RESUMO
Receptive field (RF) plasticity in primary auditory cortex of adult animals, specifically selective increased response to a tonal conditioned stimulus (CS) relative to other frequencies, can be induced both by behavioral conditioning and by pairing a tone with stimulation of the nucleus basalis (NB). This study determined whether cortical muscarinic receptors are necessary for NB-induced RF plasticity. Single units in layers II-IV were studied in Urethane anesthetized adult rats. The cortex was perfused with saline or saline+atropine sulfate. Conditioning, 30 trials of pairing a tone with NB stimulation, produced a significant CS-specific response increase (n=8). Local atropine blocked NB-induced RF plasticity, actually resulting in CS-specific response decrease (n=6). Therefore, NB-induced RF plasticity requires engagement of muscarinic receptors in auditory cortex.
Assuntos
Córtex Auditivo/metabolismo , Percepção Auditiva/fisiologia , Núcleo Basal de Meynert/metabolismo , Condicionamento Psicológico/fisiologia , Vias Neurais/metabolismo , Plasticidade Neuronal/fisiologia , Receptores Muscarínicos/metabolismo , Acetilcolina/metabolismo , Estimulação Acústica , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Animais , Atropina/farmacologia , Córtex Auditivo/citologia , Córtex Auditivo/efeitos dos fármacos , Percepção Auditiva/efeitos dos fármacos , Núcleo Basal de Meynert/citologia , Fibras Colinérgicas/efeitos dos fármacos , Fibras Colinérgicas/metabolismo , Condicionamento Psicológico/efeitos dos fármacos , Estimulação Elétrica , Masculino , Antagonistas Muscarínicos/farmacologia , Vias Neurais/citologia , Plasticidade Neuronal/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Ratos , Ratos Sprague-Dawley , Tempo de Reação/efeitos dos fármacos , Tempo de Reação/fisiologia , Receptores Muscarínicos/efeitos dos fármacosRESUMO
Temporal relationships between adjacent single cells were studied in the auditory cortex of the waking guinea pig during silence and pure tone stimulation. One cell of each pair was responsive while the other was completely unresponsive Coordinated discharge was found for spontaneous activity in 14/17 (82%) pairs, generally at and near the origin of cross correlation histograms (CCHs, 5 ms bins). These relationships, involving the same temporal intervals, were also maintained during tone driven discharges of the responsive cell. Thus, responsive neurons may participate simultaneously in specific sensory processing tasks while also responding to a presumptive common modulatory influence within a local network, without the two processes necessarily being linked. Therefore, responsive cells may have greater information processing capacity than realized.
Assuntos
Córtex Auditivo/fisiologia , Neurônios/fisiologia , Estimulação Acústica , Animais , Comunicação Celular , Cobaias , Masculino , Tempo de Reação , VigíliaRESUMO
The A-not-B error is one of the most robust and highly studied phenomena in developmental psychology. The traditional Piagetian interpretation is that the error reflects the immaturity of infants' understanding of objects as permanent entities. More recently, the error has been interpreted in terms of changes in representation, in memory, in spatial knowledge, and in inhibitory processes. Each account may be partially right but none offers a unified account of the many accumulated facts about this error. This article presents and tests a new unified explanation. The authors propose that the perseverative reach back to A is the product of the processes that take a hand to a location in visual space: the body-centered nature of the spatial code, memories for previous reaching activity, and the close coupling of looking and reaching. The results from 6 experiments support this explanation. The results are used to challenge the idea of knowledge independent of and distinct from behavior.
