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Learning Enhances Sensory Processing in Mouse V1 before Improving Behavior. J Neurosci 2017; 37:6460-6474. [PMID: 28559381 DOI: 10.1523/jneurosci.3485-16.2017] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 04/28/2017] [Accepted: 05/20/2017] [Indexed: 01/03/2023] Open
Abstract
A fundamental property of visual cortex is to enhance the representation of those stimuli that are relevant for behavior, but it remains poorly understood how such enhanced representations arise during learning. Using classical conditioning in adult mice of either sex, we show that orientation discrimination is learned in a sequence of distinct behavioral stages, in which animals first rely on stimulus appearance before exploiting its orientation to guide behavior. After confirming that orientation discrimination under classical conditioning requires primary visual cortex (V1), we measured, during learning, response properties of V1 neurons. Learning improved neural discriminability, sharpened orientation tuning, and led to higher contrast sensitivity. Remarkably, these learning-related improvements in the V1 representation were fully expressed before successful orientation discrimination was evident in the animals' behavior. We propose that V1 plays a key role early in discrimination learning to enhance behaviorally relevant sensory information.SIGNIFICANCE STATEMENT Decades of research have documented that responses of neurons in visual cortex can reflect the behavioral relevance of visual information. The behavioral relevance of any stimulus needs to be learned, though, and little is known how visual sensory processing changes, as the significance of a stimulus becomes clear. Here, we trained mice to discriminate two visual stimuli, precisely quantified when learning happened, and measured, during learning, the neural representation of these stimuli in V1. We observed learning-related improvements in V1 processing, which were fully expressed before discrimination was evident in the animals' behavior. These findings indicate that sensory and behavioral improvements can follow different time courses and point toward a key role of V1 at early stages in discrimination learning.
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102
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Familiarity Detection is an Intrinsic Property of Cortical Microcircuits with Bidirectional Synaptic Plasticity. eNeuro 2017; 4:eN-NWR-0361-16. [PMID: 28534043 PMCID: PMC5439184 DOI: 10.1523/eneuro.0361-16.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 04/26/2017] [Accepted: 04/27/2017] [Indexed: 11/21/2022] Open
Abstract
Humans instantly recognize a previously seen face as “familiar.” To deepen our understanding of familiarity-novelty detection, we simulated biologically plausible neural network models of generic cortical microcircuits consisting of spiking neurons with random recurrent synaptic connections. NMDA receptor (NMDAR)-dependent synaptic plasticity was implemented to allow for unsupervised learning and bidirectional modifications. Network spiking activity evoked by sensory inputs consisting of face images altered synaptic efficacy, which resulted in the network responding more strongly to a previously seen face than a novel face. Network size determined how many faces could be accurately recognized as familiar. When the simulated model became sufficiently complex in structure, multiple familiarity traces could be retained in the same network by forming partially-overlapping subnetworks that differ slightly from each other, thereby resulting in a high storage capacity. Fisher’s discriminant analysis was applied to identify critical neurons whose spiking activity predicted familiar input patterns. Intriguingly, as sensory exposure was prolonged, the selected critical neurons tended to appear at deeper layers of the network model, suggesting recruitment of additional circuits in the network for incremental information storage. We conclude that generic cortical microcircuits with bidirectional synaptic plasticity have an intrinsic ability to detect familiar inputs. This ability does not require a specialized wiring diagram or supervision and can therefore be expected to emerge naturally in developing cortical circuits.
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103
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Pernia M, Estevez S, Poveda C, Plaza I, Carro J, Juiz JM, Merchan MA. c-Fos and Arc/Arg3.1 expression in auditory and visual cortices after hearing loss: Evidence of sensory crossmodal reorganization in adult rats. J Comp Neurol 2017; 525:2677-2689. [PMID: 28472857 DOI: 10.1002/cne.24233] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 04/03/2017] [Accepted: 04/22/2017] [Indexed: 02/03/2023]
Abstract
Cross-modal reorganization in the auditory and visual cortices has been reported after hearing and visual deficits mostly during the developmental period, possibly underlying sensory compensation mechanisms. However, there are very few data on the existence or nature and timeline of such reorganization events during sensory deficits in adulthood. In this study, we assessed long-term changes in activity-dependent immediate early genes c-Fos and Arc/Arg3.1 in auditory and neighboring visual cortical areas after bilateral deafness in young adult rats. Specifically, we analyzed qualitatively and quantitatively c-Fos and Arc/Arg3.1 immunoreactivity at 15 and 90 days after cochlea removal. We report extensive, global loss of c-Fos and Arc/Arg3.1 immunoreactive neurons in the auditory cortex 15 days after permanent auditory deprivation in adult rats, which is partly reversed 90 days after deafness. Simultaneously, the number and labeling intensity of c-Fos- and Arc/Arg3.1-immunoreactive neurons progressively increase in neighboring visual cortical areas from 2 weeks after deafness and these changes stabilize three months after inducing the cochlear lesion. These findings support plastic, compensatory, long-term changes in activity in the auditory and visual cortices after auditory deprivation in the adult rats. Further studies may clarify whether those changes result in perceptual potentiation of visual drives on auditory regions of the adult cortex.
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Affiliation(s)
- M Pernia
- Laboratory of Neurobiology of Hearing, Institute of Neurosciences of Castilla y León (Instituto de Neurociencias de Castilla y León - INCYL), University of Salamanca (Universidad de Salamanca - US), Salamanca, Spain
| | - S Estevez
- Laboratory of Neurobiology of Hearing, Institute of Neurosciences of Castilla y León (Instituto de Neurociencias de Castilla y León - INCYL), University of Salamanca (Universidad de Salamanca - US), Salamanca, Spain
| | - C Poveda
- School of Medicine of Albacete, Institute for Research in Neurological Disabilities (Instituto de Investigación en Discapacidades Neurológicas - IDINE), University of Castilla-La Mancha (Universidad de Castilla La Mancha - UCLM), Albacete, Spain
| | - I Plaza
- Laboratory of Neurobiology of Hearing, Institute of Neurosciences of Castilla y León (Instituto de Neurociencias de Castilla y León - INCYL), University of Salamanca (Universidad de Salamanca - US), Salamanca, Spain
| | - J Carro
- Laboratory of Neurobiology of Hearing, Institute of Neurosciences of Castilla y León (Instituto de Neurociencias de Castilla y León - INCYL), University of Salamanca (Universidad de Salamanca - US), Salamanca, Spain
| | - J M Juiz
- School of Medicine of Albacete, Institute for Research in Neurological Disabilities (Instituto de Investigación en Discapacidades Neurológicas - IDINE), University of Castilla-La Mancha (Universidad de Castilla La Mancha - UCLM), Albacete, Spain
| | - M A Merchan
- Laboratory of Neurobiology of Hearing, Institute of Neurosciences of Castilla y León (Instituto de Neurociencias de Castilla y León - INCYL), University of Salamanca (Universidad de Salamanca - US), Salamanca, Spain
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104
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Guo Y, Zhang W, Chen X, Fu J, Cheng W, Song D, Qu X, Yang Z, Zhao K. Timing-dependent LTP and LTD in mouse primary visual cortex following different visual deprivation models. PLoS One 2017; 12:e0176603. [PMID: 28520739 PMCID: PMC5435181 DOI: 10.1371/journal.pone.0176603] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 04/13/2017] [Indexed: 11/23/2022] Open
Abstract
Visual deprivation during the critical period induces long-lasting changes in cortical circuitry by adaptively modifying neuro-transmission and synaptic connectivity at synapses. Spike timing-dependent plasticity (STDP) is considered a strong candidate for experience-dependent changes. However, the visual deprivation forms that affect timing-dependent long-term potentiation(LTP) and long-term depression(LTD) remain unclear. Here, we demonstrated the temporal window changes of tLTP and tLTD, elicited by coincidental pre- and post-synaptic firing, following different modes of 6-day visual deprivation. Markedly broader temporal windows were found in robust tLTP and tLTD in the V1M of the deprived visual cortex in mice after 6-day MD and DE. The underlying mechanism for the changes seen with visual deprivation in juvenile mice using 6 days of dark exposure or monocular lid suture involves an increased fraction of NR2b-containing NMDAR and the consequent prolongation of NMDAR-mediated response duration. Moreover, a decrease in NR2A protein expression at the synapse is attributable to the reduction of the NR2A/2B ratio in the deprived cortex.
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Affiliation(s)
- Yatu Guo
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
- * E-mail: (YG); (KXZ)
| | - Wei Zhang
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
| | - Xia Chen
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
| | - Junhong Fu
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
- Department of Ophthalmology, The TEDA International Hospital, Tianjin, China
| | - Wenbo Cheng
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
- Department of Ophthalmology, The TEDA International Hospital, Tianjin, China
| | - Desheng Song
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
- Department of Ophthalmology, The TEDA International Hospital, Tianjin, China
| | - Xiaolei Qu
- Department of Ophthalmology, the Second People’s Hospital of Jinan, Shandong, China
| | - Zhuo Yang
- Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Science, Nankai University, Tianjin, China
- College of Medicine, Nankai University, Tianjin, China
| | - Kanxing Zhao
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
- * E-mail: (YG); (KXZ)
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105
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Raven F, Van der Zee EA, Meerlo P, Havekes R. The role of sleep in regulating structural plasticity and synaptic strength: Implications for memory and cognitive function. Sleep Med Rev 2017. [PMID: 28641933 DOI: 10.1016/j.smrv.2017.05.002] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Dendritic spines are the major sites of synaptic transmission in the central nervous system. Alterations in the strength of synaptic connections directly affect the neuronal communication, which is crucial for brain function as well as the processing and storage of information. Sleep and sleep loss bidirectionally alter structural plasticity, by affecting spine numbers and morphology, which ultimately can affect the functional output of the brain in terms of alertness, cognition, and mood. Experimental data from studies in rodents suggest that sleep deprivation may impact structural plasticity in different ways. One of the current views, referred to as the synaptic homeostasis hypothesis, suggests that wake promotes synaptic potentiation whereas sleep facilitates synaptic downscaling. On the other hand, several studies have now shown that sleep deprivation can reduce spine density and attenuate synaptic efficacy in the hippocampus. These data are the basis for the view that sleep promotes hippocampal structural plasticity critical for memory formation. Altogether, the impact of sleep and sleep loss may vary between regions of the brain. A better understanding of the role that sleep plays in regulating structural plasticity may ultimately lead to novel therapeutic approaches for brain disorders that are accompanied by sleep disturbances and sleep loss.
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Affiliation(s)
- Frank Raven
- Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Eddy A Van der Zee
- Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Peter Meerlo
- Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Robbert Havekes
- Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands.
