bandwidths and wide primary fields of view, radio telescopes become capable of achieving many science goals simultaneously. Moreover, because many science programs are not strongly dependent on observing cadence and direction (e.g. searches for extraterrestrial intelligence and radio transient surveys), these so-called "commensal" observing programs can dramatically increase the scientific productivity and discovery potential of an observatory. In this whitepaper, we detail a project to add an Ethernet-based commensal observing mode to the Jansky Very Large Array (VLA), and discuss how this mode could be leveraged to conduct a powerful program to constrain the distribution of advanced life in the universe through a search for radio emission indicative of technology. We also discuss other potential science use-cases for the system, and how the system could be used for technology development towards next-generation processing systems for the Next Generation VLA., Comment: Astro2020 APC White Paper
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- 2019
3. A Decade of Developing Radio-Astronomy Instrumentation using CASPER Open-Source Technology
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Hickish, Jack, Abdurashidova, Zuhra, Ali, Zaki, Buch, Kaushal D., Chaudhari, Sandeep C., Chen, Hong, Dexter, Matthew, Domagalski, Rachel Simone, Ford, John, Foster, Griffin, George, David, Greenberg, Joe, Greenhill, Lincoln, Isaacson, Adam, Jiang, Homin, Jones, Glenn, Kapp, Francois, Kriel, Henno, Lacasse, Rich, Lutomirski, Andrew, MacMahon, David, Manley, Jason, Martens, Andrew, McCullough, Randy, Muley, Mekhala V., New, Wesley, Parsons, Aaron, Price, Daniel C., Primiani, Rurik A., Ray, Jason, Siemion, Andrew, Van Tonder, Verees'e, Vertatschitsch, Laura, Wagner, Mark, Weintroub, Jonathan, and Werthimer, Dan
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
The Collaboration for Astronomy Signal Processing and Electronics Research (CASPER) has been working for a decade to reduce the time and cost of designing, building and deploying new digital radio-astronomy instruments. Today, CASPER open-source technology powers over 45 scientific instruments worldwide, and is used by scientists and engineers at dozens of academic institutions. In this paper we catalog the current offerings of the CASPER collaboration, and instruments past and present built by CASPER users and developers. We describe the ongoing state of software development, as CASPER looks to support a broader range of programming environments and hardware and ensure compatibility with the latest vendor tools., Comment: 24 pages, 6 figures, 5 tables. Accepted to the Journal of Astronomical Instrumentation 26 October 2016
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- 2016
4. Whole-brain neural substrates of behavioral variability in the larval zebrafish
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Manley, Jason, primary and Vaziri, Alipasha, additional
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- 2024
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5. Simultaneous, cortex-wide and cellular-resolution neuronal population dynamics reveal an unbounded scaling of dimensionality with neuron number
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Manley, Jason, primary, Demas, Jeffrey, additional, Kim, Hyewon, additional, Martínez Traub, Francisca, additional, and Vaziri, Alipasha, additional
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- 2024
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6. High-speed, cortex-wide volumetric recording of neuroactivity at cellular resolution using light beads microscopy
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Demas, Jeffrey, Manley, Jason, Tejera, Frank, Barber, Kevin, Kim, Hyewon, Traub, Francisca Martínez, Chen, Brandon, and Vaziri, Alipasha
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- 2021
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7. New Limits on Polarized Power Spectra at 126 and 164 MHz: Relevance to Epoch of Reionization Measurements
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Moore, David, Aguirre, James E., Kohn, Saul, Parsons, Aaron, Ali, Zaki, Bradley, Richard, Carilli, Chris, DeBoer, David, Dexter, Matthew, Gugliucci, Nicole, Jacobs, Daniel, Klima, Pat, Liu, Adrian, MacMahon, David, Manley, Jason, Pober, Jonathan, Stefan, Irina, and Walbrugh, William
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Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Polarized foreground emission is a potential contaminant of attempts to measure the fluctuation power spectrum of highly redshifted 21 cm HI emission from the epoch of reionization. Using the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER), we present limits on the observed power spectra of all four Stokes parameters in two frequency bands, centered at 126 MHz ($z=10.3$) and 164 MHz ($z=7.66$) for a three-month observing campaign of a 32-antenna deployment, for which unpolarized power spectrum results have been reported at $z=7.7$ (Parsons et al 2014) and $7.5 < z < 10.5$ (Jacobs et al 2014). The power spectra in this paper are processed in the same way as in those works, and show no definitive detection of polarized power. This non-detection appears to be largely due to the suppression of polarized power by ionospheric rotation measure fluctuations, which strongly affect Stokes Q and U. We are able to show that the net effect of polarized leakage is a negligible contribution at the levels of of the limits reported in Parsons et al 2014 and Jacobs et al 2014., Comment: Accepted by ApJ
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- 2015
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8. Multi-redshift limits on the 21cm power spectrum from PAPER
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Jacobs, Daniel C., Pober, Jonathan C., Parsons, Aaron R., Aguirre, James E., Ali, Zaki, Bowman, Judd, Bradley, Richard F., Carilli, Chris L., DeBoer, David R., Dexter, Matthew R., Gugliucci, Nicole E., Klima, Pat, Liu, Adrian, MacMahon, Dave H. E., Manley, Jason R., Moore, David F., Stefan, Irina I., and Walbrugh, William P.
