@article {1679, title = {The marmoset monkey as a model for visual neuroscience.}, journal = {Neurosci Res}, volume = {93}, year = {2015}, month = {2015 Apr}, pages = {20-46}, abstract = {

The common marmoset (Callithrix jacchus) has been valuable as a primate model in biomedical research. Interest in this species has grown recently, in part due to the successful demonstration of transgenic marmosets. Here we examine the prospects of the marmoset model for visual neuroscience research, adopting a comparative framework to place the marmoset within a broader evolutionary context. The marmoset{\textquoteright}s small brain bears most of the organizational features of other primates, and its smooth surface offers practical advantages over the macaque for areal mapping, laminar electrode penetration, and two-photon and optical imaging. Behaviorally, marmosets are more limited at performing regimented psychophysical tasks, but do readily accept the head restraint that is necessary for accurate eye tracking and neurophysiology, and can perform simple discriminations. Their natural gaze behavior closely resembles that of other primates, with a tendency to focus on objects of social interest including faces. Their immaturity at birth and routine twinning also makes them ideal for the study of postnatal visual development. These experimental factors, together with the theoretical advantages inherent in comparing anatomy, physiology, and behavior across related species, make the marmoset an excellent model for visual neuroscience.

}, keywords = {Animals, Biological Evolution, Brain, Callithrix, Color Perception, Color Vision, Exploratory Behavior, Macaca, Models, Animal, Social Behavior, Vision, Binocular, Vision, Ocular, Visual Perception}, issn = {1872-8111}, doi = {10.1016/j.neures.2015.01.008}, author = {Mitchell, Jude F and Leopold, David A} } @article {198, title = {Active vision in marmosets: a model system for visual neuroscience.}, journal = {J Neurosci}, volume = {34}, year = {2014}, month = {2014 Jan 22}, pages = {1183-94}, abstract = {

The common marmoset (Callithrix jacchus), a small-bodied New World primate, offers several advantages to complement vision research in larger primates. Studies in the anesthetized marmoset have detailed the anatomy and physiology of their visual system (Rosa et al., 2009) while studies of auditory and vocal processing have established their utility for awake and behaving neurophysiological investigations (Lu et al., 2001a,b; Eliades and Wang, 2008a,b; Osmanski and Wang, 2011; Remington et al., 2012). However, a critical unknown is whether marmosets can perform visual tasks under head restraint. This has been essential for studies in macaques, enabling both accurate eye tracking and head stabilization for neurophysiology. In one set of experiments we compared the free viewing behavior of head-fixed marmosets to that of macaques, and found that their saccadic behavior is comparable across a number of saccade metrics and that saccades target similar regions of interest including faces. In a second set of experiments we applied behavioral conditioning techniques to determine whether the marmoset could control fixation for liquid reward. Two marmosets could fixate a central point and ignore peripheral flashing stimuli, as needed for receptive field mapping. Both marmosets also performed an orientation discrimination task, exhibiting a saturating psychometric function with reliable performance and shorter reaction times for easier discriminations. These data suggest that the marmoset is a viable model for studies of active vision and its underlying neural mechanisms.

}, keywords = {Animals, Callithrix, Conditioning, Operant, Models, Animal, Neurophysiology, Neurosciences, Saccades, Vision, Ocular, Visual Perception}, issn = {1529-2401}, doi = {10.1523/JNEUROSCI.3899-13.2014}, author = {Mitchell, Jude F and Reynolds, John H and Miller, Cory T} } @article {203, title = {Gamma band activity and the P3 reflect post-perceptual processes, not visual awareness.}, journal = {Neuroimage}, volume = {101}, year = {2014}, month = {2014 Nov 1}, pages = {337-50}, abstract = {

A primary goal in cognitive neuroscience is to identify neural correlates of conscious perception (NCC). By contrasting conditions in which subjects are aware versus unaware of identical visual stimuli, a number of candidate NCCs have emerged; among them are induced gamma band activity in the EEG and the P3 event-related potential. In most previous studies, however, the critical stimuli were always directly relevant to the subjects{\textquoteright} task, such that aware versus unaware contrasts may well have included differences in post-perceptual processing in addition to differences in conscious perception per se. Here, in a series of EEG experiments, visual awareness and task relevance were manipulated independently. Induced gamma activity and the P3 were absent for task-irrelevant stimuli regardless of whether subjects were aware of such stimuli. For task-relevant stimuli, gamma and the P3 were robust and dissociable, indicating that each reflects distinct post-perceptual processes necessary for carrying-out the task but not for consciously perceiving the stimuli. Overall, this pattern of results challenges a number of previous proposals linking gamma band activity and the P3 to conscious perception.

