Astrocytes respond to neuronal activity and were shown to be necessary for plasticity and memory. To test whether astrocytic activity is also sufficient to generate synaptic potentiation and enhance memory, we expressed the Gq-coupled receptor hM3Dq in CA1 astrocytes, allowing their activation by a designer drug. We discovered that astrocytic activation is not only necessary for synaptic plasticity, but also sufficient to induce NMDA-dependent de novo long-term potentiation in the hippocampus that persisted after astrocytic activation ceased. In vivo, astrocytic activation enhanced memory allocation; i.e., it increased neuronal activity in a task-specific way only when coupled with learning, but not in home-caged mice. Furthermore, astrocytic activation using either a chemogenetic or an optogenetic tool during acquisition resulted in memory recall enhancement on the following day. Conversely, directly increasing neuronal activity resulted in dramatic memory impairment. Our findings that astrocytes induce plasticity and enhance memory may have important clinical implications for cognitive augmentation treatments.

Astrocytic calcium dynamics have been implicated in the encoding of sensory information, and modulating them has been shown to impact behavior. However, real-time calcium activity of astrocytes in the hippocampus of awake mice has never been investigated. We used 2-photon microscopy to chronically image CA1 astrocytes as mice ran in familiar or novel virtual environments and obtained water rewards. We found that astrocytes exhibit persistent ramping activity towards the reward location in a familiar environment, but not in a novel one. Using linear decoders, we could precisely predict the location of the mouse in a familiar environment from astrocyte activity alone. We could not do the same in the novel environment, suggesting astrocyte spatial activity is experience dependent. This is the first indication that astrocytes can encode location in spatial contexts, thereby extending their known computational capabilities, and their role in cognitive functions.

A considerable number of fungal homologues of human apoptotic genes have been identified in recent years. Nevertheless, we are far from being able to connect the different pieces and construct a primary structure of the fungal apoptotic regulatory network. To get a better picture of the available fungal components, we generated an automatic search protocol that is based on protein sequences together with a domain-centred approach. We used this protocol to search all the available fungal databases for domains and homologues of human apoptotic proteins. Among all known apoptotic domains, only the BIR [baculovirus IAP (inhibitor of apoptosis protein) repeat] domain was found in fungi. A single protein with one or two BIR domains is present in most (but not all) fungal species. We isolated the BIR-containing protein from the grey mould fungus Botrytis cinerea and determined its role in apoptosis and pathogenicity. We also isolated and analysed BcNMA, a homologue of the yeast NMA11 gene. Partial knockout or overexpression strains of BcBIR1 confirmed that BcBir1 is anti-apoptotic and this activity was assigned to the N′-terminal part of the protein. Plant infection assays showed that the fungus undergoes massive PCD (programmed cell death) during early stages of infection. Further studies showed that fungal virulence was fully correlated with the ability of the fungus to cope with plant-induced PCD. Together, our result show that BcBir1 is a major regulator of PCD in B. cinerea and that proper regulation of the host-induced PCD is essential for pathogenesis in this and other similar fungal pathogens.

Phonological deficits in dyslexia are well documented. However, there is an ongoing discussion about whether visual deficits limit the reading skills of people with dyslexia. Here, we investigated visual crowding and backward masking. We presented a Vernier (i.e., two vertical bars slightly offset to the left or right) and asked observers to indicate the offset direction. Vernier stimuli are visually similar to letters and are strongly affected by crowding, even in the fovea. To increase task difficulty, Verniers are often followed by a mask (i.e., backward masking). We measured Vernier offset discrimination thresholds for the basic Vernier task, under crowding, and under backward masking, in students with dyslexia (n = 19) and age and intelligence matched students (n = 27). We found no group differences in any of these conditions. Controls with fast visual processing (good backward masking performance), were faster readers. By contrast, no such correlation was found among the students with dyslexia, suggesting that backward masking does not limit their reading efficiency. These findings indicate that neither elevated crowding nor elevated backward masking pose a bottleneck to reading skills of people with dyslexia.

Observation of the T +1 component of the isovector monopole and the giant dipole resonances in the reactions 90 Zr and 120 Sn(/r~,7r°) at T^-=165 MeV is reported. The isobaric analog state and T -1 component of the giant dipole resonance in the reaction 120 Sn(/r + , 7T°) were also observed. Excitation energies and widths of the monopole are given.PACS numbers: 24.30.Cz, 24.30.Eb, 25.80.Fm Macroscopic 1 as well as microscopic 2 theories of nuclear structure hypothesize the existence of a collective isovector monopole (IVM) excitation of the nucleus. The possibility of experimentally observing the IVM was discussed as early as 1958 by Danos, 3 who estimated the electroexcitation cross section. Isoscalar collective excitations with angular momentum / = 0, 2, and 3 have been observed and studied in hadron and electron scattering while the isovector dipole or giant dipole resonance (GDR) is a prominent feature of the scattering of electrons and photons from nuclei. Evidence has been given for the observation of the isovector quadrupole resonance. 4 However, at present there is no clear experimental evidence for the IVM. 5 Recently, arguments have been given that the (7r~, 77°) reaction at energies near the (3, 3) resonance might detect the IVM. 6 These arguments are supported by the previously reported observation 7 of the GDR in the (77*, TT°) reactions on 40 Ca. Pion charge-exchange excitation of the IVM is expected to have the following qualitative properties: (1) a zero-degree cross section of a few hundred microbarns per steradian; (2) a forward-peaked angular distribution; and (3) an excitation energy of approximately 170/A l/s MeV in the parent nucleus.Here we report the observation of the IVM in the (ir~9 TT°) reaction at pion kinetic energy 165 MeV on 90 Zr and 120 Sn. Results for 120 Sn(77 + , TT°) are also discussed. The experiments were carried out at the low-energy pion channel at the Clinton P. Anderson Meson Physics Facitity (LAMPF). The LAMPF TT° spectrometer 8 was used to measure the direction and energy of the outgoing 77°. Data were taken at spectrometer angles of 0° and 20° and sorted into several narrower ranges of scattering angle. The spectrometer acceptance and line shape were measured with the reaction n~p -n°n at 165 MeV. The ratio of calculated to measured acceptance was found to be independent of scattering angle to within the 4% statistical errors of the measurement. Figure 1 shows the double-differential cross sections for the reactions 120 Sn(7T + ,7r°) and 120 Sn(7r",7r°) as functions of ir° energy for scattering angles of 4.5°, 6.8% and 11,0°. The isobaric analog state (IAS) is clearly visible in the (fl" + , 77°) data at a 77° energy of 157 MeV. The cross section for excitation of this Z = 0 state is seen to decrease as the scattering angle increases. The IVM is seen in the (77", 77 0 ) data at a 77 0 energy of 150 MeV. The angular dependence is similar to that of the IAS as expected.To perform a quantitative analysis we make the assumption that the double-differential cross secti...