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Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
The epoch of reionization power spectrum is expected to evolve strongly with redshift, and it is this variation with cosmic history that will allow us to begin to place constraints on the physics of reionization. The primary obstacle to the measurement of the EoR power spectrum is bright foreground emission. We present an analysis of observations from the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) telescope which place new limits on the HI power spectrum over the redshift range of $7.5
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- 2014
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9. A Flux Scale for Southern Hemisphere 21cm EoR Experiments
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Jacobs, Daniel C., Parsons, Aaron R., Aguirre, James E., Ali, Zaki, Bowman, Judd, Bradley, Richard F., Carilli, Christopher L., DeBoer, David R., Dexter, Matthew, Gugliucci, Nicole E., Klima, Pat, MacMahon, Dave H. E., Manley, Jason R., Moore, David F., Pober, Jonathan C., Stefan, Irina I., and Walbrugh, William P.
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Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
We present a catalog of spectral measurements covering a 100-200 MHz band for 32 sources, derived from observations with a 64-antenna deployment of the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) in South Africa. For transit telescopes such as PAPER, calibration of the primary beam is a difficult endeavor, and errors in this calibration are a major source of error in the determination of source spectra. In order to decrease reliance on accurate beam calibration, we focus on calibrating sources in a narrow declination range from -46d to -40d. Since sources at similar declinations follow nearly identical paths through the primary beam, this restriction greatly reduces errors associated with beam calibration, yielding a dramatic improvement in the accuracy of derived source spectra. Extrapolating from higher frequency catalogs, we derive the flux scale using a Monte-Carlo fit across multiple sources that includes uncertainty from both catalog and measurement errors. Fitting spectral models to catalog data and these new PAPER measurements, we derive new flux models for Pictor A and 31 other sources at nearby declinations. 90% of these confirm and refine a power-law model for flux density. Of note is the new Pictor A flux model, which is accurate to 1.4% and shows, in contrast to previous models, that between 100 MHz and 2 GHz, the spectrum of Pictor A is consistent with a single power law given by a flux at 150 MHz of 382+/-5.4 Jy, and a spectral index of -0.76+/-0.01. This accuracy represents an order of magnitude improvement over previous measurements in this band, and is limited by the uncertainty in the catalog measurements used to estimate the absolute flux scale. The simplicity and improved accuracy of Pictor A's spectrum make it an excellent calibrator for experiments seeking to measure 21cm emission from the Epoch of Reionization., Comment: Accepted to ApJ, includes two data files
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- 2013
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10. New Limits on 21cm EoR From PAPER-32 Consistent with an X-Ray Heated IGM at z=7.7
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Parsons, Aaron R., Liu, Adrian, Aguirre, James E., Ali, Zaki S., Bradley, Richard F., Carilli, Chris L., DeBoer, David R., Dexter, Matthew R., Gugliucci, Nicole E., Jacobs, Daniel C., Klima, Pat, MacMahon, David H. E., Manley, Jason R., Moore, David F., Pober, Jonathan C., Stefan, Irina I., and Walbrugh, William P.
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Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
We present new constraints on the 21cm Epoch of Reionization (EoR) power spectrum derived from 3 months of observing with a 32-antenna, dual-polarization deployment of the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) in South Africa. In this paper, we demonstrate the efficacy of the delay-spectrum approach to avoiding foregrounds, achieving over 8 orders of magnitude of foreground suppression (in $\textrm{mK}^2$). Combining this approach with a procedure for removing off-diagonal covariances arising from instrumental systematics, we achieve a best 2-sigma upper limit of $(41\,\textrm{mK})^2$ for $k=0.27 h\textrm{Mpc}^{-1}$ at $z=7.7$. This limit falls within an order of magnitude of the brighter predictions of the expected 21cm EoR signal level. Using the upper limits set by these measurements, we generate new constraints on the brightness temperature of 21cm emission in neutral regions for various reionization models. We show that for several ionization scenarios, our measurements are inconsistent with cold reionization. That is, heating of the neutral intergalactic medium (IGM) is necessary to remain consistent with the constraints we report. Hence, we have suggestive evidence that by $z=7.7$, the HI has been warmed from its cold primordial state, probably by X-rays from high-mass X-ray binaries or mini-quasars. The strength of this evidence depends on the ionization state of the IGM, which we are not yet able to constrain. This result is consistent with standard predictions for how reionization might have proceeded., Comment: 24 pages, 11 figures, 3 appendices. Replaced with version accepted to ApJ
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- 2013
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11. Opening the 21cm EoR Window: Measurements of Foreground Isolation with PAPER
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Pober, Jonathan C., Parsons, Aaron R., Aguirre, James E., Ali, Zaki, Bradley, Richard F., Carilli, Chris L., DeBoer, Dave, Dexter, Matthew, Gugliucci, Nicole E., Jacobs, Daniel C., Klima, Patricia J., MacMahon, Dave, Manley, Jason, Moore, David F., Stefan, Irina I., and Walbrugh, William P.