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106
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Flashing Lights Induce Prolonged Distortions in Visual Cortical Responses and Visual Perception. eNeuro 2017; 4:eN-NWR-0304-16. [PMID: 28508035 PMCID: PMC5429040 DOI: 10.1523/eneuro.0304-16.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 04/24/2017] [Accepted: 04/28/2017] [Indexed: 01/01/2023] Open
Abstract
The primary sensory neocortex generates an internal representation of the environment, and its circuit reorganization is thought to lead to a modification of sensory perception. This reorganization occurs primarily through activity-dependent plasticity and has been well documented in animals during early developmental stages. Here, we describe a new method for the noninvasive induction of long-term plasticity in the mature brain: simple transient visual stimuli (i.e., flashing lights) can be used to induce prolonged modifications in visual cortical processing and visually driven behaviors. Our previous studies have shown that, in the primary visual cortex (V1) of mice, a flashing light stimulus evokes a long-delayed response that persists for seconds. When the mice were repetitively presented with drifting grating stimuli (conditioned stimuli) during the flash stimulus-evoked delayed response period, the V1 neurons exhibited a long-lasting decrease in responsiveness to the conditioned stimuli. The flash stimulus-induced underrepresentation of the grating motion was specific to the direction of the conditioned stimuli and was associated with a decrease in the animal's ability to detect the motion of the drifting gratings. The neurophysiological and behavioral plasticity both persisted for at least several hours and required N-methyl-d-aspartate receptor activation in the visual cortex. We propose that flashing light stimuli can be used as an experimental tool to investigate the visual function and plasticity of neuronal representations and perception after a critical period of neocortical plasticity.
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107
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Christie IK, Miller P, Van Hooser SD. Cortical amplification models of experience-dependent development of selective columns and response sparsification. J Neurophysiol 2017; 118:874-893. [PMID: 28515285 DOI: 10.1152/jn.00177.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 04/28/2017] [Accepted: 05/11/2017] [Indexed: 02/05/2023] Open
Abstract
The development of direction-selective cortical columns requires visual experience, but the neural circuits and plasticity mechanisms that are responsible for this developmental transition are unknown. To gain insight into the mechanisms that could underlie experience-dependent increases in selectivity, we explored families of cortical amplifier models that enhance weakly biased feedforward signals. Here we focused exclusively on possible contributions of cortico-cortical connections and took feedforward input to be constant. We modeled pairs of interconnected columns that received equal and oppositely biased inputs. In a single-element model of cortical columns, we found two ways that cortical columns could receive biased feedforward input and exhibit strong but unselective responses to stimuli: 1) within-column recurrent excitatory connections could be strong enough to amplify both strong and weak feedforward input, or 2) columns that received differently biased inputs could have strong excitatory cross-connections that destroy selectivity. A Hebbian plasticity rule combined with simulated experience with stimuli weakened these strong cross-connections across cortical columns, allowing the individual columns to respond selectively to their biased inputs. In a model that included both excitatory and inhibitory neurons in each column, an additional means of obtaining selectivity through the cortical circuit was uncovered: cross-column suppression of inhibition-stabilized networks. When each column operated as an inhibition-stabilized network, cross-column excitation onto inhibitory neurons forced competition between the columns but in a manner that did not involve strong null-direction inhibition, consistent with experimental measurements of direction selectivity in visual cortex. Experimental predictions of these possible contributions of cortical circuits are discussed.NEW & NOTEWORTHY Sensory circuits are initially constructed via mechanisms that are independent of sensory experience, but later refinement requires experience. We constructed models of how circuits that receive biased feedforward inputs can be initially unselective and then be modified by experience and plasticity so that the resulting circuit exhibits increased selectivity. We propose that neighboring cortical columns may initially exhibit coupling that is too strong for selectivity. Experience-dependent mechanisms decrease this coupling so individual columns can exhibit selectivity.
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Affiliation(s)
- Ian K Christie
- Department of Biology, Brandeis University, Waltham, Massachusetts.,Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts; and
| | - Paul Miller
- Department of Biology, Brandeis University, Waltham, Massachusetts.,Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts; and.,Sloan-Swartz Center for Theoretical Neurobiology, Brandeis University, Waltham, Massachusetts
| | - Stephen D Van Hooser
- Department of Biology, Brandeis University, Waltham, Massachusetts; .,Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts; and.,Sloan-Swartz Center for Theoretical Neurobiology, Brandeis University, Waltham, Massachusetts
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108
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Locomotion Induces Stimulus-Specific Response Enhancement in Adult Visual Cortex. J Neurosci 2017; 37:3532-3543. [PMID: 28258167 DOI: 10.1523/jneurosci.3760-16.2017] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/20/2017] [Accepted: 02/18/2017] [Indexed: 11/21/2022] Open
Abstract
The responses of neurons in the visual cortex (V1) of adult mammals have long been thought to be stable over long periods. Here, we investigated whether repeated exposure to specific stimuli would enhance V1 visual responses in mice using intrinsic signal imaging through the intact skull and two-photon imaging of calcium signals in single neurons. Mice ran on Styrofoam balls floating on air while viewing one of three different, high-contrast visual stimuli. V1 responses to the stimuli that were viewed by the animal were specifically enhanced, while responses to other stimuli were unaffected. Similar exposure in stationary mice or in mice in which NMDA receptors were partially blocked did not significantly enhance responses. These findings indicate that stimulus-specific plasticity in the adult visual cortex depends on concurrent locomotion, presumably as a result of the high-gain state of the visual cortex induced by locomotion.SIGNIFICANCE STATEMENT We report a rapid and persistent increase in visual cortical responses to visual stimuli presented during locomotion in intact mice. We first used a method that is completely noninvasive to image intrinsic signals through the intact skull. We then measured the same effects on single neurons using two-photon calcium imaging and found that the increase in response to a particular stimulus produced by locomotion depends on how well the neuron is initially driven by the stimulus. To our knowledge, this is the first time such enhancement has been described in single neurons or using noninvasive measurements.
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109
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Wijtenburg SA, West J, Korenic SA, Kuhney F, Gaston FE, Chen H, Roberts M, Kochunov P, Hong LE, Rowland LM. Glutamatergic metabolites are associated with visual plasticity in humans. Neurosci Lett 2017; 644:30-36. [PMID: 28189743 DOI: 10.1016/j.neulet.2017.02.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 02/01/2017] [Accepted: 02/07/2017] [Indexed: 10/20/2022]
Abstract
Long-term potentiation (LTP) is a basic cellular mechanism underlying learning and memory. LTP-like plasticity in the visual cortex can be induced by high frequency visual stimulation in rodents and humans. Since glutamate plays a fundamental role in LTP, this study investigated if visual cortical glutamate and glutamine levels, measured by proton magnetic resonance spectroscopy (MRS), relate to visual plasticity in humans. Since plasticity requires a delicate excitation and inhibition balance, GABA was also explored. Eighteen healthy participants completed MRS and a visual fMRI paradigm. Results revealed enhanced fMRI activations after high frequency visual stimulation, suggesting visual plasticity occurred. Higher activations were associated with higher resting glutamine levels after family wise error-correction. Exploratory analyses revealed that higher resting glutamate and GABA levels were associated with visual plasticity, suggesting there may be a critical excitation-inhibition balance necessary for experience dependent plasticity. This is the first empirical evidence that resting glutamine levels and potentially glutamate and GABA levels are associated with visual plasticity in humans.
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Affiliation(s)
- S Andrea Wijtenburg
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA.
| | - Jeffrey West
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Stephanie A Korenic
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Franchesca Kuhney
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Frank E Gaston
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Hongji Chen
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Meredith Roberts
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Peter Kochunov
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA; Department of Physics, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - L Elliot Hong
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA
| | - Laura M Rowland
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA; Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, 601 N. Caroline Street, Baltimore, MD 21287, USA; Department of Psychology, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
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110
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Zhao W, Yang W, Zheng S, Hu Q, Qiu P, Huang X, Hong X, Lan F. A new bioinformatic insight into the associated proteins in psychiatric disorders. SPRINGERPLUS 2016; 5:1967. [PMID: 27917343 PMCID: PMC5108746 DOI: 10.1186/s40064-016-3655-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 11/04/2016] [Indexed: 01/21/2023]
Abstract
BACKGROUND Psychiatric diseases severely affect the quality of patients' lives and bring huge economic pressure to their families. Also, the great phenotypic variability among these patients makes it difficult to investigate the pathogenesis. Nowadays, bioinformatics is hopeful to be used as an effective tool for the diagnosis of psychiatric disorders, which can identify sensitive biomarkers and explore associated signaling pathways. METHODS In this study, we performed an integrated bioinformatic analysis on 1945 mental-associated proteins including 91 secreted proteins and 593 membrane proteins, which were screened from the Universal Protein Resource (Uniport) database. Then the function and pathway enrichment analyses, ontological classification, and constructed PPI network were executed. RESULTS Our present study revealed that the majority of mental proteins were closely related to metabolic processes and cellular processes. We also identified some significant molecular biomarkers in the progression of mental disorders, such as HRAS, ALS2, SLC6A1, SLC39A12, SIL1, IDUA, NEPH2 and XPO1. Furthermore, it was found that hub proteins, such as COMT, POMC, NPS and BDNF, might be the potential targets for mental disorders therapy. Finally, we demonstrated that psychiatric disorders may share the same signaling pathways with cancers, involving ESR1, BCL2 and MAPK3. CONCLUSION Our data are expected to contribute to explaining the possible mechanisms of psychiatric diseases and providing a useful reference for the diagnosis and therapy of them.
