scholarly journals Communication between the mediodorsal thalamus and prelimbic cortex regulates timing performance in rats

2021 ◽  
Author(s):  
Benjamin J De Corte ◽  
Kelsey A Heslin ◽  
Nathan Cremers ◽  
John H Freeman ◽  
Krystal L Parker
Keyword(s):  
Decision Making ◽  
Male Rats ◽  
Time Interval ◽  
Prelimbic Cortex ◽  
Motivational Systems ◽  
Starting Point ◽  
Reciprocal Connections ◽  
Future Events ◽  
The Brain

Predicting when future events will occur and adjusting behavior accordingly is critical to adaptive behavior. Despite this, little is known about the brain networks that encode time and how this ultimately impacts decision-making. One established finding is that the prefrontal cortex (PFC) and its non-human analogues (e.g., the rodent prelimbic cortex; PL) mediate timing. This provides a starting point for exploring the networks that support temporal processing by identifying areas that interact with the PFC during timing tasks. For example, substantial work has explored the role of frontostriatal circuits in timing. However, other areas are undoubtedly involved. The mediodorsal nucleus of the thalamus (MD) is an excellent candidate region. It shares dense, reciprocal connections with PFC-areas in both humans and non-human species and is implicated in cognition. However, causal data implicating MD-PFC interactions in cognition broadly is still sparse, and their role in timing specifically is currently unknown. To address this, we trained male rats on a time-based, decision-making task referred to as the 'peak-interval' procedure. During the task, presentation of a cue instructed the rats to respond after a specific interval of time elapsed (e.g., tone-8 seconds). We incorporated two cues; each requiring a response after a distinct time-interval (e.g., tone-8 seconds / light-16 seconds). We tested the effects of either reversibly inactivating the MD or PL individually or functionally disconnecting them on performance. All manipulations caused a comparable timing deficit. Specifically, responses showed little organization in time, as if primarily guided by motivational systems. These data expand our understanding of the networks that support timing and suggest that MD-PL interactions specifically are a core component. More broadly, our results suggest that timing tasks provide a reliable assay for characterizing the role of MD-PL interactions in cognition using rodents, which has been difficult to establish in the past.

scholarly journals Consciousness, decision making, and volition: freedom beyond chance and necessity

2021 ◽  
Author(s):  
Hans Liljenström
Keyword(s):  
Decision Making ◽  
Free Will ◽  
Brain Activity ◽  
Brain Structures ◽  
Complex Process ◽  
Neural Information ◽  
Neural Information Processing ◽  
Stochastic Population Model ◽  
The Brain

AbstractWhat is the role of consciousness in volition and decision-making? Are our actions fully determined by brain activity preceding our decisions to act, or can consciousness instead affect the brain activity leading to action? This has been much debated in philosophy, but also in science since the famous experiments by Libet in the 1980s, where the current most common interpretation is that conscious free will is an illusion. It seems that the brain knows, up to several seconds in advance what “you” decide to do. These studies have, however, been criticized, and alternative interpretations of the experiments can be given, some of which are discussed in this paper. In an attempt to elucidate the processes involved in decision-making (DM), as an essential part of volition, we have developed a computational model of relevant brain structures and their neurodynamics. While DM is a complex process, we have particularly focused on the amygdala and orbitofrontal cortex (OFC) for its emotional, and the lateral prefrontal cortex (LPFC) for its cognitive aspects. In this paper, we present a stochastic population model representing the neural information processing of DM. Simulation results seem to confirm the notion that if decisions have to be made fast, emotional processes and aspects dominate, while rational processes are more time consuming and may result in a delayed decision. Finally, some limitations of current science and computational modeling will be discussed, hinting at a future development of science, where consciousness and free will may add to chance and necessity as explanation for what happens in the world.

scholarly journals Cuing both positive and negative episodic foresight reduces delay discounting but does not affect risk-taking

