Anticipatory dynamics in the human brain guide foraging for primary rewards

Foraging is a fundamental food-seeking behavior in a wide range of species that enables survival in an uncertain world. During foraging, behavioral agents constantly face a trade-off between staying in their current location or exploring another. Despite ethological generality and importance of foraging, it remains unclear how the human brain guides continuous decision in such situations. Here we show that anticipatory activity dynamics in the anterior prefrontal cortex (aPFC) and hippocampus underpin foraging for primary rewards. While functional MRI was performed, humans foraged for real liquid rewards available after tens of seconds, and continuous decision during foraging was tracked by a dynamic pattern of brain activity that reflected anticipation of a future reward. When the dynamic anticipatory activity in the aPFC was enhanced, humans remained in their current environment, but when this activity diminished, they explored a new environment. Moreover, the anticipatory activity in the aPFC and hippocampus was associated with distinct decision strategies: aPFC activity was enhanced in humans adopting an exploratory strategy, whereas those remaining stationary showed enhanced activity in the hippocampus. Our results suggest that anticipatory dynamics in the fronto-hippocampal mechanisms underlie continuous decision-making during human foraging.

Prefrontal-Striatal Mechanisms of Behavioral Impulsivity During Consumption of Delayed Real Liquid Rewards

Intertemporal choice involves the evaluation of future rewards and reflects behavioral impulsivity. After choosing a delayed reward in an intertemporal choice, a behavioral agent waits for, receives, and then consumes the reward. The current study focused on the consumption of the delayed reward and examined the neural mechanisms of behavioral impulsivity. In humans consuming delayed real liquid rewards in an intertemporal choice, the ventral striatum (VS) showed differential activity between anterior (aVS) and posterior (pVS) regions depending on the degree of behavioral impulsivity. Additionally, impulsive individuals showed activity in the anterior prefrontal cortex (aPFC). An analysis of task-related effective connectivity based on psychophysiological interaction (PPI) revealed that PPI was robust from the aPFC to pVS, but not in the opposite direction. On the other hand, strong bidirectional PPIs were observed between the aVS and pVS, but PPIs from the pVS to aVS were enhanced in impulsive individuals. These results suggest that behavioral impulsivity is reflected in aPFC-VS mechanisms during the consumption of delayed real liquid rewards.

Optimal confidence for unaware visuomotor deviations

Numerous studies have shown that humans can successfully correct deviations to ongoing movements without being aware of them, suggesting limited conscious monitoring of visuomotor performance. Here, we ask whether such limited monitoring impairs the capacity to judiciously place confidence ratings to reflect decision accuracy (metacognitive sensitivity). To this end, we recorded functional magnetic resonance imaging data while thirty-one participants reported visuomotor cursor deviations and rated their confidence retrospectively. We show that participants use a summary statistic of the unfolding visual feedback (the maximum cursor error) to detect deviations but that this information alone is insufficient to explain detection performance. The same summary statistics is used by participants to optimally adjust their confidence ratings, even for unaware deviations. At the neural level, activity in the ventral striatum tracked high confidence, whereas a broad network including the anterior prefrontal cortex encoded cursor error but not confidence, shedding new light on a role of the anterior prefrontal cortex for action monitoring rather than confidence. Together, our results challenge the notion of limited action monitoring and uncover a new mechanism by which humans optimally monitor their movements as they unfold, even when unaware of ongoing deviations.

Differences in Regional Grey Matter Volume Predict the Extent to which Openness influences Judgments of Beauty and Pleasantness of Interior Architectural Spaces

Hedonic evaluation of sensory objects varies from person to person. While this variability has been linked to differences in experience and personality traits, little is known about why stimuli lead to different evaluations in different people. We used linear mixed effect models to determine the extent to which the openness, contour, and ceiling height of interior architectural spaces influenced the beauty and pleasantness ratings of 18 participants. Then, by analyzing structural brain images acquired for the same group of participants we asked if any regional grey matter volume (rGMV) co-varied with these differences in the extent to which openness, contour and ceiling height influence beauty and pleasantness ratings. Voxel-based morphometry analysis revealed that the influence of openness on pleasantness ratings correlated with rGMV in the anterior prefrontal cortex (BA 10), and the influence of openness on beauty ratings correlated with rGMV in the temporal pole (BA 38) and posterior cingulate cortex (BA 31). There were no significant correlations involving contour or ceiling height. Our results suggest that regional variance in grey matter volume may play a role in the computation of hedonic valuation, and account for differences in the way people weigh certain attributes of interior architectural spaces.

