Modulation of cognitive control levels via manipulation of saccade trial-type probability assessed with event-related BOLD fMRI

2016 ◽  
Vol 115 (2) ◽  
pp. 763-772 ◽  
Author(s):  
Jordan E. Pierce ◽  
Jennifer E. McDowell

Cognitive control supports flexible behavior adapted to meet current goals and can be modeled through investigation of saccade tasks with varying cognitive demands. Basic prosaccades (rapid glances toward a newly appearing stimulus) are supported by neural circuitry, including occipital and posterior parietal cortex, frontal and supplementary eye fields, and basal ganglia. These trials can be contrasted with complex antisaccades (glances toward the mirror image location of a stimulus), which are characterized by greater functional magnetic resonance imaging (MRI) blood oxygenation level-dependent (BOLD) signal in the aforementioned regions and recruitment of additional regions such as dorsolateral prefrontal cortex. The current study manipulated the cognitive demands of these saccade tasks by presenting three rapid event-related runs of mixed saccades with a varying probability of antisaccade vs. prosaccade trials (25, 50, or 75%). Behavioral results showed an effect of trial-type probability on reaction time, with slower responses in runs with a high antisaccade probability. Imaging results exhibited an effect of probability in bilateral pre- and postcentral gyrus, bilateral superior temporal gyrus, and medial frontal gyrus. Additionally, the interaction between saccade trial type and probability revealed a strong probability effect for prosaccade trials, showing a linear increase in activation parallel to antisaccade probability in bilateral temporal/occipital, posterior parietal, medial frontal, and lateral prefrontal cortex. In contrast, antisaccade trials showed elevated activation across all runs. Overall, this study demonstrated that improbable performance of a typically simple prosaccade task led to augmented BOLD signal to support changing cognitive control demands, resulting in activation levels similar to the more complex antisaccade task.

2017 ◽  
Vol 29 (2) ◽  
pp. 368-381 ◽  
Author(s):  
Jordan E. Pierce ◽  
Jennifer E. McDowell

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.


2004 ◽  
Vol 92 (3) ◽  
pp. 1892-1903 ◽  
Author(s):  
Dana M. Small ◽  
Joel Voss ◽  
Y. Erica Mak ◽  
Katharine B. Simmons ◽  
Todd Parrish ◽  
...  

Flavor perception arises from the central integration of peripherally distinct sensory inputs (taste, smell, texture, temperature, sight, and even sound of foods). The results from psychophysical and neuroimaging studies in humans are converging with electrophysiological findings in animals and a picture of the neural correlates of flavor processing is beginning to emerge. Here we used event-related fMRI to evaluate brain response during perception of flavors (i.e., taste/odor liquid mixtures not differing in temperature or texture) compared with the sum of the independent presentation of their constituents (taste and/or odor). All stimuli were presented in liquid form so that olfactory stimulation was by the retronasal route. Mode of olfactory delivery is important because neural suppression has been observed in chemosensory regions during congruent taste–odor pairs when the odors are delivered by the orthonasal route and require subjects to sniff. There were 2 flavors. One contained a familiar/congruent taste–odor pair (vanilla/sweet) and the other an unfamiliar/incongruent taste–odor pair (vanilla/salty). Three unimodal stimuli, including 2 tastes (sweet and salty) and one odor (vanilla), as well as a tasteless/odorless liquid (baseline) were presented. Superadditive responses during the perception of the congruent flavor compared with the sum of its constituents were observed in the anterior cingulate cortex (ACC), dorsal insula, anterior ventral insula extending into the caudal orbitofrontal cortex (OFC), frontal operculum, ventral lateral prefrontal cortex, and posterior parietal cortex. These regions were not present in a similar analysis of the incongruent flavor compared with the sum of its constituents. All of these regions except the ventrolateral prefrontal cortex were also isolated in a direct contrast of congruent − incongruent. Additionally, the anterior cingulate, posterior parietal cortex, frontal operculum, and ventral insula/caudal OFC were also more active in vanilla + salty minus incongruent, suggesting that delivery of an unfamiliar taste–odor combination may lead to suppressed neural responses. Taken together with previous findings in the literature, these results suggest that the insula, OFC, and ACC are key components of the network underlying flavor perception and that taste–smell integration within these and other regions is dependent on 1) mode of olfactory delivery and 2) previous experience with taste/smell combinations.


2005 ◽  
Vol 17 (11) ◽  
pp. 1728-1743 ◽  
Author(s):  
F. Gregory Ashby ◽  
Shawn W. Ell ◽  
Vivian V. Valentin ◽  
Michael B. Casale

Many studies suggest that the sustained activation underlying working memory (WM) maintenance is mediated by a distributed network that includes the prefrontal cortex and other structures (e.g., posterior parietal cortex, thalamus, globus pallidus, and the caudate nucleus). A computational model of WM, called FROST (short for FROntal-Striatal-Thalamic), is proposed in which the representation of items and spatial positions is encoded in the lateral prefrontal cortex. During delay intervals, activation in these prefrontal cells is sustained via parallel, prefrontal cortical-thalamic loops. Activation reverberates in these loops because prefrontal cortical excitation of the head of the caudate nucleus leads to disinhibition of the thalamus (via the globus pallidus). FROST successfully accounts for a wide variety of WM data, including single-cell recording data and human behavioral data.


