Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 43
Filtrar
1.
J Fish Biol ; 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39192750

RESUMO

Cleaner fishes remove parasites from other fishes called "clients," thereby contributing to a healthier ecosystem. Although the behavior and learning abilities of dedicated and tropical cleaner fishes have been broadly studied, a limited number of studies investigated the behavior of facultative and temperate cleaner fishes and, to the best of our knowledge, none focused on their cognitive abilities. Here, we tested the learning abilities of a species of temperate facultative cleaner, the ornate wrasse Thalassoma pavo in laboratory conditions, based on two problems. These two problems, or tasks, are relevant in two different contexts: the first one, deemed as mutualistically relevant, the cue-based discrimination task, and the second one, the spatial-based discrimination task, which is relevant in a non-cleaning context, when fish navigate through their environment to find food and return to their territories. We found that T. pavo individuals were able to solve these two tasks but excelled at the spatial task rather than with the cue discrimination. The same individuals were also challenged to learn the reverse protocol of these tasks and were again most successful in learning the reverse spatial discrimination problem, but not the cue. Contrary to the dedicated cleaner wrasse Labroides dimidiatus, this temperate facultative cleaner wrasse is slower to learn mutualistic relevant problems but competent in solving spatially derived problems. This may be due to the specific demands of their socio-ecological environment, with facultative cleaners having a greater component of non-mutualistic skills (spatial component), which prepares them to search for alternative food sources if necessary (e.g., feeding on the substrate) or even to expand territories more easily and less prepared to deal with mutualistic exchanges compared to dedicated cleaners that specialize to become increasingly socially competent.

2.
Front Cell Neurosci ; 18: 1379438, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38694537

RESUMO

Retinoic acid (RA), derived from vitamin A (retinol), plays a crucial role in modulating neuroplasticity within the adult brain. Perturbations in RA signaling have been associated with memory impairments, underscoring the necessity to elucidate RA's influence on neuronal activity, particularly within the hippocampus. In this study, we investigated the cell type and sub-regional distribution of RA-responsive granule cells (GCs) in the mouse hippocampus and delineated their properties. We discovered that RA-responsive GCs tend to exhibit a muted response to environmental novelty, typically remaining inactive. Interestingly, chronic dietary depletion of RA leads to an abnormal increase in GC activation evoked by a novel environment, an effect that is replicated by the localized application of an RA receptor beta (RARß) antagonist. Furthermore, our study shows that prolonged RA deficiency impairs spatial discrimination-a cognitive function reliant on the hippocampus-with such impairments being reversible with RA replenishment. In summary, our findings significantly contribute to a better understanding of RA's role in regulating adult hippocampal neuroplasticity and cognitive functions.

3.
Br J Pharmacol ; 181(16): 2701-2724, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38631821

RESUMO

BACKGROUND AND PURPOSE: Transient hypofunction of the NMDA receptor represents a convergence point for the onset and further development of psychiatric disorders, including schizophrenia. Although the cumulative evidence indicates dysregulation of the hippocampal formation in schizophrenia, the integrity of the synaptic transmission and plasticity conveyed by the somatosensorial inputs to the dentate gyrus, the perforant pathway synapses, have barely been explored in this pathological condition. EXPERIMENTAL APPROACH: We identified a series of synaptic alterations of the lateral and medial perforant paths in animals postnatally treated with the NMDA antagonist MK-801. This dysregulation suggests decreased cognitive performance, for which the dentate gyrus is critical. KEY RESULTS: We identified alterations in the synaptic properties of the lateral and medial perforant paths to the dentate gyrus synapses in slices from MK-801-treated animals. Altered glutamate release and decreased synaptic strength precede an impairment in the induction and expression of long-term potentiation (LTP) and CB1 receptor-mediated long-term depression (LTD). Remarkably, by inhibiting the degradation of 2-arachidonoylglycerol (2-AG), an endogenous ligand of the CB1 receptor, we restored the LTD in animals treated with MK-801. Additionally, we showed for the first time, that spatial discrimination, a cognitive task that requires dentate gyrus integrity, is impaired in animals exposed to transient hypofunction of NMDA receptors. CONCLUSION AND IMPLICATIONS: Dysregulation of glutamatergic transmission and synaptic plasticity from the entorhinal cortex to the dentate gyrus has been demonstrated, which may explain the cellular dysregulations underlying the altered cognitive processing in the dentate gyrus associated with schizophrenia.


