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1.
Sci Data ; 9(1): 182, 2022 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-35440786

RESUMO

Establishing the cortical neural representation of visual stimuli is a central challenge of systems neuroscience. Publicly available data would allow a broad range of scientific analyses and hypothesis testing, but are rare and largely focused on the early visual system. To address the shortage of open data from higher visual areas, we provide a comprehensive dataset from a neurophysiology study in macaque monkey visual cortex that includes a complete record of extracellular action potential recordings from the extrastriate medial superior temporal (MST) area, behavioral data, and detailed stimulus records. It includes spiking activity of 172 single neurons recorded in 139 sessions from 4 hemispheres of 3 rhesus macaque monkeys. The data was collected across 3 experiments, designed to characterize the response properties of MST neurons to complex motion stimuli. This data can be used to elucidate visual information processing at the level of single neurons in a high-level area of primate visual cortex. Providing open access to this dataset also promotes the 3R-principle of responsible animal research.


Assuntos
Macaca mulatta , Percepção de Movimento , Córtex Visual , Animais , Eletrocorticografia , Movimento (Física) , Percepção de Movimento/fisiologia , Lobo Temporal , Córtex Visual/fisiologia , Vias Visuais/fisiologia
2.
Trends Neurosci ; 45(4): 323-335, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35190202

RESUMO

Oscillatory neural activity is believed to have a central role in information processing in the mammalian brain. While early studies often focussed on the function of individual frequency bands, there is emerging appreciation for the role of simultaneous activity in many distinct frequency bands and the interactions between them in high-level cognitive functions. Here, we focus on the role of cross-frequency coupling (CFC) in visual attention. First, we propose a framework that reconciles previous contrasting findings, showing how CFC could have a functional role on both intra- and interareal scales. Second, we outline how CFC between distinct frequency bands could label different submodalities of sensory information. Overall, our scheme provides a novel perspective of how interfrequency interaction contributes to efficient and dynamic processing of information across the brain.


Assuntos
Encéfalo , Mamíferos , Animais , Humanos
3.
Infancy ; 27(2): 433-458, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34981647

RESUMO

Theories of visual attention suggest a cascading development of subfunctions such as alertness, spatial orientation, attention to object features, and endogenous control. Here, we aimed to track infants' visual developmental steps from a primarily exogenously to more endogenously controlled processing style during their first months of life. In this repeated measures study, 51 infants participated in seven fortnightly assessments at postterm ages of 4-16 weeks. Infants were presented with the same set of static and dynamic paired comparison stimuli in each assessment. Visual behavior was evaluated by a newly introduced scoring scheme. Our results confirmed the suggested visual developmental hierarchy and clearly demonstrated the suitability of our scoring scheme for documenting developmental changes in visual attention during early infancy. Besides the general ontogenetic course of development, we also discuss intra- and interindividual differences which may affect single assessments, and highlight the importance of repeated measurements for reliable evaluation of developmental changes.


Assuntos
Desenvolvimento Infantil , Resolução de Problemas , Humanos , Lactente , Recém-Nascido
4.
Eur Surg Res ; 2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34915502

RESUMO

Understanding the impact routine research and laboratory procedures have on animals is crucial to improving their wellbeing and to the success and reproducibility of the research they are involved in. Cognitive measures of welfare offer insight into animals' internal psychological state, but require validation. Attention bias - the tendency to attend to one type of information over another - is a cognitive phenomenon documented in humans and animals that is known to be modulated by affective state (i.e., emotions). Hence, changes in attention bias may offer researchers a deeper perspective of their animals' psychological wellbeing. The dot-probe task is an established method for quantifying attention bias in humans (by measuring reaction time to a dot-probe replacing pairs of stimuli), but has yet to be validated in animals. We developed a dot-probe task for long-tailed macaques (Macaca fascicularis) to determine if the task can detect changes in attention bias following anesthesia, a context known to modulate attention and trigger physiological arousal in macaques. Our task included the following features: stimulus pairs of threatening and neutral facial expressions of conspecifics and their scrambled counterparts, two stimuli durations (100 and 1000 ms), and counterbalancing of the dot-probe's position on the touchscreen (left, right) and location relative to the threatening stimulus. We tested eight group-housed adult females on different days relative to being anesthetized (baseline and one-, three-, seven-, and 14-days after). At baseline, monkeys were vigilant to threatening content when stimulus pairs were presented for 100 ms, but not 1000 ms. On the day immediately following anesthesia, we found evidence that attention bias changed to an avoidance of threatening content. Attention bias returned to threat vigilance by the third day post-anesthesia and remained so up to the last day of testing (14 days after anesthesia). We also found that attention bias was independent of the type of stimuli pair (i.e., whole face vs. scrambled counterparts), suggesting that the scrambled stimuli retained aspects of the original stimuli. Nevertheless, whole faces were more salient to the monkeys as responses to these trials were generally slower than to scrambled stimulus pairs. Overall, our study suggests it is feasible to detect changes in attention bias following anesthesia using the dot-probe task in non-human primates. Our results also reveal important aspects of stimulus preparation and experimental design.

