scholarly journals Dopamine firing plays a dual role in coding reward prediction errors and signaling motivation in a working memory task

2022 ◽  
Vol 119 (2) ◽  
pp. e2113311119
Author(s):  
Stefania Sarno ◽  
Manuel Beirán ◽  
Joan Falcó-Roget ◽  
Gabriel Diaz-deLeon ◽  
Román Rossi-Pool ◽  
...  
Keyword(s):  
Working Memory ◽  
Memory Task ◽  
Reaction Times ◽  
Delay Period ◽  
Prediction Errors ◽  
Motivated Behavior ◽  
Reward Prediction ◽  
Stimulus Perception ◽  
Trial Basis ◽  
Internal Bias

Little is known about how dopamine (DA) neuron firing rates behave in cognitively demanding decision-making tasks. Here, we investigated midbrain DA activity in monkeys performing a discrimination task in which the animal had to use working memory (WM) to report which of two sequentially applied vibrotactile stimuli had the higher frequency. We found that perception was altered by an internal bias, likely generated by deterioration of the representation of the first frequency during the WM period. This bias greatly controlled the DA phasic response during the two stimulation periods, confirming that DA reward prediction errors reflected stimulus perception. In contrast, tonic dopamine activity during WM was not affected by the bias and did not encode the stored frequency. More interestingly, both delay-period activity and phasic responses before the second stimulus negatively correlated with reaction times of the animals after the trial start cue and thus represented motivated behavior on a trial-by-trial basis. During WM, this motivation signal underwent a ramp-like increase. At the same time, motivation positively correlated with accuracy, especially in difficult trials, probably by decreasing the effect of the bias. Overall, our results indicate that DA activity, in addition to encoding reward prediction errors, could at the same time be involved in motivation and WM. In particular, the ramping activity during the delay period suggests a possible DA role in stabilizing sustained cortical activity, hypothetically by increasing the gain communicated to prefrontal neurons in a motivation-dependent way.

scholarly journals Midbrain dopamine firing activity codes reward expectation and motivation in a parametric working memory task

2020 ◽  
Author(s):  
Stefania Sarno ◽  
Manuel Beirán ◽  
Gabriel Diaz-deLeon ◽  
Román Rossi-Pool ◽  
Ranulfo Romo ◽  
...  
Keyword(s):  
Working Memory ◽  
Memory Task ◽  
Frequency Discrimination ◽  
Firing Activity ◽  
Sustained Activity ◽  
Motivated Behavior ◽  
Reward Prediction ◽  
Trial Basis ◽  
Motivation Level ◽  
Midbrain Dopamine

AbstractLittle is known about how dopamine (DA) neuron firing rates behave in cognitively demanding decision-making tasks. We investigated midbrain DA activity in monkeys performing a vibrotactile frequency discrimination task that required comparing two frequencies presented sequentially in time. We found that DA activity was involved in reward prediction, motivation and working memory (WM). Further, DA phasic responses to the stimuli were greatly affected by a contraction bias. They were also related to motivated behavior on a trial-by-trial basis, exhibiting a larger engagement in more difficult trials. Otherwise, dopamine WM activity was neither tuned to the initial stored frequency nor affected by the bias, although it did code the motivation level and exhibited a ramp-like increase. This result is consistent with a DA role in stabilizing sustained activity, by increasing the gain of prefrontal neurons in a motivation-dependent way. All these DA responses could be potentially related to cognitive control.

scholarly journals Internal bias controls dopamine perceptual decision-related responses

2018 ◽  
Author(s):  
Stefania Sarno ◽  
Manuel Beirán ◽  
José Vergara ◽  
Román Rossi-Pool ◽  
Ranulfo Romo ◽  
...  
Keyword(s):  
Delay Period ◽  
Dopamine Neurons ◽  
Prediction Errors ◽  
Phasic Activity ◽  
Perceptual Decision ◽  
Reward Prediction ◽  
Internal Bias ◽  
Dopamine Signaling