Assuntos
Giro Denteado , Maleato de Dizocilpina , Plasticidade Neuronal , Via Perfurante , Receptores de N-Metil-D-Aspartato , Animais , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/metabolismo , Giro Denteado/efeitos dos fármacos , Giro Denteado/metabolismo , Maleato de Dizocilpina/farmacologia , Via Perfurante/efeitos dos fármacos , Via Perfurante/fisiologia , Plasticidade Neuronal/efeitos dos fármacos , Masculino , Ratos , Endocanabinoides/metabolismo , Receptor CB1 de Canabinoide/metabolismo , Receptor CB1 de Canabinoide/antagonistas & inibidores , Ratos Wistar , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Antagonistas de Aminoácidos Excitatórios/farmacologia , Potenciação de Longa Duração/efeitos dos fármacos
4.
Parkinsonism Relat Disord ; 116: 105868, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37827034

RESUMO

INTRODUCTION: Although pain is common in Parkinson's disease (PD), the underlying mechanism remains unknown. Scaling function and dopaminergic hypofunction may contribute to pain development because increased pain sensitivity is observed in PD and is normalized after levodopa administration. We aimed to determine whether spatial discrimination (SD) and striatal dopaminergic activity (DA) differed between PD patients with and without pain. METHODS: We divided 90 patients with drug-naïve PD into two groups based on the presence or absence of pain and compared the SD threshold (SDT). We evaluated the correlation of the SDT with pain severity in PD with pain. We also compared the DA of 48 patients and analyzed the correlation with pain severity in PD patients with pain. RESULTS: The SDTs did not differ between the two groups, but unmeasurable SDT was more frequent in PD with pain. There was a positive correlation of pain severity with the SDT of the more affected hand but no correlation with the SDT of the less affected hand. The DA did not differ between the groups. There was a negative trend of pain severity with the DA of the ventral striatum (VS) but no correlation with the other striatal subregions. CONCLUSIONS: Pain in PD may be associated with scaling dysfunction in the sensory system. The abnormal scaling function would render the PD patient hypersensitive to even mild pain. The dopamine in the VS appears to be associated with pain severity; however, the relationship of striatal dopaminergic deficits with pain occurrence requires further investigation.


Assuntos
Doença de Parkinson , Humanos , Doença de Parkinson/complicações , Levodopa/uso terapêutico , Dopamina , Corpo Estriado
5.
Behav Processes ; 213: 104947, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37797821

RESUMO

Same/different learning by pigeons has long been of interest to experimental psychologists. In one of these procedures, matching-to-sample, responses to a sample stimulus result in the presentation of two comparison stimuli, one of which matches the sample, the other of which does not, and choice of the matching stimulus is reinforced. Evidence of a matching concept has been found when transfer has been found to new stimuli. Given the transfer results, it is surprising that acquisition of two matching tasks (or two mismatching tasks), has not been found to be any faster than one matching and one mismatching task (i.e., two compatible tasks do not appear to facilitate each other). In the present experiment, we asked if matching acquisition involving three colors would be retarded if the correct response to a fourth color was not matching but was spatial (e.g., if the sample is red choose the red comparison, if the sample is green choose the green comparison, if the sample is yellow choose the yellow comparison, but if the sample is blue choose the left comparison). We found that acquisition of this task was slower than acquisition of a four color matching task (i.e., when the sample was blue, the blue comparison was correct). The results suggest that there is an interaction among matching associations, such that common rules facilitate learning compared with having to learn an inconsistent (spatial) rule. This result provides further evidence of the development of a matching concept by pigeons.


Assuntos
Aprendizagem por Discriminação , Aprendizagem , Animais , Aprendizagem por Discriminação/fisiologia , Columbidae/fisiologia
6.
Cereb Cortex ; 33(6): 2958-2968, 2023 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-35718538

RESUMO

Our representation of magnitudes such as time, distance, and size is not always veridical because it is affected by multiple biases. From a Bayesian perspective, estimation errors are considered to be the result of an optimization mechanism for the behavior in a noisy environment by integrating previous experience with the incoming sensory information. One influence of the distribution of past stimuli on perceptual decisions is represented by the regression toward the mean, a type of contraction bias. Using a spatial discrimination task with 2 stimuli presented sequentially at different distances from the center, we show that this bias is also present in macaques when comparing the magnitude of 2 distances. We found that the contraction of the first stimulus magnitude toward the center of the distribution accounted for some of the changes in performance, even more so than the effect of difficulty related to the ratio between stimulus magnitudes. At the neural level in the dorsolateral prefrontal cortex, the coding of the decision after the presentation of the second stimulus reflected the effect of the contraction bias on the discriminability of the stimuli at the behavioral level.