5.
Front Hum Neurosci ; 15: 685830, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34366813

RESUMO

Real-time gaze tracking provides crucial input to psychophysics studies and neuromarketing applications. Many of the modern eye-tracking solutions are expensive mainly due to the high-end processing hardware specialized for processing infrared-camera pictures. Here, we introduce a deep learning-based approach which uses the video frames of low-cost web cameras. Using DeepLabCut (DLC), an open-source toolbox for extracting points of interest from videos, we obtained facial landmarks critical to gaze location and estimated the point of gaze on a computer screen via a shallow neural network. Tested for three extreme poses, this architecture reached a median error of about one degree of visual angle. Our results contribute to the growing field of deep-learning approaches to eye-tracking, laying the foundation for further investigation by researchers in psychophysics or neuromarketing.

6.
PLoS One ; 16(6): e0253067, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34153081

RESUMO

Modern accounts of visual motion processing in the primate brain emphasize a hierarchy of different regions within the dorsal visual pathway, especially primary visual cortex (V1) and the middle temporal area (MT). However, recent studies have called the idea of a processing pipeline with fixed contributions to motion perception from each area into doubt. Instead, the role that each area plays appears to depend on properties of the stimulus as well as perceptual history. We propose to test this hypothesis in human subjects by comparing motion perception of two commonly used stimulus types: drifting sinusoidal gratings (DSGs) and random dot patterns (RDPs). To avoid potential biases in our approach we are pre-registering our study. We will compare the effects of size and contrast levels on the perception of the direction of motion for DSGs and RDPs. In addition, based on intriguing results in a pilot study, we will also explore the effects of a post-stimulus mask. Our approach will offer valuable insights into how motion is processed by the visual system and guide further behavioral and neurophysiological research.


Assuntos
Percepção de Movimento/fisiologia , Neurônios/fisiologia , Estimulação Luminosa/métodos , Córtex Visual/fisiologia , Campos Visuais/fisiologia , Vias Visuais/fisiologia , Percepção Visual/fisiologia , Humanos
7.
BMC Biol ; 19(1): 49, 2021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-33726757

RESUMO

BACKGROUND: Attentional modulation in the visual cortex of primates is characterized by multiplicative changes of sensory responses with changes in the attentional state of the animal. The cholinergic system has been linked to such gain changes in V1. Here, we aim to determine if a similar link exists in macaque area MT. While rhesus monkeys performed a top-down spatial attention task, we locally injected a cholinergic agonist or antagonist and recorded single-cell activity. RESULTS: Although we confirmed cholinergic influences on sensory responses, there was no additional cholinergic effect on the attentional gain changes. Neither a muscarinic blockage nor a local increase in acetylcholine led to a significant change in the magnitude of spatial attention effects on firing rates. CONCLUSIONS: This suggests that the cellular mechanisms of attentional modulation in the extrastriate cortex cannot be directly inferred from those in the primary visual cortex.


Assuntos
Atenção/fisiologia , Agonistas Colinérgicos/farmacologia , Antagonistas Colinérgicos/farmacologia , Macaca mulatta/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Acetilcolina/farmacologia , Animais , Atenção/efeitos dos fármacos , Masculino , Mecamilamina/farmacologia , Escopolamina/farmacologia , Córtex Visual/efeitos dos fármacos , Percepção Visual/efeitos dos fármacos
8.
J Neurophysiol ; 125(5): 1851-1882, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33656951

