scholarly journals Corticostriatal Plasticity Established by Initial Learning Persists After Behavioral Reversal

2020 ◽  
Author(s):  
Sanchari Ghosh ◽  
Anthony M Zador
Keyword(s):  
Neural Circuit ◽  
Neural Mechanisms ◽  
Auditory Stimuli ◽  
Reversal Task ◽  
Striatal Slices ◽  
Initial Acquisition ◽  
Initial Learning ◽  
Synaptic Changes ◽  
Corticostriatal Plasticity ◽  
Synaptic Mechanisms

AbstractThe neural mechanisms that allow animals to adapt their previously learned associations in response to changes in the environment remain poorly understood. To probe the synaptic mechanisms that mediate such adaptive behavior, we trained mice on an auditory-motor reversal task, and tracked changes in the strength of corticostriatal synapses associated with the formation of learned associations. Using a ChR2-based electrophysiological assay in acute striatal slices, we measured the strength of these synapses after animals learned to pair auditory stimuli with specific actions. Here we report that the pattern of synaptic strength initially established by learning remains unchanged even when the task contingencies are reversed. Our results suggest that synaptic changes associated with the initial acquisition of this task are not erased or over-written, and that behavioral reversal of learned associations may recruit a separate neural circuit.

scholarly journals Processing of motion boundary orientation in macaque V2

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Heng Ma ◽  
Pengcheng Li ◽  
Jiaming Hu ◽  
Xingya Cai ◽  
Qianling Song ◽  
...  
Keyword(s):  
Neural Circuit ◽  
Neuronal Response ◽  
Critical Role ◽  
Neural Mechanisms ◽  
Orientation Discrimination ◽  
Boundary Orientation ◽  
Area V2 ◽  
Correlated Activity ◽  
Object Based ◽  
Motion Boundaries

Human and nonhuman primates are good at identifying an object based on its motion, a task that is believed to be carried out by the ventral visual pathway. However, the neural mechanisms underlying such ability remains unclear. We trained macaque monkeys to do orientation discrimination for motion boundaries (MBs) and recorded neuronal response in area V2 with microelectrode arrays. We found 10.9% of V2 neurons exhibited robust orientation selectivity to MBs, and their responses correlated with monkeys’ orientation-discrimination performances. Furthermore, the responses of V2 direction-selective neurons recorded at the same time showed correlated activity with MB neurons for particular MB stimuli, suggesting that these motion-sensitive neurons made specific functional contributions to MB discrimination tasks. Our findings support the view that V2 plays a critical role in MB analysis and may achieve this through a neural circuit within area V2.

scholarly journals Reflex sympathetic tachycardia during intravenous infusions in chronic spinal cats

1976 ◽  
Vol 230 (1) ◽  
pp. 25-29 ◽  
Author(s):  
VS Bishop ◽  
F Lombardi ◽  
A Malliani ◽  
M Pagani ◽  
G Recordati
Keyword(s):  
Spinal Cord ◽  
Heart Rate ◽  
Neural Circuit ◽  
Blood Substitute ◽  
Neural Mechanisms ◽  
Resting Heart Rate ◽  
Average Increase ◽  
Vagal Blockade ◽  
Intravenous Infusions ◽  
Reflex Tachycardia

The reflex tachycardia elicited by rapid intravenous infusions of a blood substitute was studied in 21 chronic cats with spinal sections at C8. All animals could breath spontaneously. The day after section the average resting heart rate (HR) and arterial pressure (AP) were 109 beats/min and 98/67 mmHg, respectively. Vagal blockade with atropine (0.5-0.7 mg/kg iv) was performed prior to each infusion, increasing the average HR To 127 beats/min. In 39 infusions in 21 cats the average increase in HR was 10 beats/min (range from -6 to +22 beats/min). A tachycardia was observed in all but five trials, four of which were obtained in two cats that subsequently responded with a tachycardia. In seven animals the neural circuit mediating the response was partially or totally interrupted by section of several thoracic dorsal roots (T1-T4 or T1-T6) and of the spinal cord at the inferior level of these sections (between T6 and T7). The tachycardia response was progressively reduced and finally abolished by these procedures. These experiments indicate that spinal neural mechanisms are likely to contribute to the phenomenon first described by Bainbridge.