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Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
We present new observations with the Precision Array for Probing the Epoch of Reionization (PAPER) with the aim of measuring the properties of foreground emission for 21cm Epoch of Reionization experiments at 150 MHz. We focus on the footprint of the foregrounds in cosmological Fourier space to understand which modes of the 21cm power spectrum will most likely be compromised by foreground emission. These observations confirm predictions that foregrounds can be isolated to a "wedge"-like region of 2D (k-perpendicular, k-parallel)-space, creating a window for cosmological studies at higher k-parallel values. We also find that the emission extends past the nominal edge of this wedge due to spectral structure in the foregrounds, with this feature most prominent on the shortest baselines. Finally, we filter the data to retain only this "unsmooth" emission and image specific k-parallel modes of it. The resultant images show an excess of power at the lowest modes, but no emission can be clearly localized to any one region of the sky. This image is highly suggestive that the most problematic foregrounds for 21cm EoR studies will not be easily identifiable bright sources, but rather an aggregate of fainter emission., Comment: 6 pages, 5 figures, updated to match version accepted to ApJL
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- 2013
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12. Imaging on PAPER: Centaurus A at 148 MHz
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Stefan, Irina I., Carilli, Chris L., Green, David A., Ali, Zaki, Aguirre, James E., Bradley, Richard F., DeBoer, Dave, Dexter, Matthew, Gugliucci, Nicole E., Harris, D. E., Jacobs, Daniel C., Klima, Pat, MacMahon, Dave, Manley, Jason, Moore, David F., Parsons, Aaron R., Pober, Jonathan C., and Walbrugh, William P.
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present observations taken with the Precision Array for Probing the Epoch of Reionization (PAPER) of the Centaurus A field in the frequency range 114 to 188 MHz. The resulting image has a 25' resolution, a dynamic range of 3500 and an r.m.s. of 0.5 Jy\beam (for a beam size of 25' x 23'). A spectral index map of Cen A is produced across the full band. The spectral index distribution is qualitatively consistent with electron reacceleration in regions of excess turbulence in the radio lobes, as previously identified morphologically. Hence, there appears to be an association of 'severe weather' in radio lobes with energy input into the relativistic electron population. We compare the PAPER large scale radio image with the X-ray image from the ROSAT All Sky Survey. There is a tentative correlation between radio and X-ray features at the end of the southern lobe, some 200 kpc from the nucleus, as might be expected from inverse Compton scattering of the CMB by the relativistic electrons also responsible for the radio synchrotron emission. The magnetic fields derived from the (possible) IC and radio emission are of similar magnitude to fields derived under the minimum pressure assumptions, ~ 1 {\mu}G. However, the X-ray field is complex, with large scale gradients and features possibly unrelated to Cen A. If these X-ray features are unrelated to Cen A, then these fields are lower limits., Comment: 9 pages, 5 figures; Section 7 and Fig. 5 have been revised and minor corrections have been implemented throught the paper; submitted for publication to MNRAS
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- 2012
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13. New 145-MHz Source Measurements by PAPER in the Southern Sky
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Jacobs, Daniel C., Aguirre, James E., Parsons, Aaron R., Pober, Jonathan C., Bradley, Richard F., Carilli, Chris L., Gugliucci, Nicole E., Manley, Jason R., van der Merwe, Carel, Moore, David F., and Parashare, Chaitali R.
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Astrophysics - Cosmology and Extragalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
We present observations from the Precision Array for Probing the Epoch of Reionization (PAPER) in South Africa, observed in May and September 2010. Using two nights of drift scanning with PAPER's 60\arcdeg\ FWHM beam we have made a map covering the entire sky below +10 degrees declination with an effective center frequency of 145 MHz, a 70-MHz bandwidth, and a resolution of 26\arcmin. A 4800 square-degree region of this large map with the lowest Galactic emission reaches an RMS of 0.7 Jy. We establish an absolute flux scale using sources from the 160-MHz Culgoora catalog. Using the 408-MHz Molonglo Reference Catalog (MRC) as a finding survey, we identify counterparts to 480 sources in our maps, and compare our fluxes to the MRC and to 332 sources in the Culgoora catalog. For both catalogs, the ratio of PAPER to catalog flux averages to 1, with a standard deviation of 50%. This measured variation is consistent with comparisons between independent catalogs observed at different bands. The PAPER data represent new 145-MHz flux measurements for a large number of sources in the band expected to encompass cosmic reionization, and represents a significant step toward establishing a model for removing foregrounds to the reionization signal., Comment: 3 figures, 2 tables, machine readable table. Accepted by ApJL
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- 2011
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14. The Precision Array for Probing the Epoch of Reionization: 8 Station Results
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Parsons, Aaron R., Backer, Donald C., Bradley, Richard F., Aguirre, James E., Benoit, Erin E., Carilli, Chris L., Foster, Griffin S., Gugliucci, Nicole E., Herne, David, Jacobs, Daniel C., Lynch, Mervyn J., Manley, Jason R., Parashare, Chaitali R., Werthimer, Daniel J., and Wright, Melvyn C. H.