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Affiliation(s)
- Wenlong Zhao
- Department of Neurology, Affiliated Dongfang Hospital of Xiamen University (Fuzhou General Hospital), Fuzhou, Fujian People's Republic of China
| | - Wenjing Yang
- Department of Neurology, Affiliated Dongfang Hospital of Xiamen University (Fuzhou General Hospital), Fuzhou, Fujian People's Republic of China
| | - Shuanglin Zheng
- Department of Neurology, Affiliated Dongfang Hospital of Xiamen University (Fuzhou General Hospital), Fuzhou, Fujian People's Republic of China
| | - Qiong Hu
- Department of Neurology, Affiliated Dongfang Hospital of Xiamen University (Fuzhou General Hospital), Fuzhou, Fujian People's Republic of China
| | - Ping Qiu
- Department of Neurology, Affiliated Dongfang Hospital of Xiamen University (Fuzhou General Hospital), Fuzhou, Fujian People's Republic of China
| | - Xinghua Huang
- Department of Clinical Genetics and Experimental Medicine, Fuzhou General Hospital, No. 156, Xier Huan Road, Gulou District, Fuzhou, 350025 Fujian People's Republic of China
| | - Xiaoqian Hong
- Department of Neurology, Affiliated Dongfang Hospital of Xiamen University (Fuzhou General Hospital), Fuzhou, Fujian People's Republic of China
| | - Fenghua Lan
- Department of Clinical Genetics and Experimental Medicine, Fuzhou General Hospital, No. 156, Xier Huan Road, Gulou District, Fuzhou, 350025 Fujian People's Republic of China
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111
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Dose-dependent effect of donepezil administration on long-term enhancement of visually evoked potentials and cholinergic receptor overexpression in rat visual cortex. ACTA ACUST UNITED AC 2016; 110:65-74. [PMID: 27913166 DOI: 10.1016/j.jphysparis.2016.11.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 11/04/2016] [Accepted: 11/25/2016] [Indexed: 12/14/2022]
Abstract
Stimulation of the cholinergic system tightly coupled with periods of visual stimulation boosts the processing of specific visual stimuli via muscarinic and nicotinic receptors in terms of intensity, priority and long-term effect. However, it is not known whether more diffuse pharmacological stimulation with donepezil, a cholinesterase inhibitor, is an efficient tool for enhancing visual processing and perception. The goal of the present study was to potentiate cholinergic transmission with donepezil treatment (0.5 and 1mg/kg) during a 2-week visual training to examine the effect on visually evoked potentials and to profile the expression of cholinergic receptor subtypes. The visual training was performed daily, 10min a day, for 2weeks. One week after the last training session, visual evoked potentials were recorded, or the mRNA expression level of muscarinic (M1-5) and nicotinic (α/β) receptors subunits was determined by quantitative RT-PCR. The visual stimulation coupled with any of the two doses of donepezil produced significant amplitude enhancement of cortical evoked potentials compared to pre-training values. The enhancement induced by the 1mg/kg dose of donepezil was spread to neighboring spatial frequencies, suggesting a better sensitivity near the visual detection threshold. The M3, M4, M5 and α7 receptors mRNA were upregulated in the visual cortex for the higher dose of donepezil but not the lower one, and the receptors expression was stable in the somatosensory (non-visual control) cortex. Therefore, higher levels of acetylcholine within the cortex sustain the increased intensity of the cortical response and trigger the upregulation of cholinergic receptors.
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112
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Rapid recovery from the effects of early monocular deprivation is enabled by temporary inactivation of the retinas. Proc Natl Acad Sci U S A 2016; 113:14139-14144. [PMID: 27856748 DOI: 10.1073/pnas.1613279113] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A half-century of research on the consequences of monocular deprivation (MD) in animals has revealed a great deal about the pathophysiology of amblyopia. MD initiates synaptic changes in the visual cortex that reduce acuity and binocular vision by causing neurons to lose responsiveness to the deprived eye. However, much less is known about how deprivation-induced synaptic modifications can be reversed to restore normal visual function. One theoretically motivated hypothesis is that a period of inactivity can reduce the threshold for synaptic potentiation such that subsequent visual experience promotes synaptic strengthening and increased responsiveness in the visual cortex. Here we have reduced this idea to practice in two species. In young mice, we show that the otherwise stable loss of cortical responsiveness caused by MD is reversed when binocular visual experience follows temporary anesthetic inactivation of the retinas. In 3-mo-old kittens, we show that a severe impairment of visual acuity is also fully reversed by binocular experience following treatment and, further, that prolonged retinal inactivation alone can erase anatomical consequences of MD. We conclude that temporary retinal inactivation represents a highly efficacious means to promote recovery of function.
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113
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Krueger JM, Frank MG, Wisor JP, Roy S. Sleep function: Toward elucidating an enigma. Sleep Med Rev 2016; 28:46-54. [PMID: 26447948 PMCID: PMC4769986 DOI: 10.1016/j.smrv.2015.08.005] [Citation(s) in RCA: 223] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 07/16/2015] [Accepted: 08/19/2015] [Indexed: 01/11/2023]
Abstract
Sleep function remains controversial. Individual perspectives frame the issue of sleep function differently. We briefly illustrate how sleep measurement and the evolution, tissue organization levels, molecular mechanisms, and regulation of sleep could influence one's view of sleep function. Then we discuss six viable theories of sleep function. Sleep serves host-defense mechanisms and conserves caloric expenditures, but these functions likely are opportunistic functions evolving later in evolution. That sleep replenishes brain energy stores and that sleep serves a glymphatic function by removing toxic byproducts of waking activity are attractive ideas, but lack extensive supporting experimental evidence. That sleep restores performance is experimentally demonstrated and has obvious evolutionary value. However, this hypothesis lacks experimentally verified mechanisms although ideas relating to this issue are presented. Finally, the ideas surrounding the broad hypothesis that sleep serves a connectivity/plasticity function are many and attractive. There is experimental evidence that connectivity changes with sleep, sleep loss, and with changing afferent input, and that those changes are linked to sleep regulatory mechanisms. In our view, this is the leading contender for the primordial function of sleep. However, much refinement of ideas and innovative experimental approaches are needed to clarify the sleep-connectivity relationship.
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Affiliation(s)
- James M Krueger
- College of Medical Sciences, Washington State University-Spokane, WA, USA.
| | - Marcos G Frank
- College of Medical Sciences, Washington State University-Spokane, WA, USA
| | - Jonathan P Wisor
- College of Medical Sciences, Washington State University-Spokane, WA, USA
| | - Sandip Roy
- Department of Electrical Engineering, Washington State University-Pullman, WA, USA
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114
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Staubli U, Rangel-Diaz N, Alcantara M, Li YX, Yang JY, Zhang KM, Foster AC. Restoration of visual performance by d-serine in models of inner and outer retinal dysfunction assessed using sweep VEP measurements in the conscious rat and rabbit. Vision Res 2016; 127:35-48. [PMID: 27461280 DOI: 10.1016/j.visres.2016.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 07/12/2016] [Accepted: 07/12/2016] [Indexed: 10/21/2022]
Abstract
The NMDA subtype of glutamate receptor and its co-agonist d-serine play a key role in synaptic function in the central nervous system (CNS), including visual cortex and retina. In retinal diseases such as glaucoma and macular degeneration, a loss of vision arises from malfunction of retinal cells, resulting in a glutamate hypofunctional state along the visual pathway in the affected parts of the visual field. An effective strategy to remedy this loss of function might be to increase extracellular levels of d-serine and thereby boost synaptic NMDA receptor-mediated visual transmission and/or plasticity to compensate for the impairment. We tested this idea in brain slices of visual cortex exhibiting long-term potentiation, and in rodent models of visual dysfunction caused by retinal insults at a time when the injury had stabilized to look for neuroenhancement effects. An essential aspect of the in vivo studies involved adapting sweep VEP technology to conscious rats and rabbits and combining it with intracortical recording while the animals were actively attending to visual information. Using this technology allowed us to establish complete contrast sensitivity function curves. We found that systemic d-serine dose-dependently rescued the contrast sensitivity impairment in rats with blue light-induced visual dysfunction. In rabbits with inner retinal dysfunction, both systemic and intravitreal routes of d-serine provided a rescue of visual function. In sum, we show that co-agonist stimulation of the NMDA receptor via administration of exogenous d-serine might be an effective therapeutic strategy to enhance visual performance and compensate for the loss of vision resulting from retinal disease.
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Affiliation(s)
- Ursula Staubli
- Department of Biological Sciences, Allergan Inc., 2525 Dupont Drive, Irvine, CA 92612, USA
| | - Natalie Rangel-Diaz
- Department of Biological Sciences, Allergan Inc., 2525 Dupont Drive, Irvine, CA 92612, USA
| | - Miguel Alcantara
- Department of Biological Sciences, Allergan Inc., 2525 Dupont Drive, Irvine, CA 92612, USA
| | - Yong-Xin Li
- Department of Biological Sciences, Allergan Inc., 2525 Dupont Drive, Irvine, CA 92612, USA.
| | - Jia-Ying Yang
- Department of Biological Sciences, Allergan Inc., 2525 Dupont Drive, Irvine, CA 92612, USA
| | - Kai-Ming Zhang
- Department of Biological Sciences, Allergan Inc., 2525 Dupont Drive, Irvine, CA 92612, USA
| | - Alan C Foster
- Department of Biological Sciences, Allergan Inc., 2525 Dupont Drive, Irvine, CA 92612, USA
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115
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Exploring the Use of Sensorial LTP/LTD-Like Stimulation to Modulate Human Performance for Complex Visual Stimuli. PLoS One 2016; 11:e0158312. [PMID: 27341210 PMCID: PMC4920386 DOI: 10.1371/journal.pone.0158312] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 06/14/2016] [Indexed: 11/19/2022] Open
Abstract
Is it possible to passively induce visual learning/unlearning in humans for complex stimuli such as faces? We addressed this question in a series of behavioral studies using passive visual stimulation (flickering of faces at specific temporal frequencies) inspired by well-known synaptic mechanisms of learning: long-term potentiation (LTP) vs long-term depression (LTD). We administered a face identity change detection task before and after a passive stimulation protocol to test for potential changes in visual performance. First, with bilateral stimulation, subjects undergoing high-frequency LTP-like stimulation outperformed those submitted to low-frequency LTD-like stimulation despite equivalent baseline performance (exp. 1). Second, unilateral stimulation replicated the differential modulation of performance, but in a hemifield-specific way (exp. 2). Third, for both stimulation groups, a sudden temporary drop in performance on the stimulated side immediately after the stimulation, followed by progressive recovering, can suggest either 'visual fatigue' or 'face adaptation' effects due to the stimulation. Fourth, we tested the life-time of these modulatory effects, revealing they vanish after one hour delay (exp. 3). Fifth, a control study (exp. 4) using low-level visual stimuli also failed to show longer-term effects of sensory stimulation, despite reports of strong effects in the literature. Future studies should determine the necessary and sufficient conditions enabling robust long-term modulation of visual performance using this technique. This step is required to consider further use in fundamental research (e.g., to study neural circuits involved in selective visual processing) and potential educational or clinical applications (e.g., inhibiting socially-irrelevant aspects of face processing in autism).
