Transition of target-location signaling in activity of macaque lateral intraparietal neurons during delayed-response visual search

2014 ◽  
Vol 112 (6) ◽  
pp. 1516-1527 ◽  
Author(s):  
Satoshi Nishida ◽  
Tomohiro Tanaka ◽  
Tadashi Ogawa
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Cognitive Processes ◽  
Visual Discrimination ◽  
Target Location ◽  
Real Life ◽  
Neural Representation ◽  
Delayed Response ◽  
Response Modulation ◽  
Stimulus Offset

Neurons in the lateral intraparietal area (LIP) are involved in signaling the location of behaviorally relevant objects during visual discrimination and working memory maintenance. Although previous studies have examined these cognitive processes separately, they often appear as inseparable sequential processes in real-life situations. Little is known about how the neural representation of the target location is altered when both cognitive processes are continuously required for executing a task. We investigated this issue by recording single-unit activity from LIP of monkeys performing a delayed-response visual search task in which they were required to discriminate the target from distractors in the stimulus period, remember the location at which the extinguished target had been presented in the delay period, and make a saccade to that location in the response period. Target-location signaling was assessed using response modulations contingent on whether the target location was inside or opposite the receptive field. Although the population-averaged response modulation was consistent and changed only slightly during a trial, the across-neuron pattern of response modulations showed a marked and abrupt change around 170 ms after stimulus offset due to concurrent changes in the response modulations of a subset of LIP neurons, which manifested heterogeneous patterns of activity changes during the task. Our findings suggest that target-location signaling by the across-neuron pattern of LIP activity discretely changes after the stimulus disappearance under conditions that continuously require visual discrimination and working memory to perform a single behavioral task.

scholarly journals The Strength of the Medial Olivocochlear Reflex in Chinchillas Is Associated With Delayed Response Performance in a Visual Discrimination Task With Vocalizations as Distractors

2021 ◽  
Vol 15 ◽  
Author(s):  
Sergio Vicencio-Jimenez ◽  
Giuliana Bucci-Mansilla ◽  
Macarena Bowen ◽  
Gonzalo Terreros ◽  
David Morales-Zepeda ◽  
...  
Keyword(s):  
Working Memory ◽  
Cognitive Processes ◽  
Cognitive Functions ◽  
Visual Discrimination ◽  
Discrimination Task ◽  
Visual Discrimination Task ◽  
Medial Olivocochlear ◽  
Stimulus Offset ◽  
Auditory Distractors ◽  
Delayed Responses

The ability to perceive the world is not merely a passive process but depends on sensorimotor loops and interactions that guide and actively bias our sensory systems. Understanding which and how cognitive processes participate in this active sensing is still an open question. In this context, the auditory system presents itself as an attractive model for this purpose as it features an efferent control network that projects from the cortex to subcortical nuclei and even to the sensory epithelium itself. This efferent system can regulate the cochlear amplifier sensitivity through medial olivocochlear (MOC) neurons located in the brainstem. The ability to suppress irrelevant sounds during selective attention to visual stimuli is one of the functions that have been attributed to this system. MOC neurons are also directly activated by sounds through a brainstem reflex circuit, a response linked to the ability to suppress auditory stimuli during visual attention. Human studies have suggested that MOC neurons are also recruited by other cognitive functions, such as working memory and predictability. The aim of this research was to explore whether cognitive processes related to delayed responses in a visual discrimination task were associated with MOC function. In this behavioral condition, chinchillas held their responses for more than 2.5 s after visual stimulus offset, with and without auditory distractors, and the accuracy of these responses was correlated with the magnitude of the MOC reflex. We found that the animals’ performance decreased in presence of auditory distractors and that the results observed in MOC reflex could predict this performance. The individual MOC strength correlated with behavioral performance during delayed responses with auditory distractors, but not without them. These results in chinchillas, suggest that MOC neurons are also recruited by other cognitive functions, such as working memory.