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We are developing the Precision Array for Probing the Epoch of Reionization (PAPER) to detect 21cm emission from the early Universe, when the first stars and galaxies were forming. We describe the overall experiment strategy and architecture and summarize two PAPER deployments: a 4-antenna array in the low-RFI environment of Western Australia and an 8-antenna array at our prototyping site in Green Bank, WV. From these activities we report on system performance, including primary beam model verification, dependence of system gain on ambient temperature, measurements of receiver and overall system temperatures, and characterization of the RFI environment at each deployment site. We present an all-sky map synthesized between 139 MHz and 174 MHz using data from both arrays that reaches down to 80 mJy (4.9 K, for a beam size of 2.15e-5 steradians at 154 MHz), with a 10 mJy (620 mK) thermal noise level that indicates what would be achievable with better foreground subtraction. We calculate angular power spectra ($C_\ell$) in a cold patch and determine them to be dominated by point sources, but with contributions from galactic synchrotron emission at lower radio frequencies and angular wavemodes. Although the cosmic variance of foregrounds dominates errors in these power spectra, we measure a thermal noise level of 310 mK at $\ell=100$ for a 1.46-MHz band centered at 164.5 MHz. This sensitivity level is approximately three orders of magnitude in temperature above the level of the fluctuations in 21cm emission associated with reionization., Comment: 13 pages, 14 figures, submitted to AJ. Revision 2 corrects a scaling error in the x axis of Fig. 12 that lowers the calculated power spectrum temperature
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- 2009
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15. Digital Instrumentation for the Radio Astronomy Community
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Parsons, Aaron, Werthimer, Dan, Backer, Donald, Bastian, Tim, Bower, Geoffrey, Brisken, Walter, Chen, Henry, Deller, Adam, Filiba, Terry, Gary, Dale, Greenhill, Lincoln, Hawkins, David, Jones, Glenn, Langston, Glen, Lazio, Joseph, van Leeuwen, Joeri, Mitchell, Daniel, Manley, Jason, Siemion, Andrew, So, Hayden Kwok-Hay, Whitney, Alan, Woody, Dave, Wright, Melvyn, and Zarb-Adami, Kristian
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Time-to-science is an important figure of merit for digital instrumentation serving the astronomical community. A digital signal processing (DSP) community is forming that uses shared hardware development, signal processing libraries, and instrument architectures to reduce development time of digital instrumentation and to improve time-to-science for a wide variety of projects. We suggest prioritizing technological development supporting the needs of this nascent DSP community. After outlining several instrument classes that are relying on digital instrumentation development to achieve new science objectives, we identify key areas where technologies pertaining to interoperability and processing flexibility will reduce the time, risk, and cost of developing the digital instrumentation for radio astronomy. These areas represent focus points where support of general-purpose, open-source development for a DSP community should be prioritized in the next decade. Contributors to such technological development may be centers of support for this DSP community, science groups that contribute general-purpose DSP solutions as part of their own instrumentation needs, or engineering groups engaging in research that may be applied to next-generation DSP instrumentation., Comment: 11 pages, 4 figures, Astro2010 Decadal Survey White Paper in TEC: Technology Development
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- 2009
16. A Scalable Correlator Architecture Based on Modular FPGA Hardware, Reuseable Gateware, and Data Packetization
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Parsons, Aaron, Backer, Donald, Chen, Henry, Droz, Pierre, Filiba, Terry, Manley, Jason, MacMahon, David, McMahon, Peter, Parsa, Arash, Siemion, Andrew, Werthimer, Dan, and Wright, Melvyn
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Astrophysics - Abstract
A new generation of radio telescopes is achieving unprecedented levels of sensitivity and resolution, as well as increased agility and field-of-view, by employing high-performance digital signal processing hardware to phase and correlate large numbers of antennas. The computational demands of these imaging systems scale in proportion to BMN^2, where B is the signal bandwidth, M is the number of independent beams, and N is the number of antennas. The specifications of many new arrays lead to demands in excess of tens of PetaOps per second. To meet this challenge, we have developed a general purpose correlator architecture using standard 10-Gbit Ethernet switches to pass data between flexible hardware modules containing Field Programmable Gate Array (FPGA) chips. These chips are programmed using open-source signal processing libraries we have developed to be flexible, scalable, and chip-independent. This work reduces the time and cost of implementing a wide range of signal processing systems, with correlators foremost among them,and facilitates upgrading to new generations of processing technology. We present several correlator deployments, including a 16-antenna, 200-MHz bandwidth, 4-bit, full Stokes parameter application deployed on the Precision Array for Probing the Epoch of Reionization., Comment: Accepted to Publications of the Astronomy Society of the Pacific. 31 pages. v2: corrected typo, v3: corrected Fig. 13
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- 2008
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17. Publisher Correction: High-speed, cortex-wide volumetric recording of neuroactivity at cellular resolution using light beads microscopy
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Demas, Jeffrey, Manley, Jason, Tejera, Frank, Barber, Kevin, Kim, Hyewon, Traub, Francisca Martínez, Chen, Brandon, and Vaziri, Alipasha