2015 ◽  
Vol 113 (1) ◽  
pp. 44-57 ◽  
Author(s):  
Xue-Lian Qi ◽  
Anthony C. Elworthy ◽  
Bryce C. Lambert ◽  
Christos Constantinidis

Both dorsolateral prefrontal and posterior parietal cortex have been implicated in spatial working memory and representation of task information. Prior experiments training animals to recall the first of a sequence of stimuli and examining the effect of subsequent distractors have identified increased ability of the prefrontal cortex to represent remembered stimuli and filter distractors. It is unclear, however, if this prefrontal functional specialization extends to stimuli appearing earlier in a sequence, when subjects are cued to remember subsequent ones. It is also not known how task information interacts with persistent activity representing remembered stimuli and distractors in the two areas. To address these questions, we trained monkeys to remember either the first or second of two stimuli presented in sequence and recorded neuronal activity from the posterior parietal and dorsolateral prefrontal cortex. The prefrontal cortex was better able to represent the actively remembered stimulus, whereas the posterior parietal cortex was more modulated by distractors; however, task effects interfered with this representation. As a result, large proportions of neurons with persistent activity and task effects exhibited a preference for a stimulus when it appeared as a distractor in both areas. Additionally, prefrontal neurons were modulated to a greater extent by task factors during the delay period of the task. The results indicate that the prefrontal cortex is better able than the posterior parietal cortex to differentiate between distractors and actively remembered stimuli and is more modulated by the task; however, this relative preference is highly context dependent and depends on the specific requirements of the task.


2020 ◽  
Vol 46 (Supplement_1) ◽  
pp. S89-S89
Author(s):  
Anita Kwashie ◽  
Yizhou Ma ◽  
Andrew Poppe ◽  
Deanna Barch ◽  
Cameron Carter ◽  
...  

Abstract Background Cognitive control mechanisms enable an individual to regulate, coordinate, and sequence thoughts and actions to obtain desired outcomes. A theory of control specialization posits that proactive control is necessary for anticipatory planning and goal maintenance and recruits sustained lateral prefrontal activity, whereas reactive control, essential for adapting to transient changes, marshals a more extensive brain network (Braver, 2012). Increased task errors and reduced frontoparietal activity in proactive contexts is observed in severe psychopathology, including schizophrenia (Poppe et al., 2016), leading to the prediction that patients rely on reactive control more when performing such tasks. However, evidence of primate prefrontal ‘switch’ neurons, active during both proactive and reactive contexts, challenges the notion that cognitive control relies on discrete processing networks (Blackman et al., 2016). To examine this contradiction, we sought to characterize the distinctiveness between proactive and reactive control in healthy and patient populations using the Dot Pattern Expectancy Task (DPX). We also examined if a bias toward proactive or reactive control predicted behavioral metrics. Methods 44 individuals with schizophrenia (SZ) and 50 matched healthy controls (HC) completed 4 blocks of the DPX during a 3-Tesla fMRI scan (Poppe et al., 2016). Participants followed the ‘A-then-X’ rule, in which they pressed one button whenever an A cue followed an X probe, and pressed a different button for any other non-target stimulus sequence. We examined bilateral frontoparietal ROIs from the literature for evidence of cognitive control specialization as well as whole-brain analyses. Subsequent nonparametric tests and measures of neural response variation strengthened our interpretations. Participant d’-context (dependent on task accuracy) measured their tendency to engage in proactive control. Results Behavioral data revealed that HC participants showed a greater proclivity for proactive control than did their SZ counterparts. HC reaction time outpaced SZ reaction time in trials requiring successful marshalling of proactive control. Preliminary neuroimaging analyses suggest marginal between-group differences in control specialization. HC specialization appeared to be most apparent in diffuse frontal lateral regions, and bilateral posterior parietal cortex. Within the SZ group, specialization was most evident in bilateral posterior parietal cortex. Between-group control specialization differences were most apparent in right hemisphere frontal regions. Superior frontal gyrus and medial temporal lobe activity during proactive processes accounted for modest variance in d’-context. Discussion There were significant between-group differences in goal maintenance behavioral metrics such as reaction time and a tendency to engage in proactive control. Control specialization occurred more diffusely in controls compared to patient counterparts. However, activity in these regions had minimal ability to predict behavioral metrics. Overall, the relatively small size of control-specific areas compared to regions involved in dual processing offers support for the malleable nature of regions implicated in human cognitive control.


2012 ◽  
Vol 108 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Xin Zhou ◽  
Fumi Katsuki ◽  
Xue-Lian Qi ◽  
Christos Constantinidis

The dorsolateral prefrontal and posterior parietal cortices are two interconnected brain areas that are coactivated in tasks involving functions such as spatial attention and working memory. The response properties of neurons in the two areas are in many respects indistinguishable, yet only prefrontal neurons are able to resist interference by distracting stimuli when subjects are required to remember an initial stimulus. Several mechanisms have been proposed that could account for this functional difference, including the existence of specialized interneuron types, specific to the prefrontal cortex. Although such neurons with inverted tuning during the delay period of a working memory task have been described in the prefrontal cortex, no comparative data exist from other cortical areas that would establish a unique prefrontal role. To test this hypothesis, we analyzed a large database of recordings obtained in the dorsolateral prefrontal and posterior parietal cortex of the same monkeys as they performed working memory tasks. We found that in the prefrontal cortex, neurons with inverted tuning were more numerous and manifested unique properties. Our results give credence to the idea that a division of labor exists between separate neuron types in the prefrontal cortex and that this represents a functional specialization that is not present in its cortical afferents.


2000 ◽  
Vol 97 (24) ◽  
pp. 13448-13453 ◽  
Author(s):  
M.-H. Sohn ◽  
S. Ursu ◽  
J. R. Anderson ◽  
V. A. Stenger ◽  
C. S. Carter

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