scholarly journals Prefrontal Activity During Serial Probe Reproduction Task: Encoding, Mnemonic, and Retrieval Processes

2006 ◽  
Vol 95 (2) ◽  
pp. 1008-1041 ◽  
Author(s):  
Masato Inoue ◽  
Akichika Mikami
Keyword(s):  
Working Memory ◽  
Temporal Order ◽  
Critical Role ◽  
Target Object ◽  
Delay Period ◽  
Color Stimulus ◽  
Multiple Objects ◽  
Reproduction Task ◽  
Retrieval Processes ◽  
Order Of Presentation

To study the prefrontal neuronal mechanism for the encoding and mnemonic processing of multiple objects, the order of object presentation, and the retrieval of an object among objects in the working memory, we recorded neuronal activity from the lateral prefrontal cortex while two monkeys performed the serial probe reproduction task. In the task, two objects (C1 and C2) were presented sequentially interleaved with a delay (D1) period, and after the second delay (D2) period, a color cue was presented. Monkeys were trained to select one target object on the basis of the color stimulus. During the C1 and C2 periods, we found responses that depended on the order of presentation (order-selective response). During the D1 and/or D2 periods, two-thirds of the neurons with object-selective delay-period activity showed order-selective activity coding either C1 or C2. Neurons with larger response magnitudes during the C2 period showed order-selective delay-period activity during the D2 period. These order-selective responses during the C2 period could also contribute to order-selective delay-period activity, and order-selective delay-period activity during the D1 and D2 periods could play an essential role in storing information on both the object and the temporal order of presentation. During the color cue period, two-thirds of the neurons with responses showed target object selectivity (CT and T responses), although the target object was not presented during this period. The CT and T responses could play a critical role in the retrieval of an item among various items in the working memory.

scholarly journals Abstracting time in memory

2021 ◽  
Author(s):  
Sophie K Herbst ◽  
Izem Mangione ◽  
Tadeusz Kononowicz ◽  
Virginie van Wassenhove
Keyword(s):  
Working Memory ◽  
Delay Period ◽  
Abstract Representation ◽  
Time Intervals ◽  
Reproduction Task ◽  
Elapsed Time ◽  
Temporal Reproduction ◽  
The Future ◽  
Empty Time

Planning the future relies on the ability to remember how long events last, yet, how durations are stored in memory is unknown. Here, we developed a novel n-item delayed duration reproduction task to assess whether elapsed time is stored as a continuous feature or as an abstract item in memory. In three experiments (N = 58), participants listened to non-rhythmic sequences composed of empty time intervals (durations), which they had to reproduce as precisely as possible following a delay period. We manipulated the number of time intervals (n-item) and the overall sequence duration to separate their effects on recall precision. The precision of temporal reproduction systematically decreased with an increasing number of items. Our results suggest that the number of time intervals, not their duration, determines recall precision. We interpret this as evidence towards an abstract representation of duration in working memory.

scholarly journals Reward learning and working memory: Effects of massed versus spaced training and post-learning delay period

2021 ◽  
Author(s):  
G. Elliott Wimmer ◽  
Russell A. Poldrack
Keyword(s):  
Working Memory ◽  
Working Memory Capacity ◽  
Critical Role ◽  
Delay Period ◽  
Learning Mechanisms ◽  
Subsequent Performance ◽  
Feedback Learning ◽  
Massed Learning ◽  
Midbrain Dopamine ◽  
Additional Support

AbstractNeuroscience research has illuminated the mechanisms supporting learning from reward feedback, demonstrating a critical role for the striatum and midbrain dopamine system. However, in humans, short-term working memory that is dependent on frontal and parietal cortices can also play an important role, particularly in commonly used paradigms in which learning is relatively condensed in time. Given the growing use of reward-based learning tasks in translational studies in computational psychiatry, it is important to understand the extent of the influence of working memory and also how core gradual learning mechanisms can be better isolated. In our experiments, we manipulated the spacing between repetitions along with a post-learning delay preceding a test phase. We found that learning was slower for stimuli repeated after a long delay (spaced-trained) compared to those repeated immediately (massed-trained), likely reflecting the remaining contribution of feedback learning mechanisms when working memory is not available. For massed learning, brief interruptions led to drops in subsequent performance, and individual differences in working memory capacity positively correlated with overall performance. Interestingly, when tested after a delay period but not immediately, relative preferences decayed in the massed condition and increased in the spaced condition. Our results provide additional support for a large role of working memory in reward-based learning in temporally condensed designs. We suggest that spacing training within or between sessions is a promising approach to better isolate and understand mechanisms supporting gradual reward-based learning, with particular importance for understanding potential learning dysfunctions in addiction and psychiatric disorders.

