The ability to learn new skills and perfect them with practice applies not only to physical skills but also to abstract skills, like motor planning or neuroprosthetic actions. Although plasticity in ...corticostriatal circuits has been implicated in learning physical skills, it remains unclear if similar circuits or processes are required for abstract skill learning. Here we use a novel behavioural task in rodents to investigate the role of corticostriatal plasticity in abstract skill learning. Rodents learned to control the pitch of an auditory cursor to reach one of two targets by modulating activity in primary motor cortex irrespective of physical movement. Degradation of the relation between action and outcome, as well as sensory-specific devaluation and omission tests, demonstrate that these learned neuroprosthetic actions are intentional and goal-directed, rather than habitual. Striatal neurons change their activity with learning, with more neurons modulating their activity in relation to target-reaching as learning progresses. Concomitantly, strong relations between the activity of neurons in motor cortex and the striatum emerge. Specific deletion of striatal NMDA receptors impairs the development of this corticostriatal plasticity, and disrupts the ability to learn neuroprosthetic skills. These results suggest that corticostriatal plasticity is necessary for abstract skill learning, and that neuroprosthetic movements capitalize on the neural circuitry involved in natural motor learning.
A low-noise feedback amplifier (LNA) with interstage noise matching is implemented in 22-nm fully depleted silicon-on-insulator (SOI)-CMOS technology. Minimum noise figure (NF) is 1.7 dB centered at ...28 GHz, and NF remains below 1.98±0.25 dB across a 10-GHz range. Peak gain of the two-stage LNA is 21.5 dB at 22 GHz, and the bandwidth (BW) for |S 21 | is 19-36 GHz. Input and output return losses are better than 10 dB across an effective LNA BW of 22-32 GHz. The third-order input intercept is -13.4 dBm at peak gain when dissipating 17.3 mW. Continuous dc power control on the fly is implemented using modulation of FET backgates. When dc power consumption is reduced 5.6 mW, NF increases by less than 0.5 dB, peak gain decreases by 3.6 dB, and input return loss remains better than 10 dB with no change in effective BW.
A mm-wave digital transmitter based on a 60 GHz all-digital phase-locked loop (ADPLL) with wideband frequency modulation (FM) for FMCW radar applications is proposed. The fractional-N ADPLL employs a ...high-resolution 60 GHz digitally-controlled oscillator (DCO) and is capable of multi-rate two-point FM. It achieves a measured rms jitter of 590.2 fs, while the loop settles within 3 μs. The measured reference spur is only -74 dBc, the fractional spurs are below -62 dBc, with no other significant spurs. A closed-loop DCO gain linearization scheme realizes a GHz-level triangular chirp across multiple DCO tuning banks with a measured frequency error (i.e., nonlinearity) in the FMCW ramp of only 117 kHz rms for a 62 GHz carrier with 1.22 GHz bandwidth. The synthesizer is transformer-coupled to a 3-stage neutralized power amplifier (PA) that delivers +5 dBm to a 50 Ω load. Implemented in 65 nm CMOS, the transmitter prototype (including PA) consumes 89 mW from a 1.2 V supply.
"For more than a century, the vast lands of Northern Ontario have been shared among the governments of Canada, Ontario, and the First Nations who signed Treaty No. 9 in 1905. For just as long, ...details about the signing of the constitutionally recognized agreement have been known only through the accounts of two of the commissioners appointed by the Government of Canada. Treaty No. 9 provides a truer perspective on the treaty by adding the neglected account of a third commissioner and tracing the treaty's origins, negotiation, explanation, interpretation, signing, implementation, and recent commemoration."
"Restoring nearly forgotten perspectives to the historical record, John Long considers the methods used by the government of Canada to explain Treaty No. 9 to Northern Ontario First Nations. He shows that many crucial details about the treaty's contents were omitted in the transmission of writing to speech, while other promises were made orally but not included in the written treaty. Reproducing the three treaty commissioners' personal journals in their entirety, Long reveals the contradictions that suggest the treaty parchment was never fully explained to the First Nations who signed it."--pub. website.
Placoderms Long, John A; Trinajstic, Kate
Current biology,
01/2024, Letnik:
34, Številka:
2
Journal Article
Recenzirano
Odprti dostop
For over 70 million years, during the Paleozoic, the placoderms (Greek for 'plated skin'), an extinct group of armoured fishes, were the most abundant and diverse vertebrates on our planet. Some of ...the first placoderm fossils discovered - such as Bothriolepis with its bone-covered pectoral fins - seemed so bizarre that they were thought to represent turtles or ancient beetles. All placoderms bear thick overlapping dermal plates around the head (called the 'head shield') and an area of the body covered in similar overlapping plates enveloping the pectoral to anal region (called the 'trunk-shield'). Placoderm fossils (Figure 1) are known from every continent on Earth ranging from the early Silurian (∼438 million years ago) to the end Devonian (∼359 million years ago) when they became extinct.