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116
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Belagodu AP, Zendeli L, Slater BJ, Galvez R. Blocking elevated VEGF‐A attenuates non‐vasculature Fragile X syndrome abnormalities. Dev Neurobiol 2016; 77:14-25. [DOI: 10.1002/dneu.22404] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 03/15/2016] [Accepted: 05/31/2016] [Indexed: 01/19/2023]
Affiliation(s)
- Amogh P. Belagodu
- Neuroscience Program, University of Illinois at Urbana‐Champaign405 N Mathews AveUrbana Illinois61801
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana‐Champaign405 N Mathews AveUrbana Illinois61801
| | - Liridon Zendeli
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana‐Champaign405 N Mathews AveUrbana Illinois61801
| | - Bernard J. Slater
- Neuroscience Program, University of Illinois at Urbana‐Champaign405 N Mathews AveUrbana Illinois61801
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana‐Champaign405 N Mathews AveUrbana Illinois61801
| | - Roberto Galvez
- Neuroscience Program, University of Illinois at Urbana‐Champaign405 N Mathews AveUrbana Illinois61801
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana‐Champaign405 N Mathews AveUrbana Illinois61801
- Psychology DepartmentUniversity of Illinois at Urbana‐Champaign405 N Mathews AveUrbana Illinois61801
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117
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Tsokas P, Hsieh C, Yao Y, Lesburguères E, Wallace EJC, Tcherepanov A, Jothianandan D, Hartley BR, Pan L, Rivard B, Farese RV, Sajan MP, Bergold PJ, Hernández AI, Cottrell JE, Shouval HZ, Fenton AA, Sacktor TC. Compensation for PKMζ in long-term potentiation and spatial long-term memory in mutant mice. eLife 2016; 5. [PMID: 27187150 PMCID: PMC4869915 DOI: 10.7554/elife.14846] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/23/2016] [Indexed: 02/07/2023] Open
Abstract
PKMζ is a persistently active PKC isoform proposed to maintain late-LTP and long-term memory. But late-LTP and memory are maintained without PKMζ in PKMζ-null mice. Two hypotheses can account for these findings. First, PKMζ is unimportant for LTP or memory. Second, PKMζ is essential for late-LTP and long-term memory in wild-type mice, and PKMζ-null mice recruit compensatory mechanisms. We find that whereas PKMζ persistently increases in LTP maintenance in wild-type mice, PKCι/λ, a gene-product closely related to PKMζ, persistently increases in LTP maintenance in PKMζ-null mice. Using a pharmacogenetic approach, we find PKMζ-antisense in hippocampus blocks late-LTP and spatial long-term memory in wild-type mice, but not in PKMζ-null mice without the target mRNA. Conversely, a PKCι/λ-antagonist disrupts late-LTP and spatial memory in PKMζ-null mice but not in wild-type mice. Thus, whereas PKMζ is essential for wild-type LTP and long-term memory, persistent PKCι/λ activation compensates for PKMζ loss in PKMζ-null mice. DOI:http://dx.doi.org/10.7554/eLife.14846.001 How are long-term memories stored in the brain? The formation of memories is believed to depend on the strengthening of connections between neurons. During learning, neurons produce an enzyme called PKMzeta (or PKMζ), which is thought to be responsible for maintaining the newly strengthened connections. Inhibitors of PKMzeta, such as a drug called ZIP, disrupt long-term memories. This suggests that the brain may be like a computer hard disc in that its stored information — its memories — could be erased. However, recent experiments on genetically engineered mice have thrown the role of PKMzeta into question. Knockout mice that lack the gene for PKMzeta can still strengthen connections between neurons and can still learn and remember. Moreover, ZIP still works to reverse the strengthening and to erase long-term memories. This indicates that ZIP can act on something other than the PKMzeta enzyme. These results have led many neuroscientists to doubt that PKMzeta has anything to do with memory. Yet there are two possible explanations for the normal memory in PKMzeta knockout mice. First, PKMzeta is not required for memory, so getting rid of it has no effect. Second, PKMzeta is essential for long-term memory in normal mice. However, knockout mice recruit a back-up mechanism for long-term memory storage, which is also sensitive to the effects of ZIP. To test these possibilities, Tsokas et al. used a modified piece of DNA that prevents neurons with the gene for PKMzeta from producing the enzyme. The DNA blocked memory formation in normal mice, consistent with a role for PKMzeta in memory. However, it had no effect in knockout mice — the DNA had nothing to work on. This suggests that another molecule does indeed act as a back-up for PKMzeta in these animals. Further experiments revealed that an enzyme closely related to PKMzeta, called PKCiota/lambda (PKCι/λ), substitutes for PKMzeta during memory storage in the knockout mice. These findings restore PKMzeta to its early promise. They show that PKMzeta is crucial for long-term memory in normal mice, but that something as important as memory storage has a back-up mechanism should PKMzeta fail. Future work may reveal when and how this back-up becomes engaged. DOI:http://dx.doi.org/10.7554/eLife.14846.002
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Affiliation(s)
- Panayiotis Tsokas
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States.,Department of Anesthesiology, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Changchi Hsieh
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Yudong Yao
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | | | - Emma Jane Claire Wallace
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Andrew Tcherepanov
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Desingarao Jothianandan
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Benjamin Rush Hartley
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Ling Pan
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Bruno Rivard
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Robert V Farese
- Department of Internal Medicine, James A Haley Veterans Hospital, University of South Florida, Tampa, United States
| | - Mini P Sajan
- Department of Internal Medicine, James A Haley Veterans Hospital, University of South Florida, Tampa, United States
| | - Peter John Bergold
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Alejandro Iván Hernández
- Department of Pathology, State University of New York Downstate Medical Center, Brooklyn, United States
| | - James E Cottrell
- Department of Anesthesiology, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Harel Z Shouval
- Department of Neurobiology and Anatomy, University of Texas Medical School at Houston, Houston, United States
| | - André Antonio Fenton
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States.,Center for Neural Science, New York University, New York, United States
| | - Todd Charlton Sacktor
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States.,Department of Anesthesiology, State University of New York Downstate Medical Center, Brooklyn, United States.,Department of Neurology, State University of New York Downstate Medical Center, Brooklyn, United States
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118
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Form and Function of Sleep Spindles across the Lifespan. Neural Plast 2016; 2016:6936381. [PMID: 27190654 PMCID: PMC4848449 DOI: 10.1155/2016/6936381] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 03/16/2016] [Indexed: 01/11/2023] Open
Abstract
Since the advent of EEG recordings, sleep spindles have been identified as hallmarks of non-REM sleep. Despite a broad general understanding of mechanisms of spindle generation gleaned from animal studies, the mechanisms underlying certain features of spindles in the human brain, such as “global” versus “local” spindles, are largely unknown. Neither the topography nor the morphology of sleep spindles remains constant throughout the lifespan. It is likely that changes in spindle phenomenology during development and aging are the result of dramatic changes in brain structure and function. Across various developmental windows, spindle activity is correlated with general cognitive aptitude, learning, and memory; however, these correlations vary in strength, and even direction, depending on age and metrics used. Understanding these differences across the lifespan should further clarify how these oscillations are generated and their function under a variety of circumstances. We discuss these issues, and their translational implications for human cognitive function. Because sleep spindles are similarly affected in disorders of neurodevelopment (such as schizophrenia) and during aging (such as neurodegenerative conditions), both types of disorders may benefit from therapies based on a better understanding of spindle function.
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119
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Kaplan ES, Cooke SF, Komorowski RW, Chubykin AA, Thomazeau A, Khibnik LA, Gavornik JP, Bear MF. Contrasting roles for parvalbumin-expressing inhibitory neurons in two forms of adult visual cortical plasticity. eLife 2016; 5:e11450. [PMID: 26943618 PMCID: PMC4786407 DOI: 10.7554/elife.11450] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 02/03/2016] [Indexed: 01/03/2023] Open
Abstract
The roles played by cortical inhibitory neurons in experience-dependent plasticity are not well understood. Here we evaluate the participation of parvalbumin-expressing (PV+) GABAergic neurons in two forms of experience-dependent modification of primary visual cortex (V1) in adult mice: ocular dominance (OD) plasticity resulting from monocular deprivation and stimulus-selective response potentiation (SRP) resulting from enriched visual experience. These two forms of plasticity are triggered by different events but lead to a similar increase in visual cortical response. Both also require the NMDA class of glutamate receptor (NMDAR). However, we find that PV+ inhibitory neurons in V1 play a critical role in the expression of SRP and its behavioral correlate of familiarity recognition, but not in the expression of OD plasticity. Furthermore, NMDARs expressed within PV+ cells, reversibly inhibited by the psychotomimetic drug ketamine, play a critical role in SRP, but not in the induction or expression of adult OD plasticity.
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Affiliation(s)
- Eitan S Kaplan
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Sam F Cooke
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Robert W Komorowski
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Alexander A Chubykin
- Department of Biological Sciences, Purdue University, West Lafayette, United States
| | - Aurore Thomazeau
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Lena A Khibnik
- Department of Neurology, Sanford Health, Fargo, United States
| | | | - Mark F Bear
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
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120
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Affiliation(s)
- Terje Lømo
- Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway;
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121
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Eaton NC, Sheehan HM, Quinlan EM. Optimization of visual training for full recovery from severe amblyopia in adults. ACTA ACUST UNITED AC 2016; 23:99-103. [PMID: 26787781 PMCID: PMC4749829 DOI: 10.1101/lm.040295.115] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/01/2015] [Indexed: 11/25/2022]
Abstract
The severe amblyopia induced by chronic monocular deprivation is highly resistant to reversal in adulthood. Here we use a rodent model to show that recovery from deprivation amblyopia can be achieved in adults by a two-step sequence, involving enhancement of synaptic plasticity in the visual cortex by dark exposure followed immediately by visual training. The perceptual learning induced by visual training contributes to the recovery of vision and can be optimized to drive full recovery of visual acuity in severely amblyopic adults.
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Affiliation(s)
- Nicolette C Eaton
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA
| | - Hanna Marie Sheehan
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA
| | - Elizabeth M Quinlan
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA Neuroscience and Cognitive Sciences Program, University of Maryland, College Park, Maryland 20742, USA
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122
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Durkin J, Aton SJ. Sleep-Dependent Potentiation in the Visual System Is at Odds with the Synaptic Homeostasis Hypothesis. Sleep 2016; 39:155-9. [PMID: 26285006 DOI: 10.5665/sleep.5338] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/18/2015] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Two commentaries recently published in SLEEP came to very different conclusions regarding how data from a mouse model of sleep-dependent neural plasticity (orientation-specific response potentiation; OSRP) fit with the synaptic homeostasis hypothesis (SHY). To assess whether SHY offers an explanatory mechanism for OSRP, we present new data on how cortical neuron firing rates are modulated as a function of novel sensory experience and subsequent sleep in this model system. METHODS We carried out longitudinal extracellular recordings of single-neuron activity in the primary visual cortex across a period of novel visual experience and subsequent sleep or sleep deprivation. Spontaneous neuronal firing rates and visual responses were recorded from the same population of visual cortex neurons before control (blank screen) or novel (oriented grating) stimulus presentation, immediately after stimulus presentation, and after a period of subsequent ad lib sleep or sleep deprivation. RESULTS Firing rate responses to visual stimuli were unchanged across waking experience, regardless of whether a blank screen or an oriented grating stimulus was presented. Firing rate responses to stimuli of the presented stimulus orientation were selectively enhanced across post-stimulus sleep, but these changes were blocked by sleep deprivation. Neuronal firing increased significantly across bouts of post-stimulus rapid eye movement (REM) sleep and slow wave sleep (SWS), but not across bouts of wake. CONCLUSIONS The current data suggest that following novel visual experience, potentiation of a subset of V1 synapses occurs across periods of sleep. This finding cannot be explained parsimoniously by SHY.
