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Rhim I, Nauhaus I. Joint representations of color and form in mouse visual cortex described by random pooling from rods and cones. J Neurophysiol 2023; 129:619-634. [PMID: 36696968 PMCID: PMC9988525 DOI: 10.1152/jn.00138.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 12/30/2022] [Accepted: 01/18/2023] [Indexed: 01/27/2023] Open
Abstract
Spatial transitions in color can aid any visual perception task, and its neural representation, the "integration of color and form," is thought to begin at primary visual cortex (V1). Integration of color and form is untested in mouse V1, yet studies show that the ventral retina provides the necessary substrate from green-sensitive rods and ultraviolet-sensitive cones. Here, we used two-photon imaging in V1 to measure spatial frequency (SF) tuning along four axes of rod and cone contrast space, including luminance and color. We first reveal that V1's sensitivity to color is similar to luminance, yet average SF tuning is significantly shifted lowpass for color. Next, guided by linear models, we used SF tuning along all four color axes to estimate the proportion of neurons that fall into classic models of color opponency, i.e., "single-," "double-," and "non-opponent." Few neurons (∼6%) fit the criteria for double opponency, which are uniquely tuned for chromatic borders. Most of the population can be described as a unimodal distribution ranging from strongly single-opponent to non-opponent. Consistent with recent studies of the rodent and primate retina, our V1 data are well-described by a simple model in which ON and OFF channels to V1 sample the photoreceptor mosaic randomly. Finally, an analysis comparing color opponency to preferred orientation and retinotopy further validates rods, and not cone M-opsin, as opponent with cone S-opsin in the upper visual field.NEW & NOTEWORTHY This study is the first to show that mouse V1 is highly sensitive to UV-green color contrast. Furthermore, it provides a detailed characterization of "color opponency," which is the putative neural basis for color perception. Finally, using an extremely simple yet novel random wiring model, we account for our observations.
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Affiliation(s)
- Issac Rhim
- Department of Psychology, The University of Texas at Austin, Austin, Texas, United States
- Center for Perceptual Systems, The University of Texas at Austin, Austin, Texas, United States
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States
| | - Ian Nauhaus
- Department of Psychology, The University of Texas at Austin, Austin, Texas, United States
- Department of Neuroscience, The University of Texas at Austin, Austin, Texas, United States
- Center for Perceptual Systems, The University of Texas at Austin, Austin, Texas, United States
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Hussin AT, Abbaspoor S, Hoffman KL. Retrosplenial and Hippocampal Synchrony during Retrieval of Old Memories in Macaques. J Neurosci 2022; 42:7947-7956. [PMID: 36261267 PMCID: PMC9617609 DOI: 10.1523/jneurosci.0001-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 06/05/2022] [Accepted: 07/11/2022] [Indexed: 11/21/2022] Open
Abstract
Memory for events from the distant past relies on multiple brain regions, but little is known about the underlying neural dynamics that give rise to such abilities. We recorded neural activity in the hippocampus and retrosplenial cortex of two female rhesus macaques as they visually selected targets in year-old and newly acquired object-scene associations. Whereas hippocampal activity was unchanging with memory age, the retrosplenial cortex responded with greater magnitude alpha oscillations (10-15 Hz) and greater phase locking to memory-guided eye movements during retrieval of old events. A similar old-memory enhancement was observed in the anterior cingulate cortex but in a beta2/gamma band (28-35 Hz). In contrast, remote retrieval was associated with decreased gamma-band synchrony between the hippocampus and each neocortical area. The increasing retrosplenial alpha oscillation and decreasing hippocampocortical synchrony with memory age may signify a shift in frank memory allocation or, alternatively, changes in selection among distributed memory representations in the primate brain.SIGNIFICANCE STATEMENT Memory depends on multiple brain regions, whose involvement is thought to change with time. Here, we recorded neuronal population activity from the hippocampus and retrosplenial cortex as nonhuman primates searched for objects embedded in scenes. These memoranda were either newly presented or a year old. Remembering old material drove stronger oscillations in the retrosplenial cortex and led to a greater locking of neural activity to search movements. Remembering new material revealed stronger oscillatory synchrony between the hippocampus and retrosplenial cortex. These results suggest that with age, memories may come to rely more exclusively on neocortical oscillations for retrieval and search guidance and less on long-range coupling with the hippocampus.
