About

Marlene R. Cohen, PhD, is a Professor at the University of Chicago in the Department of Neurobiology and Neuroscience Institute. She holds a PhD in Neuroscience from Stanford University and dual Bachelor of Science degrees in Brain and Cognitive Sciences and Mathematics from the Massachusetts Institute of Technology. The information provided lists her academic credentials and current professional affiliation but does not include specific details about her research focus or key contributions.

Research topics

• Philosophy
• History
• Biology
• Environmental ethics
• Classics
• Art history
• Theology
• Archaeology

Selected publications

• Sequential experience reshapes population representations in visual cortex

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-03-20

  articleOpen accessSenior author

  Abstract Visual experience is organized in time. When riding the same bus route each day, the visual scene unfolds in a predictable order without requiring active choice. During goal-directed behavior, individuals organize actions into routines, such as repeatedly walking the same route to work even when alternatives are equally efficient. Because experience unfolds across sequences of events, identifying how it reshapes population activity requires examining representations over time. Many studies have shown that repeated experience reduces mean firing rates in visual cortex 1–14 . While firing rates effectively signal novelty or repetition, they are not well positioned to describe how populations of neurons represent temporal relationships. A growing body of work suggests that the geometry of population activity provides additional insight into how visual information is structured and read out 15–26 . We examined how experience with temporal structure reshapes the geometry of population activity in visual area V4. We recorded neuronal populations across three contexts that varied in temporal structure and behavioral relevance: repeated presentation of individual images, passive exposure to structured image sequences, and repeated execution of self-chosen visually guided action sequences for reward. Across contexts, experience constrained population responses toward a typical activity pattern. In sequence contexts, experience made temporal position more linearly accessible and, during active practice, increased the separability of task-relevant variables. These findings show that experience reorganizes the geometry of visual population activity to reflect temporal structure, constraining responses and altering how sequence-related information is represented.

  PublisherOA PDFDOI

• Neuronal heterogeneity of normalization strength in a circuit model

  Science Advances · 2026-01-01

  articleOpen access

  Neurons in higher-order visual areas integrate information through a canonical computation called normalization. The strength of normalization is highly heterogeneous across neurons, and this heterogeneity correlates with attention-mediated modulations in neural responses. However, the circuit mechanism underlying the heterogeneous normalization strength is unclear. In this work, we study normalization in a spiking neuron network model of visual cortex. Our model reveals that the heterogeneity of normalization strength is highly correlated with the inhibitory current each neuron receives. The correlation between inhibition and other synaptic inputs explains the experimentally observed dependence of spike count correlations on normalization strength. Further, we find that neurons with stronger normalization encode information more efficiently, and that networks with more heterogeneity in normalization encode visual stimuli with higher information and capacity. Together, our model provides a mechanistic explanation of heterogeneous normalization strengths in the visual cortex and sheds light on the computational benefits of neuronal heterogeneity.

  PublisherDOI

• Loss of neuronal population organization links pathology to behavior in a model of Alzheimer’s disease

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-03-18

  articleOpen accessSenior author

  Alzheimer's disease (AD) and related dementias (ADRD) are defined by molecular and cellular pathology and cognitive decline, but linking these levels requires understanding how pathology alters large-scale neuronal activity. We longitudinally tracked behavior, multi-area neuronal population activity, and fluid and histological biomarkers in a macaque model of early-stage ADRD. As pathology progressed, visually guided behavior became increasingly disorganized, reflected in less structured exploration despite preserved task performance. Guided by systems neuroscience principles linking neuronal population activity with organized goal-directed behavior, we found progressive reductions in coordinated neuronal population activity within and between visual and parietal cortices, even as single-neuron tuning and basic feature encoding remained stable. These changes emerged when tau pathology was largely confined to regions providing feedback to visual cortex. This disorganized state appears modifiable: proof-of-concept methylphenidate administration was associated with transient improvement in behavioral organization. Together, these findings identify disruption of neuronal population organization as a defining feature of early-stage ADRD and frame early dysfunction as a disorder of coordinated population activity.