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- 2021
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18. MeerKAT correlator-beamformer: a real-time processing back-end for astronomical observations
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van der Byl, Andrew, primary, Smith, James, additional, Martens, Andrew, additional, Manley, Jason, additional, van Balla, Tyrone, additional, Rust, Alec, additional, Patel, Amish, additional, Callanan, Gareth, additional, Isaacson, Adam, additional, New, Wesley, additional, van Wyk, Robin, additional, Kapp, Francois, additional, Kriel, Henno, additional, and Mahgoub, Omer, additional
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- 2021
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19. High-Speed, Cortex-Wide Volumetric Recording of Neuroactivity at Cellular Resolution using Light Beads Microscopy
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Demas, Jeffrey, primary, Manley, Jason, additional, Tejera, Frank, additional, Kim, Hyewon, additional, Traub, Francisca Martínez, additional, Chen, Brandon, additional, and Vaziri, Alipasha, additional
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- 2021
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20. Cerebellar Neurodynamics Predict Decision Timing and Outcome on the Single-Trial Level
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Lin, Qian, primary, Manley, Jason, additional, Helmreich, Magdalena, additional, Schlumm, Friederike, additional, Li, Jennifer M., additional, Robson, Drew N., additional, Engert, Florian, additional, Schier, Alexander, additional, Nöbauer, Tobias, additional, and Vaziri, Alipasha, additional
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- 2020
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21. Volumetric Ca2+ Imaging in the Mouse Brain Using Hybrid Multiplexed Sculpted Light Microscopy
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Weisenburger, Siegfried, primary, Tejera, Frank, additional, Demas, Jeffrey, additional, Chen, Brandon, additional, Manley, Jason, additional, Sparks, Fraser T., additional, Martínez Traub, Francisca, additional, Daigle, Tanya, additional, Zeng, Hongkui, additional, Losonczy, Attila, additional, and Vaziri, Alipasha, additional
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- 2019
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22. MeerKAT data distribution network
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Slabber, Martin J., primary, Manley, Jason, primary, Ventura, Neco, primary, and Mwangama, Joyce, primary
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- 2018
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23. Limits on Polarized Leakage for the PAPER Epoch of Reionization Measurements at 126 and 164 MHz
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Moore, David F., primary, Aguirre, James E., additional, Kohn, Saul A., additional, Parsons, Aaron R., additional, Ali, Zaki S., additional, Bradley, Richard F., additional, Carilli, Chris L., additional, DeBoer, David R., additional, Dexter, Matthew R., additional, Gugliucci, Nicole E., additional, Jacobs, Daniel C., additional, Klima, Pat, additional, Liu, Adrian, additional, MacMahon, David H. E., additional, Manley, Jason R., additional, Pober, Jonathan C., additional, Stefan, Irina I., additional, and Walbrugh, William P., additional
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- 2017
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24. A scalable packetised radio astronomy imager
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Manley, Jason Ryan and Inggs, Michael
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InformationSystems_INFORMATIONSTORAGEANDRETRIEVAL ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,Electrical Engineering - Abstract
Includes bibliographical references, Modern radio astronomy telescopes the world over require digital back-ends. The complexity of these systems depends on many site-specific factors, including the number of antennas, beams and frequency channels and the bandwidth to be processed. With the increasing popularity for ever larger interferometric arrays, the processing requirements for these back-ends have increased significantly. While the techniques for building these back-ends are well understood, every installation typically still takes many years to develop as the instruments use highly specialised, custom hardware in order to cope with the demanding engineering requirements. Modern technology has enabled reprogrammable FPGA-based processing boards, together with packet-based switching techniques, to perform all the digital signal processing requirements of a modern radio telescope array. The various instruments used by radio telescopes are functionally very different, but the component operations remain remarkably similar and many share core functionalities. Generic processing platforms are thus able to share signal processing libraries and can acquire different personalities to perform different functions simply by reprogramming them and rerouting the data appropriately. Furthermore, Ethernet-based packet-switched networks are highly flexible and scalable, enabling the same instrument design to be scaled to larger installations simply by adding additional processing nodes and larger network switches. The ability of a packetised network to transfer data to arbitrary processing nodes, along with these nodes' reconfigurability, allows for unrestrained partitioning of designs and resource allocation. This thesis describes the design and construction of the first working radio astronomy imaging instrument hosted on Ethernet-interconnected re- programmable FPGA hardware. I attempt to establish an optimal packetised architecture for the most popular instruments with particular attention to the core array functions of correlation and beamforming. Emphasis is placed on requirements for South Africa's MeerKAT array. A demonstration system is constructed and deployed on the KAT-7 array, MeerKAT's prototype. This research promises reduced instrument development time, lower costs, improved reliability and closer collaboration between telescope design teams.
