Connectivity of neuronal populations within and between areas of primate somatosensory cortex

Functions of the cerebral cortex emerge via interactions of horizontally distributed neuronal populations within and across areas. However, the connectional underpinning of these interactions is not well understood. The present study explores the circuitry of column-size cortical domains within the hierarchically organized somatosensory cortical areas 3b and 1 using tract tracing and optical intrinsic signal imaging (OIS). The anatomical findings reveal that feedforward connections exhibit high topographic specificity, while intrinsic and feedback connections have a more widespread distribution. Both intrinsic and inter-areal connections are topographically oriented across the finger representations. Compared to area 3b, the low clustering of connections and small cortical magnification factor supports that the circuitry of area 1 scaffolds a sparse functional representation that integrates peripheral information from a large area that is fed back to area 3b. Fast information exchange between areas is ensured by thick axons forming a topographically organized, reciprocal pathway. Moreover, the highest density of projecting neurons and groups of axon arborization patches corresponds well with the size and locations of the functional population response reported by OIS. The findings establish connectional motifs at the mesoscopic level that underpin the functional organization of the cerebral cortex

Synaptic organization of cortico-cortical communication in primates

In cortical circuitry synaptic communication across areas is based on two types of axon terminals, small and large, with modulatory and driving roles, respectively. In contrast, it is not known whether similar synaptic specializations exist for intra‐areal projections. Using anterograde tracing and three‐dimensional reconstruction by electron microscopy (3D‐EM) we asked if large boutons form synapses in the circuit of somatosensory cortical areas 3b and 1. In contrast to observations in macaque visual cortex, light microscopy showed both small and large boutons not only in inter‐areal pathways, but also in long‐distance intrinsic connections. 3D‐EM showed that correlation of surface and volume provides a powerful tool for classifying cortical endings. Principal component analysis supported this observation and highlighted the significance of the size of mitochondria as a distinguishing feature of bouton type. The larger mitochondrion and higher degree of perforated postsynaptic density associated with large rather than to small boutons support the driver‐like function of large boutons. In contrast to bouton size and complexity, the size of the postsynaptic density appeared invariant across the bouton types. Comparative studies in human supported that size is a major distinguishing factor of bouton type in the cerebral cortex. In conclusion, the driver‐like function of the large endings could facilitate fast dissemination of tactile information within the intrinsic and inter‐areal circuitry of areas 3b and 1

Connectivity of neuronal populations within and between areas of primate somatosensory cortex

Functions of the cerebral cortex emerge via interactions of horizontally distributed neuronal populations within and across areas. However, the connectional underpinning of these interactions is not well understood. The present study explores the circuitry of column-size cortical domains within the hierarchically organized somatosensory cortical areas 3b and 1 using tract tracing and optical intrinsic signal imaging (OIS). The anatomical findings reveal that feedforward connections exhibit high topographic specificity, while intrinsic and feedback connections have a more widespread distribution. Both intrinsic and inter-areal connections are topographically oriented across the finger representations. Compared to area 3b, the low clustering of connections and small cortical magnification factor supports that the circuitry of area 1 scaffolds a sparse functional representation that integrates peripheral information from a large area that is fed back to area 3b. Fast information exchange between areas is ensured by thick axons forming a topographically organized, reciprocal pathway. Moreover, the highest density of projecting neurons and groups of axon arborization patches corresponds well with the size and locations of the functional population response reported by OIS. The findings establish connectional motifs at the mesoscopic level that underpin the functional organization of the cerebral cortex

Synaptic organization of cortico-cortical communication in primates

In cortical circuitry synaptic communication across areas is based on two types of axon terminals, small and large, with modulatory and driving roles, respectively. In contrast, it is not known whether similar synaptic specializations exist for intra‐areal projections. Using anterograde tracing and three‐dimensional reconstruction by electron microscopy (3D‐EM) we asked if large boutons form synapses in the circuit of somatosensory cortical areas 3b and 1. In contrast to observations in macaque visual cortex, light microscopy showed both small and large boutons not only in inter‐areal pathways, but also in long‐distance intrinsic connections. 3D‐EM showed that correlation of surface and volume provides a powerful tool for classifying cortical endings. Principal component analysis supported this observation and highlighted the significance of the size of mitochondria as a distinguishing feature of bouton type. The larger mitochondrion and higher degree of perforated postsynaptic density associated with large rather than to small boutons support the driver‐like function of large boutons. In contrast to bouton size and complexity, the size of the postsynaptic density appeared invariant across the bouton types. Comparative studies in human supported that size is a major distinguishing factor of bouton type in the cerebral cortex. In conclusion, the driver‐like function of the large endings could facilitate fast dissemination of tactile information within the intrinsic and inter‐areal circuitry of areas 3b and 1

Tipologie forestali dell'Alto Adige - tipi forestali, regioni forestali, chiave dei tipi forestali

La provincia di Bolzano è coperta per il 50% da boschi, con una superficie di circa 372.000 ettari. Al fine di favorire una gestione selvicolturale differenziata sulla base dei tipi forestali presenti in Alto Adige, il Servizio forestale provinciale ha avviato il progetto “Tipologie forestali dell’Alto Adige”. Iniziato nel 2001, esso è proceduto con l’elaborazione di criteri di gestione locale e con la caratterizzazione selvicolturale e la mappatura dei tipi forestali di tutta la Provincia di Bolzano. L’obiettivo di realizzare un manuale basato su criteri scientifici, ma contemporaneamente utilizzabile nella pratica, ha favorito un intenso confronto fra tutte le parti coinvolte nel progetto. In questo modo si sono riunite in un manuale di taglio pratico le conoscenze disponibili in bibliografia, le esperienze degli operatori locali e le nuove indicazioni scientifiche elaborate in progetto. In questo volume vengono presentate le schede relative a oltre 100 tipi forestali

Tipologie forestali dell'Alto Adige - categorie forestali, comprensori naturali, glossario

La provincia di Bolzano \ue8 coperta per il 50% da boschi, con una superficie di circa 372.000 ettari. Al fine di favorire una gestione selvicolturale differenziata sulla base dei tipi forestali presenti in Alto Adige, il Servizio forestale provinciale ha avviato il progetto \u201cTipologie forestali dell\u2019Alto Adige\u201d. Iniziato nel 2001, esso \ue8 proceduto con l\u2019elaborazione di criteri di gestione locale e con la caratterizzazione selvicolturale e la mappatura dei tipi forestali di tutta la Provincia di Bolzano. L\u2019obiettivo di realizzare un manuale basato su criteri scientifici, ma contemporaneamente utilizzabile nella pratica, ha favorito un intenso confronto fra tutte le parti coinvolte nel progetto. In questo modo si sono riunite in un manuale di taglio pratico le conoscenze disponibili in bibliografia, le esperienze degli operatori locali e le nuove indicazioni scientifiche elaborate in progetto. In questo volume vengono presentate le caratteristiche ecologiche ed i sistemi selvicolturali applicabili delle diverse categorie forestali presenti nel territorio provinciale, le caratteristiche ecologico-ambientali e storiche dei comprensori forestali ed un glossario dei termini tecnici utilizzati