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Srinath R, Ni AM, Marucci C, Cohen MR, Brainard DH. Orthogonal neural representations support perceptual judgements of natural stimuli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580134. [PMID: 38464018 PMCID: PMC10925131 DOI: 10.1101/2024.02.14.580134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
In natural 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 simple backgrounds. Natural viewing, however, carries a set of challenges that are inaccessible using artificial stimuli, including neural responses to background objects that are task-irrelevant. An emerging body of evidence suggests that the visual abilities of humans and animals can be modeled through the linear decoding of task-relevant information from visual cortex. This idea suggests the hypothesis that irrelevant features of a natural scene should impair performance on a visual task only if their neural representations intrude on the linear readout of the task relevant feature, as would occur if the representations of task-relevant and irrelevant features are not orthogonal in the underlying neural population. We tested this hypothesis using human psychophysics and monkey neurophysiology, in response to parametrically variable naturalistic stimuli. We demonstrate that 1) the neural representation of one feature (the position of a central 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 task-irrelevant variation in those background features, and 3) many features of the object and the background are orthogonally represented by V4 neural responses. Our observations are consistent with the hypothesis that orthogonal neural representations can support stable perception of objects and features despite the tremendous richness of natural visual scenes.
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Affiliation(s)
- Ramanujan Srinath
- equal contribution
- Department of Neurobiology and Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Amy M. Ni
- equal contribution
- Department of Neurobiology and Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Claire Marucci
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Marlene R. Cohen
- Department of Neurobiology and Neuroscience Institute, The University of Chicago, Chicago, IL 60637, USA
- equal contribution
| | - David H. Brainard
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
- equal contribution
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Xue C, Markman SK, Chen R, Kramer LE, Cohen MR. Task interference as a neuronal basis for the cost of cognitive flexibility. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.04.583375. [PMID: 38496626 PMCID: PMC10942291 DOI: 10.1101/2024.03.04.583375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Humans and animals have an impressive ability to juggle multiple tasks in a constantly changing environment. This flexibility, however, leads to decreased performance under uncertain task conditions. Here, we combined monkey electrophysiology, human psychophysics, and artificial neural network modeling to investigate the neuronal mechanisms of this performance cost. We developed a behavioural paradigm to measure and influence participants' decision-making and perception in two distinct perceptual tasks. Our data revealed that both humans and monkeys, unlike an artificial neural network trained for the same tasks, make less accurate perceptual decisions when the task is uncertain. We generated a mechanistic hypothesis by comparing this neural network trained to produce correct choices with another network trained to replicate the participants' choices. We hypothesized, and confirmed with further behavioural, physiological, and causal experiments, that the cost of task flexibility comes from what we term task interference. Under uncertain conditions, interference between different tasks causes errors because it results in a stronger representation of irrelevant task features and entangled neuronal representations of different features. Our results suggest a tantalizing, general hypothesis: that cognitive capacity limitations, both in health and disease, stem from interference between neural representations of different stimuli, tasks, or memories.
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Affiliation(s)
- Cheng Xue
- Department of Neurobiology, University of Chicago, IL, USA
| | - Sol K Markman
- Department of Neurobiology, University of Chicago, IL, USA
- Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, MA, USA
| | - Ruoyi Chen
- Department of Biological Sciences, Carnegie Mellon University, PA, USA
| | - Lily E Kramer
- Department of Neurobiology, University of Chicago, IL, USA
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Verhein JR, Vyas S, Shenoy KV. Methylphenidate modulates motor cortical dynamics and behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.15.562405. [PMID: 37905157 PMCID: PMC10614820 DOI: 10.1101/2023.10.15.562405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Methylphenidate (MPH, brand: Ritalin) is a common stimulant used both medically and non-medically. Though typically prescribed for its cognitive effects, MPH also affects movement. While it is known that MPH noncompetitively blocks the reuptake of catecholamines through inhibition of dopamine and norepinephrine transporters, a critical step in exploring how it affects behavior is to understand how MPH directly affects neural activity. This would establish an electrophysiological mechanism of action for MPH. Since we now have biologically-grounded network-level hypotheses regarding how populations of motor cortical neurons plan and execute movements, there is a unique opportunity to make testable predictions regarding how systemic MPH administration - a pharmacological perturbation - might affect neural activity in motor cortex. To that end, we administered clinically-relevant doses of MPH to Rhesus monkeys as they performed an instructed-delay reaching task. Concomitantly, we measured neural activity from dorsal premotor and primary motor cortex. Consistent with our predictions, we found dose-dependent and significant effects on reaction time, trial-by-trial variability, and movement speed. We confirmed our hypotheses that changes in reaction time and variability were accompanied by previously established population-level changes in motor cortical preparatory activity and the condition-independent signal that precedes movements. We expected changes in speed to be a result of changes in the amplitude of motor cortical dynamics and/or a translation of those dynamics in activity space. Instead, our data are consistent with a mechanism whereby the neuromodulatory effect of MPH is to increase the gain and/or the signal-to-noise of motor cortical dynamics during reaching. Continued work in this domain to better understand the brain-wide electrophysiological mechanism of action of MPH and other psychoactive drugs could facilitate more targeted treatments for a host of cognitive-motor disorders.