Assuntos
Córtex Pré-Frontal , Animais , Teorema de Bayes , Tempo de Reação , Macaca mulatta , Viés
7.
Cochlear Implants Int ; 23(4): 203-213, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35317705

RESUMO

There is a tendency for children undergoing sequential cochlear implant after a long period of unilateral implant use to have a smaller dynamic range in their second implant compared to their first implant. This study aimed to investigate if balancing the dynamic ranges between the two implants influenced functional outcomes in sequentially implanted children. Nineteen participants with long inter-implant time delays were randomly assigned to a study group or a control group. Children in the study group received progressive minimal changes to both first and second implants over a period of nine months to achieve balanced dynamic ranges, while the children in the control group received only changes to their sequential implant. Functional outcomes were collected 24-months after sequential implantation and consisted of speech discrimination scores, spatial localisation, device use and quality of life measures. Results show that spatial discrimination skills improved over time for both groups of children; however children in the study group had smaller localisation errors compared with the children in the control group. No other differences between the two groups were observed. Balanced dynamic ranges in sequentially implanted children can contribute to better performance, particularly in spatial discrimination tasks that rely in inter-aural level differences.


Assuntos
Implante Coclear , Implantes Cocleares , Surdez , Percepção da Fala , Criança , Implante Coclear/métodos , Surdez/cirurgia , Humanos , Qualidade de Vida , Resultado do Tratamento
8.
Behav Brain Res ; 417: 113614, 2022 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-34606777

RESUMO

Spatial neglect is a common feature of right hemisphere damage in adults, but less is known about spatial inattention following early brain damage. We used a Posner-based cueing task to examine hemispatial neglect and aspects of attention in children with perinatal stroke in either left (LH) or right hemisphere (RH) and controls. A visual perception task assessed the speed of visual perception. A spatial attention cueing task (the E-task) measured the ability to discriminate the direction of a target stimulus ("E"), when presented on the left or right side of the screen. This task provided indices of performance for attention orienting, disengagement and reorienting. Children with LH lesions had slowed visual perception compared to controls. Children with RH lesions did not demonstrate similar deficits. On the E-task, groups with both LH and RH lesions demonstrated lower accuracy on both left and right sides compared to controls. Children with LH lesions also showed impaired attention orienting and disengagement on left and right sides compared to controls, while children with RH lesions were most impaired in orienting and disengagement on their contralesional side. Children with LH lesions demonstrated more extensive attentional deficits than children with RH lesions. These results suggest that development of spatial attention may require different neural networks than maintenance of attention.


Assuntos
Transtornos da Percepção/patologia , Tempo de Reação/fisiologia , Percepção Espacial/fisiologia , Acidente Vascular Cerebral/complicações , Percepção Visual/fisiologia , Adolescente , Criança , Sinais (Psicologia) , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Testes Neuropsicológicos
9.
J Clin Neurosci ; 94: 315-320, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34863456

RESUMO

This study's aim was to investigate prevalence of four non-motor symptoms in patients with cervical dystonia and healthy controls to explore whether the presence of multiple non-motor features is associated with cervical dystonia diagnosis. Fifteen patients with cervical dystonia and 15 healthy controls underwent non-invasive testing of spatial discrimination threshold, temporal discrimination threshold, vibration-induced illusion of movement, and kinesthesia. All spatial discrimination threshold, temporal discrimination threshold, and vibration-induced illusion of movement measures were converted to standardized Z scores with scores >2.0 considered abnormal. Any incorrect kinesthesia response was considered abnormal. Prevalence of each abnormal non-motor feature was compared between groups using a chi-squared test. A higher proportion of patients with cervical dystonia had abnormal spatial discrimination threshold (p = 0.01) and abnormal kinesthesia (p = 0.03) scores compared to healthy control subjects. There were no significant differences between the proportion of patients with cervical dystonia versus healthy controls for abnormal temporal discrimination threshold (p = 0.07) or abnormal vibration-induced illusion of movement (p = 0.14). Forty-seven percent of patients with cervical dystonia (7/15) demonstrated one abnormal non-motor feature, 20% (3/15) displayed two abnormal features, and 13% (2/15) displayed three abnormal features. Kinesthesia was the only non-motor feature identified as abnormal in the control group (20%, 3/15). All four tests demonstrated high specificity (80-100%) and low-moderate sensitivity (13-60%). These findings suggest that non-motor feature testing, specifically for spatial discrimination threshold and kinesthesia, could be a highly specific diagnostic tool to inform cervical dystonia diagnosis. Further investigation is needed to confirm these findings.