RESUMO

Primate visual cortex consists of dozens of distinct brain areas, each providing a highly specialized component to the sophisticated task of encoding the incoming sensory information and creating a representation of our visual environment that underlies our perception and action. One such area is the medial superior temporal cortex (MST), a motion-sensitive, direction-selective part of the primate visual cortex. It receives most of its input from the middle temporal (MT) area, but MST cells have larger receptive fields and respond to more complex motion patterns. The finding that MST cells are tuned for optic flow patterns has led to the suggestion that the area plays an important role in the perception of self-motion. This hypothesis has received further support from studies showing that some MST cells also respond selectively to vestibular cues. Furthermore, the area is part of a network that controls the planning and execution of smooth pursuit eye movements and its activity is modulated by cognitive factors, such as attention and working memory. This review of more than 90 studies focuses on providing clarity of the heterogeneous findings on MST in the macaque cortex and its putative homolog in the human cortex. From this analysis of the unique anatomical and functional position in the hierarchy of areas and processing steps in primate visual cortex, MST emerges as a gateway between perception, cognition, and action planning. Given this pivotal role, this area represents an ideal model system for the transition from sensation to cognition.


Assuntos
Cognição/fisiologia , Macaca/fisiologia , Percepção de Movimento/fisiologia , Sensação/fisiologia , Lobo Temporal/fisiologia , Córtex Visual/fisiologia , Animais , Humanos , Lobo Temporal/anatomia & histologia , Córtex Visual/anatomia & histologia
9.
Neuroimage ; 229: 117757, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33460801

RESUMO

We effortlessly perceive visual objects as unified entities, despite the preferential encoding of their various visual features in separate cortical areas. A 'binding' process is assumed to be required for creating this unified percept, but the underlying neural mechanism and specific brain areas are poorly understood. We investigated 'feature-binding' across two feature dimensions, using a novel stimulus configuration, designed to disambiguate whether a given combination of color and motion direction is perceived as bound or unbound. In the "bound" condition, two behaviorally relevant features (color and motion) belong to the same object, while in the "unbound" condition they belong to different objects. We recorded local field potentials from the lateral prefrontal cortex (lPFC) in macaque monkeys that actively monitored the different stimulus configurations. Our data show a neural representation of visual feature binding especially in the 4-12 Hz frequency band and a transmission of binding information between different lPFC neural subpopulations. This information is linked to the animal's reaction time, suggesting a behavioral relevance of the binding information. Together, our results document the involvement of the prefrontal cortex, targeted by the dorsal and ventral visual streams, in binding visual features from different dimensions, in a process that includes a dynamic modulation of low frequency inter-regional communication.


Assuntos
Percepção de Cores/fisiologia , Percepção de Movimento/fisiologia , Estimulação Luminosa/métodos , Córtex Pré-Frontal/fisiologia , Tempo de Reação/fisiologia , Animais , Macaca , Masculino , Córtex Pré-Frontal/diagnóstico por imagem , Percepção Visual/fisiologia
10.
Sci Rep ; 10(1): 20604, 2020 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-33244086

RESUMO

Small ballistic eye movements, so called microsaccades, occur even while foveating an object. Previous studies using covert attention tasks have shown that shortly after a symbolic spatial cue, specifying a behaviorally relevant location, microsaccades tend to be directed toward the cued location. This suggests that microsaccades can serve as an index for the covert orientation of spatial attention. However, this hypothesis faces two major challenges: First, effects associated with visual spatial attention are hard to distinguish from those that associated with the contemplation of foveating a peripheral stimulus. Second, it is less clear whether endogenously sustained attention alone can bias microsaccade directions without a spatial cue on each trial. To address the first issue, we investigated the direction of microsaccades in human subjects while they attended to a behaviorally relevant location and prepared a response eye movement either toward or away from this location. We find that directions of microsaccades are biased toward the attended location rather than towards the saccade target. To tackle the second issue, we verbally indicated the location to attend before the start of each block of trials, to exclude potential visual cue-specific effects on microsaccades. Our results indicate that sustained spatial attention alone reliably produces the microsaccade direction effect. Overall, our findings demonstrate that sustained spatial attention alone, even in the absence of saccade planning or a spatial cue, is sufficient to explain the direction bias observed in microsaccades.


