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Choi JW, Malekmohammadi M, Niketeghad S, Cross KA, Ebadi H, Alijanpourotaghsara A, Aron A, Rutishauser U, Pouratian N. Prefrontal-subthalamic theta signaling mediates delayed responses during conflict processing. Prog Neurobiol 2024; 236:102613. [PMID: 38631480 DOI: 10.1016/j.pneurobio.2024.102613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 02/29/2024] [Accepted: 04/12/2024] [Indexed: 04/19/2024]
Abstract
While medial frontal cortex (MFC) and subthalamic nucleus (STN) have been implicated in conflict monitoring and action inhibition, respectively, an integrated understanding of the spatiotemporal and spectral interaction of these nodes and how they interact with motor cortex (M1) to definitively modify motor behavior during conflict is lacking. We recorded neural signals intracranially across presupplementary motor area (preSMA), M1, STN, and globus pallidus internus (GPi), during a flanker task in 20 patients undergoing deep brain stimulation implantation surgery for Parkinson disease or dystonia. Conflict is associated with sequential and causal increases in local theta power from preSMA to STN to M1 with movement delays directly correlated with increased STN theta power, indicating preSMA is the MFC locus that monitors conflict and signals STN to implement a 'break.' Transmission of theta from STN-to-M1 subsequently results in a transient increase in M1-to-GPi beta flow immediately prior to movement, modulating the motor network to actuate the conflict-related action inhibition (i.e., delayed response). Action regulation during conflict relies on two distinct circuits, the conflict-related theta and movement-related beta networks, that are separated spatially, spectrally, and temporally, but which interact dynamically to mediate motor performance, highlighting complex parallel yet interacting networks regulating movement.
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Affiliation(s)
- Jeong Woo Choi
- Department of Neurological Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mahsa Malekmohammadi
- Department of Neurosurgery, University of California, Los Angeles, CA 90095, USA
| | - Soroush Niketeghad
- Department of Neurosurgery, University of California, Los Angeles, CA 90095, USA
| | - Katy A Cross
- Department of Neurology, University of California, Los Angeles, CA 90095, USA
| | - Hamasa Ebadi
- Department of Neurological Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | | | - Adam Aron
- Department of Psychology, University of California, San Diego, CA 92093, USA
| | - Ueli Rutishauser
- Departments of Neurosurgery and Neurology, and Center for Neural Science and Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Nader Pouratian
- Department of Neurological Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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Yang L, Singla D, Wu AK, Cross KA, Masmanidis SC. Dopamine lesions alter the striatal encoding of single-limb gait. eLife 2024; 12:RP92821. [PMID: 38526916 PMCID: PMC10963031 DOI: 10.7554/elife.92821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024] Open
Abstract
The striatum serves an important role in motor control, and neurons in this area encode the body's initiation, cessation, and speed of locomotion. However, it remains unclear whether the same neurons also encode the step-by-step rhythmic motor patterns of individual limbs that characterize gait. By combining high-speed video tracking, electrophysiology, and optogenetic tagging, we found that a sizable population of both D1 and D2 receptor expressing medium spiny projection neurons (MSNs) were phase-locked to the gait cycle of individual limbs in mice. Healthy animals showed balanced limb phase-locking between D1 and D2 MSNs, while dopamine depletion led to stronger phase-locking in D2 MSNs. These findings indicate that striatal neurons represent gait on a single-limb and step basis, and suggest that elevated limb phase-locking of D2 MSNs may underlie some of the gait impairments associated with dopamine loss.
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Affiliation(s)
- Long Yang
- Department of Neurobiology, University of California Los AngelesLos AngelesUnited States
| | - Deepak Singla
- Department of Bioengineering, University of California Los AngelesLos AngelesUnited States
| | - Alexander K Wu
- Department of Neurobiology, University of California Los AngelesLos AngelesUnited States
| | - Katy A Cross
- Department of Neurology, University of California Los AngelesLos AngelesUnited States
| | - Sotiris C Masmanidis
- Department of Neurobiology, University of California Los AngelesLos AngelesUnited States
- California Nanosystems Institute, University of California Los AngelesLos AngelesUnited States
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Yang L, Singla D, Wu AK, Cross KA, Masmanidis SC. Dopamine lesions alter the striatal encoding of single-limb gait. bioRxiv 2024:2023.10.06.561216. [PMID: 37873374 PMCID: PMC10592622 DOI: 10.1101/2023.10.06.561216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
The striatum serves an important role in motor control, and neurons in this area encode the body's initiation, cessation, and speed of locomotion. However, it remains unclear whether the same neurons also encode the step-by-step rhythmic motor patterns of individual limbs that characterize gait. By combining high-speed video tracking, electrophysiology, and optogenetic tagging, we found that a sizable population of both D1 and D2 receptor expressing medium spiny projection neurons (MSNs) were phase-locked to the gait cycle of individual limbs in mice. Healthy animals showed balanced limb phase-locking between D1 and D2 MSNs, while dopamine depletion led to stronger phase-locking in D2 MSNs. These findings indicate that striatal neurons represent gait on a single-limb and step basis, and suggest that elevated limb phase-locking of D2 MSNs may underlie some of the gait impairments associated with dopamine loss.