AbstractDopamine neurons produce reward-related signals that regulate learning and guide behavior. Prior expectations about forthcoming stimuli and internal biases can alter perception and choices and thus could influence dopamine signaling. We tested this hypothesis studying dopamine neurons recorded in monkeys trained to discriminate between two tactile frequencies separated by a delay period, a task affected by the contraction bias. The bias greatly controlled the animals’ choices and confidence on their decisions. During decision formation the phasic activity reflected bias-induced modulations and simultaneously coded reward prediction errors. In contrast, the activity during the delay period was not affected by the bias, was not tuned to the value of the stimuli but was temporally modulated, pointing to a role different from that of the phasic activity.

scholarly journals Spontaneous Eye Blink Rate during the Working Memory Delay Period Predicts Task Performance

2021 ◽  
Author(s):  
Jefferson Ortega ◽  
Chelsea Reichert Plaska ◽  
Bernard A Gomes ◽  
Timothy M Ellmore
Keyword(s):  
Working Memory ◽  
Task Performance ◽  
Memory Task ◽  
Delay Period ◽  
Blink Rate ◽  
Indirect Measure ◽  
Eye Blink ◽  
Non Invasive ◽  
Relationship Of ◽  
The Relationship

Spontaneous eye blink rate (sEBR) has been found to be a non-invasive indirect measure of striatal dopamine activity. Dopamine (DA) neurons project to the prefrontal cortex (PFC) through the mesocortical dopamine pathway and their activity is implicated in a range of cognitive functions, including attention and working memory (WM). The goal of the present study was to understand how fluctuations in sEBR during different phases of a working memory task relate to task performance. Across two experiments, with recordings of sEBR inside and outside of a magnetic resonance imaging bore, we observed sEBR to be positively correlated with WM performance during the WM delay period. Additionally we investigated the non-linear relationship between sEBR and WM performance, and modeled a proposed Inverted-U-shape relationship between DA and WM performance. We also investigated blink duration, which is proposed to be related to sustained attention, and found blink duration to be significantly shorter during the encoding and probe periods of the task. Taken together, these results provide support towards sEBR as an important correlate of working memory task performance. The relationship of sEBR to DA activity and the influence of DA on the PFC during WM maintenance is discussed.

Order Information in Working Memory: fMRI Evidence for Parietal and Prefrontal Mechanisms

2000 ◽  
Vol 12 (supplement 2) ◽  
pp. 130-144 ◽  
Author(s):  
Christy Marshuetz ◽  
Edward E. Smith ◽  
John Jonides ◽  
Joseph DeGutis ◽  
Thomas L. Chenevert
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Memory Task ◽  
Reaction Times ◽  
Item Memory ◽  
Order Information ◽  
Order Condition ◽  
Order Task ◽  
Common Process ◽  
The Subject

Working memory is thought to include a mechanism that allows for the coding of order information. One question of interest is how order information is coded, and how that code is neurally implemented. Here we report both behavioral and fMRI findings from an experiment that involved comparing two tasks, an item-memory task and an order-memory task. In each case, five letters were presented for storage, followed after a brief interval by a set of probe letters. In the case of the item-memory task, the two letters were identical, and the subject responded to the question, “Was this letter one of the items you saw?”. In the case of the order-memory task, the letters were different, and subjects responded to the question, “Are these two letters in the order in which you saw them?”. Behaviorally, items that were further apart in the sequence elicited faster reaction times and higher accuracy in the Order task. Areas that were significantly more activated in the Order condition included the parietal and prefrontal cortex. Parietal activations overlapped those involved in number processing, leading to the suggestion that the underlying representation of order and numbers may share a common process, coding for magnitude.

