RESUMEN
The evolutionary conservation of neural mechanisms for forming and maintaining pair bonds is unclear. Oxytocin, vasopressin and dopamine (DA) transmitter systems have been shown to be important in pair-bond formation and maintenance in several vertebrate species. We examined the role of dopamine in formation of song preference in zebra finches, a monogamous bird. Male courtship song is an honest signal of sexual fitness; thus, we measured female song preference to evaluate the role of DA in mate selection and pair-bond formation, using an operant conditioning paradigm. We found that DA acting through the D2 receptor, but not the D1 receptor, can induce a song preference in unpaired female finches and that blocking the D2 receptor abolished song preference in paired females. These results suggest that similar neural mechanisms for pair-bond formation are evolutionarily conserved in rodents and birds.
Asunto(s)
Proteínas Aviares/genética , Cortejo , Dopamina/metabolismo , Receptores de Dopamina D1/genética , Receptores de Dopamina D2/genética , Pájaros Cantores/fisiología , Vocalización Animal , Animales , Proteínas Aviares/metabolismo , Condicionamiento Operante , Femenino , Pinzones/fisiología , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismoRESUMEN
The human cortical system for face perception comprises a network of connected regions including the middle fusiform gyrus ("fusiform face area" or FFA), the inferior occipital gyrus ("occipital face area" or OFA), and the posterior superior temporal sulcus (pSTS). Here, we sought to investigate how transcranial magnetic stimulation (TMS) to the OFA affects activity within the face processing network. We used offline repetitive TMS to temporarily introduce neural noise in the right OFA in healthy subjects. We then immediately performed functional magnetic resonance imaging (fMRI) to measure changes in blood oxygenation level dependent (BOLD) signal across the face network using an fMR-adaptation (fMR-A) paradigm. We hypothesized that TMS to the right OFA would induce abnormal face identity coding throughout the face processing network in regions to which it has direct or indirect connections. Indeed, BOLD signal for face identity, but not non-face (butterfly) identity, decreased in the right OFA and FFA following TMS to the right OFA compared to both sham TMS and TMS to a control site, the nearby object-related lateral occipital area (LO). Further, TMS to the right OFA decreased face-related activation in the left FFA, without any effect in the left OFA. Our findings indicate that TMS to the right OFA selectively disrupts face coding at both the stimulation site and bilateral FFA. TMS to the right OFA also decreased BOLD signal for different identity stimuli in the right pSTS. Together with mounting evidence from patient studies, we demonstrate connectivity of the OFA within the face network and that its activity modulates face processing in bilateral FFA as well as the right pSTS. Moreover, this study shows that deep regions within the face network can be remotely probed by stimulating structures closer to the cortical surface.
Asunto(s)
Reconocimiento Facial/fisiología , Lóbulo Occipital/fisiología , Estimulación Magnética Transcraneal/métodos , Área de Wernicke/fisiología , Adulto , Mapeo Encefálico , Cara , Femenino , Lateralidad Funcional/fisiología , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Red Nerviosa/fisiología , Reconocimiento Visual de Modelos/fisiología , Estimulación Luminosa/métodos , Lóbulo Temporal/fisiopatología , Percepción Visual/fisiologíaRESUMEN
Viewing the world involves many computations across a great number of regions of the brain, all the while appearing seamless and effortless. We sought to determine the connectivity of object and scene processing regions of cortex through the influence of transient focal neural noise in discrete nodes within these networks. We consecutively paired repetitive transcranial magnetic stimulation (rTMS) with functional magnetic resonance-adaptation (fMR-A) to measure the effect of rTMS on functional response properties at the stimulation site and in remote regions. In separate sessions, rTMS was applied to the object preferential lateral occipital region (LO) and scene preferential transverse occipital sulcus (TOS). Pre- and post-stimulation responses were compared using fMR-A. In addition to modulating BOLD signal at the stimulation site, TMS affected remote regions revealing inter and intrahemispheric connections between LO, TOS, and the posterior parahippocampal place area (PPA). Moreover, we show remote effects from object preferential LO to outside the ventral perception network, in parietal and frontal areas, indicating an interaction of dorsal and ventral streams and possibly a shared common framework of perception and action.
Asunto(s)
Mapeo Encefálico , Vías Nerviosas/fisiología , Lóbulo Occipital/fisiología , Reconocimiento Visual de Modelos/fisiología , Percepción Espacial/fisiología , Estimulación Magnética Transcraneal , Adulto , Femenino , Lateralidad Funcional , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Vías Nerviosas/irrigación sanguínea , Lóbulo Occipital/irrigación sanguínea , Oxígeno , Estimulación Luminosa , Adulto JovenRESUMEN
The human cortical system for face perception is comprised of a network of connected regions including the middle fusiform gyrus ("fusiform face area" or FFA), the inferior occipital cortex ("occipital face area" or OFA), and the superior temporal sulcus. The traditional hierarchical feedforward model of visual processing suggests information flows from early visual cortex to the OFA for initial face feature analysis to higher order regions including the FFA for identity recognition. However, patient data suggest an alternative model. Patients with acquired prosopagnosia, an inability to visually recognize faces, have been documented with lesions to the OFA but who nevertheless show face-selective activation in the FFA. Moreover, their ability to categorize faces remains intact. This suggests that the FFA is not solely responsible for face recognition and the network is not strictly hierarchical, but may be organized in a reverse hierarchical fashion. We used transcranial magnetic stimulation (TMS) to temporarily disrupt processing in the OFA in neurologically-intact individuals and found participants' ability to categorize intact versus scrambled faces was unaffected, however face identity discrimination was significantly impaired. This suggests that face categorization but not recognition can occur without the "earlier" OFA being online and indicates that "lower level" face category processing may be assumed by other intact face network regions such as the FFA. These results are consistent with the patient data and support a non-hierarchical, global-to-local model with re-entrant connections between the OFA and other face processing areas.