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Affiliation(s)
- Jaclyn Durkin
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI
| | - Sara J Aton
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
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123
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Augmenting NMDA receptor signaling boosts experience-dependent neuroplasticity in the adult human brain. Proc Natl Acad Sci U S A 2015; 112:15331-6. [PMID: 26621715 DOI: 10.1073/pnas.1509262112] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Experience-dependent plasticity is a fundamental property of the brain. It is critical for everyday function, is impaired in a range of neurological and psychiatric disorders, and frequently depends on long-term potentiation (LTP). Preclinical studies suggest that augmenting N-methyl-d-aspartate receptor (NMDAR) signaling may promote experience-dependent plasticity; however, a lack of noninvasive methods has limited our ability to test this idea in humans until recently. We examined the effects of enhancing NMDAR signaling using d-cycloserine (DCS) on a recently developed LTP EEG paradigm that uses high-frequency visual stimulation (HFvS) to induce neural potentiation in visual cortex neurons, as well as on three cognitive tasks: a weather prediction task (WPT), an information integration task (IIT), and a n-back task. The WPT and IIT are learning tasks that require practice with feedback to reach optimal performance. The n-back assesses working memory. Healthy adults were randomized to receive DCS (100 mg; n = 32) or placebo (n = 33); groups were similar in IQ and demographic characteristics. Participants who received DCS showed enhanced potentiation of neural responses following repetitive HFvS, as well as enhanced performance on the WPT and IIT. Groups did not differ on the n-back. Augmenting NMDAR signaling using DCS therefore enhanced activity-dependent plasticity in human adults, as demonstrated by lasting enhancement of neural potentiation following repetitive HFvS and accelerated acquisition of two learning tasks. Results highlight the utility of considering cellular mechanisms underlying distinct cognitive functions when investigating potential cognitive enhancers.
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Kang JI, Huppé-Gourgues F, Vaucher E. Pharmacological Mechanisms of Cortical Enhancement Induced by the Repetitive Pairing of Visual/Cholinergic Stimulation. PLoS One 2015; 10:e0141663. [PMID: 26513575 PMCID: PMC4626033 DOI: 10.1371/journal.pone.0141663] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 10/12/2015] [Indexed: 11/18/2022] Open
Abstract
Repetitive visual training paired with electrical activation of cholinergic projections to the primary visual cortex (V1) induces long-term enhancement of cortical processing in response to the visual training stimulus. To better determine the receptor subtypes mediating this effect the selective pharmacological blockade of V1 nicotinic (nAChR), M1 and M2 muscarinic (mAChR) or GABAergic A (GABAAR) receptors was performed during the training session and visual evoked potentials (VEPs) were recorded before and after training. The training session consisted of the exposure of awake, adult rats to an orientation-specific 0.12 CPD grating paired with an electrical stimulation of the basal forebrain for a duration of 1 week for 10 minutes per day. Pharmacological agents were infused intracortically during this period. The post-training VEP amplitude was significantly increased compared to the pre-training values for the trained spatial frequency and to adjacent spatial frequencies up to 0.3 CPD, suggesting a long-term increase of V1 sensitivity. This increase was totally blocked by the nAChR antagonist as well as by an M2 mAChR subtype and GABAAR antagonist. Moreover, administration of the M2 mAChR antagonist also significantly decreased the amplitude of the control VEPs, suggesting a suppressive effect on cortical responsiveness. However, the M1 mAChR antagonist blocked the increase of the VEP amplitude only for the high spatial frequency (0.3 CPD), suggesting that M1 role was limited to the spread of the enhancement effect to a higher spatial frequency. More generally, all the drugs used did block the VEP increase at 0.3 CPD. Further, use of each of the aforementioned receptor antagonists blocked training-induced changes in gamma and beta band oscillations. These findings demonstrate that visual training coupled with cholinergic stimulation improved perceptual sensitivity by enhancing cortical responsiveness in V1. This enhancement is mainly mediated by nAChRs, M2 mAChRs and GABAARs. The M1 mAChR subtype appears to be involved in spreading the enhancement of V1 cortical responsiveness to adjacent neurons.
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Affiliation(s)
- Jun-Il Kang
- École d’optométrie, Université de Montréal, CP 6128 succursale centre-ville, Montréal, Qc, H3C 3J7, Canada
- Département de Neuroscience, Université de Montréal, CP 6128 succursale centre-ville, Montréal, Qc, H3C 3J7, Canada
| | - Frédéric Huppé-Gourgues
- École d’optométrie, Université de Montréal, CP 6128 succursale centre-ville, Montréal, Qc, H3C 3J7, Canada
| | - Elvire Vaucher
- École d’optométrie, Université de Montréal, CP 6128 succursale centre-ville, Montréal, Qc, H3C 3J7, Canada
- * E-mail:
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Metabotropic glutamate receptor signaling is required for NMDA receptor-dependent ocular dominance plasticity and LTD in visual cortex. Proc Natl Acad Sci U S A 2015; 112:12852-7. [PMID: 26417096 DOI: 10.1073/pnas.1512878112] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A feature of early postnatal neocortical development is a transient peak in signaling via metabotropic glutamate receptor 5 (mGluR5). In visual cortex, this change coincides with increased sensitivity of excitatory synapses to monocular deprivation (MD). However, loss of visual responsiveness after MD occurs via mechanisms revealed by the study of long-term depression (LTD) of synaptic transmission, which in layer 4 is induced by acute activation of NMDA receptors (NMDARs) rather than mGluR5. Here we report that chronic postnatal down-regulation of mGluR5 signaling produces coordinated impairments in both NMDAR-dependent LTD in vitro and ocular dominance plasticity in vivo. The data suggest that ongoing mGluR5 signaling during a critical period of postnatal development establishes the biochemical conditions that are permissive for activity-dependent sculpting of excitatory synapses via the mechanism of NMDAR-dependent LTD.
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126
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Theta Oscillations in Visual Cortex Emerge with Experience to Convey Expected Reward Time and Experienced Reward Rate. J Neurosci 2015; 35:9603-14. [PMID: 26134643 DOI: 10.1523/jneurosci.0296-15.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The primary visual cortex (V1) is widely regarded as faithfully conveying the physical properties of visual stimuli. Thus, experience-induced changes in V1 are often interpreted as improving visual perception (i.e., perceptual learning). Here we describe how, with experience, cue-evoked oscillations emerge in V1 to convey expected reward time as well as to relate experienced reward rate. We show, in chronic multisite local field potential recordings from rat V1, that repeated presentation of visual cues induces the emergence of visually evoked oscillatory activity. Early in training, the visually evoked oscillations relate to the physical parameters of the stimuli. However, with training, the oscillations evolve to relate the time in which those stimuli foretell expected reward. Moreover, the oscillation prevalence reflects the reward rate recently experienced by the animal. Thus, training induces experience-dependent changes in V1 activity that relate to what those stimuli have come to signify behaviorally: when to expect future reward and at what rate.
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127
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Lantz CL, Sipe GO, Wong EL, Majewska AK, Medina AE. Effects of Developmental Alcohol Exposure on Potentiation and Depression of Visual Cortex Responses. Alcohol Clin Exp Res 2015; 39:1434-42. [PMID: 26108422 PMCID: PMC4515209 DOI: 10.1111/acer.12775] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 05/07/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Neuronal plasticity deficits are thought to underlie abnormal neurodevelopment in fetal alcohol spectrum disorders and in animal models of this condition. Previously, we found that alcohol exposure during a period that is similar to the last months of gestation in humans disrupts ocular dominance plasticity (ODP), as measured in superficial cortical layers. We hypothesize that exposure to alcohol can differentially affect the potentiation and depression of responses that are necessary for activity-dependent sprouting and pruning of neuronal networks. ODP is an established paradigm that allows the assessment of activity-dependent depression and potentiation of responses in vivo. METHODS Mouse pups were exposed to 3.6 to 5 g/kg of ethanol in saline daily or every other day between postnatal days 4 and 9. Visual cortex plasticity was then assessed during the critical period for ODP using 2 techniques that separately record in layers 4 (visually evoked potentials [VEPs]) and 2/3 (optical imaging of intrinsic signals [OI]). RESULTS We discovered a layer-specific effect of early alcohol exposure. Recording of VEPs from layer 4 showed that while the potentiation component of ODP was disrupted in animals treated with alcohol when compared with saline controls, the depression component of ODP (Dc-ODP) was unaltered. In contrast, OI from layers 2/3 showed that Dc-ODP was markedly disrupted in alcohol-treated animals when compared with controls. CONCLUSIONS Combined with our previous work, these findings strongly suggest that developmental alcohol exposure has a distinct and layer-specific effect on the potentiation and depression of cortical responses after monocular deprivation.
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Affiliation(s)
- Crystal L Lantz
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia
- Department of Biology, University of Maryland, College Park, Maryland
| | - Grayson O Sipe
- Department of Neurobiology and Anatomy, University of Rochester Medical Center, Rochester, New York
| | - Elissa L Wong
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, New York
| | - Ania K Majewska
- Department of Neurobiology and Anatomy, University of Rochester Medical Center, Rochester, New York
| | - Alexandre E Medina
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia
- Department of Pediatrics, School of Medicine, University of Maryland, Baltimore, Maryland
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128
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Cooke SF, Bear MF. Visual recognition memory: a view from V1. Curr Opin Neurobiol 2015; 35:57-65. [PMID: 26151761 DOI: 10.1016/j.conb.2015.06.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 06/15/2015] [Indexed: 12/25/2022]
Abstract
Although work in primates on higher-order visual areas has revealed how the individual and concerted activity of neurons correlates with behavioral reports of object recognition, very little is known about the underlying mechanisms for visual recognition memory. Low-level vision, even as early as primary visual cortex (V1) and even in subjects as unsophisticated as rodents, promises to fill this void. Although this latter approach sacrifices interrogation of many of the most astounding features of visual recognition, it does provide experimental constraint, proximity to sensory input, and a wide range of interventional approaches. The tractability of rodent visual cortex promises to reveal the molecular mechanisms and circuits that are essential for a fundamental form of memory.
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Affiliation(s)
- Sam F Cooke
- The Howard Hughes Medical Institute and The Picower Institute for Learning and Memory, The Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 77, Massachusetts Avenue, Cambridge 02139, MA, USA
| | - Mark F Bear
- The Howard Hughes Medical Institute and The Picower Institute for Learning and Memory, The Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 77, Massachusetts Avenue, Cambridge 02139, MA, USA.
