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1.
Cereb Cortex ; 34(3)2024 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-38466116

RESUMO

Sound frequency and duration are essential auditory components. The brain perceives deviations from the preceding sound context as prediction errors, allowing efficient reactions to the environment. Additionally, prediction error response to duration change is reduced in the initial stages of psychotic disorders. To compare the spatiotemporal profiles of responses to prediction errors, we conducted a human electrocorticography study with special attention to high gamma power in 13 participants who completed both frequency and duration oddball tasks. Remarkable activation in the bilateral superior temporal gyri in both the frequency and duration oddball tasks were observed, suggesting their association with prediction errors. However, the response to deviant stimuli in duration oddball task exhibited a second peak, which resulted in a bimodal response. Furthermore, deviant stimuli in frequency oddball task elicited a significant response in the inferior frontal gyrus that was not observed in duration oddball task. These spatiotemporal differences within the Parasylvian cortical network could account for our efficient reactions to changes in sound properties. The findings of this study may contribute to unveiling auditory processing and elucidating the pathophysiology of psychiatric disorders.


Assuntos
Encéfalo , Eletrocorticografia , Humanos , Córtex Pré-Frontal , Som , Percepção Auditiva
2.
Cereb Cortex ; 34(2)2024 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-38183184

RESUMO

Auditory sensory processing is assumed to occur in a hierarchical structure including the primary auditory cortex (A1), superior temporal gyrus, and frontal areas. These areas are postulated to generate predictions for incoming stimuli, creating an internal model of the surrounding environment. Previous studies on mismatch negativity have indicated the involvement of the superior temporal gyrus in this processing, whereas reports have been mixed regarding the contribution of the frontal cortex. We designed a novel auditory paradigm, the "cascade roving" paradigm, which incorporated complex structures (cascade sequences) into a roving paradigm. We analyzed electrocorticography data from six patients with refractory epilepsy who passively listened to this novel auditory paradigm and detected responses to deviants mainly in the superior temporal gyrus and inferior frontal gyrus. Notably, the inferior frontal gyrus exhibited broader distribution and sustained duration of deviant-elicited responses, seemingly differing in spatio-temporal characteristics from the prediction error responses observed in the superior temporal gyrus, compared with conventional oddball paradigms performed on the same participants. Moreover, we observed that the deviant responses were enhanced through stimulus repetition in the high-gamma range mainly in the superior temporal gyrus. These features of the novel paradigm may aid in our understanding of auditory predictive coding.


Assuntos
Córtex Auditivo , Eletrocorticografia , Humanos , Eletroencefalografia , Potenciais Evocados Auditivos/fisiologia , Córtex Auditivo/fisiologia , Lobo Temporal/fisiologia , Estimulação Acústica , Percepção Auditiva/fisiologia
3.
Neuroreport ; 35(2): 107-114, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38064356

RESUMO

To make flexible decisions in dynamic environments, the brain must integrate behaviorally relevant information while simultaneously discarding irrelevant information. This study aimed to investigate the mechanisms responsible for discarding irrelevant information during context-dependent decision-making. We trained two macaque monkeys to switch between direction and depth discrimination tasks in successive trials. During decision-making, the strength of the motion or depth signal changes transiently at various times, introducing a brief pulse. We assessed the effects of pulse on behavioral choices. Consistent with previous findings, early relevant pulses, such as motion pulses during direction discrimination, had a significantly larger effect compared to late pulses. Critically, the effects of irrelevant pulses, such as motion pulses during depth discrimination, exhibited an initial minimal effect, followed by an increase and subsequent decrease as a function of pulse timing. Gating mechanisms alone, aimed at discarding irrelevant information, did not account for the observed time course of pulse effects. Instead, the observed increase in the effects of irrelevant pulses with time suggested the involvement of a leaky integration mechanism. The results suggested that the brain controls the amount of disposal in accumulating sensory evidence during flexible decision-making.