scholarly journals Working-memory capacity predicts the executive control of visual search among distractors: The influences of sustained and selective attention

2009 ◽  
Vol 62 (7) ◽  
pp. 1430-1454 ◽  
Author(s):  
Bradley J. Poole ◽  
Michael J. Kane
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Target Location ◽  
Memory Span ◽  
Working Memory Capacity ◽  
Memory Capacity ◽  
Attentional Focus ◽  
Search Tasks ◽  
Span Tasks ◽  
Target Locations

Variation in working-memory capacity (WMC) predicts individual differences in only some attention-control capabilities. Whereas higher WMC subjects outperform lower WMC subjects in tasks requiring the restraint of prepotent but inappropriate responses, and the constraint of attentional focus to target stimuli against distractors, they do not differ in prototypical visual-search tasks, even those that yield steep search slopes and engender top-down control. The present three experiments tested whether WMC, as measured by complex memory span tasks, would predict search latencies when the 1–8 target locations to be searched appeared alone, versus appearing among distractor locations to be ignored, with the latter requiring selective attentional focus. Subjects viewed target-location cues and then fixated on those locations over either long (1,500–1,550 ms) or short (300 ms) delays. Higher WMC subjects identified targets faster than did lower WMC subjects only in the presence of distractors and only over long fixation delays. WMC thus appears to affect subjects’ ability to maintain a constrained attentional focus over time.

The role of D1-dopamine receptor in working memory: local injections of dopamine antagonists into the prefrontal cortex of rhesus monkeys performing an oculomotor delayed-response task

1994 ◽  
Vol 71 (2) ◽  
pp. 515-528 ◽  
Author(s):  
T. Sawaguchi ◽  
P. S. Goldman-Rakic
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Injection Site ◽  
Target Location ◽  
Dopamine Antagonists ◽  
Dopamine Antagonist ◽  
Delayed Response ◽  
Intracerebral Injection ◽  
Control Task

1. To examine the role of dopamine receptors in the prefrontal cortex (PFC) on working memory, we injected dopamine antagonists (SCH23390, SCH39166, haloperidol, sulpiride, and raclopride) locally into the dorsolateral PFC in two monkeys trained to perform an oculomotor delayed-response (ODR) task. In the ODR task, monkeys fixate a central spot on a cathode ray tube (CRT) monitor while a visual cue is briefly (300 ms) presented in one of several peripheral locations in the visual field. After a delay of 1.5-6 s, the fixation spot is turned off, instructing the monkey to move its eyes to the target location that had been indicated by the visuospatial cue before the delay. Each monkey also performed a control task in which the cue remained on during the delay period. In this task the monkey's response was sensory rather than memory guided. 2. Local intracerebral injection of the selective dopamine antagonists SCH23390 (10-80 micrograms) and SCH39166 (1-5 micrograms) and/or the nonselective dopamine antagonist haloperidol (10-100 micrograms) induced deficits in ODR task performance at a total of 22 sites in the dorsolateral PFC. The deficit was characterized by a decrease in the accuracy of the memory-guided saccade as well as an increase in the latency of the response. The deficit usually appeared within 1-3 min after the injection, reached a peak at 20-40 min, and recovered at 60-90 min. 3. Performance change was restricted to a few specific target locations, which varied with the injection site and were most often contralateral to the injection site. 4. The degree of impairment in the ODR task occasioned by the injection of the dopamine antagonists was sensitive to the duration of delay; longer delays were associated with larger decreases in the accuracy and delayed onset of the memory-guided saccade. 5. The deficit was dose dependent; higher doses induced larger errors and increases in the onset of the memory-guided saccade. 6. Dopamine antagonists did not affect performance on the control task, which required the same eye movements but was sensory guided. Thus, in the same experimental session in which ODR performance was impaired, the accuracy and the latency of the sensory-guided saccades were normal for every target location.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals A theory of working memory without consciousness or sustained activity