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129
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Makowiecki K, Garrett A, Clark V, Graham SL, Rodger J. Reliability of VEP Recordings Using Chronically Implanted Screw Electrodes in Mice. Transl Vis Sci Technol 2015; 4:15. [PMID: 25938003 DOI: 10.1167/tvst.4.2.15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/09/2015] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Visual evoked potentials (VEPs) are widely used to objectively assess visual system function in animal models of ophthalmological diseases. Although use of chronically implanted electrodes is common in longitudinal VEP studies using rodent models, reliability of recordings over time has not been assessed. We compared VEPs 1 and 7 days after electrode implantation in the adult mouse. We also examined stimulus-independent changes over time, by assessing electroencephalogram (EEG) power and approximate entropy of the EEG signal. METHODS Stainless steel screws (600-μm diameter) were implanted into the skull overlying the right visual cortex and the orbitofrontal cortex of adult mice (C57Bl/6J, n = 7). Animals were reanesthetized 1 and 7 days after implantation to record VEP responses (flashed gratings) and EEG activity. Brain sections were stained for glial activation (GFAP) and cell death (TUNEL). RESULTS Reliability analysis, using intraclass correlation coefficients, showed VEP recordings had high reliability within the same session, regardless of time after electrode implantation and peak latencies and approximate entropy of the EEG did not change significantly with time. However, there was poorer reliability between recordings obtained on different days, and a significant decrease in VEP amplitudes and EEG power. This amplitude decrease could be normalized by scaling to EEG power (within-subjects). Furthermore, glial activation was present at both time points but there was no evidence of cell death. CONCLUSIONS These results indicate that VEP responses can be reliably recorded even after a relatively short recovery period but decrease response peak amplitude over time. Although scaling the VEP trace to EEG power normalized this decrease, our results highlight that time-dependent cortical excitability changes are an important consideration in longitudinal VEP studies. TRANSLATIONAL RELEVANCE This study shows changes in VEP characteristics over time in chronically implanted mice. Thus, future preclinical longitudinal studies should consider time in addition to amplitude and latency when designing and interpreting research.
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Affiliation(s)
- Kalina Makowiecki
- Experimental and Regenerative Neurosciences School of Animal Biology, The University of Western Australia, Crawley WA, Australia
| | - Andrew Garrett
- Experimental and Regenerative Neurosciences School of Animal Biology, The University of Western Australia, Crawley WA, Australia
| | - Vince Clark
- Experimental and Regenerative Neurosciences School of Animal Biology, The University of Western Australia, Crawley WA, Australia
| | - Stuart L Graham
- Australian School Advanced Medicine Macquarie University, New South Wales, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neurosciences School of Animal Biology, The University of Western Australia, Crawley WA, Australia
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130
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Hager AM, Gagolewicz PJ, Rodier S, Kuo MC, Dumont ÉC, Dringenberg HC. Metaplastic up-regulation of LTP in the rat visual cortex by monocular visual training: requirement of task mastery, hemispheric specificity, and NMDA-GluN2B involvement. Neuroscience 2015; 293:171-86. [PMID: 25711939 DOI: 10.1016/j.neuroscience.2015.02.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 12/26/2014] [Accepted: 02/15/2015] [Indexed: 10/23/2022]
Abstract
"Metaplasticity" is defined as an alteration of synaptic plasticity properties or mechanisms by a priming event without actual changes in synaptic strength. For example, visual discrimination training of rats leads to a facilitation of the subsequent induction of long-term potentiation (LTP) between the lateral geniculate nucleus (LGN) and the primary visual cortex (V1). Here, rats received visual discrimination training in a modified water maze, with one eye occluded during training to create monocular viewing conditions; 63% of rats acquired the task under these conditions. Following training, in vivo electrophysiology was used to examine LTP of field postsynaptic potentials (fPSPs) in V1 elicited by LGN stimulation. Rats that had successfully learned the task showed significantly greater LTP in the "trained V1" (contralateral to the open, trained eye) relative to the "untrained" hemisphere. Rats that underwent training but failed to acquire the task did not show this lateralized plasticity enhancement and had similar levels of LTP in both cerebral hemispheres. Cortical application of the NMDA receptor-GluN2B subunit antagonist Ro 25-6981 (2 mM) reversed the training-induced LTP facilitation without affecting LTP in the untrained V1. Whole-cell patch clamp recordings of V1 (layers II/III) pyramidal cells in vitro demonstrated that pharmacologically isolated NMDA currents exhibit a greater sensitivity to GluN2B blockade in the trained relative to the untrained V1. Together, these experiments reveal a surprising degree of anatomical (only in the hemisphere contralateral to the trained eye) and behavioral specificity (only in rats that mastered the task) for the effect of visual training to enhance LTP in V1. Further, cortical GluN2B subunits appear to be directly involved in this metaplastic facilitation of thalamocortical plasticity, suggesting that NMDA subunit composition or functioning is, at least in part, regulated by the exposure to behaviorally significant stimuli in an animal's sensory environment.
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Affiliation(s)
- A M Hager
- Department of Psychology, Queen's University, Kingston, Ontario, Canada
| | - P J Gagolewicz
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - S Rodier
- Department of Psychology, Queen's University, Kingston, Ontario, Canada
| | - M-C Kuo
- Department of Psychology, Queen's University, Kingston, Ontario, Canada
| | - É C Dumont
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - H C Dringenberg
- Department of Psychology, Queen's University, Kingston, Ontario, Canada; Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada.
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131
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Visual recognition memory, manifested as long-term habituation, requires synaptic plasticity in V1. Nat Neurosci 2015; 18:262-71. [PMID: 25599221 PMCID: PMC4383092 DOI: 10.1038/nn.3920] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/09/2014] [Indexed: 11/25/2022]
Abstract
Familiarity with stimuli that bring neither reward nor punishment, manifested through behavioural habituation, enables organisms to detect novelty and devote cognition to important elements of the environment. Here we describe in mice a form of long-term behavioural habituation to visual grating stimuli that is selective for stimulus orientation. Orientation-selective habituation (OSH) can be observed both in exploratory behaviour in an open arena, and in a stereotyped motor response to visual stimuli in head-restrained mice. We show that the latter behavioural response, termed a vidget, requires V1. Parallel electrophysiological recordings in V1 reveal that plasticity, in the form of stimulus-selective response potentiation (SRP), occurs in layer 4 of V1 as OSH develops. Local manipulations of V1 that prevent and reverse electrophysiological modifications likewise prevent and reverse memory demonstrated behaviourally. These findings suggest that a form of long-term visual recognition memory is stored via synaptic plasticity in primary sensory cortex.
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132
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Cirelli C, Tononi G. Sleep and synaptic homeostasis. Sleep 2015; 38:161-2. [PMID: 25325499 DOI: 10.5665/sleep.4348] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 09/26/2014] [Indexed: 02/03/2023] Open
Affiliation(s)
- Chiara Cirelli
- Department of Psychiatry, University of Wisconsin, Madison, WI
| | - Giulio Tononi
- Department of Psychiatry, University of Wisconsin, Madison, WI
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133
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Abstract
Sleep is hypothesized to play an integral role in brain plasticity. This has traditionally been investigated using behavioral assays. In the last 10-15 years, studies combining sleep measurements with in vitro and in vivo models of synaptic plasticity have provided exciting new insights into how sleep alters synaptic strength. In addition, new theories have been proposed that integrate older ideas about sleep function and recent discoveries in the field of synaptic plasticity. There remain, however, important challenges and unanswered questions. For example, sleep does not appear to have a single effect on synaptic strength. An unbiased review of the literature indicates that the effects of sleep vary widely depending on ontogenetic stage, the type of waking experience (or stimulation protocols) that precede sleep and the type of neuronal synapse under examination. In this review, I discuss these key findings in the context of current theories that posit different roles for sleep in synaptic plasticity.
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Affiliation(s)
- Marcos G Frank
- Department of Neuroscience, School of Medicine, University of Pennsylvania, 215 Stemmler Hall, 35th and Hamilton Walk, Philadelphia, PA, 19104-6074, USA,
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134
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mGlu1 receptor-induced LTD of NMDA receptor transmission selectively at Schaffer collateral-CA1 synapses mediates metaplasticity. J Neurosci 2014; 34:12223-9. [PMID: 25186764 DOI: 10.1523/jneurosci.0753-14.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hippocampal CA1 pyramidal neurons receive inputs from entorhinal cortex directly via the temporoammonic (TA) pathway and indirectly via the Schaffer collateral (SC) pathway from CA3. NMDARs at synapses of both pathways are critical for the induction of synaptic plasticity, information processing, and learning and memory. We now demonstrate that, in the rat hippocampus, activity-dependent mGlu1 receptor-mediated LTD (mGlu1-LTD) of NMDAR-mediated transmission (EPSC(NMDA)) at the SC-CA1 input prevents subsequent LTP of AMPAR-mediated transmission. In contrast, there was no activity-dependent mGlu1-LTD of EPSC(NMDA) at the TA-CA1 pathway, or effects on subsequent plasticity of AMPAR-mediated transmission. Therefore, the two major pathways delivering information to CA1 pyramidal neurons are subject to very different plasticity rules.
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135
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Strong KL, Jing Y, Prosser AR, Traynelis SF, Liotta DC. NMDA receptor modulators: an updated patent review (2013-2014). Expert Opin Ther Pat 2014; 24:1349-66. [PMID: 25351527 DOI: 10.1517/13543776.2014.972938] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION The NMDA receptor mediates a slow component of excitatory synaptic transmission, and NMDA receptor dysfunction has been implicated in numerous neurological disorders. Thus, interest in developing modulators that are capable of regulating the channel continues to be strong. Recent research has led to the discovery of a number of compounds that hold therapeutic and clinical value. Deeper insight into the NMDA intersubunit interactions and structural motifs gleaned from the recently solved crystal structures of the NMDA receptor should facilitate a deeper understanding of how these compounds modulate the receptor. AREAS COVERED This article discusses the known pharmacology of NMDA receptors. A discussion of the patent literature since 2012 is also included, with an emphasis on those that claimed new chemical entities as regulators of the NMDA receptor. EXPERT OPINION The number of patents involving novel NMDA receptor modulators suggests a renewed interest in the NMDA receptor as a therapeutic target. Subunit-selective modulators continue to show promise, and the development of new subunit-selective NMDA receptor modulators appears poised for continued growth. Although a modest number of channel blocker patents were published, successful clinical outcomes involving ketamine have led to a resurgent interest in low-affinity channel blockers as therapeutics.
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Affiliation(s)
- Katie L Strong
- Emory University, Department of Chemistry , 1521 Dickey Drive, Atlanta, GA 30322 , USA
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136
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Kang JI, Huppé-Gourgues F, Vaucher E. Boosting visual cortex function and plasticity with acetylcholine to enhance visual perception. Front Syst Neurosci 2014; 8:172. [PMID: 25278848 PMCID: PMC4167004 DOI: 10.3389/fnsys.2014.00172] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 08/31/2014] [Indexed: 11/29/2022] Open
Abstract
The cholinergic system is a potent neuromodulatory system that plays critical roles in cortical plasticity, attention and learning. In this review, we propose that the cellular effects of acetylcholine (ACh) in the primary visual cortex during the processing of visual inputs might induce perceptual learning; i.e., long-term changes in visual perception. Specifically, the pairing of cholinergic activation with visual stimulation increases the signal-to-noise ratio, cue detection ability and long-term facilitation in the primary visual cortex. This cholinergic enhancement would increase the strength of thalamocortical afferents to facilitate the treatment of a novel stimulus while decreasing the cortico-cortical signaling to reduce recurrent or top-down modulation. This balance would be mediated by different cholinergic receptor subtypes that are located on both glutamatergic and GABAergic neurons of the different cortical layers. The mechanisms of cholinergic enhancement are closely linked to attentional processes, long-term potentiation (LTP) and modulation of the excitatory/inhibitory balance. Recently, it was found that boosting the cholinergic system during visual training robustly enhances sensory perception in a long-term manner. Our hypothesis is that repetitive pairing of cholinergic and sensory stimulation over a long period of time induces long-term changes in the processing of trained stimuli that might improve perceptual ability. Various non-invasive approaches to the activation of the cholinergic neurons have strong potential to improve visual perception.