Modulation of Alpha Activity in the Parieto-occipital Area by Distractors during a Visuospatial Working Memory Task: A Magnetoencephalographic Study

2015 ◽  
Vol 27 (3) ◽  
pp. 453-463 ◽  
Author(s):  
Satoe Ichihara-Takeda ◽  
Shogo Yazawa ◽  
Takashi Murahara ◽  
Takanobu Toyoshima ◽  
Jun Shinozaki ◽  
...  
Keyword(s):  
Working Memory ◽  
Information Processing ◽  
Brain Activity ◽  
Memory Task ◽  
Alpha Activity ◽  
Delay Period ◽  
Visuospatial Working Memory ◽  
Occipital Area ◽  
Spectral Evolution ◽  
Oscillatory Brain Activity

Oscillatory brain activity is known to play an essential role in information processing in working memory. Recent studies have indicated that alpha activity (8–13 Hz) in the parieto-occipital area is strongly modulated in working memory tasks. However, the function of alpha activity in working memory is open to several interpretations, such that alpha activity may be a direct neural correlate of information processing in working memory or may reflect disengagement from information processing in other brain areas. To examine the functional contribution of alpha activity to visuospatial working memory, we introduced visuospatial distractors during a delay period and examined neural activity from the whole brain using magnetoencephalography. The strength of event-related alpha activity was estimated using the temporal spectral evolution (TSE) method. The results were as follows: (1) an increase of alpha activity during the delay period as indicated by elevated TSE curves was observed in parieto-occipital sensors in both the working memory task and a control task that did not require working memory; and (2) an increase of alpha activity during the delay period was not observed when distractors were presented, although TSE curves were constructed only from correct trials. These results indicate that the increase of alpha activity is not directly related to information processing in working memory but rather reflects the disengagement of attention from the visuospatial input.

Medial prefrontal activity during delay period contributes to learning of a working memory task

Science ◽  
2014 ◽  
Vol 346 (6208) ◽  
pp. 458-463 ◽  
Author(s):  
Ding Liu ◽  
Xiaowei Gu ◽  
Jia Zhu ◽  
Xiaoxing Zhang ◽  
Zhe Han ◽  
...  
Keyword(s):  
Working Memory ◽  
Memory Task ◽  
Delay Period

scholarly journals Working Memory Depletion Affects Intertemporal Choice Among Internet Addicts and Healthy Controls

2021 ◽  
Vol 12 ◽  
Author(s):  
Hongxia Li
Keyword(s):  
Working Memory ◽  
Delay Discounting ◽  
Intertemporal Choice ◽  
Response Times ◽  
Memory Task ◽  
Reaction Times ◽  
Self Report ◽  
The Internet ◽  
Control Group ◽  
Healthy Controls

Addiction to the Internet has emerged as a new kind of addictive behavior. Although previous studies have revealed that impairments in working memory led to suboptimal decision making (e.g., a greater willingness to choose smaller, more immediate rewards), little is known about how working memory affects intertemporal choice in Internet addicts and normal users. Thus, this study’s aim was to investigate the effect of working memory task on intertemporal choice in 33 participants addicted to internet and 25 healthy controls. Participants were administered (a) a test for Internet Addiction, (b) a single delay discounting self-report questionnaire (c) a working memory task. Differences between the Internet addicts and the control group were observed in terms of delay discounting rates, reaction times, and in memory accuracy rates. We observed significantly higher delay discounting rates among individuals addicted to the Internet. Moreover, it was documented that reaction times follow the 4-level working memory condition were significantly longer than follow the 2-level condition, in both the Internet addicts and the control group. The current findings suggest that Internet addicts are more likely to make short-sighted decisions than normal Internet users. The higher the level of working memory, the more likely an individual is to choose the present smaller reward, thus making short-sighted decisions, and have longer response times.

Mental health assessment in undergraduate students using DASS21 and Visual Working Memory Task

2021 ◽  
Author(s):  
Gautam Kumar Baboo ◽  
Veeky Baths
Keyword(s):  
Working Memory ◽  
Reaction Time ◽  
Undergraduate Students ◽  
Reading Ability ◽  
Time Window ◽  
Memory Task ◽  
Reaction Times ◽  
Emotional States ◽  
Post Intervention ◽  
The Impact