  PublisherOA PDFDOI

• Linking neural population formatting to function

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-01-04 · 5 citations

  preprintOpen accessSenior author

  Animals capable of complex behaviors tend to have more distinct brain areas than simpler organisms, and artificial networks that perform many tasks tend to self-organize into modules (1-3). This suggests that different brain areas serve distinct functions supporting complex behavior. However, a common observation is that essentially anything that an animal senses, knows, or does can be decoded from neural activity in any brain area (4-6). If everything is everywhere, why have distinct areas? Here we show that the function of a brain area is more related to how different types of information are combined (formatted) in neural representations than merely whether that information is present. We compared two brain areas: the middle temporal area (MT), which is important for visual motion perception (7, 8), and the dorsolateral prefrontal cortex (dlPFC), which is linked to decision-making and reward expectation (9, 10)). When monkeys based decisions on a combination of motion and reward information, both types of information were present in both areas. However, they were formatted differently: in MT, they were encoded separably, while in dlPFC, they were represented jointly in ways that reflected the monkeys' decision-making. A recurrent neural network (RNN) model that mirrored the information formatting in MT and dlPFC predicted that manipulating activity in these areas would differently affect decision-making. Consistent with model predictions, electrically stimulating MT biased choices midway between the visual motion stimulus and the preferred direction of the stimulated units (11), while stimulating dlPFC produced 'winner-take-all' decisions that sometimes reflected the visual motion stimulus and sometimes reflected the preference of the stimulated units, but never in between. These results are consistent with the tantalizing possibility that a modular structure enables complex behavior by flexibly reformatting information to accomplish behavioral goals.

  PublisherOA PDFDOI

• Neuronal signatures of successful one-shot memory in mid-level visual cortex

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-09-22 · 1 citations

  preprintOpen accessSenior author

  High-capacity, one-shot visual recognition memory challenges theories of learning and neural coding because it requires rapid, robust, and durable representations. Most studies have focused on the hippocampus and other higher areas. However, behavioral evidence demonstrating links between image properties and memorability and revealing image specificity of visual memory suggests an important role for mid-level visual cortex. We tested the hypothesis that area V4 contains signals that could support recognition memory. Our task increased difficulty, allowing comparisons of neuronal population responses on correct and error trials. We observed signatures of several proposed memory mechanisms including magnitude coding, repetition suppression, sparse coding, and population response consistency, but only sparse coding and population response consistency predicted behavior. Familiar images also evoked faster dynamics, consistent with pattern completion. These findings demonstrate that the building blocks of fast, high-capacity memory are present in mid-level sensory cortex, highlighting its role in distributed memory networks.

  PublisherOA PDFDOI

• Guided by Noise: Correlated Variability Channels Task-Relevant Information in Sensory Neurons

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-08-13 · 1 citations

  preprintOpen accessSenior author

  Abstract Shared trial-to-trial variability across sensory neurons is reliably reduced when perceptual performance improves, yet this variability is low-dimensional, so it could be ignored by an optimal readout mechanism. Why then is it so consistently related to behavior? We propose that shared variability both reflects circuit structure and reveals the information communicated to downstream areas . In this framework, the same connectivity that shapes signal propagation also shapes shared variability. Using a circuit model, we show that when sensory signals align with shared variability, behaviorally relevant information is amplified without compromising coding fidelity. Analyses of neural population recordings from multiple brain areas and tasks reveal that the dominant axis of shared variability consistently aligns with task-relevant stimulus features and action plans . Finally, the behavioral impact of microstimulation can be explained by the extent to which it changes projections onto the shared variability axis. These findings suggest that shared variability may illuminate, rather than obscure, the neural dimensions that guide behavior. Significance Statement The brain’s ability to use different features of sensory information flexibly across many tasks is essential for complex decision-making. Our study reveals that the correlated variability in neural responses in mid-level visual areas indicates the visual feature that is relevant for behavior. Our biologically plausible network model predicted that it is beneficial for the representation of behaviorally relevant visual information to be aligned with the correlated variability in neurons. We tested and confirmed this in five independent neural data sets. Our results suggest that trial-by-trial variability does not affect the information encoded in sensory neurons but instead is a valuable signal for us to understand which combination of the encoded features is being used by the brain to guide choices.

  PublisherOA PDFDOI

• Behavioural diversity reveals distinct regimes of multisensory integration

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-10-30

  preprintOpen accessSenior author

  Effective decision-making requires integrating multiple information sources, weighted by their reliability and context. While classic studies show near-optimal cue combination with well-learned signals and extensive feedback, everyday choices often rely on unfamiliar or cross-modal cues without such training. We examined cue combination under these conditions using an online perceptual estimation task in large and diverse participant cohorts. Participants combined unpracticed cues, including visual motion direction, spatial visual information, and auditory location, with minimal feedback and occasional cue conflict. Integration strategies varied with age and self-reported ADHD or Autism. Visual cues were combined near-optimally, whereas audio-visual combinations exhibited winner-take-all behaviour, typically but not always favouring the more reliable cue. To test the generality of these findings, we used electrical microstimulation in non-human primates, targeting unimodal or cross-modal association areas. Stimulation of visual cortex was integrated with sensory motion cues, while stimulation of prefrontal cortex promoted winner-take-all choices. These findings suggest universal circuit-level distinctions between within- and across-modality integration, with deviations potentially diagnostic for neuropsychiatric conditions.