Assuntos
Torcicolo , Humanos , Movimento , Torcicolo/diagnóstico
10.
Cell Rep ; 35(1): 108934, 2021 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-33826896

RESUMO

Cortical activity related to erroneous behavior in discrimination or decision-making tasks is rarely analyzed, yet it can help clarify which computations are essential during a specific task. Here, we use a hidden Markov model (HMM) to perform a trial-by-trial analysis of the ensemble activity of dorsolateral prefrontal cortex (PFdl) neurons of rhesus monkeys performing a distance discrimination task. By segmenting the neural activity into sequences of metastable states, HMM allows us to uncover modulations of the neural dynamics related to internal computations. We find that metastable dynamics slow down during error trials, while state transitions at a pivotal point during the trial take longer in difficult correct trials. Both these phenomena occur during the decision interval, with errors occurring in both easy and difficult trials. Our results provide further support for the emerging role of metastable cortical dynamics in mediating complex cognitive functions and behavior.


Assuntos
Discriminação Psicológica , Percepção de Distância/fisiologia , Córtex Pré-Frontal/fisiologia , Análise e Desempenho de Tarefas , Animais , Macaca mulatta , Masculino , Cadeias de Markov , Neurônios/fisiologia
11.
Eur Ann Otorhinolaryngol Head Neck Dis ; 138(5): 333-336, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33390347

RESUMO

OBJECTIVES: The main objective of this study was to test the feasibility of measuring minimum audible angle in headphones with different reference positions in the horizontal plane, and comparing different types of pre-recorded head-related transfer functions. The secondary objective was to assess spatial discrimination performance in simulated unilateral hearing loss by measuring the minimum audible angle under monaural conditions using headphones. MATERIALS AND METHODS: Minimum audible angle was assessed in 27 normal-hearing subjects, to test their spatial discrimination abilities, using 4 datasets of pre-recorded head-related transfer functions: 2 recorded on mannequins (KU100, KEMAR), and 2 individualized head-related transfer function datasets (TBM, PBM). Performance was evaluated at 3 reference positions (0°, 50° and 180°) in 1 binaural and 2 monaural conditions. RESULTS: KU100 generated minimum audible angle values smaller than KEMAR in frontal and lateral position P<0.005), with a suggestive difference (P<0.05) compared to TBM and PBM in the frontal and lateral planes. Comparison between binaural and monaural conditions showed significant differences in frontal position for MON-c (contralateral) and MON-i (ipsilateral) (P<0.001), in lateral position for MON-c only (P<0.001) and in posterior position for MON-c and MON-i (P<0.001). CONCLUSION: This study suggests that evaluation of spatial discrimination capacity using minimum audible angle with the KU100 head-related transfer dataset was reliable and robust.


Assuntos
Perda Auditiva Unilateral , Localização de Som , Testes Auditivos , Humanos
12.
Alzheimers Dement (N Y) ; 7(1): e12231, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35005208

RESUMO

The earliest abnormality associated with Alzheimer's disease (AD) is the presence of persistently phosphorylated pretangle tau in locus coeruleus (LC) neurons. LC neuron numbers and fiber density are positive predictors of cognition prior to death. Using an animal model of LC pretangle tau, we ask if LC activity patterns influence the sequelae of pretangle tau. We seeded LC neurons with a pretangle human tau gene. We provided daily novelty- or stress-associated optogenetic activation patterns to LC neurons for 6 weeks in mid-adulthood and, subsequently, probed cognitive and anatomical changes. Prior LC phasic stimulation prevented spatial and olfactory discrimination deficits and preserved LC axonal density. A stress-associated activation pattern increased indices of anxiety and depression, did not improve cognition, and worsened LC neuronal health. These results argue that variations in environmental experiences associated with differing LC activity patterns may account for individual susceptibility to development of AD in humans.

