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Diamond, M. E.

Publications and source records attributed to Diamond, M. E..

2 recordsLinked to original sources

Behavioral signatures suggest distinct modes of suppressing irrelevant information during tactile temporal attention in human participants

To make adaptive perceptual judgments, the nervous system must selectively process behaviorally relevant sensory information while filtering out competing distractions. Although attentional control has been extensively studied in the visual domain, particularly in the context of spatial selection, considerably less is known about how attention operates in the tactile modality and across time rather than space. Here, we developed a paradigm to investigate temporal tactile attention in human participants, enabling the study of attentional behavior and underlying behavioral strategies in this sensory domain. Participants were instructed to categorize the intensity of a task-relevant tactile stimulus delivered to the fingertip while ignoring an irrelevant tactile stimulus. A visual cue indicated which of two sequentially presented stimuli was relevant on each trial. In addition, participants completed self-report questionnaires assessing autistic traits and aberrant salience (the tendency to assign significance to otherwise neutral stimuli or events). Across subjects, participants performed the task with high accuracy. However, clustering analyses based on behavioral features revealed distinct response profiles. One cluster did not exhibit biases induced by the irrelevant stimulus. In contrast, a third cluster displayed a repulsive effect of the irrelevant stimulus and showed lower overall performance. These behavioral phenotypes were also reflected, to some extent, in differences in learning trajectories across training sessions. We further explored participants' metacognitive awareness through a post-experiment questionnaire assessing subjective evaluations of task difficulty and performance. Although exploratory, the results suggest a relationship between metacognitive reports, behavioral strategies, and objective task performance. In contrast, neither autistic traits nor aberrant salience scores were associated with performance measures or behavioral phenotypes. Together, these findings support the view that attentional control is implemented through multiple, individualistic behavioral strategies rather than a single mechanism pertaining to all, suggesting that task structure interacts with individual predispositions to shape distinct modes of attentional control in human participants.

neuroscience

Posterior parietal cortex represents sensory stimulus history and is necessary for its effects on behavior

Many models of cognition and of neural computations posit the use and estimation of prior stimulus statistics1-4: it has long been known that working memory and perception are strongly impacted by previous sensory experience, even when that sensory history is irrelevant for the current task at hand. Nevertheless, the neural mechanisms and brain regions necessary for computing and using such priors are unknown. Here we report that the posterior parietal cortex (PPC) is a critical locus for the representation and use of prior stimulus information. We trained rats in an auditory Parametric Working Memory (PWM) task, and found that rats displayed substantial and readily quantifiable behavioral effects of sensory stimulus history, similar to those observed in humans5,6 and monkeys7. Earlier proposals that PPC supports working memory8,9 predict that optogenetic silencing of this region would impair behavior in our working memory task. Contrary to this prediction, silencing PPC significantly improved performance. Quantitative analyses of behavior revealed that this improvement was due to the selective reduction of the effects of prior sensory stimuli. Electrophysiological recordings showed that PPC neurons carried far more information about sensory stimuli of previous trials than about stimuli of the current trial. Furthermore, the more information about previous trial sensory history in the neural firing rates of a given rats PPC, the greater the behavioral effect of sensory history in that rat, suggesting a tight link between behavior and PPC representations of stimulus history. Our results indicate that the PPC is a central component in the processing of sensory stimulus history, and open a window for neurobiological investigation of long-standing questions regarding how perception and working memory are affected by prior sensory information.

neuroscience