scholarly journals Correlates of Stimulus-Response Congruence in the Posterior Parietal Cortex

2007 ◽  
Vol 19 (2) ◽  
pp. 194-203 ◽  
Author(s):  
Gijsbert Stoet ◽  
Lawrence H. Snyder
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Motor Command ◽  
Button Press ◽  
Primate Behavior ◽  
Task Context ◽  
Stimulus Response ◽  
Additional Processing ◽  
Posterior Parietal ◽  
Time Required

Primate behavior is flexible: The response to a stimulus often depends on the task in which it occurs. Here we study how single neurons in the posterior parietal cortex (PPC) respond to stimuli which are associated with different responses in different tasks. Two rhesus monkeys performed a task-switching paradigm. Each trial started with a task cue instructing which of two tasks to perform, followed by a stimulus requiring a left or right button press. For half the stimuli, the associated responses were different in the two tasks, meaning that the task context was necessary to disambiguate the incongruent stimuli. The other half of stimuli required the same response irrespective of task context (congruent). Using this paradigm, we previously showed that behavioral responses to incongruent stimuli are significantly slower than to congruent stimuli. We now demonstrate a neural correlate in the PPC of the additional processing time required for incongruent stimuli. Furthermore, we previously found that 29% of parietal neurons encode the task being performed (task-selective cells). We now report differences in neuronal timing related to congruency in task-selective versus task nonselective cells. These differences in timing suggest that the activity in task nonselective cells reflects a motor command, whereas activity in task-selective cells reflects a decision process.

Reduced Cognitive Control Demands after Practice of Saccade Tasks in a Trial Type Probability Manipulation

2017 ◽  
Vol 29 (2) ◽  
pp. 368-381 ◽  
Author(s):  
Jordan E. Pierce ◽  
Jennifer E. McDowell
Keyword(s):  
Cognitive Control ◽  
Parietal Cortex ◽  
Trial Type ◽  
Posterior Parietal Cortex ◽  
Brain Regions ◽  
Mirror Image ◽  
Stimulus Response ◽  
Practice Group ◽  
Task Practice ◽  
Posterior Parietal

Cognitive control is engaged to facilitate stimulus–response mappings for novel, complex tasks and supervise performance in unfamiliar, challenging contexts—processes supported by pFC, ACC, and posterior parietal cortex. With repeated task practice, however, the appropriate task set can be selected in a more automatic fashion with less need for top–down cognitive control and weaker activation in these brain regions. One model system for investigating cognitive control is the ocular motor circuitry underlying saccade production, with basic prosaccade trials (look toward a stimulus) and complex antisaccade trials (look to the mirror image location) representing low and high levels of cognitive control, respectively. Previous studies have shown behavioral improvements on saccade tasks after practice with contradictory results regarding the direction of functional MRI BOLD signal change. The current study presented healthy young adults with prosaccade and antisaccade trials in five mixed blocks with varying probability of each trial type (0%, 25%, 50%, 75%, or 100% anti vs. pro) at baseline and posttest MRI sessions. Between the scans, participants practiced either the specific probability blocks used during testing or only a general 100% antisaccade block. Results indicated an overall reduction in BOLD activation within pFC, ACC, and posterior parietal cortex and across saccade circuitry for antisaccade trials. The specific practice group showed additional regions including ACC, insula, and thalamus with an activation decrease after practice, whereas the general practice group showed a little change from baseline in those clusters. These findings demonstrate that cognitive control regions recruited to support novel task behaviors were engaged less after practice, especially with exposure to mixed task contexts rather than a novel task in isolation.

scholarly journals Preservation of Partially Mixed Selectivity in Human Posterior Parietal Cortex across Changes in Task Context

eNeuro ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. ENEURO.0222-19.2019 ◽  
Author(s):  
Carey Y. Zhang ◽  
Tyson Aflalo ◽  
Boris Revechkis ◽  
Emily Rosario ◽  
Debra Ouellette ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Task Context ◽  
Posterior Parietal

scholarly journals The Involvement of Posterior Parietal Cortex in Feature and Conjunction Visuomotor Search

2011 ◽  
Vol 23 (8) ◽  
pp. 1964-1972 ◽  
Author(s):  
Alison R. Lane ◽  
Daniel T. Smith ◽  
Thomas Schenk ◽  
Amanda Ellison
Keyword(s):  
Visual Search ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Spatial Information ◽  
Target Identification ◽  
Movement Time ◽  
Button Press ◽  
Visuomotor Transformation ◽  
Feature Search ◽  
Posterior Parietal

Successful interaction with the environment often involves the identification and localization of an item. Right posterior parietal cortex (rPPC) is necessary for the completion of conjunction but not feature visual search, regardless of the attentional requirements. One account for this dissociation is that the rPPC is primarily involved in processing spatial information. For target identification, conjunction tasks require that spatial information is used to determine if features occur at the same location, whereas feature search does not require such a process. This account suggests that if the requirement to localize the target is made explicit, then rPPC may also be necessary for feature search. This was examined using TMS and by manipulating the response mode: Participants were either required to press a button indicating the presence/absence of the target or else had to point to the target. TMS over rPPC did not disrupt performance of the feature task when a button press was required but significantly increased response time and movement time for the same task in the pointing condition. Conjunction search in both response conditions was significantly impaired by TMS. Performance on a task that required pointing to a target in the absence of distractors and thus did not involve visual search was unaffected by rPPC stimulation. We conclude that rPPC is involved in coding and representing spatial information and is therefore crucial when the task requires determining whether two features spatially co-occur or when search is combined with explicit target localization via a visuomotor transformation.

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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