Localisation of Auditory Targets during Optokinetic Nystagmus

Perception ◽  
10.1068/p5849 ◽  
2007 ◽  
Vol 36 (10) ◽  
pp. 1507-1512 ◽  
Author(s):  
Kerstin Königs ◽  
Jonas Knöll ◽  
Frank Bremmer
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Temporal Pattern ◽  
Optokinetic Nystagmus ◽  
Visual Stimuli ◽  
Spatial Location ◽  
Neural Mechanisms ◽  
Auditory Target ◽  
Auditory Stimuli ◽  
Fast Phase

Previous studies have shown that the perceived location of visual stimuli briefly flashed during smooth pursuit, saccades, or optokinetic nystagmus (OKN) is not veridical. We investigated whether these mislocalisations can also be observed for brief auditory stimuli presented during OKN. Experiments were carried out in a lightproof sound-attenuated chamber. Participants performed eye movements elicited by visual stimuli. An auditory target (white noise) was presented for 5 ms. Our data clearly indicate that auditory targets are mislocalised during reflexive eye movements. OKN induces a shift of perceived location in the direction of the slow eye movement and is modulated in the temporal vicinity of the fast phase. The mislocalisation is stronger for look- as compared to stare-nystagmus. The size and temporal pattern of the observed mislocalisation are different from that found for visual targets. This suggests that different neural mechanisms are at play to integrate oculomotor signals and information on the spatial location of visual as well as auditory stimuli.

scholarly journals Auditory streaming emerges from fast excitation and slow delayed inhibition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrea Ferrario ◽  
James Rankin
Keyword(s):  
Neural Circuit ◽  
Neural Mechanisms ◽  
Rate Model ◽  
Auditory Streaming ◽  
Direct Excitation ◽  
Neural Populations ◽  
Fast Excitation ◽  
Pure Tones ◽  
Behavioural Experiments ◽  
Parameter Dependent

AbstractIn the auditory streaming paradigm, alternating sequences of pure tones can be perceived as a single galloping rhythm (integration) or as two sequences with separated low and high tones (segregation). Although studied for decades, the neural mechanisms underlining this perceptual grouping of sound remains a mystery. With the aim of identifying a plausible minimal neural circuit that captures this phenomenon, we propose a firing rate model with two periodically forced neural populations coupled by fast direct excitation and slow delayed inhibition. By analyzing the model in a non-smooth, slow-fast regime we analytically prove the existence of a rich repertoire of dynamical states and of their parameter dependent transitions. We impose plausible parameter restrictions and link all states with perceptual interpretations. Regions of stimulus parameters occupied by states linked with each percept match those found in behavioural experiments. Our model suggests that slow inhibition masks the perception of subsequent tones during segregation (forward masking), whereas fast excitation enables integration for large pitch differences between the two tones.

scholarly journals Specialized neurons in the right habenula mediate response to aversive olfactory cues

2021 ◽  
Author(s):  
Marnie E. Halpern ◽  
Jung-Hwa Choi ◽  
Erik Duboue ◽  
Michelle Macurak ◽  
Jean-Michel Chanchu
Keyword(s):  
Neural Circuit ◽  
Cholinergic Neurons ◽  
Neural Mechanisms ◽  
Olfactory Cues ◽  
Alarm Substance ◽  
Interpeduncular Nucleus ◽  
Efferent Connections ◽  
Mediate Response ◽  
Left And Right ◽  
The Right

