58 research outputs found

    Contribution of Cerebellar Sensorimotor Adaptation to Hippocampal Spatial Memory

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    Complementing its primary role in motor control, cerebellar learning has also a bottom-up influence on cognitive functions, where high-level representations build up from elementary sensorimotor memories. In this paper we examine the cerebellar contribution to both procedural and declarative components of spatial cognition. To do so, we model a functional interplay between the cerebellum and the hippocampal formation during goal-oriented navigation. We reinterpret and complete existing genetic behavioural observations by means of quantitative accounts that cross-link synaptic plasticity mechanisms, single cell and population coding properties, and behavioural responses. In contrast to earlier hypotheses positing only a purely procedural impact of cerebellar adaptation deficits, our results suggest a cerebellar involvement in high-level aspects of behaviour. In particular, we propose that cerebellar learning mechanisms may influence hippocampal place fields, by contributing to the path integration process. Our simulations predict differences in place-cell discharge properties between normal mice and L7-PKCI mutant mice lacking long-term depression at cerebellar parallel fibre-Purkinje cell synapses. On the behavioural level, these results suggest that, by influencing the accuracy of hippocampal spatial codes, cerebellar deficits may impact the exploration-exploitation balance during spatial navigation

    Evaluation of agricultural ecological environment in determining the capable areas: A case study of city of Esfahan, Iran

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    The nature of different activities in production, agriculture as well as distribution and consumption section, called as expansionist activities, largely influence the ability of the land. Production of consumable material, which is required for increasing population in various areas, and their attractions make it possible to earn more profit and it causes a significant pressure on soil and water resources and can threaten environmental pollution and human food security. A self-interested attitude on land resources has led to run short-term programs without considering the ecological capability of the land. These mentioned problems are, significantly intensified particularly in arid and semi-arid areas with severe limitations of water and soil quality and quantity. Therefore, land allocation based on ecological capability and self-purification indexes, used for land use planning, is an appropriate response to meet the deficiencies noted. This paper studies the agricultural capable lands based on land capability. The proposed study uses GIS software capabilities with application of the environmental ability evaluation model, as a holistic approach, to make sustainable development research in the region. The results indicate that suitable lands for agriculture in the whole area in different classes are widespread and with regards to dependency of more than 90 percent of people to agricultural activities, serious attention of authorities is required for providing the appropriate baseline and avoiding land use change to develop this activity

    Dynamics of Propofol-Induced Loss of Consciousness Across Primate Neocortex

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    The precise neural mechanisms underlying transitions between consciousness and anesthetic-induced unconsciousness remain unclear. Here, we studied intracortical neuronal dynamics leading to propofol-induced unconsciousness by recording single-neuron activity and local field potentials directly in the functionally interconnecting somatosensory (S1) and frontal ventral premotor (PMv) network during a gradual behavioral transition from full alertness to loss of consciousness (LOC) and on through a deeper anesthetic level. Macaque monkeys were trained for a behavioral task designed to determine the trial-by-trial alertness and neuronal response to tactile and auditory stimulation. We show that disruption of coherent beta oscillations between S1 and PMv preceded, but did not coincide with, the LOC. LOC appeared to correspond to pronounced but brief gamma-/high-beta-band oscillations (lasting ∼3 min) in PMv, followed by a gamma peak in S1. We also demonstrate that the slow oscillations appeared after LOC in S1 and then in PMv after a delay, together suggesting that neuronal dynamics are very different across S1 versus PMv during LOC. Finally, neurons in both S1 and PMv transition from responding to bimodal (tactile and auditory) stimulation before LOC to only tactile modality during unconsciousness, consistent with an inhibition of multisensory integration in this network. Our results show that propofol-induced LOC is accompanied by spatiotemporally distinct oscillatory neuronal dynamics across the somatosensory and premotor network and suggest that a transitional state from wakefulness to unconsciousness is not a continuous process, but rather a series of discrete neural changes.Foundation for Anesthesia Education and Research (Grant 5T32GM007592)Harvard Medical School. Eleanor and Miles Shore 50th Anniversary Fellowship Program for Scholars in Medicin
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