13.
Alcohol Clin Exp Res ; 44(10): 2008-2018, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32772384

RESUMO

BACKGROUND: Exposure to high levels of alcohol during development leads to alterations in neurogenesis and deficits in hippocampal-dependent learning. Evidence suggests that even more moderate alcohol consumption during pregnancy can have negative impacts on the cognitive function of offspring. Methods for assessing impairments differ greatly across species, complicating translation of preclinical findings into potential therapeutics. We have demonstrated the utility of a touchscreen operant measure for assessing hippocampal function in mice. METHODS: Here, we integrated a well-established "drinking-in-the-dark" exposure model that produces reliable, but more moderate, levels of maternal intoxication with a trial-unique, delayed nonmatching-to-location (TUNL) task to examine the effects of prenatal alcohol exposure (PAE) on hippocampal-sensitive behavior directly analogous to those used in clinical assessment. PAE and SAC offspring mice were trained to touch a single visual stimulus ("sample phase") in one of 10 possible spatial locations (2 × 5 grid) in a touchscreen operant system. After a delay, animals were simultaneously presented with the original stimulus and a rewarded stimulus in a novel location ("choice phase"). PAE and saccharin (SAC) control mice were trained on a series of problems that systematically increased the difficulty by decreasing the separation between the sample and choice stimuli. Next, a separate cohort of PAE and SAC animals were given a brief training and then tested on a challenging variant where both the separation and delay varied with each trial. RESULTS: We found that PAE mice were generally able to perform at levels similar to SAC control mice at progressively more difficult separations. When tested on the most difficult unpredictable variant immediately, PAE showed a sex-specific deficit with PAE females performing worse during long delays. CONCLUSIONS: Taken together, these data demonstrate the utility of the TUNL task for examining PAE related alterations in hippocampal function and underline the need to examine sex-by-treatment interactions in these models.


Assuntos
Aprendizagem por Discriminação/efeitos dos fármacos , Etanol/efeitos adversos , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Percepção Espacial/efeitos dos fármacos , Percepção Visual/efeitos dos fármacos , Animais , Condicionamento Operante/efeitos dos fármacos , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Efeitos Tardios da Exposição Pré-Natal/psicologia , Fatores Sexuais
14.
J Neurosci ; 40(25): 4888-4899, 2020 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-32376783

RESUMO

Age-related cognitive impairments are associated with differentially expressed genes (DEGs) linked to defined neural systems; however, studies examining multiple regions of the hippocampus fail to find links between behavior and transcription in the dentate gyrus (DG). We hypothesized that use of a task requiring intact DG function would emphasize molecular signals in the DG associated with a decline in performance. We used a water maze beacon discrimination task to characterize young and middle-age male F344 rats, followed by a spatial reference memory probe trial test. Middle-age rats showed increased variability in discriminating two identical beacons. Use of an allocentric strategy and formation of a spatial reference memory were not different between age groups; however, older animals compensated for impaired beacon discrimination through greater reliance on spatial reference memory. mRNA sequencing of hippocampal subregions indicated DEGs in the DG of middle-age rats, linked to synaptic function and neurogenesis, correlated with beacon discrimination performance, suggesting that senescence of the DG underlies the impairment. Few genes correlated with spatial memory across age groups, with a greater number in region CA1. Age-related CA1 DEGs, correlated with spatial memory, were linked to regulation of neural activity. These results indicate that the beacon task is sensitive to impairment in middle age, and distinct gene profiles are observed in neural circuits that underlie beacon discrimination performance and allocentric memory. The use of different strategies in older animals and associated transcriptional profiles could provide an animal model for examining cognitive reserve and neural compensation of aging.SIGNIFICANCE STATEMENT Hippocampal subregions are thought to differentially contribute to memory. We took advantage of age-related variability in performance on a water maze beacon task and next-generation sequencing to test the hypothesis that aging of the dentate gyrus is linked to impaired beacon discrimination and compensatory use of allocentric memory. The dentate gyrus expressed synaptic function and neurogenesis genes correlated with beacon discrimination in middle-age animals. Spatial reference memory was associated with CA1 transcriptional correlates linked to regulation of neural activity and use of an allocentric strategy. This is the first study examining transcriptomes of multiple hippocampal subregions to link age-related impairments associated with discrimination of feature overlap and alternate response strategies to gene expression in specific hippocampal subregions.