Assuntos
Tomada de Decisões , Macaca , Animais , Tempo de Reação , Encéfalo , Emprego
4.
Nat Commun ; 14(1): 6981, 2023 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-37957168

RESUMO

Although cortical feedback signals are essential for modulating feedforward processing, no feedback error signal across hierarchical cortical areas has been reported. Here, we observed such a signal in the auditory cortex of awake common marmoset during an oddball paradigm to induce auditory duration mismatch negativity. Prediction errors to a deviant tone presentation were generated as offset calcium responses of layer 2/3 neurons in the rostral parabelt (RPB) of higher-order auditory cortex, while responses to non-deviant tones were strongly suppressed. Within several hundred milliseconds, the error signals propagated broadly into layer 1 of the primary auditory cortex (A1) and accumulated locally on top of incoming auditory signals. Blockade of RPB activity prevented deviance detection in A1. Optogenetic activation of RPB following tone presentation nonlinearly enhanced A1 tone response. Thus, the feedback error signal is critical for automatic detection of unpredicted stimuli in physiological auditory processing and may serve as backpropagation-like learning.


Assuntos
Córtex Auditivo , Animais , Córtex Auditivo/fisiologia , Estimulação Acústica , Potenciais Evocados Auditivos/fisiologia , Retroalimentação , Percepção Auditiva/fisiologia , Primatas
5.
J Neurosci ; 43(33): 5893-5904, 2023 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-37495384

RESUMO

The overrepresentation of centrifugal motion in the middle temporal visual area (area MT) has long been thought to provide an efficient coding strategy for optic flow processing. However, this overrepresentation compromises the detection of approaching objects, which is essential for survival. In the present study, we revisited this long-held notion by reanalyzing motion selectivity in area MT of three macaque monkeys (two males, one female) using random-dot stimuli instead of spot stimuli. We found no differences in the number of neurons tuned to centrifugal versus centripetal motion; however, centrifugally tuned neurons showed stronger tuning than centripetally tuned neurons. This was attributed to the heightened suppression of responses in centrifugal neurons to centripetal motion compared with that of centripetal neurons to centrifugal motion. Our modeling implies that this intensified suppression accounts for superior detection performance for weak centripetal motion stimuli. Moreover, through Fisher information analysis, we establish that the population sensitivity to motion direction in peripheral vision corresponds well with retinal motion statistics during forward locomotion. While these results challenge established concepts, considering the interplay of logarithmic Gaussian receptive fields and spot stimuli can shed light on the previously documented overrepresentation of centrifugal motion. Significantly, our findings reconcile a previously found discrepancy between MT activity and human behavior, highlighting the proficiency of peripheral MT neurons in encoding motion direction efficiently.SIGNIFICANCE STATEMENT The efficient coding hypothesis states that sensory neurons are tuned to specific, frequently experienced stimuli. Whereas previous work has found that neurons in the middle temporal (MT) area favor centrifugal motion, which results from forward locomotion, we show here that there is no such bias. Moreover, we found that the response of centrifugal neurons for centripetal motion was more suppressed than that of centripetal neurons for centrifugal motion. Combined with modeling, this provides a solution to a previously known discrepancy between reported centrifugal bias in MT and better detection of centripetal motion by human observers. Additionally, we show that population sensitivity in peripheral MT neurons conforms to an efficient code of retinal motion statistics during forward locomotion.