Assuntos
Atenção , Movimentos Sacádicos , Adulto , Feminino , Humanos , Masculino , Orientação Espacial , Percepção Espacial , Percepção Visual , Adulto Jovem
12.
Front Psychol ; 11: 1645, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32765373

RESUMO

Following the expanding use and applications of virtual reality in everyday life, realistic virtual stimuli are of increasing interest in cognitive studies. They allow for control of features such as gaze, expression, appearance, and movement, which may help to overcome limitations of using photographs or video recordings to study social responses. In using virtual stimuli however, one must be careful to avoid the uncanny valley effect, where realistic stimuli can be perceived as eerie, and induce an aversion response. At the same time, it is important to establish whether responses to virtual stimuli mirror responses to depictions of a real conspecific. In the current study, we describe the development of a new virtual monkey head with realistic facial features for experiments with nonhuman primates, the "Primatar." As a first step toward validation, we assessed how monkeys respond to facial images of a prototype of this Primatar compared to images of real monkeys (RMs), and an unrealistic model. We also compared gaze responses between original images and scrambled as well as obfuscated versions of these images. We measured looking time to images in six freely moving long-tailed macaques (Macaca fascicularis) and gaze exploration behavior in three rhesus macaques (Macaca mulatta). Both groups showed more signs of overt attention to original images than scrambled or obfuscated images. In addition, we found no evidence for an uncanny valley effect; since for both groups, looking times did not differ between real, realistic, or unrealistic images. These results provide important data for further development of our Primatar for use in social cognition studies and more generally for cognitive research with virtual stimuli in nonhuman primates. Future research on the absence of an uncanny valley effect in macaques is needed, to elucidate the roots of this mechanism in humans.

13.
Proc Natl Acad Sci U S A ; 117(39): 24022-24031, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32817435

RESUMO

The recently developed new genome-editing technologies, such as the CRISPR/Cas system, have opened the door for generating genetically modified nonhuman primate (NHP) models for basic neuroscience and brain disorders research. The complex circuit formation and experience-dependent refinement of the human brain are very difficult to model in vitro, and thus require use of in vivo whole-animal models. For many neurodevelopmental and psychiatric disorders, abnormal circuit formation and refinement might be at the center of their pathophysiology. Importantly, many of the critical circuits and regional cell populations implicated in higher human cognitive function and in many psychiatric disorders are not present in lower mammalian brains, while these analogous areas are replicated in NHP brains. Indeed, neuropsychiatric disorders represent a tremendous health and economic burden globally. The emerging field of genetically modified NHP models has the potential to transform our study of higher brain function and dramatically facilitate the development of effective treatment for human brain disorders. In this paper, we discuss the importance of developing such models, the infrastructure and training needed to maximize the impact of such models, and ethical standards required for using these models.


Assuntos
Experimentação Animal/ética , Modelos Animais de Doenças , Transtornos Mentais/genética , Doenças do Sistema Nervoso/genética , Primatas/genética , Animais , Transtornos Mentais/fisiopatologia , Doenças do Sistema Nervoso/fisiopatologia , Neurociências/ética , Neurociências/métodos , Primatas/fisiologia
14.
Sci Rep ; 10(1): 11051, 2020 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-32632196

RESUMO

Optogenetics offers unprecedented possibilities to investigate cortical networks. Yet, the number of successful optogenetic applications in non-human primates is still low, and the consequences of opsin expression in the primate brain are not well documented. We assessed histologically if we can target cerebrocortical networks with three common optogenetic constructs (AAV2/5-CaMKIIα-eNpHR3.0-mCherry, -ChR2-eYFP, -C1V1-mCherry). The frontal eye field or the dorsal premotor area of rhesus macaques were virally injected, and the resulting transduction spread, expression specificity, and opsin trafficking into axons projecting to parietal and visual areas were examined. After variable periods (2-24 months), expression was robust for all constructs at the injection sites. The CaMKIIα promoter driven-expression was predominant, but not exclusive, in excitatory neurons. In the case of eNpHR3.0-mCherry and ChR2-eYFP, opsins were present in axonal projections to target areas, in which sparse, retrogradely transduced neurons could also be found. Finally, the intracellular distribution of opsins differed: ChR2-eYFP had almost exclusive membrane localization, while eNpHR3.0-mCherry and C1V1-mCherry showed additional intracellular accumulations, which might affect neuronal survival in the long-term. Results indicate that all three constructs can be used for local neuronal modulation, but axonal stimulation and long-term use require additional considerations of construct selection and verification.