2016 ◽  
Author(s):  
Darinka Trübutschek ◽  
Sébastien Marti ◽  
Andrés Ojeda ◽  
Jean-Rémi King ◽  
Yuanyuan Mi ◽  
...  
Keyword(s):  
Working Memory ◽  
Visual Masking ◽  
Target Location ◽  
Chance Level ◽  
Delayed Response ◽  
Conscious Perception ◽  
Neural Firing ◽  
Beta Band ◽  
Sustained Activity ◽  
Response Task

AbstractWorking memory and conscious perception are thought to share similar brain mechanisms, yet recent reports of non-conscious working memory challenge this view. Combining visual masking with magnetoencephalography, we demonstrate the reality of non-conscious working memory and dissect its neural mechanisms. In a spatial delayed-response task, participants reported the location of a subjectively unseen target above chance-level after a long delay. Conscious perception and conscious working memory were characterized by similar signatures: a sustained desynchronization in the alpha/beta band over frontal cortex, and a decodable representation of target location in posterior sensors. During non-conscious working memory, such activity vanished. Our findings contradict models that identify working memory with sustained neural firing, but are compatible with recent proposals of ‘activity-silent’ working memory. We present a theoretical framework and simulations showing how slowly decaying synaptic changes allow cell assemblies to go dormant during the delay, yet be retrieved above chance-level after several seconds.

scholarly journals Dissociative Effects of Methylphenidate in Nonhuman Primates: Trade-offs between Cognitive and Behavioral Performance

2012 ◽  
Vol 24 (6) ◽  
pp. 1371-1381 ◽  
Author(s):  
Abigail Z. Rajala ◽  
Jeffrey B. Henriques ◽  
Luis C. Populin
Keyword(s):  
Working Memory ◽  
Target Location ◽  
Memory Performance ◽  
Memory Task ◽  
Delayed Response ◽  
Impaired Performance ◽  
Healthy Humans ◽  
Trade Offs ◽  
Accuracy And Precision ◽  
Response Task

Low doses of methylphenidate reduce hyperactivity and improve attention in individuals with attention deficit hyperactivity disorder (ADHD) as well as in healthy humans and animals. Despite its extensive use, relatively little is known about its mechanisms of action. This study investigated the effects of methylphenidate on working memory performance, impulsivity, response accuracy and precision, and the ability to stay on task in rhesus monkeys using an oculomotor delayed response task. Methylphenidate affected task performance in an inverted-U manner in all three subjects tested. The improvements resulted from a reduction in premature responses and, importantly, not from improvement in the memory of target location. The length of time subjects participated in each session was also affected dose dependently. However, the dose at which the length of participation was maximally increased significantly impaired performance on the working memory task. This dissociation of effects has implications for the treatment of ADHD, for the nonprescription use of methylphenidate for cognitive enhancement, and for furthering the basic understanding of the neural substrate underlying these processes.

scholarly journals Capture and Control: Working Memory Modulates Attentional Capture by Reward-Related Stimuli

2019 ◽  
Vol 30 (8) ◽  
pp. 1174-1185 ◽  
Author(s):  
Poppy Watson ◽  
Daniel Pearson ◽  
Michelle Chow ◽  
Jan Theeuwes ◽  
Reinout W. Wiers ◽  
...  
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Attentional Capture ◽  
Executive Control ◽  
Memory Load ◽  
Real Life ◽  
Control Processes ◽  
High Reward ◽  
Irrelevant Distractors ◽  
And Control

Physically salient but task-irrelevant distractors can capture attention in visual search, but resource-dependent, executive-control processes can help reduce this distraction. However, it is not only physically salient stimuli that grab our attention: Recent research has shown that reward history also influences the likelihood that stimuli will capture attention. Here, we investigated whether resource-dependent control processes modulate the effect of reward on attentional capture, much as for the effect of physical salience. To this end, we used eye tracking with a rewarded visual search task and compared performance under conditions of high and low working memory load. In two experiments, we demonstrated that oculomotor capture by high-reward distractor stimuli is enhanced under high memory load. These results highlight the role of executive-control processes in modulating distraction by reward-related stimuli. Our findings have implications for understanding the neurocognitive processes involved in real-life conditions in which reward-related stimuli may influence behavior, such as addiction.

