scholarly journals Neuronal Responses in Posterior Parietal Cortex during Learning of Implied Serial Order

2019 ◽  
Author(s):  
Fabian Munoz ◽  
Greg Jensen ◽  
Benjamin C. Kennedy ◽  
Yelda Alkan ◽  
Herbert S. Terrace ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Rhesus Macaques ◽  
Distance Effect ◽  
Serial Order ◽  
Temporal Cues ◽  
Posterior Parietal ◽  
The Difference ◽  
Symbolic Distance ◽  
Relationship Of

ABSTRACTMonkeys are able to learn the implied ordering of pairs of images drawn from an ordered set, without ever seeing all of the images simultaneously and without explicit spatial or temporal cues. The learning of implied order differs from learning of explicit visual or motor sequences. We recorded the activity of parietal neurons in rhesus macaques while they learned 7-item TI lists when only 2 items were presented on each trial. Behavior and ensemble neuronal activity were significantly influenced by the ordinal relationship of the stimulus pairs, specifically symbolic distance (the difference in rank) and joint ranks (the sum of the ranks). Symbolic distance strongly predicted decision accuracy, and learning was consistently faster as symbolic distance increased. An effect of joint rank on performance was also found nested within the symbolic distance effect. Across the population of neurons, there was significant modulation of firing correlated with the relative ranks of the two stimuli presented on each trial. Neurons exhibited selectivity for stimulus rank during learning, but not before or after. The observed behavior during learning is best explained by a virtual workspace model, not by associative or reward mechanisms. The neural data support a role for posterior parietal cortex in representing several variables that contribute to serial learning, particularly information about the ordinal ranks of the stimuli presented during a given trial. Thus, parietal cortex appears to belong to a neural substrate for learning and representing abstract relationships in a virtual workspace.

scholarly journals Dopamine influences attentional rate modulation in Macaque posterior parietal cortex

2020 ◽  
Author(s):  
Jochem van Kempen ◽  
Christian Brandt ◽  
Claudia Distler ◽  
Mark A. Bellgrove ◽  
Alexander Thiele
Keyword(s):  
Spatial Attention ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Rhesus Macaques ◽  
D1 Receptor ◽  
Attention Task ◽  
Attentional Processing ◽  
Firing Rates ◽  
Pupil Light Reflex ◽  
Posterior Parietal

AbstractSelective attention facilitates the prioritization of task-relevant sensory inputs over those which are irrelevant. Although cognitive neuroscience has made great strides in understanding the neural substrates of attention, our understanding of its neuropharmacology is incomplete. Cholinergic and glutamatergic contributions have been demonstrated, but emerging evidence also suggests an important influence of dopamine (DA). DA has historically been investigated in the context of frontal/prefrontal function arguing that dopaminergic receptor density in the posterior/parietal cortex is sparse. However, this notion was derived from rodent data, whereas in primates DA innervation in parietal cortex matches that of many prefrontal areas. We recorded single- and multi-unit activity whilst iontophoretically administering dopaminergic agonists and antagonists to posterior parietal cortex of rhesus macaques engaged in a spatial attention task. Out of 88 neurons, 50 showed modulation of activity induced by drug administration. Dopamine inhibited firing rates across the population according to an inverted-U shaped dose-response curve. D1 receptor antagonists diminished firing rates in broad-spiking units according to a monotonically increasing function. Additionally, dopamine modulated attentional signals in broad, but not narrow-spiking cells. Finally, both drugs modulated the pupil light reflex. These data show that dopamine plays an important role in shaping neuronal responses and modulates attentional processing in macaque parietal cortex.Significance statementDopamine is critically involved in high-level cognitive functions, and dopaminergic dysfunctions pertain to ageing and neurological and psychiatric disorders. Most previous studies focused on dopaminergic effects on prefrontal activity or its role in basal ganglia circuitry. The effects of dopamine in other brain areas such as parietal cortex, despite its well-established role in cognition and cognitive dysfunction, have largely been overlooked. This study is the first to show dopaminergic modulation of parietal activity in general, and specific to spatial attention in the non-human primate, revealing cell-type specific effects of dopamine on attentional modulation.