  PublisherOA PDFDOI

• Orthogonal neural representations support perceptual judgments of natural stimuli

  Scientific Reports · 2025-02-12 · 2 citations

  articleOpen access

  In natural visually guided behavior, observers must separate relevant information from a barrage of irrelevant information. Many studies have investigated the neural underpinnings of this ability using artificial stimuli presented on blank backgrounds. Natural images, however, contain task-irrelevant background elements that might interfere with the perception of object features. Recent studies suggest that visual feature estimation can be modeled through the linear decoding of task-relevant information from visual cortex. So, if the representations of task-relevant and irrelevant features are not orthogonal in the neural population, then variation in the task-irrelevant features would impair task performance. We tested this hypothesis using human psychophysics and monkey neurophysiology combined with parametrically variable naturalistic stimuli. We demonstrate that (1) the neural representation of one feature (the position of an object) in visual area V4 is orthogonal to those of several background features, (2) the ability of human observers to precisely judge object position was largely unaffected by those background features, and (3) many features of the object and the background (and of objects from a separate stimulus set) are orthogonally represented in V4 neural population responses. Our observations are consistent with the hypothesis that orthogonal neural representations can support stable perception of object features despite the richness of natural visual scenes.

  PublisherOA PDFDOI

• Coordinated Response Modulations Enable Flexible Use of Visual Information

  bioRxiv (Cold Spring Harbor Laboratory) · 2024-07-15 · 3 citations

  preprintOpen accessSenior author

  Abstract We use sensory information in remarkably flexible ways. We can generalize by ignoring task-irrelevant features, report different features of a stimulus, and use different actions to report a perceptual judgment. These forms of flexible behavior are associated with small modulations of the responses of sensory neurons. While the existence of these response modulations is indisputable, efforts to understand their function have been largely relegated to theory, where they have been posited to change information coding or enable downstream neurons to read out different visual and cognitive information using flexible weights. Here, we tested these ideas using a rich, flexible behavioral paradigm, multi-neuron, multi-area recordings in primary visual cortex (V1) and mid-level visual area V4. We discovered that those response modulations in V4 (but not V1) contain the ingredients necessary to enable flexible behavior, but not via those previously hypothesized mechanisms. Instead, we demonstrated that these response modulations are precisely coordinated across the population such that downstream neurons have ready access to the correct information to flexibly guide behavior without making changes to information coding or synapses. Our results suggest a novel computational role for task-dependent response modulations: they enable flexible behavior by changing the information that gets out of a sensory area, not by changing information coding within it. Significance Natural perceptual judgments are continuous, generalized, and flexible. We estimate the ripeness of a piece of fruit on a continuous scale, we generalize by judging the ripeness of either a mango or an avocado even though they look very different, we flexibly judge either the size or the ripeness of the same piece of fruit, and we can flexibly indicate the same perceptual judgment using a variety of behaviors such as by speaking or writing any of many languages. Here, we show that the response modulations in visual cortex long associated with cognitive processes, surround modulation, or motor planning are sufficient to guide all these aspects of natural perceptual decision-making. We find that across the population, these response modulations reorient and reformat visual representations so that the relevant information is used to guide behavior via communication with downstream neurons. Our results are an example of a general computational principle for flexible behavior that emerges from the coordinated activity of large populations of neurons.

  PublisherDOI

• Author response: Multiple objects evoke fluctuating responses in several regions of the visual pathway

  2024-01-29

  peer-reviewOpen access
  PublisherDOI

Frequent coauthors

• Roberto Car

  Princeton University

  48 shared

• Adam Wasserman

  Purdue University West Lafayette

  47 shared

• Kieron Burke

  University of California, Irvine

  39 shared

• Joshua Jortner

  Tel Aviv University

  34 shared

• E. N. Economou

  Foundation for Research and Technology Hellas

  31 shared

• Iddo Eliazar

  28 shared

• Annabella Selloni

  Princeton University

  27 shared

• Federico Zipoli

  IBM Research - Zurich

  24 shared

Labs

• Cohen LabPI

  Not provided

Education

• Ph.D., Neurobiology

  University of Chicago

  1990

• B.S., Biology

  University of California, San Diego

  1984

Awards & honors

• Eppendorf winner