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Fiber Photometry System

Perform Three-Color Photometry with the iX7

Overview

Fiber Photometry is a recording technique that uses low-powered light from LEDs to detect calcium or neurotransmitter activity in cell populations via genetically encoded fluorescent indicators (GEFIs) [10.1016/j.neuron.2023.11.016]. Neurons, glial cells, and astrocytes can be targeted with viral vectors so that only specific receptor types express fluorescent proteins. This localization and easy chronic recording setup makes fiber photometry a great choice for studying the roles of select brain nuclei and neurotransmitters in behavioral assays.

TDT is the long-time industry leader in fiber photometry. 

Our turn-key optical solutions have been used by researchers to pioneer the field of fiber photometry. Our lock-in amplifier systems are proven to be the most sensitive and versatile systems on the market.

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Pre-configured systems

Starting points our application scientists recommend. Every setup can be changed or expanded; tell us about your experiment and we will adapt it.

Most Popular

Three Color Photometry with Video and External Equipment Synchronization

Three color (purple, green, red) photometry and video with 24 channels of digital I/O for synchronizing external equipment. The iL24 provides precision-timestamped TTL communication for coordinating with Arduinos, FED3 devices, external imaging systems, Med Associates SuperPorts, and more.

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Three Color Photometry with Flexible Isosbestic Channel

Three color (purple, green, red) photometry using the iX6 and LxM6, which lets users change the isosbestic filter for different GFP sensors. The system also includes video and 24 channels of digital I/O for synchronizing external equipment.

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Dual Site Three-Color Photometry

Our most popular system with an added iX7 for a second photometry recording site or subject.

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Published research: Fiber Photometry

The newest papers in Fiber Photometry that used TDT systems.

See all 495 papers →
bioRxiv · 2026

Central lipid sensing tunes accumbal D2R-neuron activity in appetitive behaviours

Guangping Li, Julien Castel, Anthony Ansoult, … Serge Luquet

Energy homeostasis and motivated behaviours are tightly interconnected processes coordinated by peripheral metabolic signals and central reward circuits. Among these signals, circulating triglycerides (TG) have emerged as neuromodulators of mesolimbic dopamine functions and reward processing. However, whether TG directly regulate the activity of defined neuronal populations within the nucleus accumbens (NAc) during appetitive behaviours remains unknown. Here, we investigated how central TG availability shapes the in vivo activity of NAc dopamine D2 receptor-expressing spiny projection neurons (D2R-SPNs) across distinct nutritional and metabolic states. Using in vivo fiber photometry in Drd2 -Cre mice, we monitored D2R-SPN Ca 2+ dynamics during appetitive Pavlovian conditioning and refeeding. D2R-SPNs progressively developed robust responses to a reward-predictive conditioned stimulus (CS + ) over the course of learning, while their activity during reward consumption remained stable. Acute elevation of central TG levels through carotid infusion did not alter D2R-SPN activity or behavioural performance in lean chow-fed mice, irrespective of whether they were fed or food-restricted. In contrast, in mice exposed to a high-fat diet (HFD), central TG delivery suppressed cue-evoked D2R-SPN activity in food-restricted animals without affecting reward consumption or behavioural outputs. Likewise, TG significantly reduced refeeding-evoked D2R-SPN activation in fasted HFD-mice, while leaving novelty-induced neuronal responses unchanged. Together, these findings demonstrate that obesogenic conditions reveal a metabolic state-dependent sensitivity of accumbal D2R-SPNs to circulating lipids. This work identifies TG as context-dependent modulators of D2R-SPN function and uncovers a mechanism through which dietary history interacts with current metabolic state to reshape the neural encoding of reward-predictive cues and food-directed behaviours.

Read the paper → (Central lipid sensing tunes accumbal D2R-neuron activity in appetitive behaviours, opens in a new tab)
Science Advances · 2026

A male-biased hypothalamic circuit modulates postmating sleep suppression in mice

Jin Zhao, Linhao Jiang, Qian Zhang, … Zhe Zhang

Many species display mating-related sleep suppression to maximize reproductive success, yet the underlying neural mechanisms in mammals remain unclear. Here, we report that male mice exhibit delayed sleep onset and reduced sleep duration in periods following successful mating, while females are unaffected. Single-cell transcriptomics identifies a group of sleep-promoting Rxfp1-expressing neurons in the preoptic area of hypothalamus (POA Rxfp1 neurons), and fiber photometry reveals selective inhibition of them during and after mating in male mice. Lifting this inhibition via chemogenetic activation reverses sleep suppression in mated males. Monosynaptic retrograde tracing from these POA Rxfp1 neurons identifies male-biased γ-aminobutyric acid–releasing inputs from the principal nucleus of the bed nucleus of the stria terminalis (BNSTpr). Notably, optogenetic activation of these neurons induces immediate wakefulness specifically in male mice, and BNSTpr → POA Rxfp1 neurons are hyperactive after mating. Together, these findings establish a BNSTpr → POA Rxfp1 circuit that integrates reproductive signals for male-specific sleep suppression in mice.