Substantial adolescence is spent in an academic environment where the student can experience varying intensities of depression, stress, and anxiety, which can be fatal. To address this concern, we utilized the Depression Anxiety and Stress Survey (DASS) 21 and Modified Sternberg working memory, thereby assessing the emotional states and assessing the impact on the cognitive ability of students (n=37, F=7) in terms of working memory. An intervention was provided (Art of Living YES+ program) for ten days. The assessment is carried out in the time window of two months before and after the intervention. F-test and T-test(p≤0.05) on the scores and reaction time are performed for hypothesis testing. This statistical analysis reveals that both the depression category and stress category reject the null hypothesis. Among the thirty-seven, only five students took part in the post-intervention assessment, the scores in 28% of the questions had lower scores, and 19 % did not have any change; however, there was an increase in the scores in 42% of the questions. No significant changes are observed in the working memory ability of the students. Based on reaction time analysis: 11.62%, 16.27%, and 25.58% are outliers for each type of question, respectively. Two participants showed significantly lower reaction times, indicating a faster reading ability than the rest. This study shows that the intervention can positively impact emotional states-depression, stress, and affect working memory abilities.

Test Anxiety and Working Memory System

1996 ◽  
Vol 82 (3_suppl) ◽  
pp. 1223-1231 ◽  
Author(s):  
Maki Ikeda ◽  
Makoto Iwanaga ◽  
Hidetoshi Seiwa
Keyword(s):  
Working Memory ◽  
Spatial Memory ◽  
Test Anxiety ◽  
Verbal Memory ◽  
Memory Task ◽  
Reaction Times ◽  
Memory System ◽  
Anxiety Group ◽  
Spatial Memory Task

The purpose was to examine the effect of test anxiety on deficits in the articulatory loop in the working memory system. We used a verbal memory task to occupy the articulatory loop and a spatial memory task to occupy the visuospatial scratch pad. 17 highly test-anxious and 19 low-anxiety subjects performed both tasks under an anxiety-inducing situation during which they were observed by a monitor camera. Percentage of correct responses and reaction times were measured as indices of task performance. Highly anxious subjects reported feeling worry and cognitive self-concern more than the low-anxiety group. Highly anxious subjects showed a longer mean reaction time on the verbal memory task than the low-anxiety group. On the spatial memory task there was no difference in quality of performance. This finding might suggest that anxiety such as worry and cognitive self-concern interferes with information processing in the articulatory loop of the working memory system.

scholarly journals Monkey prefrontal neurons during Sternberg task performance: full contents of working memory or most recent item?

2017 ◽  
Vol 117 (6) ◽  
pp. 2269-2281 ◽  
Author(s):  
R. O. Konecky ◽  
M. A. Smith ◽  
C. R. Olson
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Firing Rate ◽  
Dorsolateral Prefrontal Cortex ◽  
Memory Task ◽  
Delay Period ◽  
Population Activity ◽  
Storage Mechanism ◽  
Dorsolateral Prefrontal ◽  
Recent Item

To explore the brain mechanisms underlying multi-item working memory, we monitored the activity of neurons in the dorsolateral prefrontal cortex while macaque monkeys performed spatial and chromatic versions of a Sternberg working-memory task. Each trial required holding three sequentially presented samples in working memory so as to identify a subsequent probe matching one of them. The monkeys were able to recall all three samples at levels well above chance, exhibiting modest load and recency effects. Prefrontal neurons signaled the identity of each sample during the delay period immediately following its presentation. However, as each new sample was presented, the representation of antecedent samples became weak and shifted to an anomalous code. A linear classifier operating on the basis of population activity during the final delay period was able to perform at approximately the level of the monkeys on trials requiring recall of the third sample but showed a falloff in performance on trials requiring recall of the first or second sample much steeper than observed in the monkeys. We conclude that delay-period activity in the prefrontal cortex robustly represented only the most recent item. The monkeys apparently based performance of this classic working-memory task on some storage mechanism in addition to the prefrontal delay-period firing rate. Possibilities include delay-period activity in areas outside the prefrontal cortex and changes within the prefrontal cortex not manifest at the level of the firing rate. NEW & NOTEWORTHY It has long been thought that items held in working memory are encoded by delay-period activity in the dorsolateral prefrontal cortex. Here we describe evidence contrary to that view. In monkeys performing a serial multi-item working memory task, dorsolateral prefrontal neurons encode almost exclusively the identity of the sample presented most recently. Information about earlier samples must be encoded outside the prefrontal cortex or represented within the prefrontal cortex in a cryptic code.

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