Hemispheric specializations are well studied at the functional level but less is known about the underlying neural mechanisms. We identified a small cluster of cholinergic neurons in the right dorsal habenula (dHb) of zebrafish, defined by their expression of the lecithin retinol acyltransferase domain containing 2a (lratd2a) gene and their efferent connections with a subregion of the ventral interpeduncular nucleus (vIPN). The unilateral lratd2a-expressing neurons are innervated by a subset of mitral cells from both the left and right olfactory bulb and are activated upon exposure of adult zebrafish to the aversive odorant cadaverine that provokes avoidance behavior. Using an intersectional strategy to drive expression of the botulinum neurotoxin specifically in these neurons, we find that adults no longer show protracted avoidance to cadaverine. Mutants with left-isomerized dHb that lack these neurons are less repelled by cadaverine and their behavioral response to alarm substance, a potent aversive cue, is diminished. However mutants in which both dHb have right identity appear more reactive to alarm substance. The results implicate an asymmetric dHb-vIPN neural circuit in processing of aversive olfactory cues and modulating resultant behavioral responses.

Temporal Dependency of Multisensory Audiovisual Integration

2013 ◽  
pp. 320-326
Author(s):  
Jingjing Yang ◽  
Qi Li ◽  
Yulin Gao ◽  
Jinglong Wu
Keyword(s):  
Human Brain ◽  
Everyday Life ◽  
Multisensory Integration ◽  
Time Window ◽  
Visual Input ◽  
Audiovisual Integration ◽  
Neural Mechanisms ◽  
Auditory Stimuli ◽  
Complex Environment ◽  
Temporal Factor

In everyday life, our brains integrate various kinds of information from different modalities to perceive our complex environment. Spatial and temporal proximity of multisensory stimuli is required for multisensory integration. Many researches have shown that temporal asynchrony of visual-auditory stimuli can influence multisensory integration. However, the neural mechanisms of asynchrony inputs were not well understood. Some researchers believe that humans have a relatively broad time window, in which stimuli from different modalities and asynchronous inputs tends to be integrated into a single unified percept. Others believe that the human brain can actively coordinate the auditory and visual input so that we do not notice the asynchronous inputs of multisensory stimuli. This review focuses on the question of how the temporal factor affects the processing of audiovisual information.

scholarly journals Updating Existing Emotional Memories Involves the Frontopolar/Orbito-frontal Cortex in Ways that Acquiring New Emotional Memories Does Not

2011 ◽  
Vol 23 (11) ◽  
pp. 3498-3514 ◽  
Author(s):  
Michiko Sakaki ◽  
Kazuhisa Niki ◽  
Mara Mather
Keyword(s):  
Emotional Memory ◽  
Neural Mechanisms ◽  
Emotional Stimuli ◽  
Memory Updating ◽  
General Role ◽  
New Associations ◽  
Emotional Memories ◽  
Fmri Study ◽  
Initial Learning ◽  
Opposing Effects

In life, we must often learn new associations to people, places, or things we already know. The current fMRI study investigated the neural mechanisms underlying emotional memory updating. Nineteen participants first viewed negative and neutral pictures and learned associations between those pictures and other neutral stimuli, such as neutral objects and encoding tasks. This initial learning phase was followed by a memory updating phase, during which participants learned picture-location associations for old pictures (i.e., pictures previously associated with other neutral stimuli) and new pictures (i.e., pictures not seen in the first phase). There was greater frontopolar/orbito-frontal (OFC) activity when people learned picture–location associations for old negative pictures than for new negative pictures, but frontopolar OFC activity did not significantly differ during learning locations of old versus new neutral pictures. In addition, frontopolar activity was more negatively correlated with the amygdala when participants learned picture–location associations for old negative pictures than for new negative or old neutral pictures. Past studies revealed that the frontopolar OFC allows for updating the affective values of stimuli in reversal learning or extinction of conditioning [e.g., Izquierdo, A., & Murray, E. A. Opposing effects of amygdala and orbital PFC lesions on the extinction of instrumental responding in macaque monkeys. European Journal of Neuroscience, 22, 2341–2346, 2005]; our findings suggest that it plays a more general role in updating associations to emotional stimuli.