Assuntos
Córtex Cerebral/anatomia & histologia , Macaca mulatta/anatomia & histologia , Optogenética/métodos , Animais , Córtex Cerebral/citologia , Córtex Cerebral/fisiologia , Lobo Frontal/anatomia & histologia , Lobo Frontal/fisiologia , Proteínas Luminescentes/metabolismo , Macaca mulatta/fisiologia , Masculino , Modelos Neurológicos , Rede Nervosa/anatomia & histologia , Rede Nervosa/fisiologia , Opsinas/metabolismo , Lobo Parietal/anatomia & histologia , Lobo Parietal/fisiologia , Córtex Visual/anatomia & histologia , Córtex Visual/fisiologia
15.
Nat Commun ; 11(1): 2128, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358494

RESUMO

Attention enhances the neural representations of behaviorally relevant stimuli, typically by a push-pull increase of the neuronal response gain to attended vs. unattended stimuli. This selectively improves perception and consequently behavioral performance. However, to enhance the detectability of stimulus changes, attention might also distort neural representations, compromising accurate stimulus representation. We test this hypothesis by recording neural responses in the visual cortex of rhesus monkeys during a motion direction change detection task. We find that attention indeed amplifies the neural representation of direction changes, beyond a similar effect of adaptation. We further show that humans overestimate such direction changes, providing a perceptual correlate of our neurophysiological observations. Our results demonstrate that attention distorts the neural representations of abrupt sensory changes and consequently perceptual accuracy. This likely represents an evolutionary adaptive mechanism that allows sensory systems to flexibly forgo accurate representation of stimulus features to improve the encoding of stimulus change.


Assuntos
Atenção/fisiologia , Eletrofisiologia , Percepção Visual/fisiologia , Adulto , Animais , Feminino , Humanos , Macaca mulatta , Masculino , Neurônios/citologia , Neurônios/metabolismo , Córtex Visual/fisiologia , Adulto Jovem
16.
Sci Rep ; 10(1): 4837, 2020 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-32179777

RESUMO

Attention selectively routes the most behaviorally relevant information from the stream of sensory inputs through the hierarchy of cortical areas. Previous studies have shown that visual attention depends on the phase of oscillatory brain activities. These studies mainly focused on the stimulus presentation period, rather than the pre-stimulus period. Here, we hypothesize that selective attention controls the phase of oscillatory neural activities to efficiently process relevant information. We document an attentional modulation of pre-stimulus inter-trial phase coherence (a measure of deviation between instantaneous phases of trials) of low frequency local field potentials (LFP) in visual area MT of macaque monkeys. Our data reveal that phase coherence increases following a spatial cue deploying attention towards the receptive field of the recorded neural population. We further show that the attentional enhancement of phase coherence is positively correlated with the modulation of the stimulus-induced firing rate, and importantly, a higher phase coherence is associated with a faster behavioral response. These results suggest a functional utilization of intrinsic neural oscillatory activities for an enhanced processing of upcoming stimuli.


Assuntos
Atenção/fisiologia , Neurônios/fisiologia , Estimulação Luminosa/métodos , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Animais , Potenciais Evocados Visuais , Macaca
17.
Sci Rep ; 10(1): 4216, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-32144331

RESUMO

The lateral prefrontal cortex of primates (lPFC) plays a central role in complex cognitive behavior, in decision-making as well as in guiding top-down attention. However, how and where in lPFC such behaviorally relevant signals are computed is poorly understood. We analyzed neural recordings from chronic microelectrode arrays implanted in lPFC region 8Av/45 of two rhesus macaques. The animals performed a feature match-to-sample task requiring them to match both motion and color information in a test stimulus. This task allowed to separate the encoding of stimulus motion and color from their current behavioral relevance on a trial-by-trial basis. We found that upcoming motor behavior can be robustly predicted from lPFC activity. In addition, we show that 8Av/45 encodes the color of a visual stimulus, regardless of its behavioral relevance. Most notably, whether a color matches the searched-for color can be decoded independent of a trial's motor outcome and while subjects detect unique feature conjunctions of color and motion. Thus, macaque area 8Av/45 computes, among other task-relevant information, the behavioral relevance of visual color features. Such a signal is most critical for both the selection of responses as well as the deployment of top-down modulatory signals, like feature-based attention.


Assuntos
Potenciais de Ação , Atenção/fisiologia , Comportamento Animal , Cor , Percepção de Movimento/fisiologia , Estimulação Luminosa , Córtex Pré-Frontal/fisiologia , Animais , Mapeamento Encefálico , Macaca mulatta , Masculino , Tempo de Reação
18.
PLoS Biol ; 17(8): e3000387, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31386656