Assuntos
Percepção de Movimento , Masculino , Animais , Humanos , Feminino , Percepção de Movimento/fisiologia , Percepção Visual/fisiologia , Neurônios/fisiologia , Retina , Macaca mulatta , Estimulação Luminosa
6.
Commun Biol ; 5(1): 690, 2022 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-35858997

RESUMO

Flexible decision making is an indispensable ability for humans. A subanesthetic dose of ketamine, an N-methyl-D-aspartate receptor antagonist, impairs this flexibility in a manner that is similar to patients with schizophrenia; however how it affects neural processes related to decision making remains unclear. Here, we report that ketamine administration impairs neural processing related to context-dependent decision making, and delays the onset of decision making. We recorded single unit activity in the lateral intraparietal area (LIP) while monkeys switched between a direction-discrimination task and a depth-discrimination task. Ketamine impaired choice accuracy for incongruent stimuli that required different decisions depending on the task, for the direction-discrimination task. Neural sensitivity to irrelevant depth information increased with ketamine during direction discrimination in LIP, indicating impaired processing of irrelevant information. Furthermore, the onset of decision-related neural activity was delayed in conjunction with an increased reaction time irrespective of task and stimulus congruency. Neural sensitivity and response onset of the middle temporal area (MT) were not modulated by ketamine, indicating that ketamine worked on neural decision processes downstream of MT. These results suggest that ketamine administration may impair what information to process and when to process it for the purpose of achieving flexible decision making.


Assuntos
Ketamina , Receptores de N-Metil-D-Aspartato , Animais , Tomada de Decisões/fisiologia , Humanos , Ketamina/farmacologia , Macaca mulatta , Lobo Parietal/fisiologia
7.
Front Psychiatry ; 13: 557954, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35558420

RESUMO

Sensory prediction is considered an important element of mismatch negativity (MMN) whose reduction is well known in patients with schizophrenia. Omission MMN is a variant of the MMN which is elicited by the absence of a tone previously sequentially presented. Omission MMN can eliminate the effects of sound differences in typical oddball paradigms and affords the opportunity to identify prediction-related signals in the brain. Auditory predictions are thought to reflect bottom-up and top-down processing within hierarchically organized auditory areas. However, the communications between the various subregions of the auditory cortex and the prefrontal cortex that generate and communicate sensory prediction-related signals remain poorly understood. To explore how the frontal and temporal cortices communicate for the generation and propagation of such signals, we investigated the response in the omission paradigm using electrocorticogram (ECoG) electrodes implanted in the temporal, lateral prefrontal, and orbitofrontal cortices of macaque monkeys. We recorded ECoG data from three monkeys during the omission paradigm and examined the functional connectivity between the temporal and frontal cortices by calculating phase-locking values (PLVs). This revealed that theta- (4-8 Hz), alpha- (8-12 Hz), and low-beta- (12-25 Hz) band synchronization increased at tone onset between the higher auditory cortex and the frontal pole where an early omission response was observed in the event-related potential (ERP). These synchronizations were absent when the tone was omitted. Conversely, low-beta-band (12-25 Hz) oscillation then became stronger for tone omission than for tone presentation approximately 200 ms after tone onset. The results suggest that auditory input is propagated to the frontal pole via the higher auditory cortex and that a reciprocal network may be involved in the generation of auditory prediction and prediction error. As impairments of prediction may underlie MMN reduction in patients with schizophrenia, an aberrant hierarchical temporal-frontal network might be related to this pathological condition.

8.
Cereb Cortex ; 32(21): 4657-4670, 2022 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-35088074

RESUMO

Much of our flexible behavior is dependent on responding efficiently to relevant information while discarding irrelevant information. Little is known, however, about how neural pathways governing sensory-motor associations can rapidly switch to accomplish such flexibility. Here, we addressed this question by electrically microstimulating middle temporal (MT) neurons selective for both motion direction and binocular disparity in monkeys switching between direction and depth discrimination tasks. Surprisingly, we frequently found that the observed psychophysical bias precipitated by delivering microstimulation to neurons whose preferred direction and depth were related to opposite choices in the two tasks was substantially shifted toward a specific movement. Furthermore, these effects correlated with behavioral switching performance. Our findings suggest that the outputs of sensory signals are task specific and that irrelevant sensory-motor pathways are gated depending on task demand so as to accomplish rapid attentional switching.


