Grasp-specific high-frequency broadband mirror neuron activity during reach-and-grasp movements in humans

Abstract:

Broadly congruent mirror neurons, responding to any grasp movement, and strictly congruent mirror neurons, responding only to specific grasp movements, have been reported in single-cell studies with primates. Delineating grasp properties in humans is essential to understand the human mirror neuron system with implications for behavior and social cognition. We analyzed electrocorticography data from a natural reach-and-grasp movement observation and delayed imitation task with 3 different natural grasp types of everyday objects. We focused on the classification of grasp types from high-frequency broadband mirror activation patterns found in classic mirror system areas, including sensorimotor, supplementary motor, inferior frontal, and parietal cortices. Classification of grasp types was successful during movement observation and execution intervals but not during movement retention. Our grasp type classification from combined and single mirror electrodes provides evidence for grasp-congruent activity in the human mirror neuron system potentially arising from strictly congruent mirror neurons.

Authros:

• Alexander M. Dreyer

• Leo Michalke

• Anat Perry

• Edward F. Chang

• Jack J. Lin

• Robert T. Knight

• Jochem W. Rieger

Date: 2022

DOI: https://doi.org/10.1093/cercor/bhac504

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Gender bias in academia: A lifetime problem that needs solutions

Summary:

Despite increased awareness of the lack of gender equity in academia and a growing number of initiatives to address issues of diversity, change is slow, and inequalities remain. A major source of inequity is gender bias, which has a substantial negative impact on the careers, work-life balance, and mental health of underrepresented groups in science. Here, we argue that gender bias is not a single problem but manifests as a collection of distinct issues that impact researchers’ lives. We disentangle these facets and propose concrete solutions that can be adopted by individuals, academic institutions, and society.

Authors:

• Anaïs Llorens

• Athina Tzovara

• Ludovic Bellier

• Ilina Bhaya-Grossman

• Aurélie Bidet-Caulet

• William K Chang

• Zachariah R Cross

• Rosa Dominguez-Faus

• Adeen Flinker

• Yvonne Fonken

• Mark A Gorenstein

• Chris Holdgraf

• Colin W Hoy

• Maria V Ivanova

• Richard T Jimenez

• Soyeon Jun

• Julia WY Kam

• Celeste Kidd

• Enitan Marcelle

• Deborah Marciano

• Stephanie Martin

• Nicholas E Myers

• Karita Ojala

• Anat Perry

• Pedro Pinheiro-Chagas

• Stephanie K Riès

• Ignacio Saez

• Ivan Skelin

• Katarina Slama

• Brooke Staveland

• Danielle S Bassett

• Elizabeth A Buffalo

• Adrienne L Fairhall

• Nancy J Kopell

• Laura J Kray

• Jack J Lin

• Anna C Nobre

• Dylan Riley

• Anne-Kristin Solbakk

• Joni D Wallis

• Xiao-Jing Wang

• Shlomit Yuval-Greenberg

• Sabine Kastner

• Robert T Knight

• Nina F Dronkers

Date: 2021

DOI: https://doi.org/10.1016/j.neuron.2021.06.002

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Behavioral and EEG Measures Show no Amplifying Effects of Shared Attention on Attention or Memory

Abstract:

Shared attention experiments examine the potential differences in function or behavior when stimuli are experienced alone or in the presence of others, and when simultaneous attention of the participants to the same stimulus or set is involved. Previous work has found enhanced reactions to emotional stimuli in social situations, yet these changes might represent enhanced communicative or motivational purposes. This study examines whether viewing emotional stimuli in the presence of another person influences attention to or memory for the stimulus. Participants passively viewed emotionally-valenced stimuli while completing another task (counting flowers). Each participant performed this task both alone and in a shared attention condition (simultaneously with another person in the same room) while EEG signals were measured. Recognition of the emotional pictures was later measured. A significant shared attention behavioral effect was found in the attention task but not in the recognition task. Compared to event-related potential responses for neutral pictures, we found higher P3b response for task relevant stimuli (flowers), and higher Late Positive Potential (LPP) responses for emotional stimuli. However, no main effect was found for shared attention between presence conditions. To conclude, shared attention may therefore have a more limited effect on cognitive processes than previously suggested.

