The Floor Projection Maze was specifically designed to advance the understanding of visual information processing, learning, memory, and attention as per the publication “Automated Visual Cognitive Tasks for Recording Neural Activity Using a Floor Projection Maze” by Burwell et al 2014.

The floor maze projects two-dimensional visual cues onto the maze floor from beneath, utilizing a semi-transparent surface illuminated by a digital projector. This particular etup is biologically optimal for rodents, naturally aligning with their downward gaze. The maze’s adaptable structure facilitates the use of interchangeable testing environments, thereby accommodating a diverse range of behavioral study designs. Furthermore, its under-floor projection system integrates seamlessly with neural implants, enabling simultaneous recording of brain activity and behavior, and remains fully compatible with overhead video tracking. The system also supports automated behavioral reward delivery and offers customizable conditioning paradigms. Researchers have already successfully employed this maze to explore complex areas such as visual attention, decision-making, learning processes, spatial navigation, and visual discrimination.

Key Features of the Floor Maze

  • Floor-Based 2D Visual Stimulus Presentation
    The maze presents two-dimensional visual stimuli projected directly onto the semi-transparent underside of its clear Plexiglas floor using back-projection from a digital projector and a mirror setup.
  • Optimized for Rodents’ Visual Field
    Rodents naturally process visual information from their lower visual field more effectively. Projecting stimuli onto the floor leverages this innate anatomical and behavioural tendency, increasing task performance and experimental validity.
  • Option for Fully Automated System Integrating Tracking, Presentation, and Rewards
    The setup includes overhead video tracking (via camera plus ConductVision), automated control over stimulus presentation, and precisely timed reward delivery. 
  • Use of Intracranial Stimulation (ICS) for Instant Reward
    Instead of traditional food or liquid rewards, the system employs intracranial stimulation of the medial forebrain bundle. This method provides immediate, powerful reinforcement, speeding up learning and allowing for more trials per session.
  • Ideal for Simultaneous Electrophysiological Recording
    The maze was explicitly designed to support neural recordings—allowing researchers to capture neural activity in freely moving rodents during visually guided tasks. This integration enables investigation of neural correlates of cognition, like attention, learning, and decision-making.
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Price & Dimensions

Rat Floor Maze

$ 4990

Per Month
  • Arena: Acrylic open field without walls, 140 × 110 cm; clear
  • Transparent acrylic floor (0.6 cm)
  • Underside of floor: Unity-gain Dual Vision Fabric screen stretched over a second acrylic sheet (150 × 110 × 1.25 cm) for rear projection with a short-throw projector
  • Project available on request

Documentation

Apparatus & Equipment

  • Overhead Camera (with or without Tracking System)
    Positioned above the maze, it continuously monitors the rat’s position and movements. The camera feeds data to behavioral control software in real time. Cameras and ConductVision tracking software available.

  • Clear Acrylic Floor (Arena Surface)
    The subject moves freely on this transparent floor. It serves as the main behavioral arena and allows visual stimuli to be projected from underneath.

  • Digital Projector + Mirror Assembly (Stimulus Presentation)
    Below the acrylic floor, a digital projector shines images onto a mirror angled upward. The mirror reflects the stimuli directly onto the underside of the floor, creating sharp, high-contrast visual patterns or cues that the rat can see and respond to.

  • Reward System (Intracranial Stimulation, ICS)
    When the subject performs the correct action, the software delivers a reward via implanted electrodes targeting the medial forebrain bundle. This provides immediate and strong reinforcement without the delays of food or liquid delivery. However, modular lickometers and pellet dispensers are also available.

  • Conduct Software (Automation & Integration)
    A computer system integrates all functions—tracking, stimulus presentation, and reward delivery—so tasks are fully automated, reducing experimenter bias and increasing trial efficiency.

Training Protocol

Apparatus

Arena as an open field with transparent acrylic floor (0.6 cm), unity-gain Dual Vision Fabric screen stretched over a second acrylic rectangle for rear projection with a short-throw projector, and software, overhead camera with video tracking.

Test arena: place a matte-white acrylic arena directly on the floor (typical wall height 45–50 cm). The example uses a double-sided “bowtie” arena with four software-defined areas: East Image, West Image, East Trial-Ready, West Trial-Ready.

Software: Create visual cues using a projector and Dual vision screen.

ICS delivery: bipolar square-wave stimulation via a programmable stimulator (PC-controlled). Recommended parameters: pulse 1 & 2 = 500 µs; inter-pulse delay = 500 µs; 100 Hz. Manual delivery possible via button box if needed.