scholarly journals Learned Representation of Implied Serial Order in Posterior Parietal Cortex

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Fabian Munoz ◽  
Greg Jensen ◽  
Benjamin C. Kennedy ◽  
Yelda Alkan ◽  
Herbert S. Terrace ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Serial Order ◽  
Posterior Parietal

scholarly journals Influence of Rule and Reward-based Strategies on Inferences of Serial Order by Monkeys

2021 ◽  
Author(s):  
Allain-Thibeault Ferhat ◽  
Greg Jensen ◽  
Herbert S. Terrace ◽  
Vincent P. Ferrera
Keyword(s):  
Reward Magnitude ◽  
Rank Order ◽  
Rhesus Macaques ◽  
Distance Effect ◽  
Serial Order ◽  
Cognitive Mechanisms ◽  
Rule Based ◽  
The Face ◽  
Symbolic Distance ◽  
Selection Of

Knowledge of transitive relationships between items can contribute to learning the order of a set of stimuli from pairwise comparisons. However, cognitive mechanisms of transitive inferences based on rank order remain unclear, as are contributions of reward magnitude and rule-based inference. To explore these issues, we created a conflict between rule- and reward-based learning during a serial ordering task. Rhesus macaques learned two lists, each containing five stimuli, that were trained exclusively with adjacent pairs. Selection of the higher-ranked item resulted in rewards. "Small reward" lists yielded 2 drops of fluid reward, while "large reward" lists yielded 5 drops. Following training of adjacent pairs, monkeys were tested on novels pairs. One item was selected from each list, such that a ranking rule could conflict with preferences for large rewards. Differences in associated reward magnitude had a strong influence on accuracy, but we also observed a symbolic distance effect. That provided evidence of a rule-based influence on decisions. Reaction time comparisons suggested a conflict between rule and reward-based processes. We conclude that performance reflects the contributions of two strategies, and that a model-based strategy is employed in the face of a strong countervailing reward incentive.

Posterior parietal cortex mediates encoding processes in change blindness

2009 ◽  
Author(s):  
Philip Tseng ◽  
Cassidy Sterling ◽  
Adam Cooper ◽  
Bruce Bridgeman ◽  
Neil G. Muggleton ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Change Blindness ◽  
Posterior Parietal

The Grasp Cell Hypothesis: Near-miss effect points to common neurological machinery in posterior parietal cortex for controllable objects and concepts

2018 ◽  
Author(s):  
Imogen M Kruse
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Near Miss ◽  
Illusion Of Control ◽  
Gambling Behaviour ◽  
Drug Seeking ◽  
Spatial Influence ◽  
Reward Probability ◽  
Posterior Parietal ◽  
Action Value

The near-miss effect in gambling behaviour occurs when an outcome which is close to a win outcome invigorates gambling behaviour notwithstanding lack of associated reward. In this paper I postulate that the processing of concepts which are deemed controllable is rooted in neurological machinery located in the posterior parietal cortex specialised for the processing of objects which are immediately actionable or controllable because they are within reach. I theorise that the use of a common machinery facilitates spatial influence on the perception of concepts such that the win outcome which is 'almost complete' is perceived as being 'almost within reach'. The perceived realisability of the win increases subjective reward probability and the associated expected action value which impacts decision-making and behaviour. This novel hypothesis is the first to offer a neurological model which can comprehensively explain many empirical findings associated with the near-miss effect as well as other gambling phenomena such as the ‘illusion of control’. Furthermore, when extended to other compulsive behaviours such as drug addiction, the model can offer an explanation for continued drug-seeking following devaluation and for the increase in cravings in response to perceived opportunity to self-administer, neither of which can be explained by simple reinforcement models alone. This paper therefore provides an innovative and unifying perspective for the study and treatment of behavioural and substance addictions.

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