2019 ◽  
Vol 72 (8) ◽  
pp. 1998-2017 ◽  
Author(s):  
Adam Bulley ◽  
Beyon Miloyan ◽  
Gillian V Pepper ◽  
Matthew J Gullo ◽  
Julie D Henry ◽  
...  
Keyword(s):  
Decision Making ◽  
Delay Discounting ◽  
Risk Taking ◽  
Future Scenarios ◽  
Balloon Analogue Risk Task ◽  
Episodic Simulation ◽  
The Future ◽  
Future Events ◽  
Monetary Choice Questionnaire

Humans frequently create mental models of the future, allowing outcomes to be inferred in advance of their occurrence. Recent evidence suggests that imagining positive future events reduces delay discounting (the devaluation of reward with time until its receipt), while imagining negative future events may increase it. Here, using a sample of 297 participants, we experimentally assess the effects of cued episodic simulation of positive and negative future scenarios on decision-making in the context of both delay discounting (monetary choice questionnaire) and risk-taking (balloon-analogue risk task). Participants discounted the future less when cued to imagine positive and negative future scenarios than they did when cued to engage in control neutral imagery. There were no effects of experimental condition on risk-taking. Thus, although these results replicate previous findings suggesting episodic future simulation can reduce delay discounting, they indicate that this effect is not dependent on the valence of the thoughts, and does not generalise to all other forms of “impulsive” decision-making. We discuss various interpretations of these results, and suggest avenues for further research on the role of prospection in decision-making.

Inflammation and Pruning May Inform Risk to Psychiatric Disorders. Lessons From Large Genetic Data

2017 ◽  
Vol 41 (S1) ◽  
pp. S56-S56
Author(s):  
C. Crisafulli
Keyword(s):  
Psychiatric Disorders ◽  
Molecular Mechanics ◽  
Association Studies ◽  
Molecular Pathway ◽  
Starting Point ◽  
Single Effect ◽  
Competing Interest ◽  
The Brain ◽  
New Hypothesis

BackgroundIt's known that psychiatric disorders are caused to either environmental and genetics factors. Through the years several hypotheses were tested and many genes were screened for association, resulting in a huge amount of data available for the scientific community. Despite that, the molecular mechanics behind psychiatric disorders remains largely unknown. Traditional association studies may be not enough to pinpoint the molecular underpinnings of psychiatric disorder. We tried to applying a methodology that investigates molecular-pathway-analysis that takes into account several genes per time, clustered in consistent molecular groups and may successfully capture the signal of a number of genetic variations with a small single effect on the disease. This approach might reveal more of the molecular basis of psychiatric disorders.Methodsi)We collected data on studies available in literature for the studied disorder (e.g. Schizophrenia, Bipolar Disorder);ii)We extracted a pool of genes that are likely involved with the disease;iii)We used these genes as starting point to map molecular cascades function-linked. The molecular cascades are then analyzed and pathways and sub-pathways, possibly involved with them, are identified and tested for association.Results/discussionWe obtained interesting results. In particular, signals of enrichment (association) were obtained multiple times on the molecular pathway associated with the pruning activity and inflammation. Molecular mechanics related to neuronal pruning were focused as a major and new hypothesis for the pathophysiology of psychiatric disorders and the role of inflammatory events has been extensively investigated in psychiatry. intersting, inflammatory mechanics in the brain may also play a role in neuronal pruning during the early development of CNS.Disclosure of interestThe author has not supplied his declaration of competing interest.

scholarly journals Reducing future fears by suppressing the brain mechanisms underlying episodic simulation

2016 ◽  
Vol 113 (52) ◽  
pp. E8492-E8501 ◽  
Author(s):  
Roland G. Benoit ◽  
Daniel J. Davies ◽  
Michael C. Anderson
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Ventromedial Prefrontal Cortex ◽  
Episodic Simulation ◽  
Dorsolateral Prefrontal ◽  
Future Events ◽  
The Right ◽  
Development Of Anxiety ◽  
The Brain