Your verbal questions beginning with 'what' will rapidly deactivate the left prefrontal cortex of listeners

The left prefrontal cortex is essential for verbal communication. It remains uncertain at what timing, to what extent, and what type of phrase initiates left-hemispheric dominant prefrontal activation during comprehension of spoken sentences. We clarified this issue by measuring event-related high-gamma activity during a task to respond to three-phrase questions configured in different orders. Questions beginning with a wh-interrogative deactivated the left posterior prefrontal cortex right after the 1st phrase offset and the anterior prefrontal cortex after the 2nd phrase offset. Left prefrontal high-gamma activity augmented subsequently and maximized around the 3rd phrase offset. Conversely, questions starting with a concrete phrase deactivated the right orbitofrontal region and then activated the left posterior prefrontal cortex after the 1st phrase offset. Regardless of sentence types, high-gamma activity emerged earlier, by one phrase, in the left posterior prefrontal than anterior prefrontal region. Sentences beginning with a wh-interrogative may initially deactivate the left prefrontal cortex to prioritize the bottom-up processing of upcoming auditory information. A concrete phrase may obliterate the inhibitory function of the right orbitofrontal region and facilitate top-down lexical prediction by the left prefrontal cortex. The left anterior prefrontal regions may be recruited for semantic integration of multiple concrete phrases.

Is Virtual Reality Breathing Better Than Mindful Breathing For Pain Modulation? Our Yin-Yang Brains Have The Answers! (Preprint)

UNSTRUCTURED Pain is a complex experience that involves sensory-discriminative and cognitive-emotional neuronal processes. It has long been known across cultures to be relieved by mindful breathing (MB). There is a common assumption that MB exerts its analgesic effect by interoception and distraction. Interoception means the conscious refocusing of the mind’s attention to the physical sensation of an organ function, while distraction consists of the competing attention of concurrent sensory experiences. In the current study, we dissected these central analgesic processes by imaging the brains of two groups of healthy subjects exposed to either a traditional MB (TMB) or a virtual reality breathing (VRB) protocol. The VRB protocol involved an in-house developed VR 3D-lungs that synchronized with the participants’ breathing cycles in real-time, providing the participant with an immersive visual-auditory experience. We found that both breathing techniques led to significant pain threshold increase after week-long practices, measured by a thermal quantitative sensory test. However, their underlying analgesic neural mechanisms were opposite as revealed by the functional near-infrared spectroscopy (fNIRS) data. The TMB technique induced a mind-body connection pattern in the brain. The anterior prefrontal cortex (aPFC) connected with and modulated other cortical regions to a state of mindfulness, reappraising the ascending noxious inputs. Whereas the VRB practice induced a mind-body disconnection pattern, in which the overpowered audio-visual cortical regions functionally disconnected from the primary somatosensory cortex (S1), disengaging the central sensory-discriminative processing of the ascending noxious inputs by the immersive 3D experience.

Violence Exposure Is Associated With Atypical Appraisal of Threat Among Women: An EEG Study

IntroductionThe present study investigates the association of lifetime interpersonal violence (IPV) exposure, related posttraumatic stress disorder (IPV-PTSD), and appraisal of the degree of threat posed by facial avatars.MethodsWe recorded self-rated responses and high-density electroencephalography (HD-EEG) among women, 16 of whom with lifetime IPV-PTSD and 14 with no PTSD, during a face-evaluation task that displayed male face avatars varying in their degree of threat as rated along dimensions of dominance and trustworthiness.ResultsThe study found a significant association between lifetime IPV exposure, under-estimation of dominance, and over-estimation of trustworthiness. Characterization of EEG microstates supported that lifetime IPV-PTSD modulates emotional appraisal, specifically in encoding and decoding processing associated with N170 and LPP evoked potentials. EEG source localization demonstrated an overactivation of the limbic system, in particular the parahippocampal gyrus, in response to non-threatening avatars. Additionally, dysfunctional involvement of attention-related processing anterior prefrontal cortex (aPFC) was found in response to relatively trustworthy avatars in IPV-PTSD individuals compared with non-PTSD controls.DiscussionThis study showed that IPV exposure and related PTSD modulate individuals’ evaluation of facial characteristics suggesting threat. Atypical processing of these avatar characteristics was marked by group differences in brain regions linked to facial processing, emotion regulation, and memory.

Brain Substrates of Time-Based Prospective Memory Decline in Aging: A Voxel-Based Morphometry and Diffusion Tensor Imaging Study

Time-based prospective memory (TBPM) allows us to remember to perform intended actions at a specific time in the future. TBPM is sensitive to the effects of age, but the neural substrates of this decline are still poorly understood. The aim of the present study was thus to better characterize the brain substrates of the age-related decline in TBPM, focusing on macrostructural gray matter and microstructural white matter integrity. We administered a TBPM task to 22 healthy young (26 ± 5.2 years) and 23 older (63 ± 5.9 years) participants, who also underwent volumetric magnetic resonance imaging and diffusion tensor imaging scans. Neuroimaging analyses revealed lower gray matter volumes in several brain areas in older participants, but these did not correlate with TBPM performance. By contrast, an age-related decline in fractional anisotropy in several white-matter tracts connecting frontal and occipital regions did correlate with TBPM performance, whereas there was no significant correlation in healthy young subjects. According to the literature, these tracts are connected to the anterior prefrontal cortex and the thalamus, 2 structures involved in TBPM. These results confirm the view that a disconnection process occurs in aging and contributes to cognitive decline.