The Role of the Lateral Intraparietal Area in (the Study of) Decision Making

Abstract

Over the past two decades, neurophysiological responses in the lateral intraparietal area (LIP) have received extensive study for insight into decision-making. In a parallel manner, inferred cognitive processes have enriched interpretations of LIP activity. Because of this bidirectional interplay between physiology and cognition, LIP has served as fertile ground for developing quantitative models that link neural activity with decision-making. These models stand as some of the most important frameworks for linking brain and mind, and they are now mature enough to be evaluated in finer detail and integrated with other lines of investigation of LIP function. Here, we focus on the relationship between LIP responses and known sensory and motor events in perceptual decision-making tasks, as assessed by correlative and causal methods. The resulting sensorimotor-focused approach offers an account of LIP activity as a multiplexed amalgam of sensory, cognitive, and motor-related activity, with a complex and often indirect relationship to decision processes. Our data-driven focus on multiplexing (and de-multiplexing) of various response components can complement decision-focused models and provides more detailed insight into how neural signals might relate to cognitive processes such as decision-making.

Decoding vibrotactile choice independent of stimulus order and saccade selection during sequential comparisons

“…Notably, the most likely source of the beta band modulation moved according to the response effector: the medial premotor cortex for manual responses (Herding, Spitzer, & Blankenburg, 2016) and the frontal eye field for saccades (Herding, Ludwig, & Blankenburg, 2017). This raises the question of whether the previously reported premotor regions would still encode perceptual choices when choices are independent of action selection (cf., Huk, Katz, & Yates, 2017). Moreover, these findings align well with a large body of literature on monkey studies in the visual domain which suggests that perceptual decisions are mainly formed in brain regions involved in preparing and selecting actions (Cisek & Kalaska, 2010;Gold & Shadlen, 2007).…”

“…Note however, that previously reported decision-related signals in the FEF and LIP were mainly observed in studies in which perceptual choice was directly mapped to a specific, predictable saccade direction. A significant portion of decision-related signals in the FEF or LIP disappeared when saccade directions were decorrelated from perceptual choices (Bennur & Gold, 2011;Gold & Shadlen, 2003; reviewed in Huk et al, 2017). Similarly, recent human fMRI studies also failed to capture decision-related signals in the FEF or IPS when there was no fixed mapping between choice and saccade direction (Filimon et al, 2013;Hebart et al, 2012;Li Hegner, Lindner, & Braun, 2015).…”

“…Furthermore, each perceptual choice is most often directly mapped to a movement toward a specific spatial target so that brain signals reflecting perceptual choice cannot be separated from brain signals related to action selection. This raises the question of whether the previously reported premotor regions would still encode perceptual choices when choices are independent of action selection (cf., Huk, Katz, & Yates, 2017). This is particularly relevant in light of a growing body of evidence suggesting that abstract, motorindependent choices are represented by brain regions that are not primarily associated with action selection (Filimon, Philiastides, Nelson, Kloosterman, & Heekeren, 2013;Hebart, Donner, & Haynes, 2012).…”

Strategic and Dynamic Temporal Weighting for Perceptual Decisions in Humans and Macaques

“…Standard viewing-duration analyses do not distinguish between the stimulus and the neural signals that are actually used. These two issues likely interact, with the potential for dynamic strategic weighting to either mirror or compensate for the dynamics of the incoming sensory stream—making canonical functional forms of the relations between accuracy and duration rather imperfect tests of a unique posited mechanism (Huk et al, 2017). …”

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

“…responses did not vary depending on whether the choice saccade was directed toward or away from the receptive field. This result is surprising given the extensive literature on target selection and decision-making in LIP (see Gold and Shadlen, 2007;Huk et al, 2017), but may be accounted for by two features of the current task. First, the decision required that subjects attend to and compare two stimuli in different locations.…”