Evidence for Linear but Not Helical Automatic Representation of Pitch in the Human Auditory System

2019 ◽  
Vol 31 (5) ◽  
pp. 669-685 ◽  
Author(s):  
Tamar I. Regev ◽  
Israel Nelken ◽  
Leon Y. Deouell
Keyword(s):  
Working Memory ◽  
Cognitive Processes ◽  
Neural Activity ◽  
Pure Tone ◽  
Automatic Detection ◽  
Complex Tone ◽  
Neural Representation ◽  
Pitch Height ◽  
G 21 ◽  
Complex Tones

The perceptual organization of pitch is frequently described as helical, with a monotonic dimension of pitch height and a circular dimension of pitch chroma, accounting for the repeating structure of the octave. Although the neural representation of pitch height is widely studied, the way in which pitch chroma representation is manifested in neural activity is currently debated. We tested the automaticity of pitch chroma processing using the MMN—an ERP component indexing automatic detection of deviations from auditory regularity. Musicians trained to classify pure or complex tones across four octaves, based on chroma—C versus G (21 participants, Experiment 1) or C versus F# (27, Experiment 2). Next, they were passively exposed to MMN protocols designed to test automatic detection of height and chroma deviations. Finally, in an “attend chroma” block, participants had to detect the chroma deviants in a sequence similar to the passive MMN sequence. The chroma deviant tones were accurately detected in the training and the attend chroma parts both for pure and complex tones, with a slightly better performance for complex tones. However, in the passive blocks, a significant MMN was found only to height deviations and complex tone chroma deviations, but not to pure tone chroma deviations, even for perfect performers in the active tasks. These results indicate that, although height is represented preattentively, chroma is not. Processing the musical dimension of chroma may require higher cognitive processes, such as attention and working memory.

Attenuation of Delay-Period Activity of Monkey Prefrontal Neurons by an α2-Adrenergic Antagonist During an Oculomotor Delayed-Response Task

1998 ◽  
Vol 80 (4) ◽  
pp. 2200-2205 ◽  
Author(s):  
T. Sawaguchi
Keyword(s):  
Working Memory ◽  
Target Location ◽  
Spatial Working Memory ◽  
Delay Period ◽  
Delayed Response ◽  
Peripheral Cues ◽  
Adrenergic Antagonist ◽  
Neuronal Processes ◽  
Response Task ◽  
Delayed Response Task

Sawaguchi, T. Attenuation of delay-period activity of monkey prefrontal neurons by an α2-adrenergic antagonist during an oculomotor delayed-response task. J. Neurophysiol. 80: 2200–2205, 1998. To examine the role of norepinephrine receptors in spatial working memory processes mediated by the prefrontal cortex (PFC), noradrenergic antagonists (yohimbine for α2, prazosin for α1, and propranolol for β receptors) were applied iontophoretically to neurons of the dorsolateral PFC in rhesus monkeys that performed an oculomotor delayed-response (ODR) task. The ODR task was initiated when the monkeys fixated on a central spot on a computer monitor and consisted of fixation (1 s), cue (1 of 4 peripheral cues, 0.5 s), delay (fixation cue only, 4 s), and go periods. In the go period, the subject made a memory-guided saccade to the target location that was cued before the delay period. I focused on 49 neurons that showed directional delay-period activity, i.e., a sustained increase in activity during the delay period, the magnitude of which varied significantly with the memorized target location. Iontophoretic (usually 50 nA) application of yohimbine, but not prazosin or propranolol, significantly decreased the activities of most of the neurons with directional delay-period activity ( n = 41/49, 81%). Furthermore, yohimbine attenuated the sharpness of tuning, examined by a tuning index, of delay-period activity and had a greater attenuating effect on delay-period activity than on background activity. These findings suggest that the activation of α2-adrenergic receptors in the dorsolateral PFC plays a modulatory role in neuronal processes for visuospatial working memory.