Imagining future events conveys adaptive benefits, yet recurrent simulations of feared situations may help to maintain anxiety. In two studies, we tested the hypothesis that people can attenuate future fears by suppressing anticipatory simulations of dreaded events. Participants repeatedly imagined upsetting episodes that they feared might happen to them and suppressed imaginings of other such events. Suppressing imagination engaged the right dorsolateral prefrontal cortex, which modulated activation in the hippocampus and in the ventromedial prefrontal cortex (vmPFC). Consistent with the role of the vmPFC in providing access to details that are typical for an event, stronger inhibition of this region was associated with greater forgetting of such details. Suppression further hindered participants’ ability to later freely envision suppressed episodes. Critically, it also reduced feelings of apprehensiveness about the feared scenario, and individuals who were particularly successful at down-regulating fears were also less trait-anxious. Attenuating apprehensiveness by suppressing simulations of feared events may thus be an effective coping strategy, suggesting that a deficiency in this mechanism could contribute to the development of anxiety.

Intervals of Intervention : Micro-Decisions and the Temporal Autonomy of Self-Driving Cars

2021 ◽  
Author(s):  
Florian Sprenger
Keyword(s):  
Decision Making ◽  
Media Archaeology ◽  
Starting Point ◽  
New Meanings ◽  
Technical Systems ◽  
Alternative Scenarios ◽  
Self Driving Cars

Self-driving vehicles do not simply translate algorithmic definitions of their interaction with the environment into material actions. In the implementation of microdecisions, temporality itself becomes an element of the success of operations. Taking the fascination for a non-human and distributed capability of decision-making as a starting point, the paper explores how the temporality of microdecisions is integrated into technical systems that interact with their surroundings. On the basis of a media archaeology of these temporalities, it develops a heuristic of autonomous technologies that explores the role of micro-decisions. With self-driving cars, terms such as agency (based on algorithms), temporality (in different intervals of intervention), decision (in reference to alternative scenarios), and autonomy achieve new meanings worthy of a re-interpretation.

scholarly journals A Possible Mechanism for the Action of Adrenomedullin in Brain to Stimulate Stress Hormone Secretion

Endocrinology ◽  
2004 ◽  
Vol 145 (11) ◽  
pp. 4890-4896 ◽  
Author(s):  
Meghan M. Taylor ◽  
Willis K. Samson
Keyword(s):  
Hpa Axis ◽  
Hormone Secretion ◽  
Plasma Corticosterone ◽  
Male Rats ◽  
Stress Hormone ◽  
Elevated Plasma ◽  
The Central Nervous System ◽  
Neuroendocrine Responses ◽  
The Brain

Abstract Adrenomedullin (AM) has been reported to have actions at each level of the hypothalamo-pituitary-adrenal (HPA) axis, suggesting that the peptide plays a role in the organization of the neuroendocrine responses to stress. We examined the mechanism by which AM regulates the central nervous system branch of the HPA axis as well as the possible role of AM in the modulation of the releases of two other hormones, prolactin and GH, whose secretions also are altered by stress. Intracerebroventricular administration of AM led to elevated plasma corticosterone levels in unrestrained, conscious male rats. This effect was abrogated by pretreatment with a CRH antagonist, suggesting that AM activates the HPA axis by causing the release of CRH into hypophyseal portal vessels. In addition, AM given intracerebroventricularly stimulated the release of prolactin but did not alter the secretion of GH. We propose that AM produced in the brain may be an important neuromodulator of the hormonal stress response.

scholarly journals Individuals with ventromedial frontal damage have more unstable but still fundamentally transitive preferences

2018 ◽  
Author(s):  
Linda Q. Yu ◽  
Jason Dana ◽  
Joseph W. Kable
Keyword(s):  
Decision Making ◽  
Decision Maker ◽  
Decision Process ◽  
Healthy Controls ◽  
Rational Decision ◽  
Rational Choices ◽  
The Brain ◽  
Intransitive Preferences ◽  
Rational Decisions