Assuntos
Percepção de Movimento , Disparidade Visual , Neurônios/fisiologia , Emprego , Percepção de Movimento/fisiologia , Estimulação Luminosa
9.
Cereb Cortex ; 31(10): 4518-4532, 2021 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-33907804

RESUMO

Gamma oscillations are physiological phenomena that reflect perception and cognition, and involve parvalbumin-positive γ-aminobutyric acid-ergic interneuron function. The auditory steady-state response (ASSR) is the most robust index for gamma oscillations, and it is impaired in patients with neuropsychiatric disorders such as schizophrenia and autism. Although ASSR reduction is known to vary in terms of frequency and time, the neural mechanisms are poorly understood. We obtained high-density electrocorticography recordings from a wide area of the cortex in 8 patients with refractory epilepsy. In an ASSR paradigm, click sounds were presented at frequencies of 20, 30, 40, 60, 80, 120, and 160 Hz. We performed time-frequency analyses and analyzed intertrial coherence, event-related spectral perturbation, and high-gamma oscillations. We demonstrate that the ASSR is globally distributed among the temporal, parietal, and frontal cortices. The ASSR was composed of time-dependent neural subcircuits differing in frequency tuning. Importantly, the frequency tuning characteristics of the late-latency ASSR varied between the temporal/frontal and parietal cortex, suggestive of differentiation along parallel auditory pathways. This large-scale survey of the cortical ASSR could serve as a foundation for future studies of the ASSR in patients with neuropsychiatric disorders.


Assuntos
Córtex Cerebral/fisiopatologia , Eletrocorticografia/métodos , Ritmo Gama/fisiologia , Estimulação Acústica , Adolescente , Adulto , Córtex Cerebral/diagnóstico por imagem , Epilepsia Resistente a Medicamentos/fisiopatologia , Eletrocorticografia/instrumentação , Potenciais Evocados/fisiologia , Potenciais Evocados Auditivos , Feminino , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/fisiopatologia , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiopatologia , Adulto Jovem
10.
Front Psychiatry ; 11: 557932, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33132932

RESUMO

Traditional neuroscience sees sensory perception as a simple feedforward process. This view is challenged by the predictive coding model in recent years due to the robust evidence researchers had found on how our prediction could influence perception. In the first half of this article, we reviewed the concept of predictive brain and some empirical evidence of sensory prediction in visual and auditory processing. The predictive function along the auditory pathway was mainly studied by mismatch negativity (MMN)-a brain response to an unexpected disruption of regularity. We summarized a range of MMN paradigms and discussed how they could contribute to the theoretical development of the predictive coding neural network by the mechanism of adaptation and deviance detection. Such methodological and conceptual evolution sharpen MMN as a tool to better understand the structural and functional brain abnormality for neuropsychiatric disorder such as schizophrenia.

11.
Front Psychiatry ; 11: 874, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33005162

RESUMO

Mismatch negativity (MMN) is a negative deflection of the auditory event-related potential (ERP) elicited by an abrupt change in a sound presented repeatedly. In patients with schizophrenia, MMN is consistently reduced, which makes it a promising biomarker. A non-human primate (NHP) model of MMN based on scalp electroencephalogram (EEG) recordings can provide a useful translational tool, given the high structural homology of the prefrontal and auditory cortices between NHPs, such as macaques, and humans. However, in previous MMN studies, the NHP models used did not allow for comparison with humans because of differences in task settings. Moreover, duration-deviant MMN (dMMN), whose reduction is larger than that in the frequency-deviant MMN (fMMN) in patients with schizophrenia, has never been demonstrated in NHP models. In this study, we determined whether dMMN can be observed in macaque scalp EEG recordings. EEGs were recorded from frontal electrodes (Fz) in two Japanese macaques. Consistent with clinical settings, auditory stimuli consisted of two pure tones, a standard and a deviant tone, in an oddball paradigm. The deviant and standard tones differed in duration (50 and 100 ms for the standard and deviant tones, respectively). A robust dMMN with a latency of around 200 ms, comparable to that in humans, was observed in both monkeys. A comparison with fMMN showed that the dMMN latency was the longer of the two. By bridging the gap between basic and clinical research, our results will contribute to the development of innovative therapeutic strategies for schizophrenia.