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Affiliation(s)
- Jun Il Kang
- École d'optométrie, Université de Montréal Montréal, QC, Canada ; Département de Neuroscience, Université de Montréal Montréal, QC, Canada
| | | | - Elvire Vaucher
- École d'optométrie, Université de Montréal Montréal, QC, Canada
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137
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Gavornik JP, Bear MF. Higher brain functions served by the lowly rodent primary visual cortex. ACTA ACUST UNITED AC 2014; 21:527-33. [PMID: 25225298 PMCID: PMC4175492 DOI: 10.1101/lm.034355.114] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
It has been more than 50 years since the first description of ocular dominance plasticity--the profound modification of primary visual cortex (V1) following temporary monocular deprivation. This discovery immediately attracted the intense interest of neurobiologists focused on the general question of how experience and deprivation modify the brain as a potential substrate for learning and memory. The pace of discovery has quickened considerably in recent years as mice have become the preferred species to study visual cortical plasticity, and new studies have overturned the dogma that primary sensory cortex is immutable after a developmental critical period. Recent work has shown that, in addition to ocular dominance plasticity, adult visual cortex exhibits several forms of response modification previously considered the exclusive province of higher cortical areas. These "higher brain functions" include neural reports of stimulus familiarity, reward-timing prediction, and spatiotemporal sequence learning. Primary visual cortex can no longer be viewed as a simple visual feature detector with static properties determined during early development. Rodent V1 is a rich and dynamic cortical area in which functions normally associated only with "higher" brain regions can be studied at the mechanistic level.
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Affiliation(s)
- Jeffrey P Gavornik
- Howard Hughes Medical Institute, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Mark F Bear
- Howard Hughes Medical Institute, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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138
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Frank MG, Cantera R. Sleep, clocks, and synaptic plasticity. Trends Neurosci 2014; 37:491-501. [PMID: 25087980 PMCID: PMC4152403 DOI: 10.1016/j.tins.2014.06.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 06/12/2014] [Accepted: 06/30/2014] [Indexed: 01/24/2023]
Abstract
Sleep is widely believed to play an essential role in synaptic plasticity. However, the precise mechanisms governing this presumptive function are largely unknown. There is also evidence for independent circadian oscillations in synaptic strength and morphology. Therefore, synaptic changes observed after sleep reflect interactions between state-dependent (e.g., wake versus sleep) and state-independent (circadian) processes. In this review we consider how sleep and biological clocks influence synaptic plasticity. We discuss these findings in the context of current plasticity-based theories of sleep function and propose a new model that integrates circadian and brain-state influences on synaptic plasticity.
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Affiliation(s)
- Marcos G. Frank
- Department of Neuroscience Perelman School of Medicine University of Pennsylvania Philadelphia, PA 19104
| | - Rafael Cantera
- Zoology Department Stockholm University Stockholm, Sweden Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
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139
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Bonaccorsi J, Berardi N, Sale A. Treatment of amblyopia in the adult: insights from a new rodent model of visual perceptual learning. Front Neural Circuits 2014; 8:82. [PMID: 25076874 PMCID: PMC4100600 DOI: 10.3389/fncir.2014.00082] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 06/27/2014] [Indexed: 11/19/2022] Open
Abstract
Amblyopia is the most common form of impairment of visual function affecting one eye, with a prevalence of about 1–5% of the total world population. Amblyopia usually derives from conditions of early functional imbalance between the two eyes, owing to anisometropia, strabismus, or congenital cataract, and results in a pronounced reduction of visual acuity and severe deficits in contrast sensitivity and stereopsis. It is widely accepted that, due to a lack of sufficient plasticity in the adult brain, amblyopia becomes untreatable after the closure of the critical period in the primary visual cortex. However, recent results obtained both in animal models and in clinical trials have challenged this view, unmasking a previously unsuspected potential for promoting recovery even in adulthood. In this context, non invasive procedures based on visual perceptual learning, i.e., the improvement in visual performance on a variety of simple visual tasks following practice, emerge as particularly promising to rescue discrimination abilities in adult amblyopic subjects. This review will survey recent work regarding the impact of visual perceptual learning on amblyopia, with a special focus on a new experimental model of perceptual learning in the amblyopic rat.
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Affiliation(s)
- Joyce Bonaccorsi
- Department of Medicine, Institute of Neuroscience CNR, National Research Council (CNR) Pisa, Italy
| | - Nicoletta Berardi
- Department of Medicine, Institute of Neuroscience CNR, National Research Council (CNR) Pisa, Italy ; Department of Psychology, Florence University Florence, Italy
| | - Alessandro Sale
- Department of Medicine, Institute of Neuroscience CNR, National Research Council (CNR) Pisa, Italy
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140
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Bronfman ZZ, Ginsburg S, Jablonka E. Shaping the learning curve: epigenetic dynamics in neural plasticity. Front Integr Neurosci 2014; 8:55. [PMID: 25071483 PMCID: PMC4083220 DOI: 10.3389/fnint.2014.00055] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 06/18/2014] [Indexed: 12/22/2022] Open
Abstract
A key characteristic of learning and neural plasticity is state-dependent acquisition dynamics reflected by the non-linear learning curve that links increase in learning with practice. Here we propose that the manner by which epigenetic states of individual cells change during learning contributes to the shape of the neural and behavioral learning curve. We base our suggestion on recent studies showing that epigenetic mechanisms such as DNA methylation, histone acetylation, and RNA-mediated gene regulation are intimately involved in the establishment and maintenance of long-term neural plasticity, reflecting specific learning-histories and influencing future learning. Our model, which is the first to suggest a dynamic molecular account of the shape of the learning curve, leads to several testable predictions regarding the link between epigenetic dynamics at the promoter, gene-network, and neural-network levels. This perspective opens up new avenues for therapeutic interventions in neurological pathologies.
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Affiliation(s)
- Zohar Z Bronfman
- The Cohn Institute for the History and Philosophy of Science and Ideas, Faculty of Humanities, Tel-Aviv University Tel-Aviv, Israel ; School of Psychology, Faculty of Social Science, Tel-Aviv University Tel-Aviv, Israel
| | - Simona Ginsburg
- Natural Science Department, The Open University of Israel Raanana, Israel
| | - Eva Jablonka
- The Cohn Institute for the History and Philosophy of Science and Ideas, Faculty of Humanities, Tel-Aviv University Tel-Aviv, Israel
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141
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Aton SJ, Suresh A, Broussard C, Frank MG. Sleep promotes cortical response potentiation following visual experience. Sleep 2014; 37:1163-70. [PMID: 25061244 DOI: 10.5665/sleep.3830] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
STUDY OBJECTIVES Sleep has been hypothesized to globally reduce synaptic strength. However, recent findings suggest that in the context of learning and memory consolidation, sleep may promote synaptic potentiation. We tested the requirement for sleep in a naturally occurring form of experience-dependent synaptic potentiation in the adult mouse visual cortex (V1), which is initiated by patterned visual experience. DESIGN Visual responses were recorded in individual V1 neurons before and after presentation of an oriented grating stimulus, and after subsequent sleep or sleep deprivation. MEASUREMENTS AND RESULTS We find that V1 response potentiation-associated with a shift in orientation preference in favor of the presented stimulus-occurs only after sleep and only during the entrained circadian sleep phase, and is blocked by sleep deprivation. Induction of plasticity following stimulus presentation is associated with an increase in principal neuron firing in V1, which is present in all behavioral states and occurs regardless of time of day. Sleep dependent potentiation is proportional to phase-locking of neuronal activity with thalamocortical spindle oscillations. CONCLUSIONS Our results suggest that sleep can promote cortical synaptic potentiation in vivo, and that this potentiation may be mediated by slow wave sleep spindles. CITATION Aton SJ, Suresh A, Broussard C, Frank MG. Sleep promotes cortical response potentiation following visual experience.
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Affiliation(s)
- Sara J Aton
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Aneesha Suresh
- Committee on Computational Neuroscience, University of Chicago, Chicago, IL
| | - Christopher Broussard
- College of Literature, Science, and the Arts Information Technology Advocacy and Research Support, University of Michigan, Ann Arbor, MI
| | - Marcos G Frank
- University of Pennsylvania School of Medicine, Department of Neuroscience, Philadelphia, PA
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142
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Rodríguez-Durán LF, Escobar ML. NMDA receptor activation and PKC but not PKA lead to the modification of the long-term potentiation in the insular cortex induced by conditioned taste aversion: Differential role of kinases in metaplasticity. Behav Brain Res 2014; 266:58-62. [DOI: 10.1016/j.bbr.2014.02.049] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 02/20/2014] [Accepted: 02/27/2014] [Indexed: 11/15/2022]
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143
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Van Hooser SD, Escobar GM, Maffei A, Miller P. Emerging feed-forward inhibition allows the robust formation of direction selectivity in the developing ferret visual cortex. J Neurophysiol 2014; 111:2355-73. [PMID: 24598528 PMCID: PMC4099478 DOI: 10.1152/jn.00891.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 03/03/2014] [Indexed: 11/22/2022] Open
Abstract
The computation of direction selectivity requires that a cell respond to joint spatial and temporal characteristics of the stimulus that cannot be separated into independent components. Direction selectivity in ferret visual cortex is not present at the time of eye opening but instead develops in the days and weeks following eye opening in a process that requires visual experience with moving stimuli. Classic Hebbian or spike timing-dependent modification of excitatory feed-forward synaptic inputs is unable to produce direction-selective cells from unselective or weakly directionally biased initial conditions because inputs eventually grow so strong that they can independently drive cortical neurons, violating the joint spatial-temporal activation requirement. Furthermore, without some form of synaptic competition, cells cannot develop direction selectivity in response to training with bidirectional stimulation, as cells in ferret visual cortex do. We show that imposing a maximum lateral geniculate nucleus (LGN)-to-cortex synaptic weight allows neurons to develop direction-selective responses that maintain the requirement for joint spatial and temporal activation. We demonstrate that a novel form of inhibitory plasticity, postsynaptic activity-dependent long-term potentiation of inhibition (POSD-LTPi), which operates in the developing cortex at the time of eye opening, can provide synaptic competition and enables robust development of direction-selective receptive fields with unidirectional or bidirectional stimulation. We propose a general model of the development of spatiotemporal receptive fields that consists of two phases: an experience-independent establishment of initial biases, followed by an experience-dependent amplification or modification of these biases via correlation-based plasticity of excitatory inputs that compete against gradually increasing feed-forward inhibition.
