Functional segregation within the dorsal frontoparietal network: a multimodal dynamic causal modeling study

Abstract

Discrimination and integration of motion direction requires the interplay of multiple brain areas. Theoretical accounts of perception suggest that stimulus-related (i.e., exogenous) and decision-related (i.e., endogenous) factors affect distributed neuronal processing at different levels of the visual hierarchy. To test these predictions, we measured brain activity of healthy participants during a motion discrimination task, using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). We independently modeled the impact of exogenous factors (task demand) and endogenous factors (perceptual decision-making) on the activity of the motion discrimination network and applied Dynamic Causal Modeling (DCM) to both modalities. DCM for event-related potentials (DCM-ERP) revealed that task demand impacted the reciprocal connections between the primary visual cortex (V1) and medial temporal areas (V5). With practice, higher visual areas were increasingly involved, as revealed by DCM-fMRI. Perceptual decision-making modulated higher levels (e.g., V5-to-Frontal Eye Fields, FEF), in a manner predictive of performance. Our data suggest that lower levels of the visual network support early, feature-based selection of responses, especially when learning strategies have not been implemented. In contrast, perceptual decision-making operates at higher levels of the visual hierarchy by integrating sensory information with the internal state of the subject.

Pathway and directional specificity of Hebbian plasticity in the cortical visual motion processing network

“…To examine whether the changes in EEG activity and interareal connectivity translated into perceptual changes, we used a 2-alternative, forced-choice, left-right, global direction discrimination and integration task, as previously described. 21 , 54 , 55 , 56 , 57 Subjects were asked to discriminate the left–right direction of motion of random-dot stimuli centered at Cartesian coordinates [-5°, 5°] (i.e., the bottom left quadrant of the visual field, relative to central fixation, see Figure 3 E). Self-confidence was rated (low/medium/high) after each trial.…”

“…We can speculate that V1 is more robust to plastic changes while MT shows more flexible patterns of activity as demonstrated earlier. 76 …”

“…We used a well-established 2-alternative, forced-choice, left-right, global direction discrimination and integration task (150 trials in total), as previously described. 21 , 54 , 55 , 56 , 57 Subjects were asked to discriminate the left–right direction of motion of random-dot stimuli. They performed 150 trials, with each trial initiated by fixation of a small spot of light within an electronic window 2 × 2° in size.…”

Pathway and directional specificity of Hebbian plasticity induction in the cortical visual motion processing network

“…We used the same 2-alternative, forced-choice, left-right, global direction discrimination and integration task (150 trials in total), as previously described (Huxlin et al, 2009; Martin et al, 2010; Salamanca-Giron et al, 2021, Raffin et al, 2021). The stimuli consisted of a group of black dots moving globally left-or rightwards at a density of 2.6 dots/° and in a 5° diameter circular aperture centred at cartesian coordinates [-5°, 5°] (i.e., the bottom left quadrant of the visual field, relative to central fixation, see Figure 1D).…”

Effective connectivity predicts distributed neural coding of perceptual decision confidence, uncertainty and speed

“…While functional magnetic resonance imaging (fMRI) and electroencephalography (EEG)-informed fMRI have been the primary tools for identifying active brain regions and examining functional connectivity 12 , directed connectivity approaches such as dynamic causal modelling (DCM) can offer invaluable insights into the causal relationships between these regions 13 . Existing studies employing DCM have elucidated the effective connectivity between brain regions during various perceptual decision-making tasks, revealing specific directed connections between frontal, parietal, and temporal regions that are critical for decision-making processes [14][15][16][17][18][19] . However, there is limited investigation using DCM for understanding decision confidence, with the only study focusing on the neural dynamics underlying belief updating and confidence in the dorsolateral prefrontal and anterior cingulate cortices 20 .…”