}, keywords = {Adult, Attention, Awareness, Consciousness, Electroencephalography, Event-Related Potentials, P300, Female, Gamma Rhythm, Humans, Male, Psychomotor Performance, Visual Perception, Young Adult}, issn = {1095-9572}, doi = {10.1016/j.neuroimage.2014.07.024}, author = {Pitts, Michael A and Padwal, Jennifer and Fennelly, Daniel and Mart{\'\i}nez, Ant{\'\i}gona and Hillyard, Steven A} } @article {1671, title = {Rats and humans differ in processing collinear visual features.}, journal = {Front Neural Circuits}, volume = {7}, year = {2013}, month = {2013}, pages = {197}, abstract = {

Behavioral studies in humans and rats demonstrate that visual detection of a target stimulus is sensitive to surrounding spatial patterns. In both species, the detection of an oriented visual target is affected when the surrounding region contains flanking stimuli that are collinear to the target. In many studies, collinear flankers have been shown to improve performance in humans, both absolutely (compared to performance with no flankers) and relative to non-collinear flankers. More recently, collinear flankers have been shown to impair performance in rats both absolutely and relative to non-collinear flankers. However, these observations spanned different experimental paradigms. Past studies in humans have shown that the magnitude and even sign of flanker effects can depend critically on the details of stimulus and task design. Therefore either task differences or species could explain the opposite findings. Here we provide a direct comparison of behavioral data between species and show that these differences persist--collinear flankers improve performance in humans, and impair performance in rats--in spite of controls that match stimuli, experimental paradigm, and learning procedure. There is evidence that the contrasts of the target and the flankers could affect whether surround processing is suppressive or facilitatory. In a second experiment, we explored a range of contrast conditions in the rat, to determine if contrast could explain the lack of collinear facilitation. Using different pairs of target and flanker contrast, the rat{\textquoteright}s collinear impairment was confirmed to be robust across a range of contrast conditions. We conclude that processing of collinear features is indeed different between rats and humans. We speculate that the observed difference between rat and human is caused by the combined impact of differences in the statistics in natural retinal images, the representational capacity of neurons in visual cortex, and attention.

}, keywords = {Animals, Attention, Contrast Sensitivity, Humans, Orientation, Pattern Recognition, Visual, Photic Stimulation, Rats, Visual Cortex, Visual Perception}, issn = {1662-5110}, doi = {10.3389/fncir.2013.00197}, author = {Meier, Philip M and Reinagel, Pamela} } @article {202, title = {Visual processing of contour patterns under conditions of inattentional blindness.}, journal = {J Cogn Neurosci}, volume = {24}, year = {2012}, month = {2012 Feb}, pages = {287-303}, abstract = {

An inattentional blindness paradigm was adapted to measure ERPs elicited by visual contour patterns that were or were not consciously perceived. In the first phase of the experiment, subjects performed an attentionally demanding task while task-irrelevant line segments formed square-shaped patterns or random configurations. After the square patterns had been presented 240 times, subjects{\textquoteright} awareness of these patterns was assessed. More than half of all subjects, when queried, failed to notice the square patterns and were thus considered inattentionally blind during this first phase. In the second phase of the experiment, the task and stimuli were the same, but following this phase, all of the subjects reported having seen the patterns. ERPs recorded over the occipital pole differed in amplitude from 220 to 260 msec for the pattern stimuli compared with the random arrays regardless of whether subjects were aware of the patterns. At subsequent latencies (300-340 msec) however, ERPs over bilateral occipital-parietal areas differed between patterns and random arrays only when subjects were aware of the patterns. Finally, in a third phase of the experiment, subjects viewed the same stimuli, but the task was altered so that the patterns became task relevant. Here, the same two difference components were evident but were followed by a series of additional components that were absent in the first two phases of the experiment. We hypothesize that the ERP difference at 220-260 msec reflects neural activity associated with automatic contour integration whereas the difference at 300-340 msec reflects visual awareness, both of which are dissociable from task-related postperceptual processing.