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Affiliation(s)
- Long Yang
- Department of Neurobiology, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Deepak Singla
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Alexander K. Wu
- Department of Neurobiology, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Katy A. Cross
- Department of Neurology, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Sotiris C. Masmanidis
- Department of Neurobiology, University of California Los Angeles, Los Angeles, California 90095, USA
- California Nanosystems Institute, University of California Los Angeles, Los Angeles, California 90095, USA
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Cross KA, Malekmohammadi M, Woo Choi J, Pouratian N. Movement-related changes in pallidocortical synchrony differentiate action execution and observation in humans. Clin Neurophysiol 2021; 132:1990-2001. [PMID: 33980469 DOI: 10.1016/j.clinph.2021.03.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 02/02/2021] [Accepted: 03/15/2021] [Indexed: 01/21/2023]
Abstract
OBJECTIVE Suppression of local and network alpha and beta oscillations in the human basal ganglia-thalamocortical (BGTC) circuit is a prominent feature of movement, including suppression of local alpha/beta power, cross-region beta phase coupling, and cortical and subcortical phase-amplitude coupling (PAC). We hypothesized that network-level coupling is more directly related to movement execution than local power changes, given the role of pathological network hypersynchrony in movement disorders such as Parkinson disease (PD). Understanding the specificity of these movement-related signals is important for designing novel therapeutics. METHODS We recorded globus pallidus internus (GPi) and motor cortical local field potentials during movement execution, passive movement observation and rest in 12 patients with PD undergoing deep brain stimulator implantation. RESULTS Local alpha/beta power is suppressed in the globus pallidus and motor cortex during both action execution and action observation, although less so during action observation. In contrast, pallidocortical phase synchrony and GPi and motor cortical alpha/beta-gamma PAC are suppressed only during action execution. CONCLUSIONS The functional dissociation across tasks in pallidocortical network activity suggests a particularly important role of network coupling in motor execution. SIGNIFICANCE Network level recordings provide important specificity in differentiating motor behavior and may provide significant value for future closed loop therapies.
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Affiliation(s)
- Katy A Cross
- Department of Neurology, University of California, Los Angeles, USA.
| | | | - Jeong Woo Choi
- Department of Neurosurgery, University of California, Los Angeles, USA
| | - Nader Pouratian
- Department of Neurosurgery, University of California, Los Angeles, USA
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Choi JW, Malekmohammadi M, Sparks H, Kashanian A, Cross KA, Bordelon Y, Pouratian N. Altered Pallidocortical Low-Beta Oscillations During Self-Initiated Movements in Parkinson Disease. Front Syst Neurosci 2020; 14:54. [PMID: 32792918 PMCID: PMC7390921 DOI: 10.3389/fnsys.2020.00054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/06/2020] [Indexed: 11/20/2022] Open
Abstract
Background Parkinson disease (PD) patients have difficulty with self-initiated (SI) movements, presumably related to basal ganglia thalamocortical (BGTC) circuit dysfunction, while showing less impairment with externally cued (EC) movements. Objectives We investigate the role of BGTC in movement initiation and the neural underpinning of impaired SI compared to EC movements in PD using multifocal intracranial recordings and correlating signals with symptom severity. Methods We compared time-resolved neural activities within and between globus pallidus internus (GPi) and motor cortex during between SI and EC movements recorded invasively in 13 PD patients undergoing deep brain stimulation implantation. We compared cortical (but not subcortical) dynamics with those recorded in 10 essential tremor (ET) patients, who do not have impairments in movement initiation. Results SI movements in PD are associated with greater low-beta (13–20 Hz) power suppression during pre-movement period in GPi and motor cortex compared to EC movements in PD and compared to SI movements in ET (motor cortex only). SI movements in PD are uniquely associated with significant low-beta pallidocortical coherence suppression during movement execution that correlates with bradykinesia severity. In ET, motor cortex neural dynamics during EC movements do not significantly differ from that observed in PD and do not significantly differ between SI and EC movements. Conclusion These findings implicate low beta BGTC oscillations in impaired SI movements in PD. These results provide a physiological basis for the strategy of using EC movements in PD, circumventing diseased neural circuits associated with SI movements and instead engaging circuits that function similarly to those without PD.