RESUMO

Attending to visual stimuli enhances the gain of those neurons in primate visual cortex that preferentially respond to the matching locations and features (on-target gain). Although this is well suited to enhance the neuronal representation of attended stimuli, it is nonoptimal under difficult discrimination conditions, as in the presence of similar distractors. In such cases, directing attention to neighboring neuronal populations (off-target gain) has been shown to be the most efficient strategy, but although such a strategic deployment of attention has been shown behaviorally, its underlying neural mechanisms are unknown. Here, we investigated how attention affects the population responses of neurons in the middle temporal (MT) visual area of rhesus monkeys to bidirectional movement inside the neurons' receptive field (RF). The monkeys were trained to focus their attention onto the fixation spot or to detect a direction or speed change in one of the motion directions (the "target"), ignoring the distractor motion. Population activity profiles were determined by systematically varying the patterns' directions while maintaining a constant angle between them. As expected, the response profiles show a peak for each of the 2 motion directions. Switching spatial attention from the fixation spot into the RF enhanced the peak representing the attended stimulus and suppressed the distractor representation. Importantly, the population data show a direction-dependent attentional modulation that does not peak at the target feature but rather along the slopes of the activity profile representing the target direction. Our results show that attentional gains are strategically deployed to optimize the discriminability of target stimuli, in line with an optimal gain mechanism proposed by Navalpakkam and Itti.


Assuntos
Atenção/fisiologia , Percepção de Movimento/fisiologia , Córtex Visual/metabolismo , Potenciais de Ação/fisiologia , Animais , Macaca mulatta/fisiologia , Masculino , Neurônios/metabolismo , Neurônios/fisiologia , Estimulação Luminosa/métodos , Primatas/fisiologia , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Lobo Temporal/fisiologia , Córtex Visual/fisiologia
19.
J Biomed Opt ; 24(7): 1-11, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31286726

RESUMO

To refine animal research, vital signs, activity, stress, and pain must be monitored. In chronic studies, some measures can be assessed using telemetry sensors. Although this methodology provides high-precision data, an initial surgery for device implantation is necessary, potentially leading to stress, wound infections, and restriction of motion. Recently, camera systems have been adapted for animal research. We give an overview of parameters that can be assessed using imaging in the visible, near-infrared, and thermal spectrum of light. It focuses on heart activity, respiration, oxygen saturation, and motion, as well as on wound analysis. For each parameter, we offer recommendations on the minimum technical requirements of appropriate systems, regions of interest, and light conditions, among others. In general, these systems demonstrate great performance. For heart and respiratory rate, the error was <4 beats / min and 5 breaths/min. Furthermore, the systems are capable of tracking animals during different behavioral tasks. Finally, studies indicate that inhomogeneous temperature distribution around wounds might be an indicator of (pending) infections. In sum, camera-based techniques have several applications in animal research. As vital parameters are currently only assessed in sedated animals, the next step should be the integration of these modalities in home-cage monitoring.


Assuntos
Monitorização Fisiológica , Imagem Óptica , Gravação em Vídeo , Animais , Frequência Cardíaca/fisiologia , Ciência dos Animais de Laboratório , Camundongos , Movimento/fisiologia , Oxigênio/sangue , Ratos , Termografia , Cicatrização/fisiologia
20.
Proc Natl Acad Sci U S A ; 116(25): 12506-12515, 2019 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-31147468

RESUMO

Efficient transfer of sensory information to higher (motor or associative) areas in primate visual cortical areas is crucial for transforming sensory input into behavioral actions. Dynamically increasing the level of coordination between single neurons has been suggested as an important contributor to this efficiency. We propose that differences between the functional coordination in different visual pathways might be used to unambiguously identify the source of input to the higher areas, ensuring a proper routing of the information flow. Here we determined the level of coordination between neurons in area MT in macaque visual cortex in a visual attention task via the strength of synchronization between the neurons' spike timing relative to the phase of oscillatory activities in local field potentials. In contrast to reports on the ventral visual pathway, we observed the synchrony of spikes only in the range of high gamma (180 to 220 Hz), rather than gamma (40 to 70 Hz) (as reported previously) to predict the animal's reaction speed. This supports a mechanistic role of the phase of high-gamma oscillatory activity in dynamically modulating the efficiency of neuronal information transfer. In addition, for inputs to higher cortical areas converging from the dorsal and ventral pathway, the distinct frequency bands of these inputs can be leveraged to preserve the identity of the input source. In this way source-specific oscillatory activity in primate cortex can serve to establish and maintain "functionally labeled lines" for dynamically adjusting cortical information transfer and multiplexing converging sensory signals.


Assuntos
Sincronização Cortical , Macaca/fisiologia , Córtex Visual/fisiologia , Potenciais de Ação/fisiologia , Animais , Comportamento Animal , Masculino , Vias Visuais/fisiologia
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