12.
Front Psychiatry ; 11: 586, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32670112

RESUMO

Auditory mismatch negativity (MMN) is an electrophysiological response to a deviation from regularity. This response is considered pivotal to understanding auditory processing, particularly in the pre-attentive phase. However, previous findings suggest that MMN is a product of N1 adaptation/enhancement, which reflects lower-order auditory processing. The separability of these two components remains unclear and is considered an important issue in the field of neuroscience. The aim of the present study was to spatiotemporally differentiate MMN from N1 adaptation using human electrocorticography (ECoG). Auditory evoked potentials under the classical oddball (OD) task as well as the many standards (MS) task were recorded in three patients with epilepsy whose lateral cortices were widely covered with high-density electrodes. Close observation identified an electrode at which N1 adaptation was temporally separated from MMN, whereas N1 adaptation was partially incorporated into MMN at other electrodes. Since N1 adaptation occurs in the N1 population, we spatially compared MMN with N1 obtained from the MS task instead of N1 adaptation. As a result, N1 was observed in a limited area around the Sylvian fissure adjacent to A1, whereas MMN was noted in wider areas, including the temporal, frontal, and parietal lobes. MMN was thus considered to be differentiated from N1 adaptation. The results suggest that MMN is not merely a product of the neural adaptation of N1 and instead represents higher-order processes in auditory deviance detection. These results will contribute to strengthening the foundation of future research in this field.

13.
Clin EEG Neurosci ; 51(4): 234-243, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31402699

RESUMO

Altered gamma oscillations have attracted considerable attention as an index of the excitation/inhibition (E/I) imbalance in schizophrenia and other neuropsychiatric disorders. The auditory steady-state response (ASSR) has been the most robust probe of abnormal gamma oscillatory dynamics in schizophrenia. Here, we review recent ASSR studies in patients with schizophrenia and other neuropsychiatric disorders. Preclinical ASSR research, which has contributed to the elucidation of the underlying pathophysiology of these diseases, is also discussed. The developmental trajectory of the ASSR has been explored and may show signs of the maturation and disruption of E/I balance in adolescence. Animal model studies have shown that synaptic interactions between parvalbumin-positive GABAergic interneurons and pyramidal neurons contribute to the regulation of E/I balance, which is related to the generation of gamma oscillation. Therefore, ASSR alteration may be a significant electrophysiological finding related to the E/I imbalance in neuropsychiatric disorders, which is a cross-disease feature and may reflect clinical staging. Future studies regarding ASSR generation, especially in nonhuman primate models, will advance our understanding of the brain circuit and the molecular mechanisms underlying neuropsychiatric disorders.


Assuntos
Esquizofrenia , Estimulação Acústica , Eletroencefalografia , Potenciais Evocados Auditivos , Ritmo Gama , Humanos , Neurofisiologia
14.
Sci Rep ; 9(1): 8454, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31186500

RESUMO

The auditory steady-state response (ASSR) has been used to detect auditory processing deficits in patients with psychiatric disorders. However, the methodology of ASSR recording from the brain surface has not been standardized in preclinical studies, limiting its use as a translational biomarker. The sites of maximal ASSR in humans are the vertex and/or middle frontal area, although it has been suggested that the auditory cortex is the source of the ASSR. We constructed and validated novel methods for ASSR recording using a switchable pedestal which allows ASSR recording alternatively from temporal or parietal cortex with a wide range of frequencies in freely moving rats. We further evaluated ASSR as a translational tool by assessing the effect of ketamine. The ASSR measured at parietal cortex did not show clear event-related spectral perturbation (ERSP) or inter-trial coherence (ITC) in any frequency bands or a change with ketamine. In contrast, the ASSR at temporal cortex showed clear ERSP and ITC where 40 Hz was maximal in both gamma-band frequencies. Ketamine exerted a biphasic effect in ERSP at gamma bands. These findings suggest that temporal cortex recording with a wide frequency range is a robust methodology to detect ASSR, potentially enabling application as a translational biomarker in psychiatric and developmental disorders.


