Different neural codes serve long and short-term memory functions in primate Hippocampus and Lateral Prefrontal Cortex during virtual navigation

AbstractThe primate hippocampus (HPC) and lateral prefrontal cortex (LPFC) are two brain structures deemed essential to long- and short-term memory functions respectively. Here we hypothesize that although both structures may encode similar information about the environment, the neural codes mediating neuronal communication in HPC and LPFC have differentially evolved to serve their corresponding memory functions. We used a virtual reality task in which animals navigated through a maze using a joystick and selected one of two targets in the arms of the maze according to a learned context-color rule. We found that neurons and neuronal populations in both regions encode similar information about the different task periods. Moreover, using statistical analyses and linear classifiers, we demonstrated that many HPC neurons concentrate spikes temporally into bursts, whereas most LPFC neurons sparsely distribute spikes over time. When integrating spike rates over short intervals, HPC neuronal ensembles reached maximum decoded information with fewer neurons than LPFC ensembles. We propose that HPC principal cells have evolved intrinsic properties that enable burst firing and temporal summation of synaptic potentials that ultimately facilitates synaptic plasticity and long-term memory formation. On the other hand, LPFC pyramidal cells have intrinsic properties that allow sparsely distributing spikes over time enabling encoding of short-term memories via persistent firing without necessarily triggering rapid changes in the synapses.

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Reward learning over weeks versus minutes increases the neural representation of value in the human brain

10.1101/158964 ◽

2017 ◽

Author(s):

G. Elliott Wimmer ◽

Jamie K. Li ◽

Krzysztof J. Gorgolewski ◽

Russell A. Poldrack

Keyword(s):

Prefrontal Cortex ◽

Temporal Lobe ◽

Medial Temporal Lobe ◽

Short Term Memory ◽

Neural Representation ◽

Reward Learning ◽

Short Term ◽

Term Memory ◽

Feedback Learning ◽

Over Time

AbstractOver the past few decades, neuroscience research has illuminated the neural mechanisms supporting learning from reward feedback. Learning paradigms are increasingly being extended to study mood and psychiatric disorders as well as addiction. However, one potentially critical characteristic that this research ignores is the effect of time on learning: human feedback learning paradigms are usually conducted in a single rapidly paced session, while learning experiences in ecologically relevant circumstances and in animal research are almost always separated by longer periods of time. In our experiments, we examined reward learning in short condensed sessions distributed across weeks vs. learning completed in a single “massed” session in male and female participants. As expected, we found that after equal amounts of training, accuracy was matched between the spaced and massed conditions. However, in a 3-week follow-up, we found that participants exhibited significantly greater memory for the value of spaced-trained stimuli. Supporting a role for short-term memory in massed learning, we found a significant positive correlation between initial learning and working memory capacity. Neurally, we found that patterns of activity in the medial temporal lobe and prefrontal cortex showed stronger discrimination of spaced-vs. massed-trained reward values. Further, patterns in the striatum discriminated between spaced-and massed-trained stimuli overall. Our results indicate that single-session learning tasks engage partially distinct learning mechanisms from spaced sessions of training. Our studies begin to address a large gap in our knowledge of human learning from reinforcement, with potential implications for our understanding of mood disorders and addiction.Significance statementHumans and animals learn to associate predictive value with stimuli and actions, and these values then guide future behavior. Such reinforcement-based learning often happens over long time periods, in contrast to most studies of reward-based learning in humans. In experiments that tested the effect of spacing on learning, we found that associations learned in a single massed session were correlated with short-term memory and significantly decayed over time, while associations learned in short massed sessions over weeks were well-maintained. Additionally, patterns of activity in the medial temporal lobe and prefrontal cortex discriminated the values of stimuli learned over weeks but not minutes. These results highlight the importance of studying learning over time, with potential applications to drug addiction and psychiatry.