Assuntos
Envelhecimento Cognitivo/fisiologia , Giro Denteado/fisiologia , Hipocampo/fisiologia , Transcriptoma , Animais , Aprendizagem em Labirinto/fisiologia , Ratos , Ratos Endogâmicos F344 , Memória Espacial/fisiologia
15.
J Neurosci ; 39(45): 8900-8915, 2019 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-31548234

RESUMO

Spontaneous correlated activity in cortical columns is critical for postnatal circuit refinement. We used spatial discrimination techniques to explore the late maturation of synaptic pathways through the laminar distribution of the field potential (FP) generators underlying spontaneous and evoked activities of the S1HL cortex in juvenile (P14-P16) and adult anesthetized rats. Juveniles exhibit an intermittent FP pattern resembling Up/Down states in adults, but with much reduced power and different laminar distribution. Whereas FPs in active periods are dominated by a layer VI generator in juveniles, in adults a developing multipart generator takes over, displaying current sinks in middle layers (III-V). The blockade of excitatory transmission in upper and middle layers of adults recovered the juvenile-like FP profiles. In addition to the layer VI generator, a gamma-specific generator in supragranular layers was the same in both age groups. While searching for dynamical coupling among generators in juveniles we found significant cross-correlation in ∼one-half of the tested pairs, whereas excessive coherence hindered their efficient separation in adults. Also, potentials evoked by tactile and electrical stimuli showed different short-latency dipoles between the two age groups, and the juveniles lacked the characteristic long latency UP state currents in middle layers. In addition, the mean firing rate of neurons was lower in juveniles. Thus, cortical FPs originate from different intra-columnar segments as they become active postnatally. We suggest that although some cortical segments are active early postnatally, a functional sensory-motor control relies on a delayed maturation and network integration of synaptic connections in middle layers.SIGNIFICANCE STATEMENT Early postnatal activity in the rodent cortex is mostly endogenous, whereas it becomes driven by peripheral input at later stages. The precise schedule for the maturation of synaptic pathways is largely unknown. We explored this in the somatosensory hindlimb cortex at an age when animals begin to use their limbs by uncovering the laminar distribution of the field potential generators underlying the dominant delta waves in juveniles and adults. Our results suggest that field potentials are mostly generated by a pathway in deep layers, whereas other pathways mature later in middle layers and take over in adults. We suggest that a functional sensory-motor control relies on a delayed maturation and network integration of synaptic connections in middle layers.


Assuntos
Potenciais Somatossensoriais Evocados , Neurogênese , Córtex Somatossensorial/fisiologia , Animais , Feminino , Ritmo Gama , Masculino , Ratos , Ratos Wistar , Tempo de Reação , Córtex Somatossensorial/citologia , Córtex Somatossensorial/crescimento & desenvolvimento , Tato
17.
Hear Res ; 377: 282-291, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31029039

RESUMO

The present study investigated spatial hearing in children aged 6-12 years diagnosed with Auditory Processing Disorders (APD) and compared their results to those of a group of control children matched in age. Sound source localization accuracy was quantified using an absolute localization task and sound source discrimination by measuring the minimum audible angle. Low- and high-frequency noise bursts were presented from eight loudspeaker positions in the left and right hemifields (0°, 30, 60°, and 90° azimuth). Median absolute localization accuracy did not differ between children with APD and control children. However, the intra-individual variability of pointing behavior was higher for children with APD. In contrast, children with APD had significantly higher minimum audible angle thresholds than control children. These findings show that APD impairs sound source discrimination, but does not affect the median relationship between actual and judged sound source locations.