}, keywords = {Adult, Attention, Awareness, Brain, Brain Mapping, Electroencephalography, Evoked Potentials, Visual, Female, Humans, Male, Perceptual Masking, Photic Stimulation, Reaction Time, Visual Perception}, issn = {1530-8898}, doi = {10.1162/jocn_a_00111}, author = {Pitts, Michael A and Mart{\'\i}nez, Ant{\'\i}gona and Hillyard, Steven A} } @article {195, title = {Rat performance on visual detection task modeled with divisive normalization and adaptive decision thresholds.}, journal = {J Vis}, volume = {11}, year = {2011}, month = {2011}, abstract = {

Performance on any perceptual task depends on both the perceptual capacity and the decision strategy of the subject. We provide a model to fit both aspects and apply it to data from rats performing a detection task. When rats must detect a faint visual target, the presence of other nearby stimuli ("flankers") increases the difficulty of the task. In this study, we consider two specific factors. First, flankers could diminish the sensory response to the target via spatial contrast normalization in early visual processing. Second, rats may treat the sensory signal caused by the flankers as if it belonged to the target. We call this source confusion, which may be sensory, cognitive, or both. We account for contrast normalization and source confusion by fitting model parameters to the likelihood of the observed behavioral data. We test multiple combinations of target and flanker contrasts using a yes/no detection task. Contrast normalization was crucial to explain the rats{\textquoteright} flanker-induced detection impairment. By adding a decision variable to the contrast normalization framework, our model provides a new tool to assess differences in visual or cognitive brain function between normal and abnormal rodents.

}, keywords = {Adaptation, Physiological, Animals, Choice Behavior, Cognition, Conditioning (Psychology), Contrast Sensitivity, Male, Models, Neurological, Photic Stimulation, Psychomotor Performance, Rats, Rats, Long-Evans, Visual Perception}, issn = {1534-7362}, doi = {10.1167/11.9.1}, author = {Meier, Philip and Reinagel, Pamela} } @article {147, title = {Dopaminergic modulation of arousal in Drosophila.}, journal = {Curr Biol}, volume = {15}, year = {2005}, month = {2005 Jul 12}, pages = {1165-75}, abstract = {

BACKGROUND: Arousal levels in the brain set thresholds for behavior, from simple to complex. The mechanistic underpinnings of the various phenomena comprising arousal, however, are still poorly understood. Drosophila behaviors have been studied that span different levels of arousal, from sleep to visual perception to psychostimulant responses.

RESULTS: We have investigated neurobiological mechanisms of arousal in the Drosophila brain by a combined behavioral, genetic, pharmacological, and electrophysiological approach. Administration of methamphetamine (METH) suppresses sleep and promotes active wakefulness, whereas an inhibitor of dopamine synthesis promotes sleep. METH affects courtship behavior by increasing sexual arousal while decreasing successful sexual performance. Electrophysiological recordings from the medial protocerebrum of wild-type flies showed that METH ingestion has rapid and detrimental effects on a brain response associated with perception of visual stimuli. Recordings in genetically manipulated animals show that dopaminergic transmission is required for these responses and that visual-processing deficits caused by attenuated dopaminergic transmission can be rescued by METH.

CONCLUSIONS: We show that changes in dopamine levels differentially affect arousal for behaviors of varying complexity. Complex behaviors, such as visual perception, degenerate when dopamine levels are either too high or too low, in accordance with the inverted-U hypothesis of dopamine action in the mammalian brain. Simpler behaviors, such as sleep and locomotion, show graded responses that follow changes in dopamine level.

}, keywords = {Animals, Animals, Genetically Modified, Arousal, Brain, Dopa Decarboxylase, Dopamine, Dose-Response Relationship, Drug, Drosophila, Drosophila Proteins, Dynamins, Electrophysiology, Methamphetamine, Mutation, Sexual Behavior, Animal, Sleep, Visual Perception}, issn = {0960-9822}, doi = {10.1016/j.cub.2005.05.025}, author = {Andretic, Rozi and van Swinderen, Bruno and Greenspan, Ralph J} } @article {149, title = {Salience modulates 20-30 Hz brain activity in Drosophila.}, journal = {Nat Neurosci}, volume = {6}, year = {2003}, month = {2003 Jun}, pages = {579-86}, abstract = {

Fruit flies selectively orient toward the visual stimuli that are most salient in their environment. We recorded local field potentials (LFPs) from the brains of Drosophila melanogaster as they responded to the presentation of visual stimuli. Coupling of salience effects (odor, heat or novelty) to these stimuli modulated LFPs in the 20-30 Hz range by evoking a transient, selective increase. We demonstrated the association of these responses with behavioral tracking and initiated a genetic approach to investigating neural correlates of perception.

}, keywords = {Action Potentials, Animals, Attention, Behavior, Animal, Brain, Cues, Drosophila, Drosophila Proteins, Exploratory Behavior, Mutation, Neurons, Orientation, Retina, Smell, Synaptic Transmission, Thermosensing, Visual Pathways, Visual Perception}, issn = {1097-6256}, doi = {10.1038/nn1054}, author = {van Swinderen, Bruno and Greenspan, Ralph J} }