scholarly journals A neural circuit mechanism of categorical perception: top-down signaling in the primate cortex

2020 ◽  
Author(s):  
Bin Min ◽  
Daniel P. Bliss ◽  
Arup Sarma ◽  
David J. Freedman ◽  
Xiao-Jing Wang
Keyword(s):  
Visual Motion ◽  
Neural Circuit ◽  
Categorical Perception ◽  
Neural Mechanisms ◽  
Behavioral Data ◽  
Functional Explanation ◽  
Top Down ◽  
Delayed Matching ◽  
Feature Based ◽  
High Level

AbstractIn contrast to feedforward architecture commonly used in deep networks at the core of today’s AI revolution, the biological cortex is endowed with an abundance of feedback projections. Feedback signaling is often difficult to differentially identify, and its computational roles remain poorly understood. Here, we investigated a cognitive phenomenon, called categorical perception (CP), that reveals the influences of high-level category learning on low-level feature-based perception, as a putative signature of top-down signaling. By examining behavioral data from a visual motion delayed matching experiment in non-human primates, we found that, after categorization training, motion directions closer to (respectively, away from) a category center became more (less) difficult to discriminate. This distance-dependent discrimination performance change along the dimension relevant to the learned categories provides direct evidence for the CP phenomenon. To explain this experimental finding, we developed a neural circuit model that incorporated key neurophysiological findings in visual categorization, working memory and decision making. Our model accounts for the behavioral data indicative of CP, pinpoints its circuit basis, suggests novel experimentally testable predictions and provides a functional explanation for its existence. Our work shows that delayed matching paradigms in non-human primates combined with biologically-based modeling can serve as a promising model system for elucidating the neural mechanisms of CP, as a manifestation of top-down signaling in the cortex.Significant StatementCategorical perception is a cognitive phenomenon revealing the influences of high-level category learning on low-level feature-based perception. However, its underlying neural mechanisms are largely unknown. Here, we found behavioral evidence for this phenomenon from a visual motion delayed matching experiment in non-human primates. We developed a neural circuit model that can account for this behavioral data, pinpoints its circuit basis, suggests novel experimentally testable predictions and provides a functional explanation for its existence. Our work shows that delayed matching paradigms in non-human primates combined with biologically-based modeling can serve as a promising model system for elucidating the neural mechanisms of categorical perception, as a manifestation of top-down signaling in the cortex.

scholarly journals Audiovisual integration in the Mauthner cell enhances escape probability and reduces response latency

2021 ◽  
Author(s):  
Nicolas Martorell ◽  
Violeta Medan
Keyword(s):  
Multisensory Integration ◽  
Response Latency ◽  
Neural Circuit ◽  
Escape Behavior ◽  
Audiovisual Integration ◽  
Auditory Stimuli ◽  
Threat Detection ◽  
Direct Link ◽  
Neural Basis ◽  
Mauthner Cell

Fast and accurate threat detection is critically important for animal survival. Reducing perceptual ambiguity by integrating multiple sources of sensory information can enhance threat detection and reduce response latency. However, studies showing a direct link between behavioral correlates of multisensory integration and its underlying neural basis are rare. In fish, an explosive escape behavior known as C-start is driven by an identified neural circuit centered on the Mauthner cell. The Mauthner cell can trigger C-starts in response to visual and auditory stimuli allowing to investigate how multisensory integration in a single neuron affects behavioral outcome after threat detection. Here we demonstrate that in goldfish visual looms and brief auditory stimuli can be integrated to increase C-start probability and that this enhancement is inversely correlated to the saliency of the cues with weaker auditory cues producing a proportionally stronger multisensory effect. We also show that multisensory stimuli reduce response latency locked to the presentation of the auditory cue. Finally, we make a direct link between behavioral data and its underlying neural mechanism by reproducing empirical data with an integrate-and-fire computational model of the Mauthner cell.

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