Frontotemporal Regulation of Subjective Value to Suppress Impulsivity in Intertemporal Choices

Abstract:

Impulsive decisions arise from preferring smaller but sooner rewards compared with larger but later rewards. How neural activity and attention to choice alternatives contribute to reward decisions during temporal discounting is not clear. Here we probed (1) attention to and (2) neural representation of delay and reward information in humans (both sexes) engaged in choices. We studied behavioral and frequency-specific dynamics supporting impulsive decisions on a fine-grained temporal scale using eye tracking and MEG recordings. In one condition, participants had to decide for themselves but pretended to decide for their best friend in a second prosocial condition, which required perspective taking. Hence, conditions varied in the value for themselves versus that pretending to choose for another person. Stronger impulsivity was reliably found across three independent groups for prosocial decisions. Eye tracking revealed a systematic shift of attention from the delay to the reward information and differences in eye tracking between conditions predicted differences in discounting. High-frequency activity (175-250 Hz) distributed over right frontotemporal sensors correlated with delay and reward information in consecutive temporal intervals for high value decisions for oneself but not the friend. Collectively, the results imply that the high-frequency activity recorded over frontotemporal MEG sensors plays a critical role in choice option integration.

Authors:

• Stefan Dürschmid

• Andre Maric

• Marcel S Kehl

• Robert T Knight

• Hermann Hinrichs

• Hans-Jochen Heinze

Date: 2021

DOI: https://doi.org/10.1523/JNEUROSCI.1196-20.2020

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Fronto-temporal regulation of subjective value to suppress impulsivity in intertemporal choices

Abstract:

Impulsive decisions arise from preferring smaller but sooner rewards compared to larger but later rewards. How neural activity and attention to choice alternatives contribute to reward decisions during temporal discounting is not clear. Here we probed (i) attention to and (ii) neural representation of delay and reward information in humans (both sexes) engaged in choices. We studied behavioral and frequency specific dynamics supporting impulsive decisions on a fine-grained temporal scale using eye tracking and magnetoencephalographic (MEG) recordings. In one condition participants had to decide for themselves but pretended to decide for their best friend in a second prosocial condition, which required perspective taking. Hence, conditions varied in the value for themselves versus that pretending to choose for another person. Stronger impulsivity was reliably found across three independent groups for prosocial decisions. Eye tracking revealed a systematic shift of attention from the delay to the reward information and differences in eye tracking between conditions predicted differences in discounting. High frequency activity (HFA: 175-250 Hz) distributed over right fronto-temporal sensors correlated with delay and reward information in consecutive temporal intervals for high value decisions for oneself but not the friend. Collectively the results imply that the HFA recorded over fronto-temporal MEG sensors plays a critical role in choice option integration.

Authors:

• Stefan Dürschmid

• Andre Maric

• Marcel S Kehl

• Robert T Knight

• Hermann Hinrichs

• Hans-Jochen Heinz

Date: 2020

DOI: https://doi.org/10.1523/JNEUROSCI.1196-20.2020

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Sleep as a potential biomarker of tau and β-amyloid burden in the human brain

Abstract:

Recent proposals suggest that sleep may be a factor associated with accumulation of two core pathological features of Alzheimer's disease (AD): tau and β-amyloid (Aβ). Here we combined PET measures of Aβ and tau, electroencephalogram sleep recordings, and retrospective sleep evaluations to investigate the potential utility of sleep measures in predicting in vivo AD pathology in male and female older adults. Regression analyses revealed that the severity of impaired slow oscillation-sleep spindle coupling predicted greater medial temporal lobe tau burden. Aβ burden was not associated with coupling impairment but instead predicted the diminished amplitude of <1 Hz slow-wave-activity, results that were statistically dissociable from each other. Additionally, comparisons of AD pathology and retrospective, self-reported changes in sleep duration demonstrated that changes in sleep across the lifespan can predict late-life Aβ and tau burden. Thus, quantitative and qualitative features of human sleep represent potential noninvasive, cost-effective, and scalable biomarkers (current and future forecasting) of AD pathology, and carry both therapeutic and public health implications.