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Dopamine affects short-term memory corruption over time in Parkinson’s disease

npj Parkinson s Disease ◽

10.1038/s41531-019-0088-2 ◽

2019 ◽

Vol 5 (1) ◽

Author(s):

Sean James Fallon ◽

Matthew Gowell ◽

Maria Raquel Maio ◽

Masud Husain

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Short Term Memory ◽

Short Term ◽

Term Memory ◽

Over Time

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Decreased synaptic plasticity in the medial prefrontal cortex underlies short-term memory deficits in 6-OHDA-lesioned rats

Behavioural Brain Research ◽

10.1016/j.bbr.2015.12.011 ◽

2016 ◽

Vol 301 ◽

pp. 43-54 ◽

Cited By ~ 14

Author(s):

Filipe C. Matheus ◽

Daniel Rial ◽

Joana I. Real ◽

Cristina Lemos ◽

Juliana Ben ◽

...

Keyword(s):

Prefrontal Cortex ◽

Synaptic Plasticity ◽

Medial Prefrontal Cortex ◽

Short Term Memory ◽

Memory Deficits ◽

Short Term ◽

Term Memory

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Short-Term Memory for Auditory Scenes is Not Lost Over Time

PsycEXTRA Dataset ◽

10.1037/e505772014-160 ◽

2013 ◽

Author(s):

Melissa K. Gregg ◽

Joel S. Snyder

Keyword(s):

Short Term Memory ◽

Short Term ◽

Term Memory ◽

Auditory Scenes ◽

Over Time

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Faculty Opinions recommendation of Theta coupling between V4 and prefrontal cortex predicts visual short-term memory performance.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717949904.793455104 ◽

2012 ◽

Author(s):

Susan Courtney ◽

Akiko Ikkai

Keyword(s):

Prefrontal Cortex ◽

Short Term Memory ◽

Memory Performance ◽

Short Term ◽

Term Memory ◽

Visual Short Term Memory

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(Eye) tracking short-term memory over time

Aphasiology ◽

10.1080/02687038.2011.587179 ◽

2012 ◽

Vol 26 (3-4) ◽

pp. 536-555 ◽

Cited By ~ 2

Author(s):

C. Papagno ◽

E. Bricolo ◽

D. Mussi ◽

R. Daini ◽

C. Cecchetto

Keyword(s):

Eye Tracking ◽

Short Term Memory ◽

Short Term ◽

Term Memory ◽

Over Time

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Short-term memory loss over time without retroactive stimulus interference

Psychonomic Bulletin & Review ◽

10.3758/pbr.15.1.230 ◽

2008 ◽

Vol 15 (1) ◽

pp. 230-235 ◽

Cited By ~ 27

Author(s):

N. COWAN ◽

A. M. AUBUCHON

Keyword(s):

Short Term Memory ◽

Memory Loss ◽

Short Term ◽

Term Memory ◽

Over Time

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Acute Paraxanthine Ingestion Improves Cognition and Short-Term Memory and Helps Sustain Attention in a Double-Blind, Placebo-Controlled, Crossover Trial

Nutrients ◽

10.3390/nu13113980 ◽

2021 ◽

Vol 13 (11) ◽

pp. 3980

Author(s):

Choongsung Yoo ◽

Dante Xing ◽

Drew Gonzalez ◽

Victoria Jenkins ◽

Kay Nottingham ◽

...

Keyword(s):