Accurate pathogenicity prediction of missense variants is critically important in genetic studies and clinical diagnosis. Previously published prediction methods have facilitated the interpretation ...of missense variants but have limited performance. Here, we describe MVP (Missense Variant Pathogenicity prediction), a new prediction method that uses deep residual network to leverage large training data sets and many correlated predictors. We train the model separately in genes that are intolerant of loss of function variants and the ones that are tolerant in order to take account of potentially different genetic effect size and mode of action. We compile cancer mutation hotspots and de novo variants from developmental disorders for benchmarking. Overall, MVP achieves better performance in prioritizing pathogenic missense variants than previous methods, especially in genes tolerant of loss of function variants. Finally, using MVP, we estimate that de novo coding variants contribute to 7.8% of isolated congenital heart disease, nearly doubling previous estimates.
A series of recent studies recovered consistent phylogenetic scenarios of jawed vertebrates, such as the paraphyly of placoderms with respect to crown gnathostomes, and antiarchs as the sister group ...of all other jawed vertebrates. However, some of the phylogenetic relationships within the group have remained controversial, such as the positions of Entelognathus, ptyctodontids, and the Guiyu-lineage that comprises Guiyu, Psarolepis and Achoania. The revision of the dataset in a recent study reveals a modified phylogenetic hypothesis, which shows that some of these phylogenetic conflicts were sourced from a few inadvertent miscodings. The interrelationships of early gnathostomes are addressed based on a combined new dataset with 103 taxa and 335 characters, which is the most comprehensive morphological dataset constructed to date. This dataset is investigated in a phylogenetic context using maximum parsimony (MP), Bayesian inference (BI) and maximum likelihood (ML) approaches in an attempt to explore the consensus and incongruence between the hypotheses of early gnathostome interrelationships recovered from different methods. Our findings consistently corroborate the paraphyly of placoderms, all 'acanthodians' as a paraphyletic stem group of chondrichthyans, Entelognathus as a stem gnathostome, and the Guiyu-lineage as stem sarcopterygians. The incongruence using different methods is less significant than the consensus, and mainly relates to the positions of the placoderm Wuttagoonaspis, the stem chondrichthyan Ramirosuarezia, and the stem osteichthyan Lophosteus-the taxa that are either poorly known or highly specialized in character complement. Given that the different performances of each phylogenetic approach, our study provides an empirical case that the multiple phylogenetic analyses of morphological data are mutually complementary rather than redundant.
This article describes a single-pole, single-throw (SPST) CMOS switch aimed at integrated transceiver applications. The SPST switch realizes better than 50-dB isolation (ISO) across dc-to-43 GHz ...while maintaining an insertion loss (IL) below 3 dB. To maximize ISO, substrate coupling is compensated using bilateral RF signal cancellation in a fully differential circuit topology. Measured RF input power for 1-dB compression (IP 1dB ) of the IL is +19.6 dBm, and the measured input third-order intercept point is +30.4 dBm (both assuming differential inputs at 20 GHz). The prototype is fabricated in GlobalFoundries 45-nm RF-SOI CMOS technology and has an active area of 0.0058 mm 2 . Monte Carlo simulations predict variations due to processing of 8.3% and 2.75% in IL and ISO, respectively, ±0.2 dB variation (for both IL and ISO) from a 5% change in supply voltage, and ±0.1-dB variation (both IL and ISO) for a 0 °C-85 °C temperature sweep.
The neurocranium of sarcopterygian fishes was originally divided into an anterior (ethmosphenoid) and posterior (otoccipital) portion by an intracranial joint, and underwent major changes in its ...overall geometry before fusing into a single unit in lungfishes and early tetrapods
. Although the pattern of these changes is well-documented, the developmental mechanisms that underpin variation in the form of the neurocranium and its associated soft tissues during the evolution of sarcopterygian fishes remain poorly understood. The coelacanth Latimeria is the only known living vertebrate that retains an intracranial joint
. Despite its importance for understanding neurocranial evolution, the development of the neurocranium of this ovoviviparous fish remains unknown. Here we investigate the ontogeny of the neurocranium and brain in Latimeria chalumnae using conventional and synchrotron X-ray micro-computed tomography as well as magnetic resonance imaging, performed on an extensive growth series for this species. We describe the neurocranium at the earliest developmental stage known for Latimeria, as well as the major changes that the neurocranium undergoes during ontogeny. Changes in the neurocranium are associated with an extreme reduction in the relative size of the brain along with an enlargement of the notochord. The development of the notochord appears to have a major effect on the surrounding cranial components, and might underpin the formation of the intracranial joint. Our results shed light on the interplay between the neurocranium and its adjacent soft tissues during development in Latimeria, and provide insights into the developmental mechanisms that are likely to have underpinned the evolution of neurocranial diversity in sarcopterygian fishes.
A 60-GHz band, three-stage pseudo-differential power amplifier (PA) is implemented with input and output baluns on-chip. Each stage consists of a neutralized common-source amplifier pair. ...Neutralization mitigates the intrinsic gate-drain feedback of each transistor for increased power gain and reverse isolation. Shielded transformers couple the gain stages and allow low supply voltage operation. Fabricated in a 65-nm bulk CMOS process, the measured small-signal gain of the 0.13 × 0.41 mm 2 PA is 16 dB at 60 GHz with 3-dB bandwidth more than 8.5 GHz, while consuming 50 mW from a 1-V supply. Reverse isolation is better than 42 dB from 55 to 65 GHz. Maximum saturated output power is 11.5 dBm with a peak PAE of 15.2% measured at 62 GHz; from 58 to 65 GHz, the measured PAE is above 10%.
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