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Affiliation(s)
- Jessica R Verhein
- Medical Scientist Training Program, Stanford School of Medicine, Stanford University, Stanford, CA
- Neurosciences Graduate Program, Stanford School of Medicine, Stanford University, Stanford, CA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA
- Current affiliations: Psychiatry Research Residency Training Program, University of California, San Francisco, San Francisco, CA
| | - Saurabh Vyas
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA
- Department of Bioengineering, Stanford University, Stanford, CA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY
| | - Krishna V Shenoy
- Neurosciences Graduate Program, Stanford School of Medicine, Stanford University, Stanford, CA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA
- Department of Bioengineering, Stanford University, Stanford, CA
- Department of Electrical Engineering, Stanford University, Stanford, CA
- Howard Hughes Medical Institute at Stanford University, Stanford, CA
- Department of Neurobiology, Stanford University, Stanford, CA
- Bio-X Program, Stanford University, Stanford, CA
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Parlatini V, Radua J, Solanes Font A, Wichers R, Maltezos S, Sanefuji M, Dell'Acqua F, Catani M, Thiebaut de Schotten M, Murphy D. Poor response to methylphenidate is associated with a smaller dorsal attentive network in adult Attention-Deficit/Hyperactivity Disorder (ADHD). Transl Psychiatry 2023; 13:303. [PMID: 37777529 PMCID: PMC10542768 DOI: 10.1038/s41398-023-02598-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 09/18/2023] [Accepted: 09/18/2023] [Indexed: 10/02/2023] Open
Abstract
Stimulants, such as methylphenidate (MPH), are effective in treating attention-deficit/hyperactivity disorder (ADHD), but there is individual variability in response, especially in adults. To improve outcomes, we need to understand the factors associated with adult treatment response. This longitudinal study investigated whether pre-treatment anatomy of the fronto-striatal and fronto-parietal attentional networks was associated with MPH treatment response. 60 adults with ADHD underwent diffusion brain imaging before starting MPH treatment, and response was measured at two months. We tested the association between brain anatomy and treatment response by using regression-based approaches; and compared the identified anatomical characteristics with those of 20 matched neurotypical controls in secondary analyses. Finally, we explored whether combining anatomical with clinical and neuropsychological data through machine learning provided a more comprehensive profile of factors associated with treatment response. At a group level, a smaller left dorsal superior longitudinal fasciculus (SLF I), a tract responsible for the voluntary control of attention, was associated with a significantly lower probability of being responders to two-month MPH-treatment. The association between the volume of the left SLF I and treatment response was driven by improvement on both inattentive and hyperactive/impulsive symptoms. Only non-responders significantly differed from controls in this tract metric. Finally, our machine learning approach identified clinico-neuropsychological factors associated with treatment response, such as higher cognitive performance and symptom severity at baseline. These novel findings add to our understanding of the pathophysiological mechanisms underlying response to MPH, pointing to the dorsal attentive network as playing a key role.
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Affiliation(s)
- Valeria Parlatini
- Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 8AF, London, UK.