Assuntos
Transtornos da Percepção Auditiva/psicologia , Comportamento Infantil , Discriminação Psicológica , Localização de Som , Estimulação Acústica , Fatores Etários , Vias Auditivas/fisiopatologia , Transtornos da Percepção Auditiva/diagnóstico , Transtornos da Percepção Auditiva/fisiopatologia , Estudos de Casos e Controles , Criança , Feminino , Humanos , Julgamento , Masculino
18.
Cereb Cortex ; 29(12): 5234-5254, 2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-30941394

RESUMO

Brain field potentials (FPs) can reach far from their sources, making difficult to know which waves come from where. We show that modern algorithms efficiently segregate the local and remote contributions to cortical FPs by recovering the generator-specific spatial voltage profiles. We investigated experimentally and numerically the local and remote origin of FPs in different cortical areas in anesthetized rats. All cortices examined show significant state, layer, and region dependent contribution of remote activity, while the voltage profiles help identify their subcortical or remote cortical origin. Co-activation of different cortical modules can be discriminated by the distinctive spatial features of the corresponding profiles. All frequency bands contain remote activity, thus influencing the FP time course, in cases drastically. The reach of different FP patterns is boosted by spatial coherence and curved geometry of the sources. For instance, slow cortical oscillations reached the entire brain, while hippocampal theta reached only some portions of the cortex. In anterior cortices, most alpha oscillations have a remote origin, while in the visual cortex the remote theta and gamma even surpass the local contribution. The quantitative approach to local and distant FP contributions helps to refine functional connectivity among cortical regions, and their relation to behavior.


Assuntos
Córtex Cerebral/fisiologia , Potenciais Evocados/fisiologia , Modelos Neurológicos , Animais , Eletroencefalografia , Ratos , Ratos Wistar
19.
Brain Struct Funct ; 224(2): 829-846, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30515567

RESUMO

Disruption in cholinergic signaling has been linked to many environmental and/or pathological conditions known to modify adult neurogenesis. The α7 nAChRs are in the family of cys-loop receptor channels which have been shown to be neuroprotective in adult neurons and are thought to be critical for survival and integration of immature neurons. However, in developing neurons, poor calcium buffering may cause α7 nAChR activation to be neurotoxic. To investigate whether the α7 nAChR regulates neurogenesis in the hippocampus, we used a combination of mouse genetics and imaging to quantify neural stem cell (NSC) densities located in the dentate gyrus of adult mice. In addition, we considered whether the loss of α7 nAChRs had functional consequences on a spatial discrimination task that is thought to rely on pattern separation mechanisms. We found that the loss of α7 nAChRs resulted in increased neurogenesis in male mice only, while female mice showed increased cell divisions and intermediate progenitors but no change in neurogenesis. Knocking out the α7 nAChR from nestin+ NSCs and their progeny showed signaling in these cells contributes to regulating neurogenesis. In addition, male, but not female, mice lacking α7 nAChRs performed significantly worse in the spatial discrimination task. This task was sexually dimorphic in wild-type mice, but not in the absence of α7 nAChRs. We conclude that α7 nAChRs regulate adult neurogenesis and impact spatial discrimination function in male, but not female mice, via a mechanism involving nestin+ NSCs and their progeny.


Assuntos
Hipocampo/citologia , Neurogênese/fisiologia , Neurônios/citologia , Caracteres Sexuais , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Animais , Discriminação Psicológica/fisiologia , Feminino , Hipocampo/metabolismo , Masculino , Camundongos , Camundongos Knockout , Neurônios/metabolismo , Percepção Espacial/fisiologia , Receptor Nicotínico de Acetilcolina alfa7/genética
20.
Anim Behav ; 142: 87-93, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30147111

RESUMO

To understand how natural selection may act on cognitive processes, it is necessary to reliably determine interindividual variation in cognitive abilities. However, an individual's performance in a cognitive test may be influenced by the social environment. The social environment explains variation between species in cognitive performances, with species that live in larger groups purportedly demonstrating more advanced cognitive abilities. It also explains variation in cognitive performances within species, with larger groups more likely to solve novel problems than smaller groups. Surprisingly, an effect of group size on individual variation in cognitive performance has rarely been investigated and much of our knowledge stems from impaired performance of individuals reared in isolation. Using a within-subjects design we assayed individual learning performance of adult female pheasants, Phasianus colchicus, while housed in groups of three and five. Individuals experienced the group sizes in a different order, but were presented with two spatial discrimination tasks, each with a distinct cue set, in a fixed order. We found that across both tasks individuals housed in the large groups had higher levels of success than individuals housed in the small groups. Individuals had higher levels of success on their second than their first task, irrespective of group size. We suggest that the expression of individual learning performance is responsive to the current social environment but the mechanisms underpinning this relationship require further investigation. Our study demonstrates that it is important to account for an individual's social environment when attempting to characterize cognitive capacities. It also demonstrates the flexibility of an individual's cognitive performance depending on the social context.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA