Neuroscience graduate student in the Sabatini Lab @harvard
Joined October 2020
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Bart Lodder retweeted
Neuron classes are distinguished by expression of many genes, including those for ion channel subunits. In cortex, PV+ neurons are the major expressors of Kcng4, which encodes for the K-channel "silent" subunit Kv6.4. @SanikaGanesh led this work showing that Kv6.4 regulates
Bart Lodder retweeted
Not sure who is still out there but we're proud of this work led by @lodder_bart that (1) propose a new method to turn intensity sensors into lifetime sensors and (2) applies it to GCAMP8m to make an excellent lifetime Ca sensor.
biorxiv.org/content/10.64898…
5. We show, in behaving mice, that baseline calcium is correlated with the firing rate of individual neurons and that baseline calcium dynamically changes in response to visual stimulation and changes in firing rate
4. We show that LifeCamp allows for more accurate measurement of population activity, using fluorescence lifetime photometry at high temporal resolution (FLIPR). LifeCamp is insensitive to intensity artifacts and allows for the capture of long term changes in calcium levels.
3. We show that LifeCamp allows for the capture of neuronal firing and the comparison of baseline calcium across cells. In addition, we show that LifeCamp can be used to estimate the health of neurons in brain slice preparations.
2. LifeCamp was developed by linking GCaMP8m to BrUSLEE. We show that LifeCamp has high sensitivity for calcium and a large change in fluorescence lifetime upon calcium binding (>1ns).
1. LifeCamp was developed using the rapid lifetime development (RALISED) platform, which allows for the transformation of existing intensity sensors into lifetime sensors, in a fast, affordable and straightforward manner.
We posted a new paper on biorxiv describing LifeCamp, a new high speed calcium lifetime sensor. LifeCamp enables detection of baseline calcium, neuronal firing and artifact insensitive comparisons across experiments, brain regions and long timescales.
biorxiv.org/content/10.64898…
Bart Lodder retweeted
Excited to share some of my PhD work out today in @NeuroCellPress! We use our novel lifetime photometry system with the new dLight3.8 sensor to study hunger induced changes in exploration and risk assessment derive from AgRP modulation of dopamine signaling in tail of striatum.
Our latest led by @TVKamath with important contributions by collaborators including Nao Uchida, Mitsuko Watabe-Uchida and @LinTianPhD
Hunger modulates exploration through suppression of dopamine signaling in the tail of the striatum: Neuron cell.com/neuron/fulltext/S08…
Bart Lodder retweeted
Our latest led by @TVKamath with important contributions by collaborators including Nao Uchida, Mitsuko Watabe-Uchida and @LinTianPhD
Hunger modulates exploration through suppression of dopamine signaling in the tail of the striatum: Neuron cell.com/neuron/fulltext/S08…
6/ Altogether, FLIPR allows for easy and robust absolute measurement of fast and slow neurotransmitter release and together with new lifetime sensors such as dLight3.8 will give neuroscientist new capabilities to measure neuronal signals for fundamental and disease research
5/ Finally, we developed a two-color FLIPR system, which allowed us to simultaneously record absolute dopamine and calcium in D1 receptor neurons in freely moving mice.
4/ We compared dopamine responses in the nucleus accumbens and tail of striatum to appetitive and aversive stimuli and found region specific dynamic tonic and phasic responses. We also found increased tonic dopamine in the TS compared to the NAC outside of a behavior task
3/ To highlight the utility of FLIPR we validated the dopamine sensor dLight3.8 in vivo, allowing for the measurement of absolute fast (phasic) and slow (tonic) dopamine in freely moving mice.
2/ In freely moving mice, we show that lifetime measurement using FLIPR is more stable than intensity measurements, possibly due to the insensitivity of lifetime to hemodynamic and motion artifacts. Moreover, we show that FLIPR can be used to detect lifetime across days.
1/ FLIPR allows for detection of fluorescence lifetime through the use of an analog frequency domain lifetime processor, that is easy and affordable to build. High photon rate stability allows for the system to be used at high speed and with picosecond resolution in vivo/vitro
Our fluorescence lifetime photometry at high temporal resolution (FLIPR) paper is now online at Neuron. FLIPR allows for fast (10Hz-1 kHz) and slow (min-hrs) measurement of absolute neuronal signals in freely moving mice. We highlight the utility by measuring tonic and phasic DA.
Online now: Absolute measurement of fast and slow neuronal signals with fluorescence lifetime photometry at high temporal resolution dlvr.it/TN1Sqp
Thank you for the suggestion! This chemogenetic tool is very useful and can be used simultaneously with FLIPR to boost the tonic signal. In order to claim absolute measurement one would have to of course very carefully characterize the stable regime of DETQ affinity modulation
5/ In this preprint, we show that FLIPR is a powerful technology that will allow the community access to absolute fast and slow signal measurement in vivo. Thank you to my mentors @blsabatini Roger Adan, coauthors and Sabatini lab members