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- 2015
25. MeerKAT data distribution network.
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Slabber, Martin J., Manley, Jason. R., Mwangama, Joyce, and Ventura, Neco
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- 2018
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26. Tissue Regeneration and Biomineralization in Sea Urchins: Role of Notch Signaling and Presence of Stem Cell Markers
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Reinardy, Helena C., primary, Emerson, Chloe E., additional, Manley, Jason M., additional, and Bodnar, Andrea G., additional
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- 2015
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27. MULTIREDSHIFT LIMITS ON THE 21 cm POWER SPECTRUM FROM PAPER
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Jacobs, Daniel C., primary, Pober, Jonathan C., additional, Parsons, Aaron R., additional, Aguirre, James E., additional, Ali, Zaki S., additional, Bowman, Judd, additional, Bradley, Richard F., additional, Carilli, Chris L., additional, DeBoer, David R., additional, Dexter, Matthew R., additional, Gugliucci, Nicole E., additional, Klima, Pat, additional, Liu, Adrian, additional, MacMahon, David H. E., additional, Manley, Jason R., additional, Moore, David F., additional, Stefan, Irina I., additional, and Walbrugh, William P., additional
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- 2015
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28. NEW LIMITS ON 21 cm EPOCH OF REIONIZATION FROM PAPER-32 CONSISTENT WITH AN X-RAY HEATED INTERGALACTIC MEDIUM ATz= 7.7
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Parsons, Aaron R., primary, Liu, Adrian, additional, Aguirre, James E., additional, Ali, Zaki S., additional, Bradley, Richard F., additional, Carilli, Chris L., additional, DeBoer, David R., additional, Dexter, Matthew R., additional, Gugliucci, Nicole E., additional, Jacobs, Daniel C., additional, Klima, Pat, additional, MacMahon, David H. E., additional, Manley, Jason R., additional, Moore, David F., additional, Pober, Jonathan C., additional, Stefan, Irina I., additional, and Walbrugh, William P., additional
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- 2014
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29. MeerKAT data distribution network
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Guzman, Juan C., Ibsen, Jorge, Slabber, Martin J., Manley, Jason, Mwangama, Joyce, and Ventura, Neco
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- 2018
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30. A FLUX SCALE FOR SOUTHERN HEMISPHERE 21 cm EPOCH OF REIONIZATION EXPERIMENTS
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Jacobs, Daniel C., primary, Parsons, Aaron R., additional, Aguirre, James E., additional, Ali, Zaki, additional, Bowman, Judd, additional, Bradley, Richard F., additional, Carilli, Chris L., additional, DeBoer, David R., additional, Dexter, Matthew R., additional, Gugliucci, Nicole E., additional, Klima, Pat, additional, MacMahon, Dave H. E., additional, Manley, Jason R., additional, Moore, David F., additional, Pober, Jonathan C., additional, Stefan, Irina I., additional, and Walbrugh, William P., additional
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- 2013
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31. OPENING THE 21 cm EPOCH OF REIONIZATION WINDOW: MEASUREMENTS OF FOREGROUND ISOLATION WITH PAPER
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Pober, Jonathan C., primary, Parsons, Aaron R., additional, Aguirre, James E., additional, Ali, Zaki, additional, Bradley, Richard F., additional, Carilli, Chris L., additional, DeBoer, Dave, additional, Dexter, Matthew, additional, Gugliucci, Nicole E., additional, Jacobs, Daniel C., additional, Klima, Patricia J., additional, MacMahon, Dave, additional, Manley, Jason, additional, Moore, David F., additional, Stefan, Irina I., additional, and Walbrugh, William P., additional
- Published
- 2013
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32. Imaging on PAPER: Centaurus A at 148 MHz
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Stefan, Irina I., primary, Carilli, Chris L., additional, Green, David A., additional, Ali, Zaki, additional, Aguirre, James E., additional, Bradley, Richard F., additional, DeBoer, David, additional, Dexter, Matthew, additional, Gugliucci, Nicole E., additional, Harris, D. E., additional, Jacobs, Daniel C., additional, Klima, Pat, additional, MacMahon, David, additional, Manley, Jason, additional, Moore, David F., additional, Parsons, Aaron R., additional, Pober, Jonathan C., additional, and Walbrugh, William P., additional
- Published
- 2013
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33. Meeting MeerKAT's signal processing challenges
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Manley, Jason, primary, Malan, Sias, additional, and Kapp, Francois, additional