scholarly journals Reward learning and working memory: effects of massed versus spaced training and post-learning delay period

2020 ◽  
Author(s):  
G. Elliott Wimmer ◽  
Russell A. Poldrack
Keyword(s):  
Working Memory ◽  
Working Memory Capacity ◽  
Critical Role ◽  
Delay Period ◽  
Learning Performance ◽  
Reward Learning ◽  
Subsequent Performance ◽  
Neuroscience Research ◽  
Massed Learning ◽  
Midbrain Dopamine

AbstractOver the past few decades, neuroscience research has illuminated the neural mechanisms supporting learning from reward feedback, demonstrating a critical role for the striatum and ascending midbrain dopamine system. However, in humans, short-term working memory can also play an important role in reward-based learning, particularly in common paradigms that are relatively compressed in time. Given the growing use of reward-based learning tasks in translational studies in computational psychiatry, it is important to further investigate the degree to which apparent reinforcement learning is driven by working memory contributions. In our experiments, we manipulated the spacing between repetitions and also the post-learning delay period duration. Supporting a significant role for working memory in reward-based learning, we found that learning was faster for massed-trained compared to spaced-trained stimuli, and that brief interruptions of massed learning led to drops in subsequent performance. Further, individual differences in working memory capacity positively correlated with massed learning performance. Critically, after a delay period but not immediately, relative performance decayed in the massed condition and increased in the spaced condition. Overall, our results provide further support that working memory plays a large role in temporally condensed reward learning designs. We suggest that spacing training across or between sessions is a promising direction to pursue in future studies investigating the mechanisms of reward-based learning, and particularly in translational research.

scholarly journals The Neural Basis of Reversible Sentence Comprehension: Evidence from Voxel-based Lesion Symptom Mapping in Aphasia

2012 ◽  
Vol 24 (1) ◽  
pp. 212-222 ◽  
Author(s):  
Malathi Thothathiri ◽  
Daniel Y. Kimberg ◽  
Myrna F. Schwartz
Keyword(s):  
Working Memory ◽  
Parietal Cortex ◽  
Sentence Comprehension ◽  
Critical Role ◽  
Broca's Area ◽  
Neural Basis ◽  
Phonological Working Memory ◽  
Large Group ◽  
Complex Sentences ◽  
Lesion Symptom Mapping

We explored the neural basis of reversible sentence comprehension in a large group of aphasic patients (n = 79). Voxel-based lesion symptom mapping revealed a significant association between damage in temporo-parietal cortex and impaired sentence comprehension. This association remained after we controlled for phonological working memory. We hypothesize that this region plays an important role in the thematic or what–where processing of sentences. In contrast, we detected weak or no association between reversible sentence comprehension and the ventrolateral pFC, which includes Broca's area, even for syntactically complex sentences. This casts doubt on theories that presuppose a critical role for this region in syntactic computations.

scholarly journals Active information maintenance in working memory by a sensory cortex

2018 ◽  
Author(s):  
Xiaoxing Zhang ◽  
Wenjun Yan ◽  
Wenliang Wang ◽  
Hongmei Fan ◽  
Ruiqing Hou ◽  
...  
Keyword(s):  
Working Memory ◽  
Piriform Cortex ◽  
Delay Period ◽  
Sensory Cortex ◽  
Critical Function ◽  
Impaired Performance ◽  
Anterior Piriform Cortex ◽  
Electrophysiological Recordings ◽  
Dual Task Paradigm ◽  
The Brain