Authors:

• Noam Mairon

• Mor Nahum

• Arjen Stolk

• Robert T Knight

• Anat Perry

Date: 2020

DOI: 10.1038/s41598-020-65311-7

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Effects of prefrontal cortex damage on emotion understanding: EEG and behavioural evidence

ABSTRACT

Humans are highly social beings that interact with each other on a daily basis. In these complex interactions, we get along by being able to identify others’ actions and infer their intentions, thoughts and feelings. One of the major theories accounting for this critical ability assumes that the understanding of social signals is based on a primordial tendency to simulate observed actions by activating a mirror neuron system. If mirror neuron regions are important for action and emotion recognition, damage to regions in this network should lead to deficits in these domains. In the current behavioural and EEG study, we focused on the lateral prefrontal cortex including dorsal and ventral prefrontal cortex and utilized a series of task paradigms, each measuring a different aspect of recognizing others’ actions or emotions from body cues. We examined 17 patients with lesions including (n = 8) or not including (n = 9) the inferior frontal gyrus, a core mirror neuron system region, and compared their performance to matched healthy control subjects (n = 18), in behavioural tasks and in an EEG observation—execution task measuring mu suppression. Our results provide support for the role of the lateral prefrontal cortex in understanding others’ emotions, by showing that even unilateral lesions result in deficits in both accuracy and reaction time in tasks involving the recognition of others’ emotions. In tasks involving the recognition of actions, patients showed a general increase in reaction time, but not a reduction in accuracy. Deficits in emotion recognition can be seen by either direct damage to the inferior frontal gyrus, or via damage to dorsal lateral prefrontal cortex regions, resulting in deteriorated performance and less EEG mu suppression over sensorimotor cortex.

AUTHORS

• Anat Perry

• Samantha N. Saunders

• Jennifer Stiso

• Callum Dewar

• James Lubell

• Torstein Meling

• Anne-Kristin Solbakk

• Tor Endestad

• Robert T. Knight

Date: 2017

DOI: 10.1093/brain/awx031

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Mirroring in the Human Brain: Deciphering the Spatial-Temporal Patterns of the Human Mirror Neuron System

ABSTRACT

Embodied theories of cognition emphasize the central role of sensorimotor transformations in the representation of others’ actions. Support for these theories is derived from the discovery of the mirror neuron system (MNS) in primates, from noninvasive techniques in humans, and from a limited number of intracranial studies. To understand the neural dynamics of the human MNS, more studies with precise spatial and temporal resolutions are essential. We used electrocorticography to define activation patterns in sensorimotor, parietal and/or frontal neuronal populations, during a viewing and grasping task. Our results show robust high gamma activation for both conditions in classic MNS sites. Furthermore, we provide novel evidence for 2 different populations of neurons: sites that were only active for viewing and grasping (“pure mirroring”) and sites that were also active between viewing and grasping, and perhaps serve a more general attentional role. Lastly, a subgroup of parietal electrodes showed earlier peaks than all other regions. These results highlight the complexity of spatial-temporal patterns within the MNS and provide a critical link between single-unit research in monkeys and noninvasive techniques in human.

AUTHORS

• Anat Perry

• Jennifer Stiso

• Edward F Chang

• Jack J Lin

• Josef Parvizi

• Robert T Knight

Date: 2017

DOI: 10.1093/cercor/bhx013

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The role of the orbitofrontal cortex in regulation of interpersonal space: evidence from frontal lesion and frontotemporal dementia patients

ABSTRACT

Interpersonal distance is central to communication and complex social behaviors but the neural correlates of interpersonal distance preferences are not defined. Previous studies suggest that damage to the orbitofrontal cortex (OFC) is associated with impaired interpersonal behavior. To examine whether the OFC is critical for maintaining appropriate interpersonal distance, we tested two groups of patients with OFC damage: Patients with OFC lesions and patients with behavioral variant frontotemporal dementia. These two groups were compared to healthy controls and to patients with lesions restricted to the dorsolateral prefrontal cortex. Only patients with OFC damage showed abnormal interpersonal distance preferences, which were significantly different from both controls and patients with dorsolateral prefrontal damage. The comfortable distances these patients chose with strangers were significantly closer than the other groups and resembled distances normally used with close others. These results shed light on the role of the OFC in regulating social behavior and may serve as a simple diagnostic tool for dementia or lesion patients.

AUTHORS

• Anat Perry

• Sandy J. Lwi

• Alice Verstaen

• Callum Dewar

• Robert W. Levenson

• Robert T. Knight

Date: 2016

DOI: 10.1093/scan/nsw109

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Where Does One Stand: A Biological Account of Preferred Interpersonal Distance

Authors:

• Anat Perry

• Nikolay Nichiporuk

• Robert T. Knight

Date: 2015

DOI: 10.1093/scan/nsv115

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Abstract:

What determines how close you choose to stand to someone? Why do some people prefer farther distances than others? We hypothesized that an important factor is one's sensory sensitivity level, i.e. how sensitive one is to nearby visual stimulation, noise, touch or smell. The current study characterizes the behavioral, hormonal and electrophysiological metrics of interpersonal distance (IPD) preferences in relation to levels of sensory sensitivity. Using both an ecologically realistic task and EEG we found that sensory sensitivity levels predicted IPD preferences, such that the more sensitive one is the farther distance they prefer. Furthermore, electrophysiological evidence revealed that individuals with higher sensory sensitivity show more alpha suppression for approaching stimuli, strengthening the notion that early sensory cortical excitability is involved in one's social decision of how close to stand to another. The results provide evidence that a core human metric of social interaction is influenced by individual levels of sensory sensitivity.