Read the paper → (A male-biased hypothalamic circuit modulates postmating sleep suppression in mice, opens in a new tab)
Nature Communications · 2026

Increased encoding of aversive stimuli by lateral habenula neurons during 9-tetrahydrocannabinol withdrawal

Eun-Kyung Hwang, Deborah Daphne, Charlie J. Maddox, … Carl R. Lupica

The lateral habenula (LHb) integrates cortical and basal forebrain (BF) input and is implicated in negative affective states, but its involvement in negative affect associated with cannabis withdrawal is unknown. Here, effects of withdrawal from the psychoactive cannabis constituent, Δ 9 -tetrahydrocannabinol (Δ 9 -THC), on fear conditioning (FC) and LHb function were measured in rats using calcium photometry and electrophysiology. FC-associated LHb calcium signals, freezing behavior, and LHb excitatory-inhibitory (E-I) ratios were increased during Δ 9 -THC withdrawal, and local GABA release was impaired, indicating disinhibition of LHb output neurons. GABA release was also impaired at optogenetically activated BF-LHb axons, and not from ventral tegmental area-LHb inputs. The results indicate that Δ 9 -THC withdrawal increases LHb excitability through disinhibition, contributing to increased fear of primary and conditioned aversive stimuli. Our findings implicate the LHb in cannabis withdrawal-associated negative affect and offer insight into the neural mechanisms of cannabis use disorder.

Read the paper → (Increased encoding of aversive stimuli by lateral habenula neurons during 9-tetrahydrocannabinol withdrawal, opens in a new tab)

A Legacy Perfected

The iX7 is TDT’s most streamlined and sensitive fiber photometry offering to date. The setup for the user is as simple as possible – there is just a single port for connection to the subject.

The iX7 is the perfect device for any researcher who wants to use fiber photometry or optogenetics to investigate neural circuitry.

See why TDT has been the leader in fiber photometry since the beginning [10.1073/pnas.1521238113]

iX7 Video Introduction

 

Fiber photometry hardware has never been this straightforward

Simple Subject Connection

Easily connect your subject patch cord to the iX7 directly or with a commercial rotary joint for freely-moving behavior.

Record RED and GREEN fluorescent responses simultaneously in just a few clicks of our Synapse software. Everything auto-detects so you can start recording right away.

Our built-in Q-factor fluorescence detection and power meter make checking signal quality easier than all other existing systems.

 

Real-time Lock-In Amplification

TDT Fiber Photometry systems use a technique called ‘Lock-in Amplification’ to detect very small changes in fluorescence from active neurons.

How Does Lock-In Amplification Work?

This works by modulating different wavelength LEDs (e.g. 415 nm, 465 nm, 560 nm) at different sinusoidal frequencies and sending them through a series of optical filters and dichroic mirrors. The lights are on simultaneously and do not interfere with one another, unlike CMOS-based imaging systems.

Lock-in amplification is then applied and uses the carrier frequency of the LEDs to extract the fluorophore signal from the noise of the raw signal. In addition, multiple LEDs can be driven at different frequencies. This allows for the simultaneous detection of multiple signals like GFP, RFP, and isosbestic controls.

Detect, Connect and Go!

Real-time demodulation and dFF calculations, closed-loop optogenetic stimulation – Synapse can do it all. Every aspect of the iX7 is configurable with just a few mouse clicks. Go from unpacking to data collection in minutes. No complex coding required.

Run-time controls let users measure and adjust the level to control the power, run timed recording intervals, adjust online filter settings, and much more.

Data courtesy of Eric Yttri lab 

Streamlined Green Fluorescence Options

iX5 – Green Photometry with Red Opto Stim

iX5 fiber photometry module with 415 nm and 465 nm LEDs and

TDT offers a version of the iX7 for performing standard green fluorescence recordings (GCaMP, GRAB sensors, dLight) plus red opto stim. The iX5 is a cost-effective option if you are not planning to record red fluorophores.

TDT offers upgrade paths to a full iX7 when you are ready to expand!

iX4 – Green Photometry

iX4 photometry module with 415 nm isosbestic excitation and 465 nm blue excitation for standard green photometry

If you just want to record green fluorescence without paying for add ons, then consider the iX4 as the best option. Stack multiple iX4s in an iCon for simple same subject multi-site photometry recordings.

TDT offers upgrade paths to a full iX7 when you are ready to expand!

Every Novel Sensor Has a Home

iX6 for Flexible Isosbestic Options

The iX6 brings the power and flexibility of TDT’s popular RZ10X processor to the iCon family. It features integrated LUX LEDs and Photosensors that plug into its front panel enabling three-color fiber photometry. Multiple iX6 devices can be employed to facilitate multi-site and multi-subject recording.

Use with TDT’s LxM optical manifolds for a turn-key system with unparalleled sensitivity and versatility. The iX6 uses TDT’s Lux line of interchangeable LEDs and Sensors for unparalleled flexibility for your calcium imaging and optogenetics experiments. Easily and cost-effectively change LEDs/wavelengths as the biological sensors in your research change over time.

Data Import and Analysis

Offline Analysis

TDT’s Synapse software data can be exported to Matlab, Python, Excel, or another analysis software of your choice. With TDT’s Fiber Photometry systems, you no longer need to worry about precisely aligning behavioral codes with neural responses. The integration of your behavioral, video, and fiber photometry data into one data structure ensures consistent synchronized timing.

Check out the these Matlab and Python examples for offline analysis code for fiber photometry.

Why TDT?

When you choose a TDT behavioral neuroscience recording system you choose legacy, innovation, and commitment. Every system is designed and assembled at our headquarters in Alachua, Florida by our long-time employees.

All images of animals include artwork (modified or otherwise) from BioRender.