SummaryWorking memory is a critical function of the brain to maintain and manipulate information over delay periods of seconds. Sensory areas have been implicated in working memory; however, it is debated whether the delay-period activity of sensory regions is actively maintaining information or passively reflecting top-down inputs. We hereby examined the anterior piriform cortex, an olfactory cortex, in head-fixed mice performing a series of olfactory working memory tasks. Information maintenance is necessary in these tasks, especially in a dual-task paradigm in which mice are required to perform another distracting task while actively maintaining information during the delay period. Optogenetic suppression of the piriform cortex activity during the delay period impaired performance in all the tasks.Furthermore, electrophysiological recordings revealed that the delay-period activity of the anterior piriform cortex encoded odor information with or without the distracting task.Thus, this sensory cortex is critical for active information maintenance in working memory.

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.

scholarly journals Prefrontal and Parietal Attractor Networks Mediate Working Memory Judgments

2020 ◽  
Author(s):  
Sihai Li ◽  
Christos Constantinidis ◽  
Xue-Lian Qi
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Critical Role ◽  
Memory Task ◽  
Delayed Response ◽  
Persistent Activity ◽  
Neural Basis ◽  
Brain Areas ◽  
Dorsolateral Prefrontal

ABSTRACTThe dorsolateral prefrontal cortex plays a critical role in spatial working memory and its activity predicts behavioral responses in delayed response tasks. Here we addressed whether this predictive ability extends to categorical judgments based on information retained in working memory, and is present in other brain areas. We trained monkeys in a novel, Match-Stay, Nonmatch-Go task, which required them to observe two stimuli presented in sequence with an intervening delay period between them. If the two stimuli were different, the monkeys had to saccade to the location of the second stimulus; if they were the same, they held fixation. Neurophysiological recordings were performed in areas 8a and 46 of the dlPFC and 7a and lateral intraparietal cortex (LIP) of the PPC. We hypothesized that random drifts causing the peak activity of the network to move away from the first stimulus location and towards the location of the second stimulus would result in categorical errors. Indeed, for both areas, when the first stimulus appeared in a neuron’s preferred location, the neuron showed significantly higher firing rates in correct than in error trials. When the first stimulus appeared at a nonpreferred location and the second stimulus at a preferred, activity in error trials was higher than in correct. The results indicate that the activity of both dlPFC and PPC neurons is predictive of categorical judgments of information maintained in working memory, and the magnitude of neuronal firing rate deviations is revealing of the contents of working memory as it determines performance.SIGNIFICANCE STATEMENTThe neural basis of working memory and the areas mediating this function is a topic of controversy. Persistent activity in the prefrontal cortex has traditionally been thought to be the neural correlate of working memory, however recent studies have proposed alternative mechanisms and brain areas. Here we show that persistent activity in both the dorsolateral prefrontal cortex and posterior parietal cortex predicts behavior in a working memory task that requires a categorical judgement. Our results offer support to the idea that a network of neurons in both areas act as an attractor network that maintains information in working memory, which informs behavior.

Concurrent verbal working memory load constrains cross-linguistic translation activation: A visual world eye-tracking study on Hindi–English bilinguals

2020 ◽  
pp. 1-30
Author(s):  
Seema Prasad ◽  
Ramesh Kumar Mishra
Keyword(s):  
Working Memory ◽  
Memory Load ◽  
Critical Role ◽  
Verbal Working Memory ◽  
Spoken Word ◽  
Cognitive Resources ◽  
Visual World ◽  
Sequence Recognition ◽  
Word Onset ◽  
Study Participants

Abstract Does a concurrent verbal working memory (WM) load constrain cross-linguistic activation? In a visual world study, participants listened to Hindi (L1) or English (L2) spoken words and viewed a display containing the phonological cohort of the translation equivalent (TE cohort) of the spoken word and 3 distractors. Experiment 1 was administered without a load. Participants then maintained two or four letters (Experiment 2) or two, six or eight letters (Experiment 3) in WM and were tested on backward sequence recognition after the visual world display. Greater looks towards TE cohorts were observed in both the language directions in Experiment 1. With a load, TE cohort activation was inhibited in the L2 – L1 direction and observed only in the early stages after word onset in the L1 – L2 direction suggesting a critical role of language direction. These results indicate that cross-linguistic activation as seen through eye movements depends on cognitive resources such as WM.

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