AbstractThough the ventromedial frontal lobes (VMF) are clearly important for decision-making, the precise causal role of the VMF in the decision process has still not yet fully been established. Previous studies have suggested that individuals with VMF damage violate a hallmark axiom of rational decisions by having intransitive preferences (i.e., preferring A to B, B to C, but C to A), as these individuals are more likely to make cyclical choices (i.e., choosing C over A after previously choosing A over B and B over C). However, these prior studies cannot properly distinguish between two possibilities regarding effects of VMF damage: are individuals with VMF damage prone to choosing irrationally, or are their preferences simply more variable? We had individuals with focal VMF damage, individuals with other frontal damage, and healthy controls make repeated choices across three categories – artwork, chocolate bar brands, and gambles. Using sophisticated tests of transitivity, we find that, without exception, individuals with VMF damage made rational decisions consistent with transitive preferences, even though they more frequently exhibit choice cycles due to a greater variability in their preferences across time. That is, the VMF is necessary for having strong and reliable preferences across time and context, but not for being a rational decision maker. We conclude that VMF damage affects the noisiness with which value is assessed, but not the consistency with which value is sought.Significance statementThe VMF is a part of the brain that is thought to be one of the most important for preference-based choice. Despite this, whether it is needed to make rational choices at all is unknown. Previous studies have not discriminated between different possibilities regarding the critical necessary role that the VMF plays in value-based choice. Our study shows that individuals with VMF damage still make rational decisions consistent with what they prefer, but their choices are more variable and less reliable. That is, the VMF is important for the noisiness with which value is assessed, but not the consistency with which value is sought. This result has widespread implications for rethinking the role of VMF in decision-making.

The Role of Executive Function in Shaping Reinforcement Learning

2020 ◽  
Author(s):  
Milena Rmus ◽  
Samuel McDougle ◽  
Anne Collins
Keyword(s):  
Decision Making ◽  
Reinforcement Learning ◽  
Instrumental Behavior ◽  
Complex Environments ◽  
Neural Computations ◽  
Human Decision ◽  
Brain And Behavior ◽  
And Behavior ◽  
The Brain

Reinforcement learning (RL) models have advanced our understanding of how animals learn and make decisions, and how the brain supports some aspects of learning. However, the neural computations that are explained by RL algorithms fall short of explaining many sophisticated aspects of human decision making, including the generalization of learned information, one-shot learning, and the synthesis of task information in complex environments. Instead, these aspects of instrumental behavior are assumed to be supported by the brain’s executive functions (EF). We review recent findings that highlight the importance of EF in learning. Specifically, we advance the theory that EF sets the stage for canonical RL computations in the brain, providing inputs that broaden their flexibility and applicability. Our theory has important implications for how to interpret RL computations in the brain and behavior.

scholarly journals Importance of the Paraventricular Nucleus of the Hypothalamus as a Component of a Neural Pathway between the Brain and the Testes that Modulates Testosterone Secretion Independently of the Pituitary

Endocrinology ◽  
2003 ◽  
Vol 144 (2) ◽  
pp. 594-598 ◽  
Author(s):  
Daniel J. Selvage ◽  
Catherine Rivier
Keyword(s):  
Paraventricular Nucleus ◽  
Leydig Cell ◽  
Pseudorabies Virus ◽  
Cell Function ◽  
Brain Area ◽  
Male Rats ◽  
Neural Pathway ◽  
Electrolytic Lesions ◽  
The Brain