Animals & handling:

Start with naïve male Long-Evans rats (~P22). Pair-house 1 week; handle ~5 min/day. Begin food scheduling at 250–275 g to maintain 85–90% free-feeding weight (increase target by 10 g/month to 350 g). Single-house ≥1 week before surgery.

Electrode implantation: Anesthetize with isoflurane. Expose skull; identify bregma/lambda; make craniotomies; place anchor screws. Implant ICS electrode in medial forebrain bundle (MFB): AP −2.7 mm (from bregma), ML ±1.8 mm, DV −8.5 mm (from skull). Optionally implant a backup ICS electrode contralaterally. Secure with bone cement (do not cement the ICS pedestal). Implant recording electrodes at your target site; secure with cement; position ICS pedestal away from the recording device. Recover ≥7 days.

Behavioral shaping (progresses Early → Intermediate → Late)

  • Early shaping (goal: explore and learn key zones)

    • Day 1: Habituate to room 10 min (equipment on)

    • Day 2: Habituate to arena 10 min

    • Day 3: Connect ICS & headstage tethers; 10 min arena

    • Day 4: Titrate ICS amplitude by informal place-preference; typical 20–80 µA.

    • Day 5: Deliver ICS to associate the Ready Area and East/West Image Areas with reward until the rat alternates sides.

  • Intermediate shaping (goal: hold a “ready position”)

    • Trial start signaled by white noise (50 dB); turn off when the rat enters the Ready Area.

    • Automate ICS for Ready-Area entry and successful holds; gradually reduce reward probability so that the final probability for successful holds is ~5–10%.

    • Start ready-hold at ~200 ms; increase in 100 ms steps; restart trial (white noise on) if the rat breaks early. Advance when the rat can hold up to ~1,200 ms.

  • Late shaping (task-specific automation): Visual biconditional discrimination (vBCD)

    • Start trial with white noise; impose random ready-latency 700–1,200 ms; reinforce holds as needed.

    • Present a pair of images; reward a correct zone entry; on Day 1 only, a 75 dB white-noise burst can deter incorrect choices; use correction trials (same side & latency as prior error).

    • After simple discrimination is learned, add two distinct floor patterns so the correct image depends on the current floor context; pseudorandomize context and side; retain correction trials.

  • Visuospatial attention (VSA): Random ready-latency 1,000–1,600 ms; after a successful hold, briefly illuminate one of several predefined circle locations; reward entry into the illuminated target zone.

    • Begin with illumination held until approach or 5 s timeout; omissions trigger whole-floor illumination and no reward.

    • At ~80% correct: shorten illumination to 1 s (5 s choice window); later to 500 ms; target locations randomized each trial; do not reward incorrect/omission trials; next trial starts on the opposite side.

Data Analysis

Behavioral Performance Analysis

  • Accuracy / % Correct

    • In tasks like visual biconditional discrimination (vBCD) or visuospatial attention (VSA), calculate correct vs. incorrect choices per session or block.

  • Reaction Time (RTs)

    • Measure latency from stimulus onset to entry into the target zone.

  • Omissions / Perseverative Errors

    • Count trials where the rat fails to respond, or repeatedly enters incorrect zones.

  • Learning Curves

    • Track improvement in accuracy or RTs across days to quantify training efficiency.

Spatial & Trajectory Analysis

  • Path Tracking

    • Use overhead video to reconstruct rat trajectories.

  • Zone Dwell Time

    • Quantify time spent in predefined zones (e.g., Ready Area, Image Area).

  • Approach Bias

    • Analyze left vs. right preference over trials.

  • Exploration Metrics

    • Path length, speed, and thigmotaxis (tendency to stay near walls) to assess motivation or anxiety.

Stimulus-Dependent Behavior

  • Context-Dependent Choice

    • In vBCD, determine how floor pattern context changes image selection.

  • Attention Shifts

    • In VSA, measure detection accuracy and speed as a function of target location or distance from ready zone.

  • Cue Salience

    • Test how stimulus brightness, size, or contrast affect response probability.

Neural & Electrophysiological Analysis

(if simultaneous recording is used)

  • Spike Sorting & Unit Activity

    • Identify neurons and assess firing rate changes during stimulus presentation, decision, or reward delivery.

  • Event-Related Firing

    • Align spikes to trial events (stimulus onset, choice, reward).