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Affiliation(s)
- Jeong Woo Choi
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, United States
| | - Mahsa Malekmohammadi
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, United States
| | - Hiro Sparks
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, United States
| | - Alon Kashanian
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, United States
| | - Katy A Cross
- Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Yvette Bordelon
- Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Nader Pouratian
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States.,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
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Horan WP, Iacoboni M, Cross KA, Korb A, Lee J, Nori P, Quintana J, Wynn JK, Green MF. Self-reported empathy and neural activity during action imitation and observation in schizophrenia. Neuroimage Clin 2014; 5:100-8. [PMID: 25009771 PMCID: PMC4087183 DOI: 10.1016/j.nicl.2014.06.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 06/12/2014] [Accepted: 06/16/2014] [Indexed: 01/11/2023]
Abstract
Introduction Although social cognitive impairments are key determinants of functional outcome in schizophrenia their neural bases are poorly understood. This study investigated neural activity during imitation and observation of finger movements and facial expressions in schizophrenia, and their correlates with self-reported empathy. Methods 23 schizophrenia outpatients and 23 healthy controls were studied with functional magnetic resonance imaging (fMRI) while they imitated, executed, or simply observed finger movements and facial emotional expressions. Between-group activation differences, as well as relationships between activation and self-reported empathy, were evaluated. Results Both patients and controls similarly activated neural systems previously associated with these tasks. We found no significant between-group differences in task-related activations. There were, however, between-group differences in the correlation between self-reported empathy and right inferior frontal (pars opercularis) activity during observation of facial emotional expressions. As in previous studies, controls demonstrated a positive association between brain activity and empathy scores. In contrast, the pattern in the patient group reflected a negative association between brain activity and empathy. Conclusions Although patients with schizophrenia demonstrated largely normal patterns of neural activation across the finger movement and facial expression tasks, they reported decreased self perceived empathy and failed to show the typical relationship between neural activity and self-reported empathy seen in controls. These findings suggest that patients show a disjunction between automatic neural responses to low level social cues and higher level, integrative social cognitive processes involved in self-perceived empathy. Comparable activation patterns were present in both groups for finger and facial stimuli. There were no group differences on any of the activation tasks. Self-reported empathy differentially related to neural activation in the two groups. Empathy related to right inferior frontal activity in controls but not in patients. Patients showed a disconnect between low- and high-level social cognitive processes.
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Affiliation(s)
- William P. Horan
- VA Greater Los Angeles Healthcare System, USA
- University of California, Los Angeles, USA
- Corresponding author at: University of California, Los Angeles & VA Greater Los Angeles Healthcare System, MIRECC 210A, Bldg. 210, 11301 Wilshire Blvd., Los Angeles, CA 90073, USA. Tel.: + 1 310 478 3711x44041; fax: + 1 310 268 4056.
| | | | | | - Alex Korb
- University of California, Los Angeles, USA
| | - Junghee Lee
- VA Greater Los Angeles Healthcare System, USA
- University of California, Los Angeles, USA
| | - Poorang Nori
- VA Greater Los Angeles Healthcare System, USA
- University of California, Los Angeles, USA
| | - Javier Quintana
- VA Greater Los Angeles Healthcare System, USA
- University of California, Los Angeles, USA
| | - Jonathan K. Wynn
- VA Greater Los Angeles Healthcare System, USA
- University of California, Los Angeles, USA
| | - Michael F. Green
- VA Greater Los Angeles Healthcare System, USA
- University of California, Los Angeles, USA
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Abstract
Humans have an automatic tendency to imitate others. Previous studies on how we control these tendencies have focused on reactive mechanisms, where inhibition of imitation is implemented after seeing an action. This work suggests that reactive control of imitation draws on at least partially specialized mechanisms. Here, we examine preparatory imitation control, where advance information allows control processes to be employed before an action is observed. Drawing on dual route models from the spatial compatibility literature, we compare control processes using biological and non-biological stimuli to determine whether preparatory imitation control recruits specialized neural systems that are similar to those observed in reactive imitation control. Results indicate that preparatory control involves anterior prefrontal, dorsolateral prefrontal, posterior parietal and early visual cortices regardless of whether automatic responses are evoked by biological (imitative) or non-biological stimuli. These results indicate both that preparatory control of imitation uses general mechanisms, and that preparatory control of imitation draws on different neural systems from reactive imitation control. Based on the regions involved, we hypothesize that preparatory control is implemented through top-down attentional biasing of visual processing.
