Luis D. Ramirez

I'm a researcher interested in how the brain constructs stable visual representations. My investigations combine psychophysics, computational modeling, and fMRI.


Google Scholar. GitHub.

Currently, as a postdoctoral researcher in the Serences Lab at UCSD, I'm studying the encoding of image statistics in early visual cortex and its interaction with sensory and perceptual history.


I completed my PhD in Neuroscience at Boston University with Sam Ling. There, I studied the mechanisms underlying temporal attention, and the influence of feature-based attention and emotion on population spatial frequency tuning (pSFT). I've also contributed to investigations of scale invariance and amblyopia.


I earned a BSc in Science and Technology Studies at NYU Tandon School of Engineering, where I explored philosophy and history of science, physics, and neuroscience with the aim of understanding how the brain and society make sense of reality. That our understanding of reality (physics) is deeply intertwined with the brain (neuroscience, psychology) drives much of my work. (You can imagine my surprise when I learned about psychophysics.) I was fortunate to gain hands-on research experience in the Carrasco Lab at NYU (with Dr. Rachel Denison) and the Tong Lab at Vanderbilt University while being supported by the NIH BP-ENDURE program.


And here we are, more than a decade later.

The Population Spatial Frequency Toolbox

Ramirez, L. D., Wang, F., Wiecek, E., Vinke, L. N., & Ling, S. 2026. The Population Spatial Frequency Toolbox. Journal of Open Research Software. https://doi.org/10.5334/jors.610.

We developed an open-source MATLAB package to provide a standardized, reproducible pipeline for characterizing population spatial frequency tuning (pSFT) from fMRI data. The toolbox facilitates stimulus generation, data collection, and voxel-wise parameter optimization, bridging the gap between raw BOLD signals and interpretable neural tuning curves. It includes a measure-pSFT module for Psychtoolbox-based stimulus presentation and an estimate-pSFT module for fitting log-Gaussian models to voxel data. To ensure computational rigor, we included a validation sub-module that uses synthetic BOLD data to benchmark parameter recovery across varying signal-to-noise ratios. The pSFT approach has been successfully deployed across multiple studies (see below).

The Population Spatial Frequency Toolbox Figure

Attention Alters Population Spatial Frequency Tuning

Ramirez, L. D., Wang, F. & Ling, S. 2025. Attention alters population spatial frequency tuning. Journal of Neuroscience. https://doi.org/10.1523/JNEUROSCI.0251-25.2025.

This project utilized pSFT to investigate how feature-based attention reshapes voxel-wise SF tuning profiles in the early visual cortex (V1–V3). By measuring these changes in a task-irrelevant hemifield, we were able to isolate the global effects of feature-based attention as they spread across the visual field. We discovered that attention elicits significant "attractive shifts" in SF preference toward the attended frequency, demonstrating that neural populations flexibly adjust their tuning to prioritize task-relevant details. This work provides direct evidence that voluntary attention can dynamically reconfigure the fundamental building blocks of early human vision.

Attention Alters Population Spatial Frequency Tuning Figure

Emotion Alters Population Spatial Frequency Tuning

Ramirez, L. D., Pan, J., & Ling, S. 2024 “How does emotional arousal modulate population spatial frequency tuning?” Poster. Vision Sciences Society Conference. https://doi.org/10.1167/jov.24.10.912

This study used pSFT to measure how negative emotion reconfigures SF tuning. Negative emotion was induced using valenced auditory stimuli while measuring SF tuning in the early visual cortex. Contrary to the long-held belief that negative emotion solely sacrifices fine detail for coarse "gist," we found that negative emotion triggered systematic increases in preferred SF and selectivity, particularly in the extrastriate cortex. In other words, the visual system can dynamically increase spatial resolution to enhance the processing of fine details during states of negative emotion.

Emotion Project Figure

Spatial Frequency Tuning Follows Scale Invariance in the Human Visual Cortex

Wiecek, E., Ramirez, L. D., Klimova, M., & Ling, S. 2026. Spatial frequency tuning follows scale invariance in human visual cortex. Journal of Neuroscience. https://doi.org/10.1523/JNEUROSCI.1490-25.2025.

Here we provide a direct test of the scale invariance principle in the human visual cortex—the theory that the resolution of spatial sampling remains constant relative to receptive field (RF) size. By introducing the "Cycles Per Receptive Field" (CPF) metric, we showed that SF preferences scale inversely with population RF size across V1–V3. This project combined population receptive field (pRF) mapping with pSFT to characterize the functional sampling properties of neural populations across the visual field. Our findings validate a fundamental assumption in visual neuroscience and establish a new framework for studying atypical visual development.