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- 2012
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34. The MeerKAT array and its digital signal processor
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Manley, Jason, primary and Kapp, Francois, additional
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- 2012
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35. NEW 145 MHz SOURCE MEASUREMENTS BY PAPER IN THE SOUTHERN SKY
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Jacobs, Daniel C., primary, Aguirre, James E., additional, Parsons, Aaron R., additional, Pober, Jonathan C., additional, Bradley, Richard F., additional, Carilli, Chris L., additional, Gugliucci, Nicole E., additional, Manley, Jason R., additional, van der Merwe, Carel, additional, Moore, David F., additional, and Parashare, Chaitali R., additional
- Published
- 2011
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36. THE PRECISION ARRAY FOR PROBING THE EPOCH OF RE-IONIZATION: EIGHT STATION RESULTS
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Parsons, Aaron R., primary, Backer, Donald C., additional, Foster, Griffin S., additional, Wright, Melvyn C. H., additional, Bradley, Richard F., additional, Gugliucci, Nicole E., additional, Parashare, Chaitali R., additional, Benoit, Erin E., additional, Aguirre, James E., additional, Jacobs, Daniel C., additional, Carilli, Chris L., additional, Herne, David, additional, Lynch, Mervyn J., additional, Manley, Jason R., additional, and Werthimer, Daniel J., additional
- Published
- 2010
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37. A Scalable Correlator Architecture Based on Modular FPGA Hardware, Reuseable Gateware, and Data Packetization
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Parsons, Aaron, primary, Backer, Donald, additional, Siemion, Andrew, additional, Chen, Henry, additional, Werthimer, Dan, additional, Droz, Pierre, additional, Filiba, Terry, additional, Manley, Jason, additional, McMahon, Peter, additional, Parsa, Arash, additional, MacMahon, David, additional, and Wright, Melvyn, additional
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- 2008
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38. MeerKAT correlator-beamformer: a real-time processing back-end for astronomical observations.
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van der Byl, Andrew, Smith, James, Martens, Andrew, Manley, Jason, van Balla, Tyrone, Rust, Alec, Patel, Amish, Callanan, Gareth, Isaacson, Adam, New, Wesley, van Wyk, Robin, Kapp, Francois, Kriel, Henno, and Mahgoub, Omer
- Published
- 2022
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39. NEW LIMITS ON 21 cm EPOCH OF REIONIZATION FROM PAPER-32 CONSISTENT WITH AN X-RAY HEATED INTERGALACTIC MEDIUM AT z = 7.7.
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Parsons, Aaron R., Liu, Adrian, Aguirre, James E., Ali, Zaki S., Bradley, Richard F., Carilli, Chris L., DeBoer, David R., Dexter, Matthew R., Gugliucci, Nicole E., Jacobs, Daniel C., Klima, Pat, MacMahon, David H. E., Manley, Jason R., Moore, David F., Pober, Jonathan C., Stefan, Irina I., and Walbrugh, William P.
- Subjects
INTERSTELLAR medium ,METAPHYSICAL cosmology ,IONIZATION (Atomic physics) ,X-ray binaries ,ASTROPHYSICS research - Abstract
We present new constraints on the 21 cm Epoch of Reionization (EoR) power spectrum derived from three months of observing with a 32 antenna, dual-polarization deployment of the Donald C. Backer Precision Array for Probing the Epoch of Reionization in South Africa. In this paper, we demonstrate the efficacy of the delay-spectrum approach to avoiding foregrounds, achieving over eight orders of magnitude of foreground suppression (in mK
2 ). Combining this approach with a procedure for removing off-diagonal covariances arising from instrumental systematics, we achieve a best 2σ upper limit of (41 mK)2 for k = 0.27 h Mpc–1 at z = 7.7. This limit falls within an order of magnitude of the brighter predictions of the expected 21 cm EoR signal level. Using the upper limits set by these measurements, we generate new constraints on the brightness temperature of 21 cm emission in neutral regions for various reionization models. We show that for several ionization scenarios, our measurements are inconsistent with cold reionization. That is, heating of the neutral intergalactic medium (IGM) is necessary to remain consistent with the constraints we report. Hence, we have suggestive evidence that by z = 7.7, the H I has been warmed from its cold primordial state, probably by X-rays from high-mass X-ray binaries or miniquasars. The strength of this evidence depends on the ionization state of the IGM, which we are not yet able to constrain. This result is consistent with standard predictions for how reionization might have proceeded. [ABSTRACT FROM AUTHOR]- Published
- 2014
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40. Whole-brain neural substrates of behavioral variability in the larval zebrafish.