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Affiliation(s)
- Katy A Cross
- Interdepartmental Neuroscience Program, University of California, , Los Angeles, CA 90035, USA
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Cross KA, Iacoboni M. To imitate or not: Avoiding imitation involves preparatory inhibition of motor resonance. Neuroimage 2014; 91:228-36. [PMID: 24473096 DOI: 10.1016/j.neuroimage.2014.01.027] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 01/13/2014] [Accepted: 01/17/2014] [Indexed: 11/30/2022] Open
Abstract
Stimulus-response compatibility (SRC)-the fact that some stimulus-response pairs are faster than others-is attributed in part to automatic activation of the stimulus-compatible response representation. Cognitive models of SRC propose that automatic response activation can be strategically suppressed if the automatic response is likely to interfere with behavior; in particular, suppression is thought to occur in preparation for incompatible responses and when the required stimulus-response mapping is unknown before stimulus presentation. We test this preparatory suppression hypothesis in the context of imitation, a special form of SRC particularly relevant to human social behavior. Using TMS, we measured muscle-specific corticospinal excitability during action observation (motor resonance) while human participants prepared to perform imitative and counterimitative responses to action videos. Motor resonance was suppressed during preparation to counterimitate and for unknown mappings, compared to preparation to imitate and a baseline measure of motor resonance. These results provide novel neurophysiological evidence that automatic activation of stimulus-compatible responses can be strategically suppressed when the automatic response is likely to interfere with task goals. Insofar as motor resonance measures mirror neuron system activity, these results also suggest that preparatory control of automatic imitative tendencies occurs through modulation of mirror neuron system activity.
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Affiliation(s)
- Katy A Cross
- Interdepartmental Neuroscience Program, University of California, Los Angeles, Los Angeles, CA 90095, USA; Ahmanson-Lovelace Brain Mapping Center, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Marco Iacoboni
- Interdepartmental Neuroscience Program, University of California, Los Angeles, Los Angeles, CA 90095, USA; Ahmanson-Lovelace Brain Mapping Center, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Psychiatry & Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA 90095, USA; Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
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Losin EAR, Cross KA, Iacoboni M, Dapretto M. Neural processing of race during imitation: self-similarity versus social status. Hum Brain Mapp 2013; 35:1723-39. [PMID: 23813738 DOI: 10.1002/hbm.22287] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 02/05/2013] [Accepted: 02/14/2013] [Indexed: 11/07/2022] Open
Abstract
People preferentially imitate others who are similar to them or have high social status. Such imitative biases are thought to have evolved because they increase the efficiency of cultural acquisition. Here we focused on distinguishing between self-similarity and social status as two candidate mechanisms underlying neural responses to a person's race during imitation. We used fMRI to measure neural responses when 20 African American (AA) and 20 European American (EA) young adults imitated AA, EA and Chinese American (CA) models and also passively observed their gestures and faces. We found that both AA and EA participants exhibited more activity in lateral frontoparietal and visual regions when imitating AAs compared with EAs or CAs. These results suggest that racial self-similarity is not likely to modulate neural responses to race during imitation, in contrast with findings from previous neuroimaging studies of face perception and action observation. Furthermore, AA and EA participants associated AAs with lower social status than EAs or CAs, suggesting that the social status associated with different racial groups may instead modulate neural activity during imitation of individuals from those groups. Taken together, these findings suggest that neural responses to race during imitation are driven by socially learned associations rather than self-similarity. This may reflect the adaptive role of imitation in social learning, where learning from higher status models can be more beneficial. This study provides neural evidence consistent with evolutionary theories of cultural acquisition.