Scale Invariance Figure

Temporal Attention Selectively Enhances Target Features

Ramirez, L. D., Foster, J. J., & Ling, S. 2021. Temporal attention selectively enhances target features. Journal of Vision. https://doi.org/10.1167/jov.21.6.6.

This research examined the computational mechanisms of temporal attention—the allocation of attention to a specific moment in time. Using a fine-orientation discrimination task paired with an equivalent noise paradigm, we teased apart how attention improves perception under varying levels of external noise. Formal model comparisons revealed that temporal attention acts through a combination of signal and stimulus enhancement, selectively increasing gain for target features. By fitting variants of a divisive normalization model to behavioral data, we provided evidence that the brain can selectively "tune in" to relevant signals even when they are embedded in noise.

Temporal Attention Figure

Google Scholar. GitHub.

Last updated: 02.05.2026

Google Scholar

Last updated: 02.05.2026

Invited Talks

  • 2023 Experimental Psychology: Cognitive Neuroscience Boston University CAS NE 329
  • 2022 Experimental Psychology: Cognitive Neuroscience Boston University CAS NE 329

Conference Presentations

  • 2025 How feature-based attention alters representations in human visual cortex Ling, S., Foster, J. J., Wang, F., & Ramirez, L. D. Talk. Vision Sciences Society Conference. St. Pete Beach, FL
  • 2024 How does emotional arousal modulate population spatial frequency tuning? Ramirez, L. D., Pan, J., & Ling, S. Poster. Vision Sciences Society Conference. St. Pete Beach, FL
  • 2024 Are visual deficits in amblyopia driven by spatial frequency tuning? Wiecek, E., Ramirez, L. D., Klimova, M., & Ling, S. Poster. Vision Sciences Society Conference. St. Pete Beach, FL
  • 2024 Is the loss of spatial resolution in amblyopia linked to a deviation in scale invariance? Wiecek, E., Klimova, M., Ramirez, L. D., & Ling, S. Poster. Association for Research in Vision and Ophthalmology Conference. Seattle, WA
  • 2023 Feature-based attention modulates spatial frequency processing in early human visual cortex Ramirez, L. D., Wang, F., Ling, S. Poster. Vision Sciences Society Conference. St. Pete Beach, FL
  • 2023 Characterizing the relationship between population spatial frequency tuning and receptive field size Wiecek, E., Ramirez, L. D. Klimova, M., & Ling, S. Poster. Vision Sciences Society Conference. St. Pete Beach, FL
  • 2022 How does feature-based attention modulate spatial frequency processing in early human visual cortex? Ramirez, L. D., Wang, F., Ling, S. Poster. Society for Neuroscience Conference. San Diego, CA
  • 2021 What mechanisms underlie top-down modulation of human visual cortex? Ramirez, L. D. Talk. Writing Your Own Blueprint: The NIH Blueprint Diversity Conference. Virtual
  • 2020 Temporal attention selectively enhances gain only for target features Ramirez, L. D., Foster, J. J., Ling, S. Talk. Vision Sciences Society Conference. Virtual
  • 2019 Spatial location does not elicit normalization in visual memory Ramirez, L. D., Schwartz, J., Bloem, I. M., Ling, S., Kibbe, M. M. Poster. Vision Sciences Society Conference. St. Pete Beach, FL
  • 2019 Exogenous temporal attention improves perception via signal enhancement Ramirez, L. D. Talk. Boston University Brain, Behavior, & Cognition Student Seminar. Boston, MA
  • 2018 Temporal attention enhances visual perception through both signal enhancement and noise exclusion Ramirez, L. D., Ling, S. Poster. Vision Sciences Society Conference. St. Pete Beach, FL
  • 2016 Development and evaluation of a new test of face perception and face memory ability Ramirez, L. D., Park, Y., Tong, F. Poster. Society for Neuroscience Conference. San Diego, CA
  • 2016 Evaluation of a new test of face perception and face memory ability Ramirez, L. D., Park, Y., Tong, F. Poster. Vanderbilt Summer Science Academy. Nashville, TN
  • 2015 Emergence in the Fractional Quantum Hall Effect Ramirez, L. D., Bain, J. Poster. New York University Tandon Summer Undergraduate Research Program. Brooklyn, NY
  • 2021–present F99/K00 NIH Blueprint and BRAIN Initiative D-SPAN Award
  • 2021 Hispanic Scholarship Fund (HSF) Scholar
  • 2020 BU Diversity & Inclusion: Inclusion Catalyst Grant
  • 2020 HHMI Gilliam Fellowship for Advanced Study Nominee
  • 2017 NYU Tandon Achievement in Science and Technology Studies
  • 2017 R25 NIH Blueprint ENDURE Fellowship