Response Time ◽

Side Effect ◽

Repeated Measures ◽

Short Term Memory ◽

Short Term ◽

Double Blind ◽

Term Memory ◽

Double Blind Placebo ◽

Psychomotor Vigilance ◽

Over Time

This study examined the effects of acute paraxanthine (PXN) ingestion on markers of cognition, executive function, and psychomotor vigilance. In a randomized, double blind, placebo-controlled, crossover, and counterbalanced manner, 13 healthy male and female participants were randomly assigned to consume a placebo (PLA) or 200 mg of PXN (ENFINITY™, Ingenious Ingredients, L.P.). Participants completed stimulant sensitivity and side effect questionnaires and then performed the Berg Wisconsin Card Sorting Test (BCST), the Go/No-Go test (GNG), the Sternberg task test (STT), and the psychomotor vigilance task test (PVTT). Participants then ingested one capsule of PLA or PXN treatment. Participants completed side effect and cognitive function tests after 1, 2, 3, 4, 5, and 6 h after ingestion of the supplement. After 7 days, participants repeated the experiment while consuming the alternative treatment. Data were analyzed by general linear model (GLM) univariate analyses with repeated measures using body mass as a covariate, and by assessing mean and percent changes from baseline with 95% confidence intervals (CIs) expressed as means (LL, UL). PXN decreased BCST errors (PXN −4.7 [−0.2, −9.20], p = 0.04; PXN −17.5% [−36.1, 1.0], p = 0.06) and perseverative errors (PXN −2.2 [−4.2, −0.2], p = 0.03; PXN −32.8% [−64.4, 1.2], p = 0.04) at hour 6. GNG analysis revealed some evidence that PXN ingestion better maintained mean accuracy over time and Condition R Round 2 response time (e.g., PXN −25.1 [−52.2, 1.9] ms, p = 0.07 faster than PLA at 1 h), suggesting better sustained attention. PXN ingestion improved STT two-letter length absent and present reaction times over time as well as improving six-letter length absent reaction time after 2 h (PXN −86.5 ms [−165, −7.2], p = 0.03; PXN −9.0% [−18.1, 0.2], p = 0.05), suggesting that PXN enhanced the ability to store and retrieve random information of increasing complexity from short-term memory. A moderate treatment x time effect size (ηp2 = 0.08) was observed in PVTT, where PXN sustained vigilance during Trial 2 after 2 h (PXN 840 ms [103, 1576], p = 0.03) and 4 h (PXN 1466 ms [579, 2353], p = 0.002) compared to PL. As testing progressed, the response time improved during the 20 trials and over the course of the 6 h experiment in the PXN treatment, whereas it significantly increased in the PL group. The results suggest that acute PXN ingestion (200 mg) may affect some measures of short-term memory, reasoning, and response time to cognitive challenges and help sustain attention.

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Temporal dynamics of implicit memory underlying serial dependence

10.1101/2020.11.17.386821 ◽

2020 ◽

Author(s):

Cristiano Moraes Bilacchi ◽

Esaú Ventura Pupo Sirius ◽

André M. Cravo ◽

Raymundo Machado de Azevedo Neto

Keyword(s):

Short Term Memory ◽

Temporal Dynamics ◽

Response Variability ◽

Serial Dependence ◽

Short Term ◽

Term Memory ◽

Memory Mechanism ◽

Current Information ◽

Visuomotor Task ◽

Over Time

AbstractSerial dependence is the effect in which the immediately preceding trial influences participants’ responses to the current stimulus. But for how long does this bias last in the absence of interference from other stimuli? Here, we had 20 healthy young adult participants (12 women) perform a coincident timing task using different inter-trial intervals to characterize the serial dependence effect as the time between trials increases. Our results show that serial dependence abruptly decreases after 1 s inter-trial interval, but it remains pronounced after that for up to 8 s. In addition, participants’ response variability slightly decreases over longer intervals. We discuss these results in light of recent models suggesting that serial dependence might rely on a short-term memory trace kept through changes in synaptic weights, which might explain its long duration and apparent stability over time.Statement of RelevanceRecent perceptual and motor experiences bias human behavior. For this serial bias to take place, the brain must keep information for at least the time between events to blend past and current information. Understanding the temporal dynamics of such memory traces might shed light into the short-term memory mechanism and integration of prior and current information. Here, we characterized the temporal dynamics of the serial biases that emerge in a visuomotor task by varying the length of the interval between successive events. Our results show response biases are still present even after intervals as long as 8 s and that participants’ response variability decreases over time. Serial dependence thus seems to rely on a memory mechanism that is both long lasting in the absence of interference and stable.

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