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Affiliation(s)
- Elizabeth A Reynolds Losin
- Interdepartmental Neuroscience Program, University of California Los Angeles, Los Angeles, California; FPR-UCLA Center for Culture, Brain and Development, University of California Los Angeles, Los Angeles, California; Ahmanson-Lovelace Brain Mapping Center, University of California Los Angeles, Los Angeles, California; Institute for Cognitive Science, University of Colorado at Boulder, Colorado
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Cross KA, Torrisi S, Reynolds Losin EA, Iacoboni M. Controlling automatic imitative tendencies: interactions between mirror neuron and cognitive control systems. Neuroimage 2013; 83:493-504. [PMID: 23811412 DOI: 10.1016/j.neuroimage.2013.06.060] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 06/12/2013] [Accepted: 06/18/2013] [Indexed: 10/26/2022] Open
Abstract
Humans have an automatic tendency to imitate others. Although several regions commonly observed in social tasks have been shown to be involved in imitation control, there is little work exploring how these regions interact with one another. We used fMRI and dynamic causal modeling to identify imitation-specific control mechanisms and examine functional interactions between regions. Participants performed a pre-specified action (lifting their index or middle finger) in response to videos depicting the same two actions (biological cues) or dots moving with similar trajectories (non-biological cues). On congruent trials, the stimulus and response were similar (e.g. index finger response to index finger or left side dot stimulus), while on incongruent trials the stimulus and response were dissimilar (e.g. index finger response to middle finger or right side dot stimulus). Reaction times were slower on incongruent compared to congruent trials for both biological and non-biological stimuli, replicating previous findings that suggest the automatic imitative or spatially compatible (congruent) response must be controlled on incongruent trials. Neural correlates of the congruency effects were different depending on the cue type. The medial prefrontal cortex, anterior cingulate, inferior frontal gyrus pars opercularis (IFGpo) and the left anterior insula were involved specifically in controlling imitation. In addition, the IFGpo was also more active for biological compared to non-biological stimuli, suggesting that the region represents the frontal node of the human mirror neuron system (MNS). Effective connectivity analysis exploring the interactions between these regions, suggests a role for the mPFC and ACC in imitative conflict detection and the anterior insula in conflict resolution processes, which may occur through interactions with the frontal node of the MNS. We suggest an extension of the previous models of imitation control involving interactions between imitation-specific and general cognitive control mechanisms.
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Affiliation(s)
- Katy A Cross
- Interdepartmental Neuroscience Program, University of California, Los Angeles, USA; Ahmanson-Lovelace Brain Mapping Center, University of California, Los Angeles, USA.
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Losin EAR, Iacoboni M, Martin A, Cross KA, Dapretto M. Race modulates neural activity during imitation. Neuroimage 2011; 59:3594-603. [PMID: 22062193 DOI: 10.1016/j.neuroimage.2011.10.074] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 10/15/2011] [Accepted: 10/22/2011] [Indexed: 10/15/2022] Open
Abstract
Imitation plays a central role in the acquisition of culture. People preferentially imitate others who are self-similar, prestigious or successful. Because race can indicate a person's self-similarity or status, race influences whom people imitate. Prior studies of the neural underpinnings of imitation have not considered the effects of race. Here we measured neural activity with fMRI while European American participants imitated meaningless gestures performed by actors of their own race, and two racial outgroups, African American, and Chinese American. Participants also passively observed the actions of these actors and their portraits. Frontal, parietal and occipital areas were differentially activated while participants imitated actors of different races. More activity was present when imitating African Americans than the other racial groups, perhaps reflecting participants' reported lack of experience with and negative attitudes towards this group, or the group's lower perceived social status. This pattern of neural activity was not found when participants passively observed the gestures of the actors or simply looked at their faces. Instead, during face-viewing neural responses were overall greater for own-race individuals, consistent with prior race perception studies not involving imitation. Our findings represent a first step in elucidating neural mechanisms involved in cultural learning, a process that influences almost every aspect of our lives but has thus far received little neuroscientific study.
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Affiliation(s)
- Elizabeth A Reynolds Losin
- Interdepartmental Neuroscience Program, University of California Los Angeles, Los Angeles, CA 90095-7085, USA.
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12
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Cross KA, Iacoboni M. Optimized neural coding? Control mechanisms in large cortical networks implemented by connectivity changes. Hum Brain Mapp 2011; 34:213-25. [PMID: 21976418 DOI: 10.1002/hbm.21428] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 06/09/2011] [Accepted: 07/11/2011] [Indexed: 11/12/2022] Open
Abstract
Using functional magnetic resonance imaging, we show that a distributed fronto-parietal visuomotor integration network is recruited to overcome automatic responses to both biological and nonbiological cues. Activity levels in these areas are similar for both cue types. The functional connectivity of this network, however, reveals differential coupling with thalamus and precuneus (biological cues) and extrastriate cortex (nonbiological cues). This suggests that a set of cortical areas equally activated in two tasks may accomplish task goals differently depending on their network interactions. This supports models of brain organization that emphasize efficient coding through changing patterns of integration between regions of specialized function.
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Affiliation(s)
- Katy A Cross
- Neuroscience Interdepartmental Program, University of California, Los Angeles, CA, USA.
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Boone RW, Cross KA. Preparing a medical malpractice defense. Med Staff Couns 1989; 2:57-65. [PMID: 10290185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
This article examines the preparation of a medical malpractice case and outlines, for the benefit of the physician, the various stages involved. The authors believe that a physician familiar with the basic elements involved in preparing a defense is in a better position to deal with the case dispassionately, and can more effectively aid in his or her own defense.
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