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Manley J and Vaziri A
- Abstract
Animals engaged in naturalistic behavior can exhibit a large degree of behavioral variability even under sensory invariant conditions. Such behavioral variability can include not only variations of the same behavior, but also variability across qualitatively different behaviors driven by divergent cognitive states, such as fight-or-flight decisions. However, the neural circuit mechanisms that generate such divergent behaviors across trials are not well understood. To investigate this question, here we studied the visual-evoked responses of larval zebrafish to moving objects of various sizes, which we found exhibited highly variable and divergent responses across repetitions of the same stimulus. Given that the neuronal circuits underlying such behaviors span sensory, motor, and other brain areas, we built a novel Fourier light field microscope which enables high-resolution, whole-brain imaging of larval zebrafish during behavior. This enabled us to screen for neural loci which exhibited activity patterns correlated with behavioral variability. We found that despite the highly variable activity of single neurons, visual stimuli were robustly encoded at the population level, and the visual-encoding dimensions of neural activity did not explain behavioral variability. This robustness despite apparent single neuron variability was due to the multi-dimensional geometry of the neuronal population dynamics: almost all neural dimensions that were variable across individual trials, i.e. the "noise" modes, were orthogonal to those encoding for sensory information. Investigating this neuronal variability further, we identified two sparsely-distributed, brain-wide neuronal populations whose pre-motor activity predicted whether the larva would respond to a stimulus and, if so, which direction it would turn on a single-trial level. These populations predicted single-trial behavior seconds before stimulus onset, indicating they encoded time-varying internal modulating behavior, perhaps organizing behavior over longer timescales or enabling flexible behavior routines dependent on the animal's internal state. Our results provide the first whole-brain confirmation that sensory, motor, and internal variables are encoded in a highly mixed fashion throughout the brain and demonstrate that de-mixing each of these components at the neuronal population level is critical to understanding the mechanisms underlying the brain's remarkable flexibility and robustness.
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- 2024
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41. Simultaneous, cortex-wide and cellular-resolution neuronal population dynamics reveal an unbounded scaling of dimensionality with neuron number.
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Manley J, Demas J, Kim H, Traub FM, and Vaziri A
- Abstract
The brain's remarkable properties arise from collective activity of millions of neurons. Widespread application of dimensionality reduction to multi-neuron recordings implies that neural dynamics can be approximated by low-dimensional "latent" signals reflecting neural computations. However, what would be the biological utility of such a redundant and metabolically costly encoding scheme and what is the appropriate resolution and scale of neural recording to understand brain function? Imaging the activity of one million neurons at cellular resolution and near-simultaneously across mouse cortex, we demonstrate an unbounded scaling of dimensionality with neuron number. While half of the neural variance lies within sixteen behavior-related dimensions, we find this unbounded scaling of dimensionality to correspond to an ever-increasing number of internal variables without immediate behavioral correlates. The activity patterns underlying these higher dimensions are fine-grained and cortex-wide, highlighting that large-scale recording is required to uncover the full neural substrates of internal and potentially cognitive processes., Competing Interests: DECLARATION OF INTERESTS The authors declare no competing interests.
- Published
- 2024
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42. Volumetric Ca 2+ Imaging in the Mouse Brain Using Hybrid Multiplexed Sculpted Light Microscopy.
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Weisenburger S, Tejera F, Demas J, Chen B, Manley J, Sparks FT, Martínez Traub F, Daigle T, Zeng H, Losonczy A, and Vaziri A
- Subjects
- Animals, Brain physiology, Calcium metabolism, Female, Hippocampus physiology, Male, Mice, Mice, Inbred C57BL, Neurons physiology, Single-Cell Analysis methods, Microscopy methods, Molecular Imaging methods, Neuroimaging methods
- Abstract
Calcium imaging using two-photon scanning microscopy has become an essential tool in neuroscience. However, in its typical implementation, the tradeoffs between fields of view, acquisition speeds, and depth restrictions in scattering brain tissue pose severe limitations. Here, using an integrated systems-wide optimization approach combined with multiple technical innovations, we introduce a new design paradigm for optical microscopy based on maximizing biological information while maintaining the fidelity of obtained neuron signals. Our modular design utilizes hybrid multi-photon acquisition and allows volumetric recording of neuroactivity at single-cell resolution within up to 1 × 1 × 1.22 mm volumes at up to 17 Hz in awake behaving mice. We establish the capabilities and potential of the different configurations of our imaging system at depth and across brain regions by applying it to in vivo recording of up to 12,000 neurons in mouse auditory cortex, posterior parietal cortex, and hippocampus., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2019
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