Assuntos
Córtex Auditivo/fisiopatologia , Encéfalo/fisiopatologia , Transtornos Mentais/fisiopatologia , Esquizofrenia/fisiopatologia , Estimulação Acústica/efeitos adversos , Adulto , Animais , Córtex Auditivo/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Modelos Animais de Doenças , Eletroencefalografia/métodos , Potenciais Evocados Auditivos/efeitos dos fármacos , Potenciais Evocados Auditivos/fisiologia , Humanos , Ketamina/farmacologia , Transtornos Mentais/diagnóstico por imagem , Transtornos Mentais/tratamento farmacológico , Ratos , Esquizofrenia/diagnóstico por imagem , Esquizofrenia/tratamento farmacológico , Pesquisa Translacional Biomédica
15.
Int J Psychophysiol ; 145: 5-14, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-30831138

RESUMO

Mismatch negativity (MMN) reduction is one of the most robust findings among several neurophysiological and neurocognitive measures in patients with schizophrenia. MMN is a promising biomarker for schizophrenia because of the following properties: 1) its relationship with early psychosis, including clinical high-risk (CHR); 2) its relationship with the functional abilities of patients; and 3) its translatability into basic research using animal models. Specifically, the utility of the passive auditory oddball paradigm that does not require subjects to make behavioral responses enables identical physiological activities to be obtained from both experimental animals and patients. This advantage has contributed to clarifying the generating mechanism of MMN in various animal studies. We reviewed clinical reports focused on early psychosis; specifically differential effects of deviance type and relationships to clinical and functional outcome. For the utility of MMN as a tool for translational research, we next reviewed recent MMN studies in rodents and nonhuman primates (NHP) as well as studies using intracranial recordings in humans, a rare opportunity to detect neural signals in vivo in humans. Neural computations of MMN, such as adaptation, deviance detection, and predictive coding, have been recent topics for understanding MMN generating mechanisms. Finally, several significant research questions were provided for future directions. MMN research could contribute to innovative, novel, therapeutic strategies in the future by becoming a bridge between basic and clinical research.


Assuntos
Córtex Auditivo/fisiopatologia , Percepção Auditiva/fisiologia , Potenciais Evocados Auditivos/fisiologia , Transtornos Psicóticos/fisiopatologia , Esquizofrenia/fisiopatologia , Animais , Modelos Animais de Doenças , Eletroencefalografia , Humanos , Pesquisa Translacional Biomédica
16.
Hum Brain Mapp ; 40(4): 1184-1194, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30353997

RESUMO

Auditory contextual processing has been assumed to be based on a hierarchical structure consisting of the primary auditory cortex, superior temporal gyrus (STG), and frontal lobe. Recent invasive studies on mismatch negativity (MMN) have revealed functional segregation for auditory contextual processing such as neural adaptation in the primary auditory cortex and prediction in the frontal lobe. However, the role of the STG remains unclear. We obtained induced activity in the high gamma band as mismatch response (MMR), an electrocorticographic (ECoG) counterpart to scalp MMN, and the components of MMR by analyzing ECoG data from patients with refractory epilepsy in an auditory oddball task paradigm. We found that MMR localized mainly in the bilateral posterior STGs, and that deviance detection largely accounted for MMR. Furthermore, adaptation was identified in a limited number of electrodes on the superior temporal plane. Our findings reveal a mixed contribution of deviance detection and adaptation depending on location in the STG. Such spatial considerations could lead to further understanding of the pathophysiology of relevant psychiatric disorders.