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 8AF, London, UK.
| | - Joaquim Radua
- Institut d'Investigacions Biomediques August Pi i Sunyer, CIBERSAM, Instituto de Salud Carlos III, University of Barcelona, Barcelona, Spain
| | - Aleix Solanes Font
- Institut d'Investigacions Biomediques August Pi i Sunyer, CIBERSAM, Instituto de Salud Carlos III, University of Barcelona, Barcelona, Spain
| | - Rob Wichers
- Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 8AF, London, UK
| | - Stefanos Maltezos
- Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 8AF, London, UK
| | - Masafumi Sanefuji
- Research Centre for Environment and Developmental Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Flavio Dell'Acqua
- Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 8AF, London, UK
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 8AF, London, UK
- Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King's College London, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 8AF, London, UK
| | - Marco Catani
- Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 8AF, London, UK
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 8AF, London, UK
| | - Michel Thiebaut de Schotten
- Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 8AF, London, UK
- Brain Connectivity and Behaviour Group, Sorbonne Universities, Paris, France
- Groupe d'Imagerie Neurofonctionnelle, Institut des Maladies Neurodégénératives-UMR 5293, CNRS, CEA University of Bordeaux, Bordeaux, France
| | - Declan Murphy
- Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 8AF, London, UK
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Mozumder R, Constantinidis C. Single-neuron and population measures of neuronal activity in working memory tasks. J Neurophysiol 2023; 130:694-705. [PMID: 37609703 PMCID: PMC10649843 DOI: 10.1152/jn.00245.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/17/2023] [Accepted: 08/17/2023] [Indexed: 08/24/2023] Open
Abstract
Information represented in working memory is reflected in the firing rate of neurons in the prefrontal cortex and brain areas connected to it. In recent years, there has been an increased realization that population measures capture more accurately neural correlates of cognitive functions. We examined how single neuron firing in the prefrontal and posterior parietal cortex of two male monkeys compared with population measures in spatial working memory tasks. Persistent activity was observed in the dorsolateral prefrontal and posterior parietal cortex and firing rate predicted working memory behavior, particularly in the prefrontal cortex. These findings had equivalents in population measures, including trajectories in state space that became less separated in error trials. We additionally observed rotations of stimulus representations in the neuronal state space for different task conditions, which were not obvious in firing rate measures. These results suggest that population measures provide a richer view of how neuronal activity is associated with behavior, largely confirming that persistent activity is the core phenomenon that maintains visual-spatial information in working memory.NEW & NOTEWORTHY Recordings from large numbers of neurons led to a reevaluation of neural correlates of cognitive functions, which traditionally were defined based on responses of single neurons or averages of firing rates. Analysis of neuronal recordings from the dorsolateral prefrontal and posterior parietal cortex revealed that properties of neuronal firing captured in classical studies of persistent activity can account for population representations, though some population characteristics did not have clear correlates in single neuron activity.
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Affiliation(s)
- Rana Mozumder
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States
| | - Christos Constantinidis
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States
- Program in Neuroscience, Vanderbilt University, Nashville, Tennessee, United States
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States
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Heller CR, David SV. Targeted dimensionality reduction enables reliable estimation of neural population coding accuracy from trial-limited data. PLoS One 2022; 17:e0271136. [PMID: 35862300 PMCID: PMC9302847 DOI: 10.1371/journal.pone.0271136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 06/23/2022] [Indexed: 11/30/2022] Open
Abstract
Rapidly developing technology for large scale neural recordings has allowed researchers to measure the activity of hundreds to thousands of neurons at single cell resolution in vivo. Neural decoding analyses are a widely used tool used for investigating what information is represented in this complex, high-dimensional neural population activity. Most population decoding methods assume that correlated activity between neurons has been estimated accurately. In practice, this requires large amounts of data, both across observations and across neurons. Unfortunately, most experiments are fundamentally constrained by practical variables that limit the number of times the neural population can be observed under a single stimulus and/or behavior condition. Therefore, new analytical tools are required to study neural population coding while taking into account these limitations. Here, we present a simple and interpretable method for dimensionality reduction that allows neural decoding metrics to be calculated reliably, even when experimental trial numbers are limited. We illustrate the method using simulations and compare its performance to standard approaches for dimensionality reduction and decoding by applying it to single-unit electrophysiological data collected from auditory cortex.
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Affiliation(s)
- Charles R. Heller
- Neuroscience Graduate Program, Oregon Health and Science University, Portland, Oregon, United States of America
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Stephen V. David
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
- * E-mail:
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Hacker CM, Rust NC. Ritalin as a causal perturbation. Trends Cogn Sci 2022; 26:542-543. [DOI: 10.1016/j.tics.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 04/15/2022] [Indexed: 10/18/2022]
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