We previously reported that in adult male rats, the intracerebroventricular (icv) injection of corticotropin-releasing factor (CRF) or the β-adrenergic agonist isoproterenol (ISO) significantly inhibited the ability of human chorionic gonadotropin (hCG) to stimulate testosterone (T) secretion. The finding that this phenomenon also took place when LH release had been blocked with an LHRH antagonist suggested that icv CRF and ISO did not alter Leydig cell function by influencing the activity of pituitary gonadotrophs. We therefore proposed the existence of a neural pathway connecting the brain to the testes, whose activation by icv CRF or ISO interfered with T secretion. Based on the intratesticular injection of the transganglionic tracer pseudorabies virus, we recently identified the paraventricular nucleus (PVN) of the hypothalamus as a component of this neural link. The aim of the present work was to investigate the functional role of this brain area in mediating the ability of CRF and ISO to inhibit the ability of hCG to stimulate T secretion. We first demonstrated that local microinfusion of CRF or ISO directly into the PVN mimicked the effect of their icv injection, suggesting that the PVN does indeed represent a site of action of ISO and CRF in altering Leydig cell responsiveness to gonadotropin. In contrast, neither CRF nor ISO microinfusion into the central amygdala or the frontal cortex influenced hCG-stimulated T secretion. To further investigate the role of the PVN in ISO- and CRF-induced blunting of hCG stimulation of T, we determined the effect of icv CRF or ISO on testicular activity of rats with electrolytic lesions of the PVN. These lesions, which did not in themselves influence Leydig cell responsiveness to hCG, blocked the effect of both icv ISO and CRF on hCG-induced T release. Collectively, these results support the hypothesis that CRF- and ISO-induced activation of cells in the area of the PVN decreases the ability of gonadotropin to release T and suggests that this nucleus represents an important site of the proposed neural connection between the brain and the testes.

scholarly journals Sites and sources of sympathoexcitation in obese male rats: role of brain insulin

2020 ◽  
Vol 318 (3) ◽  
pp. R634-R648 ◽  
Author(s):  
Zhigang Shi ◽  
Ding Zhao ◽  
Priscila A. Cassaglia ◽  
Virginia L. Brooks
Keyword(s):  
Insulin Receptors ◽  
Male Rats ◽  
Melanocortin Receptor ◽  
Sprague Dawley ◽  
Intracerebroventricular Infusion ◽  
Sprague Dawley Rats ◽  
Y1 Receptors ◽  
The Brain ◽  
Obese Male

In males, obesity increases sympathetic nerve activity (SNA), but the mechanisms are unclear. Here, we investigate insulin, via an action in the arcuate nucleus (ArcN), and downstream neuropathways, including melanocortin receptor 3/4 (MC3/4R) in the hypothalamic paraventricular nucleus (PVN) and dorsal medial hypothalamus (DMH). We studied conscious and α-chloralose-anesthetized Sprague-Dawley rats fed a high-fat diet, which causes obesity prone (OP) rats to accrue excess fat and obesity-resistant (OR) rats to maintain fat content, similar to rats fed a standard control (CON) diet. Nonspecific blockade of the ArcN with muscimol and specific blockade of ArcN insulin receptors (InsR) decreased lumbar SNA (LSNA), heart rate (HR), and mean arterial pressure (MAP) in OP, but not OR or CON, rats, indicating that insulin supports LSNA in obese males. In conscious rats, intracerebroventricular infusion of insulin increased MAP only in OP rats and also improved HR baroreflex function from subnormal to supranormal. The brain sensitization to insulin may elucidate how insulin can drive central SNA pathways when transport of insulin across the blood-brain barrier may be impaired. Blockade of PVN, but not DMH, MC3/4R with SHU9119 decreased LSNA, HR, and, MAP in OP, but not OR or CON, rats. Interestingly, nanoinjection of the MC3/4R agonist melanotan II (MTII) into the PVN increased LSNA only in OP rats, similar to PVN MTII-induced increases in LSNA in CON rats after blockade of sympathoinhibitory neuropeptide Y Y1 receptors. ArcN InsR expression was not increased in OP rats. Collectively, these data indicate that obesity increases SNA, in part via increased InsR signaling and downstream PVN MC3/4R.

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