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Affiliation(s)
- Ahmed T Hussin
- Department of Biology, Centre for Vision Research, York University, Toronto Ontario M3J 1P3, Canada
| | | | - Kari L Hoffman
- Department of Biology, Centre for Vision Research, York University, Toronto Ontario M3J 1P3, Canada
- Departments of Psychology
- Biomedical Engineering, Vanderbilt Vision Research Center, Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37240
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Suri H, Rothschild G. Enhanced stability of complex sound representations relative to simple sounds in the auditory cortex. eNeuro 2022; 9:ENEURO.0031-22.2022. [PMID: 35868858 PMCID: PMC9347310 DOI: 10.1523/eneuro.0031-22.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 06/29/2022] [Accepted: 06/30/2022] [Indexed: 11/29/2022] Open
Abstract
Typical everyday sounds, such as those of speech or running water, are spectrotemporally complex. The ability to recognize complex sounds (CxS) and their associated meaning is presumed to rely on their stable neural representations across time. The auditory cortex is critical for processing of CxS, yet little is known of the degree of stability of auditory cortical representations of CxS across days. Previous studies have shown that the auditory cortex represents CxS identity with a substantial degree of invariance to basic sound attributes such as frequency. We therefore hypothesized that auditory cortical representations of CxS are more stable across days than those of sounds that lack spectrotemporal structure such as pure tones (PTs). To test this hypothesis, we recorded responses of identified L2/3 auditory cortical excitatory neurons to both PTs and CxS across days using two-photon calcium imaging in awake mice. Auditory cortical neurons showed significant daily changes of responses to both types of sounds, yet responses to CxS exhibited significantly lower rates of daily change than those of PTs. Furthermore, daily changes in response profiles to PTs tended to be more stimulus-specific, reflecting changes in sound selectivity, as compared to changes of CxS responses. Lastly, the enhanced stability of responses to CxS was evident across longer time intervals as well. Together, these results suggest that spectrotemporally CxS are more stably represented in the auditory cortex across time than PTs. These findings support a role of the auditory cortex in representing CxS identity across time.Significance statementThe ability to recognize everyday complex sounds such as those of speech or running water is presumed to rely on their stable neural representations. Yet, little is known of the degree of stability of single-neuron sound responses across days. As the auditory cortex is critical for complex sound perception, we hypothesized that the auditory cortical representations of complex sounds are relatively stable across days. To test this, we recorded sound responses of identified auditory cortical neurons across days in awake mice. We found that auditory cortical responses to complex sounds are significantly more stable across days as compared to those of simple pure tones. These findings support a role of the auditory cortex in representing complex sound identity across time.
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Affiliation(s)
- Harini Suri
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Gideon Rothschild
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, MI 48109, USA
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Corbo J, McClure JP, Erkat OB, Polack PO. Dynamic Distortion of Orientation Representation after Learning in the Mouse Primary Visual Cortex. J Neurosci 2022; 42:4311-4325. [PMID: 35477902 PMCID: PMC9145234 DOI: 10.1523/jneurosci.2272-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/24/2022] [Accepted: 02/13/2022] [Indexed: 11/21/2022] Open
Abstract
Learning is an essential cognitive mechanism allowing behavioral adaptation through adjustments in neuronal processing. It is associated with changes in the activity of sensory cortical neurons evoked by task-relevant stimuli. However, the exact nature of those modifications and the computational advantages they may confer are still debated. Here, we investigated how learning an orientation discrimination task alters the neuronal representations of the cues orientations in the primary visual cortex (V1) of male and female mice. When comparing the activity evoked by the task stimuli in naive mice and the mice performing the task, we found that the representations of the orientation of the rewarded and nonrewarded cues were more accurate and stable in trained mice. This better cue representation in trained mice was associated with a distortion of the orientation representation space such that stimuli flanking the task-relevant orientations were represented as the task stimuli themselves, suggesting that those stimuli were generalized as the task cues. This distortion was context dependent as it was absent in trained mice passively viewing the task cues and enhanced in the behavioral sessions where mice performed best. Those modifications of the V1 population orientation representation in performing mice were supported by a suppression of the activity of neurons tuned for orientations neighboring the orientations of the task cues. Thus, visual processing in V1 is dynamically adapted to enhance the reliability of the representation of the learned cues and favor generalization in the task-relevant computational space.SIGNIFICANCE STATEMENT Performance improvement in a task often requires facilitating the extraction of the information necessary to its execution. Here, we demonstrate the existence of a suppression mechanism that improves the representation of the orientations of the task stimuli in the V1 of mice performing an orientation discrimination task. We also show that this mechanism distorts the V1 orientation representation space, leading stimuli flanking the task stimuli orientations to be generalized as the task stimuli themselves.