Assuntos
Percepção Auditiva/fisiologia , Lobo Temporal/fisiologia , Adulto , Córtex Auditivo/fisiologia , Mapeamento Encefálico/métodos , Eletrocorticografia , Potenciais Evocados Auditivos/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
17.
Tohoku J Exp Med ; 244(1): 7-14, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29279456

RESUMO

In Japan, traditional gender roles of women, especially the role of motherhood, may cause early career resignations in female physicians and a shortage of female researchers. Besides this gender issue, a general physician shortage is affecting basic science fields. Our previous study suggested that female physicians could be good candidates for the basic sciences because such work offers good work-life balance. However, the attractiveness for female physicians of working in the basic sciences, including work-life balance, is not known. In a 2012 nationwide cross-sectional questionnaire survey, female physicians holding tenured positions in the basic sciences at Japan's medical schools were asked an open-ended question about positive aspects of basic sciences that clinical medicine lacks, and we analyzed 58 respondents' comments. Qualitative analysis using the Kawakita Jiro method revealed four positive aspects: research attractiveness, priority on research productivity, a healthy work-life balance, and exemption from clinical duties. The most consistent positive aspect was research attractiveness, which was heightened by medical knowledge and clinical experience. The other aspects were double-edged swords; for example, while the priority on research productivity resulted in less gender segregation, it sometimes created tough competition, and while exemption from clinical duties contributed to a healthy work-life balance, it sometimes lowered motivation as a physician and provided unstable income. Overall, if female physicians lack an intrinsic interest in research and seek good work-life balance, they may drop out of research fields. Respecting and cultivating students' research interest is critical to alleviating the physician shortage in the basic sciences.


Assuntos
Médicas , Ciência , Escolha da Profissão , Feminino , Humanos , Inquéritos e Questionários
18.
Eur J Neurosci ; 46(11): 2662-2673, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28949036

RESUMO

Both the subthalamic nucleus (STN) and the globus pallidus pars interna (GPi) are major targets for neuromodulation therapy for movement disorders. An example of such a therapy is deep brain stimulation (DBS). The striatum is the primary target for pharmacological treatment of these disorders. To further our understanding of both the functional relationships among motor nuclei and the mechanisms of therapies for movement disorders, it is important to clarify how changing the neuronal activity of one target, either by medication or by artificial electrical stimulation, affects the other connected nuclei. To investigate this point, we recorded single-unit activity from tonically active neurons (TANs), which are putative cholinergic interneurons in the striatum, of healthy monkeys (Macaca fuscata) during electrical stimulation of the STN or GPi. Both STN stimulation and GPi stimulation reduced the TAN spike rate. Local infusion of a D2 receptor antagonist in the striatum blocked the reduction in spike rate induced by STN stimulation but not that induced by GPi stimulation. Further, STN stimulation induced phasic dopamine release in the striatum as revealed by in vivo fast-scan cyclic voltammetry. These results suggest the presence of multiple, strong functional relationships among the STN, GPi, and striatum that have different pathways and imply distinct therapeutic mechanisms for STN- and GPi-DBS.


Assuntos
Corpo Estriado/citologia , Corpo Estriado/fisiologia , Globo Pálido/citologia , Globo Pálido/fisiologia , Neurônios/fisiologia , Núcleo Subtalâmico/citologia , Núcleo Subtalâmico/fisiologia , Potenciais de Ação/fisiologia , Animais , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Dopamina/metabolismo , Antagonistas dos Receptores de Dopamina D2/farmacologia , Eletrodos Implantados , Macaca
19.
Hum Resour Health ; 15(1): 65, 2017 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-28915887