Construct Validity of the Stroop Color-Word Test: Influence of Speed of Visual Search, Verbal Fluency, Working Memory, Cognitive Flexibility, and Conflict Monitoring

2020 ◽  
Author(s):  
José A Periáñez ◽  
Genny Lubrini ◽  
Ana García-Gutiérrez ◽  
Marcos Ríos-Lago
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Cognitive Flexibility ◽  
Cognitive Processes ◽  
Verbal Fluency ◽  
Word Reading ◽  
Color Word ◽  
Color Naming ◽  
Conflict Monitoring ◽  
Cognitive Mechanisms

Abstract Objective 85 years after the description of the Stroop interference effect, there is still a lack of consensus regarding the cognitive constructs underlying scores from standardized versions of the test. The present work aimed to clarify the cognitive mechanisms underlying direct (word-reading, color-naming, and color-word) and derived scores (interference, difference, ratio, and relative scores) from Golden’s standardized version of the test. Method After a comprehensive review of the literature, five cognitive processes were selected for analysis: speed of visual search, phonemic verbal fluency, working memory, cognitive flexibility, and conflict monitoring. These constructs were operationalized by scoring five cognitive tasks (WAIS-IV Digit Symbol, phonemic verbal fluency [letter A], WAIS-IV Digit Span, TMT B-A, and reaction times to the incongruent condition of a computerized Stroop task, respectively). About 83 healthy individuals (mean age = 25.2 years) participated in the study. Correlation and regression analyses were used to clarify the contribution of the five cognitive processes on the prediction of Stroop scores. Results Data analyses revealed that Stroop word-reading reflected speed of visual search. Stroop color-naming reflected working memory and speed of visual search. Stroop color-word reflected working memory, conflict monitoring, and speed of visual search. Whereas the interference score was predicted by both conflict monitoring and working memory, the ratio score (color-word divided by color-naming) was predicted by conflict monitoring alone. Conclusion The present results will help neuropsychologists to interpret altered patient scores in terms of a failure of the cognitive mechanisms detailed here, benefitting from the solid background of preceding experimental work.

scholarly journals A theory of working memory without consciousness or sustained activity

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Darinka Trübutschek ◽  
Sébastien Marti ◽  
Andrés Ojeda ◽  
Jean-Rémi King ◽  
Yuanyuan Mi ◽  
...  
Keyword(s):  
Working Memory ◽  
Visual Masking ◽  
Target Location ◽  
Chance Level ◽  
Delayed Response ◽  
Conscious Perception ◽  
Neural Firing ◽  
Beta Band ◽  
Sustained Activity ◽  
Response Task

Working memory and conscious perception are thought to share similar brain mechanisms, yet recent reports of non-conscious working memory challenge this view. Combining visual masking with magnetoencephalography, we investigate the reality of non-conscious working memory and dissect its neural mechanisms. In a spatial delayed-response task, participants reported the location of a subjectively unseen target above chance-level after several seconds. Conscious perception and conscious working memory were characterized by similar signatures: a sustained desynchronization in the alpha/beta band over frontal cortex, and a decodable representation of target location in posterior sensors. During non-conscious working memory, such activity vanished. Our findings contradict models that identify working memory with sustained neural firing, but are compatible with recent proposals of ‘activity-silent’ working memory. We present a theoretical framework and simulations showing how slowly decaying synaptic changes allow cell assemblies to go dormant during the delay, yet be retrieved above chance-level after several seconds.

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