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Affiliation(s)
- Julien Corbo
- Center for Molecular and Behavioral Neuroscience, Rutgers University-Newark, Newark, New Jersey 07102
| | - John P McClure
- Center for Molecular and Behavioral Neuroscience, Rutgers University-Newark, Newark, New Jersey 07102
- Behavioral and Neural Sciences Graduate Program, Rutgers University-Newark, Newark, New Jersey 07102
| | - O Batuhan Erkat
- Center for Molecular and Behavioral Neuroscience, Rutgers University-Newark, Newark, New Jersey 07102
- Behavioral and Neural Sciences Graduate Program, Rutgers University-Newark, Newark, New Jersey 07102
| | - Pierre-Olivier Polack
- Center for Molecular and Behavioral Neuroscience, Rutgers University-Newark, Newark, New Jersey 07102
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McFadyen JR, Heider B, Karkhanis AN, Cloherty SL, Muñoz F, Siegel RM, Morris AP. Robust Coding of Eye Position in Posterior Parietal Cortex despite Context-Dependent Tuning. J Neurosci 2022; 42:4116-4130. [PMID: 35410881 PMCID: PMC9121829 DOI: 10.1523/jneurosci.0674-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 03/30/2022] [Accepted: 03/30/2022] [Indexed: 11/21/2022] Open
Abstract
Neurons in posterior parietal cortex (PPC) encode many aspects of the sensory world (e.g., scene structure), the posture of the body, and plans for action. For a downstream computation, however, only some of these dimensions are relevant; the rest are "nuisance variables" because their influence on neural activity changes with sensory and behavioral context, potentially corrupting the read-out of relevant information. Here we show that a key postural variable for vision (eye position) is represented robustly in male macaque PPC across a range of contexts, although the tuning of single neurons depended strongly on context. Contexts were defined by different stages of a visually guided reaching task, including (1) a visually sparse epoch, (2) a visually rich epoch, (3) a "go" epoch in which the reach was cued, and (4) during the reach itself. Eye position was constant within trials but varied across trials in a 3 × 3 grid spanning 24° × 24°. Using demixed principal component analysis of neural spike-counts, we found that the subspace of the population response encoding eye position is orthogonal to that encoding task context. Accordingly, a context-naive (fixed-parameter) decoder was nevertheless able to estimate eye position reliably across contexts. Errors were small given the sample size (∼1.78°) and would likely be even smaller with larger populations. Moreover, they were comparable to that of decoders that were optimized for each context. Our results suggest that population codes in PPC shield encoded signals from crosstalk to support robust sensorimotor transformations across contexts.SIGNIFICANCE STATEMENT Neurons in posterior parietal cortex (PPC) which are sensitive to gaze direction are thought to play a key role in spatial perception and behavior (e.g., reaching, navigation), and provide a potential substrate for brain-controlled prosthetics. Many, however, change their tuning under different sensory and behavioral contexts, raising the prospect that they provide unreliable representations of egocentric space. Here, we analyze the structure of encoding dimensions for gaze direction and context in PPC during different stages of a visually guided reaching task. We use demixed dimensionality reduction and decoding techniques to show that the coding of gaze direction in PPC is mostly invariant to context. This suggests that PPC can provide reliable spatial information across sensory and behavioral contexts.
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Affiliation(s)
- Jamie R McFadyen
- Neuroscience Program, Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, VIC, 3800, Australia
| | - Barbara Heider
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, 07102
| | - Anushree N Karkhanis
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, 07102
| | - Shaun L Cloherty
- School of Engineering, RMIT University, Melbourne, VIC, 3001, Australia
| | - Fabian Muñoz
- Department of Neuroscience, Columbia University, New York, NY, 10027
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027
| | - Ralph M Siegel
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, 07102
| | - Adam P Morris
- Neuroscience Program, Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, VIC, 3800, Australia
- Monash Data Futures Institute, Monash University, Clayton, VIC, 3800, Australia
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