Authors:

• Joseph R Winer

• Bryce A Mander

• Randolph F Helfrich

• Anne Maass

• Theresa M Harrison

• Suzanne L Baker

• Robert T Knight

• William J Jagust

• Matthew P Walker

Date: 2019

DOI: https://doi.org/10.1523/JNEUROSCI.0503-19.2019

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Temporal dynamics and response modulation across the human visual system in a spatial attention task: an ECoG study

Abstract:

The selection of behaviorally relevant information from cluttered visual scenes (often referred to as “attention”) is mediated by a cortical large-scale network consisting of areas in occipital, temporal, parietal, and frontal cortex that is organized into a functional hierarchy of feedforward and feedback pathways. In the human brain, little is known about the temporal dynamics of attentional processing from studies at the mesoscopic level of electrocorticography (ECoG), that combines millisecond temporal resolution with precise anatomical localization of recording sites. We analyzed high-frequency broadband responses (HFB) responses from 626 electrodes implanted in 8 epilepsy patients who performed a spatial attention task. Electrode locations were reconstructed using a probabilistic atlas of the human visual system. HFB responses showed high spatial selectivity and tuning, constituting ECoG response fields (RFs), within and outside the topographic visual system. In accordance with monkey physiology studies, both RF widths and onset latencies increased systematically across the visual processing hierarchy. We used the spatial specificity of HFB responses to quantitatively study spatial attention effects and their temporal dynamics to probe a hierarchical top-down model suggesting that feedback signals back propagate the visual processing hierarchy. Consistent with such a model, the strengths of attentional modulation were found to be greater and modulation latencies to be shorter in posterior parietal cortex, middle temporal cortex and ventral extrastriate cortex compared with early visual cortex. However, inconsistent with such a model, attention effects were weaker and more delayed in anterior parietal and frontal cortex.

Authors:

• Anne B. Martin

• Xiaofang Yang

• Yuri B. Saalmann

• Liang Wang

• Avgusta Shestyuk

• Jack J. Lin

• Josef Parvizi

• Robert T. Knight

• Sabine Kastner

Date: 2019

DOI: 10.1523/JNEUROSCI.1889-18.2018

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Should a Few Null Findings Falsify Prefrontal Theories of Conscious Perception?

ABSTRACT

Is activity in prefrontal cortex (PFC) critical for conscious perception? Major theories of consciousness make distinct predictions about the role of PFC, providing an opportunity to arbitrate between these views empirically. Here we address three common misconceptions: (1) PFC lesions do not affect subjective perception; (2) PFC activity does not reflect specific perceptual content; and (3) PFC involvement in studies of perceptual awareness is solely driven by the need to make reports required by the experimental tasks rather than subjective experience per se. These claims are incompatible with empirical findings, unless one focuses only on studies using methods with limited sensitivity. The literature highlights PFC's essential role in enabling the subjective experience in perception, contra the objective capacity to perform visual tasks; conflating the two can also be a source of confusion.

AUTHORS

• Brian Odegaard

• Robert T. Knight 

• Hakwan Lau

Date: 2017

DOI: 10.1523/JNEUROSCI.3217-16.2017

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Effects of lesions of temporal-parietal junction on perceptual and attentional processing in humans

ABSTRACT

When stimuli with larger forms (global) containing smaller forms (local) are presented to subjects with large lesions in the right hemisphere, they are more likely to miss the global form than the local form, whereas subjects with large lesions in the left are more likely to miss the local than the global form. The present study tested whether the global/local impairment in subjects with posterior lesions was due to deficits in controlled attentional processes, passive perceptual processes, or both. Attentional control was examined by measuring reaction time changes when the probability of a target appearing at either the global or local level was varied. Patients with unilateral right or left lesions centered in temporal-parietal regions and age-matched controls served as subjects. Because neurophysiological and neuropsychological evidence have implicated temporal regions in visual discrimination and inferior parietal regions in the allocation of attention to locations in the visual field, patients with left hemisphere lesions were further subdivided into those with lesions centered in the superior temporal gyrus (LSTG) or rostral inferior parietal lobule (LIPL). Patients with right hemisphere injury could not be analogously subdivided. The results revealed that the LSTG group was able to control the allocation of attention to global and local levels normally, while the LIPL group was not. In contrast, the LSTG group showed a strong baseline reaction time advantage toward global targets, while normals and the LIPL group showed no advantage toward one level or the other. Finally, the perceptual component was affected differentially by lesions in the right hemisphere and LSTG, with lesions in the left favoring global targets and lesions in the right favoring local targets. These findings indicate that the hemispheric global/local asymmetry is due to a perceptual mechanism with a critical anatomical locus centered in the STG.

AUTHORS

• Lynn C. Robertson

• Marvin R. Lamb

• Robert T. Knight

Date: 1988

DOI: 10.1523/JNEUROSCI.08-10-03757.1988

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