  • Local Field Potentials (LFPs)

    • Study oscillatory activity related to attention, working memory, or learning.

  • Cross-Region Interactions

    • If multi-site recording is done, analyze coherence or cross-correlations between brain areas.

Integrated Behavioral–Neural Correlations

  • Performance vs. Neural Dynamics

    • Relating accuracy, RTs, or errors to neural firing patterns.

  • Plasticity & Learning Signals

    • Track how neural representations evolve with task learning across sessions.

  • Attention & Decision Markers

    • Identify neural correlates of shifts in attention, stimulus discrimination, or choice bias.

Advanced Analyses

  • Machine Learning Classifiers

    • Train decoders to predict trial outcome, stimulus identity, or choice direction from neural or behavioral data.

  • State-Space Modeling

    • Capture dynamics of decision processes or attentional shifts over time.

  • Computational Modeling

    • Fit reinforcement learning models (Q-learning, Bayesian models) to choice patterns and compare with neural signals.

Literature Review

Functional Differentiation of Dorsal and Ventral Posterior Parietal Cortex of the Rat: Implications for Controlled and Stimulus-Driven Attention

Cerebral Cortex, 2022;32: 1787–1803

Yang, Dokovna, and Burwell (2022) used the Floor Projection Maze to investigate functional differentiation in the rat posterior parietal cortex (PPC). By combining anatomical tract-tracing with simultaneous electrophysiological recordings during a visuospatial attention (VSA) task, the study found clear evidence for division of labor within PPC. Anatomical data showed that the ventral PPC (VPPC) had stronger reciprocal connections with the postrhinal cortex (POR) and received preferential input from specific thalamic subdivisions, suggesting a role in bottom–up processing. Electrophysiological analyses revealed that VPPC neurons responded more rapidly and in greater numbers to stimulus onset compared to dorsal PPC (DPPC), indicating a specialization for stimulus-driven (bottom–up) attention. In contrast, DPPC neurons were more engaged in task-related signals and top–down control, supporting perception-to-action processes. Together, these results provide the first evidence that dorsal and ventral PPC in rats are functionally distinct, with DPPC mediating controlled, top–down attention and VPPC mediating fast, stimulus-driven attention.

 

Neuronal Activity in the Rat Pulvinar Correlates with Multiple Higher-Order Cognitive Functions

Yang & Burwell (2020)  used the Floor Projection Maze to record neuronal activity in the rat pulvinar (lateral posterior thalamus) during a visuospatial attention (VSA) task. Rats monitored three possible stimulus locations, and their neural responses were analyzed across key behavioral epochs (stimulus onset, target selection, reward approach).

The findings showed that over three-quarters of pulvinar neurons (74–79%) exhibited task-related activity, demonstrating that this thalamic nucleus participates in multiple higher-order cognitive processes. Specifically:

  • Stimulus-driven and controlled attention: Some neurons increased firing immediately after stimulus onset (bottom–up attention), while others showed activity during pre-stimulus monitoring (top–down attention).

  • Decision-making: A significant subset of cells differentiated correct vs. incorrect target selections, indicating involvement in guiding choice behavior.

  • Reward processing: Many neurons signaled trial outcomes during the reward-approach phase, encoding success or failure.

  • Spatial reference frames: About 37% of cells encoded allocentric (east vs. west side) location and 30% encoded egocentric (left, center, right) position; importantly, some cells showed mixed selectivity for both frames, suggesting pulvinar’s role in translating spatial information across reference systems.

References

  1. Jacobson TK, Ho JW, Kent BW, Yang FC, Burwell RD. Automated visual cognitive tasks for recording neural activity using a floor projection maze. J Vis Exp. 2014 Feb 20;(84):e51316. doi: 10.3791/51316. PMID: 24638057; PMCID: PMC4130232.
  2. Yang FC, Dokovna LB, Burwell RD. Functional Differentiation of Dorsal and Ventral Posterior Parietal Cortex of the Rat: Implications for Controlled and Stimulus-Driven Attention. Cereb Cortex. 2022 Apr 20;32(9):1787-1803. doi: 10.1093/cercor/bhab308. PMID: 34546356; PMCID: PMC9070340.
  3. Yang FC, Burwell RD. Neuronal Activity in the Rat Pulvinar Correlates with Multiple Higher-Order Cognitive Functions. Vision (Basel). 2020 Mar 1;4(1):15. doi: 10.3390/vision4010015. PMID: 32121530; PMCID: PMC7157601.

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