RESUMO

BACKGROUND: In Japan, the field of Basic Sciences encompasses clinical, academic, and translational research, as well as the teaching of medical sciences, with both an MD and PhD typically required. In this study, it was hypothesized that the characteristics of a Basic Sciences career path could offer the professional advancement and personal fulfillment that many female medical doctors would find advantageous. Moreover, encouraging interest in Basic Sciences could help stem shortages that Japan is experiencing in medical fields, as noted in the three principal contributing factors: premature resignation of female clinicians, an imbalance of female physicians engaged in research, and a shortage of medical doctors in the Basic Sciences. This study examines the professional and personal fulfillment expressed by Japanese female medical doctors who hold positions in Basic Sciences. Topics include career advancement, interest in medical research, and greater flexibility for parenting. METHODS: A cross-sectional questionnaire survey was distributed at all 80 medical schools in Japan, directed to 228 female medical doctors whose academic rank was assistant professor or higher in departments of Basic Sciences in 2012. Chi-square tests and the binary logistic regression model were used to investigate the impact of parenthood on career satisfaction, academic rank, salary, etc. RESULTS: The survey response rate of female physicians in Basic Sciences was 54.0%. Regardless of parental status, one in three respondents cited research interest as their rationale for entering Basic Sciences, well over twice other motivations. A majority had clinical experience, with clinical duties maintained part-time by about half of respondents and particularly parents. Only one third expressed afterthoughts about relinquishing full-time clinical practice, with physicians who were parents expressing stronger regrets. Parental status had little effect on academic rank and income within the Basic Sciences, CONCLUSION: Scientific curiosity and a desire to improve community health are hallmarks of those choosing a challenging career in medicine. Therefore, it is unsurprising that interest in research is the primary motivation for a female medical doctor to choose a career in Basic Sciences. Additionally, as with many young professionals with families, female doctors seek balance in professional and private lives. Although many expressed afterthoughts relinquishing a full-time clinical practice, mothers generally benefited from greater job flexibility, with little significant effect on career development and income as Basic Scientists.


Assuntos
Atitude , Pesquisa Biomédica , Escolha da Profissão , Satisfação no Emprego , Médicas , Ciência , Equilíbrio Trabalho-Vida , Adulto , Estudos Transversais , Docentes de Medicina , Família , Feminino , Humanos , Japão , Masculino , Medicina , Pessoa de Meia-Idade , Motivação , Poder Familiar , Faculdades de Medicina , Inquéritos e Questionários , Adulto Jovem
20.
J Neurosci ; 36(48): 12192-12202, 2016 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-27903728

RESUMO

Switching behavior based on multiple rules is a fundamental ability of flexible behavior. Although interactions among the frontal, parietal, and sensory cortices are necessary for such flexibility, little is known about the neural computations concerning context-dependent information readouts. Here, we provide evidence that neurons in the lateral intraparietal area (LIP) accumulate relevant information preferentially depending on context. We trained monkeys to switch between direction and depth discrimination tasks and analyzed the buildup activity in the LIP depending on task context. In accordance with behavior, the rate of buildup to identical visual stimuli differed between tasks and buildup was prominent only for the stimulus dimension relevant to the task. These results indicate that LIP neurons accumulate relevant information depending on context to decide flexibly where to move the eye, suggesting that flexibility is, at least partly, implemented in the form of temporal integration gain control. SIGNIFICANCE STATEMENT: Flexible behavior depending on context is a hallmark of human cognition. During flexible behavior, the frontal and parietal cortices have complex representations that hinder efforts to conceptualize their underlying computations. We now provide evidence that neurons in the lateral intraparietal area accumulate relevant information preferentially depending on context. We suggest that behavioral flexibility is implemented in the form of temporal integration gain control in the parietal cortex.


Assuntos
Adaptação Fisiológica/fisiologia , Compreensão/fisiologia , Tomada de Decisões/fisiologia , Lobo Parietal/fisiologia , Tempo de Reação/fisiologia , Percepção Visual/fisiologia , Animais , Macaca , Masculino , Rede Nervosa/fisiologia
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