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Affiliation(s)
- Stephen D Van Hooser
- Department of Biology, Brandeis University, Waltham, Massachusetts; Sloan-Swartz Center for Theoretical Neurobiology, Brandeis University, Waltham, Massachusetts; Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts;
| | - Gina M Escobar
- Department of Biology, Brandeis University, Waltham, Massachusetts; Sloan-Swartz Center for Theoretical Neurobiology, Brandeis University, Waltham, Massachusetts; Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts
| | - Arianna Maffei
- Department of Neurobiology and Behavior, State University of New York-Stony Brook, Stony Brook, New York; and SUNY Eye Institute, State University of New York-Stony Brook, Stony Brook, New York
| | - Paul Miller
- Department of Biology, Brandeis University, Waltham, Massachusetts; Sloan-Swartz Center for Theoretical Neurobiology, Brandeis University, Waltham, Massachusetts; Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts
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144
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Ortiz T, Poch J, Santos JM, Martínez AM, Ortiz-Terán L, Requena C, Barcia JA, de Erausquin GA, Pascual-Leone A. Occipital cortex activation by long-term repetitive tactile stimulation is necessary for object recognition in blinds: a case report. Neurocase 2014; 20:273-82. [PMID: 23819463 DOI: 10.1080/13554794.2013.770878] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Tactile vision has been approached from a variety of angles using different techniques. So far, a certain kind of object (and text) recognition has been shown, though seeing as such has not been achieved yet, and it remains unclear. Trough repetitive passive tactile stimulation perceptual processing is transferred from temporo-parietal to occipital areas, which affects object recognition. We report the results of passive tactile stimulation, as well as rTMS, applied to a 50 year old left handed blind male with over 97% loss of vision, who suffers from Peter's anomaly and microphthalmia. After 15 weeks of passive tactile stimulation, the subject showed increased activity in occipital areas associated with the development of visual-like perception which remained unchanged after three months without passive tactile stimulation. Inhibitory rTMS over the visual cortex led to noticeable reduction of spatial recognition performance and visual sensations in this subject. Stable changes in occipital cortical activity can be associated with subjective sensations of seeing. Once occipital activation has been achieved, it is necessary for spatial object recognition. Both facts highlight the implication of occipital areas in tactile vision and the cortical plasticity of passive tactile long-term stimulation in people with blindness.
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Affiliation(s)
- Tomás Ortiz
- a Departamento de Psiquiatría, Facultd de Medicina , Universidad Complutense , Madrid , Spain
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145
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Crossmodal induction of thalamocortical potentiation leads to enhanced information processing in the auditory cortex. Neuron 2014; 81:664-73. [PMID: 24507197 DOI: 10.1016/j.neuron.2013.11.023] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2013] [Indexed: 11/21/2022]
Abstract
Sensory systems do not work in isolation; instead, they show interactions that are specifically uncovered during sensory loss. To identify and characterize these interactions, we investigated whether visual deprivation leads to functional enhancement in primary auditory cortex (A1). We compared sound-evoked responses of A1 neurons in visually deprived animals to those from normally reared animals. Here, we show that visual deprivation leads to improved frequency selectivity as well as increased frequency and intensity discrimination performance of A1 neurons. Furthermore, we demonstrate in vitro that in adults visual deprivation strengthens thalamocortical (TC) synapses in A1, but not in primary visual cortex (V1). Because deafening potentiated TC synapses in V1, but not A1, crossmodal TC potentiation seems to be a general property of adult cortex. Our results suggest that adults retain the capability for crossmodal changes whereas such capability is absent within a sensory modality. Thus, multimodal training paradigms might be beneficial in sensory-processing disorders.
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146
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Gavornik JP, Bear MF. Learned spatiotemporal sequence recognition and prediction in primary visual cortex. Nat Neurosci 2014; 17:732-7. [PMID: 24657967 PMCID: PMC4167369 DOI: 10.1038/nn.3683] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Accepted: 02/27/2014] [Indexed: 12/16/2022]
Abstract
Learning to recognize and predict temporal sequences is fundamental to sensory perception, and is impaired in several neuropsychiatric disorders, but little is known about where and how this occurs in the brain. We discovered that repeated presentations of a visual sequence over a course of days causes evoked response potentiation in mouse V1 that is highly specific for stimulus order and timing. Remarkably, after V1 is trained to recognize a sequence, cortical activity regenerates the full sequence even when individual stimulus elements are omitted. This novel neurophysiological report of sequence learning advances the understanding of how the brain makes “intelligent guesses” based on limited information to form visual percepts and suggests that it is possible to study the mechanistic basis of this high–level cognitive ability by studying low–level sensory systems.
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Affiliation(s)
- Jeffrey P Gavornik
- Howard Hughes Medical Institute, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Mark F Bear
- 1] Howard Hughes Medical Institute, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA. [2]
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147
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Abstract
Achieving high-level skills is generally considered to require intense training, which is thought to optimally engage neuronal plasticity mechanisms. Recent work, however, suggests that intensive training may not be necessary for skill learning. Skills can be effectively acquired by a complementary approach in which the learning occurs in response to mere exposure to repetitive sensory stimulation. Such training-independent sensory learning induces lasting changes in perception and goal-directed behaviour in humans, without any explicit task training. We suggest that the effectiveness of this form of learning in different sensory domains stems from the fact that the stimulation protocols used are optimized to alter synaptic transmission and efficacy. While this approach directly links behavioural research in humans with studies on cellular plasticity, other approaches show that learning can occur even in the absence of an actual stimulus. These include learning through imagery or feedback-induced cortical activation, resulting in learning without task training. All these approaches challenge our understanding of the mechanisms that mediate learning. Apparently, humans can learn under conditions thought to be impossible a few years ago. Although the underlying mechanisms are far from being understood, training-independent sensory learning opens novel possibilities for applications aimed at augmenting human cognition.
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Affiliation(s)
- Christian Beste
- Institute for Cognitive Neuroscience, Department of Biopsychology, Ruhr-Universität Bochum, Universitätsstrasse 150, D-44780 Bochum, Germany.
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148
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Sale A, Berardi N, Maffei L. Environment and Brain Plasticity: Towards an Endogenous Pharmacotherapy. Physiol Rev 2014; 94:189-234. [DOI: 10.1152/physrev.00036.2012] [Citation(s) in RCA: 265] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Brain plasticity refers to the remarkable property of cerebral neurons to change their structure and function in response to experience, a fundamental theoretical theme in the field of basic research and a major focus for neural rehabilitation following brain disease. While much of the early work on this topic was based on deprivation approaches relying on sensory experience reduction procedures, major advances have been recently obtained using the conceptually opposite paradigm of environmental enrichment, whereby an enhanced stimulation is provided at multiple cognitive, sensory, social, and motor levels. In this survey, we aim to review past and recent work concerning the influence exerted by the environment on brain plasticity processes, with special emphasis on the underlying cellular and molecular mechanisms and starting from experimental work on animal models to move to highly relevant work performed in humans. We will initiate introducing the concept of brain plasticity and describing classic paradigmatic examples to illustrate how changes at the level of neuronal properties can ultimately affect and direct key perceptual and behavioral outputs. Then, we describe the remarkable effects elicited by early stressful conditions, maternal care, and preweaning enrichment on central nervous system development, with a separate section focusing on neurodevelopmental disorders. A specific section is dedicated to the striking ability of environmental enrichment and physical exercise to empower adult brain plasticity. Finally, we analyze in the last section the ever-increasing available knowledge on the effects elicited by enriched living conditions on physiological and pathological aging brain processes.
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Affiliation(s)
- Alessandro Sale
- Institute of Neuroscience, National Research Council, Pisa, Italy; Department of Psychology, Florence University, Florence, Italy; and Scuola Normale Superiore, Pisa, Italy
| | - Nicoletta Berardi
- Institute of Neuroscience, National Research Council, Pisa, Italy; Department of Psychology, Florence University, Florence, Italy; and Scuola Normale Superiore, Pisa, Italy
| | - Lamberto Maffei
- Institute of Neuroscience, National Research Council, Pisa, Italy; Department of Psychology, Florence University, Florence, Italy; and Scuola Normale Superiore, Pisa, Italy
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149
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Cooke SF, Bear MF. How the mechanisms of long-term synaptic potentiation and depression serve experience-dependent plasticity in primary visual cortex. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130284. [PMID: 24298166 DOI: 10.1098/rstb.2013.0284] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Donald Hebb chose visual learning in primary visual cortex (V1) of the rodent to exemplify his theories of how the brain stores information through long-lasting homosynaptic plasticity. Here, we revisit V1 to consider roles for bidirectional 'Hebbian' plasticity in the modification of vision through experience. First, we discuss the consequences of monocular deprivation (MD) in the mouse, which have been studied by many laboratories over many years, and the evidence that synaptic depression of excitatory input from the thalamus is a primary contributor to the loss of visual cortical responsiveness to stimuli viewed through the deprived eye. Second, we describe a less studied, but no less interesting form of plasticity in the visual cortex known as stimulus-selective response potentiation (SRP). SRP results in increases in the response of V1 to a visual stimulus through repeated viewing and bears all the hallmarks of perceptual learning. We describe evidence implicating an important role for potentiation of thalamo-cortical synapses in SRP. In addition, we present new data indicating that there are some features of this form of plasticity that cannot be fully accounted for by such feed-forward Hebbian plasticity, suggesting contributions from intra-cortical circuit components.
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Affiliation(s)
- Sam F Cooke
- Howard Hughes Medical Institute and The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, , 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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150
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Takeuchi T, Duszkiewicz AJ, Morris RGM. The synaptic plasticity and memory hypothesis: encoding, storage and persistence. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130288. [PMID: 24298167 DOI: 10.1098/rstb.2013.0288] [Citation(s) in RCA: 362] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The synaptic plasticity and memory hypothesis asserts that activity-dependent synaptic plasticity is induced at appropriate synapses during memory formation and is both necessary and sufficient for the encoding and trace storage of the type of memory mediated by the brain area in which it is observed. Criteria for establishing the necessity and sufficiency of such plasticity in mediating trace storage have been identified and are here reviewed in relation to new work using some of the diverse techniques of contemporary neuroscience. Evidence derived using optical imaging, molecular-genetic and optogenetic techniques in conjunction with appropriate behavioural analyses continues to offer support for the idea that changing the strength of connections between neurons is one of the major mechanisms by which engrams are stored in the brain.
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Affiliation(s)
- Tomonori Takeuchi
- Centre for Cognitive and Neural Systems, University of Edinburgh, , 1 George Square, Edinburgh EH8 9JZ, UK
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