Neural subspaces of imagined movements in parietal cortex remain stable over several years in humans

A crucial goal in brain-machine interfacing is long-term stability of neural decoding performance, ideally without regular retraining. Here we demonstrate stable neural decoding over several years in two human participants, achieved by latent subspace alignment of multi-unit intracortical recordings in posterior parietal cortex. These results can be practically applied to significantly expand the longevity and generalizability of future movement decoding devices.

Augmented manipulation ability in humans with six-fingered hands

Neurotechnology attempts to develop supernumerary limbs, but can the human brain deal with the complexity to control an extra limb and yield advantages from it? Here, we analyzed the neuromechanics and manipulation abilities of two polydactyly subjects who each possess six fingers on their hands. Anatomical MRI of the supernumerary finger (SF) revealed that it is actuated by extra muscles and nerves, and fMRI identified a distinct cortical representation of the SF. In both subjects, the SF was able to move independently from the other fingers. Polydactyly subjects were able to coordinate the SF with their other fingers for more complex movements than five fingered subjects, and so carry out with only one hand tasks normally requiring two hands. These results demonstrate that a body with significantly more degrees-of-freedom can be controlled by the human nervous system without causing motor deficits or impairments and can instead provide superior manipulation abilities.

Concurrent control of a brain-computer interface and natural overt movements

OBJECTIVE

A primary control signal in brain-computer interfaces (BCIs) have been cortical signals related to movement. However, in cases where natural motor function remains, BCI control signals may interfere with other possibly simultaneous activity for useful ongoing movement. We sought to determine if the brain could learn to control both a BCI and concurrent overt movement execution in such cases.

APPROACH

We designed experiments where BCI and overt movements must be used concurrently and in coordination to achieve a 2D centre out control. Power in the 70-90 Hz band of human electrocorticography (ECoG) signals, was used to generate BCI control commands for vertical movement of the cursor. These signals were deliberately recorded from the same human cortical site that produced the strongest movement related activity associated with the concurrent overt finger movements required for the horizontal movement of the cursor.

MAIN RESULTS

We demonstrate that three subjects were able to perform the concurrent BCI task, controlling BCI and natural movements simultaneously and to a large extent independently. We conclude that the brain is capable of dissociating the original control signal dependency on movement, producing specific BCI control signals in the presence of motor related responses from the ongoing overt behaviour with which the BCI signal was initially correlated.

SIGNIFICANCE

We demonstrate a novel human brain-computer interface (BCI) which can be used to control movement concurrently and in coordination with movements of the natural limbs. This demonstrates the dissociation of cortical activity from the behaviour with which it was originally associated despite the ongoing behaviour and shows the feasibility of achieving simultaneous BCI control of devices with natural movements.

The major secreted product of the whipworm, Trichuris, is a pore-forming protein

The data presented here describe the first unequivocable characterization of a pore-forming protein in any helminth parasite. The excretory/secretory (E/S) material of the human whipworm T. trichiura contains a highly abundant protein of molecular mass 47 kDa (TT47); the murine model parasite, T. muris, contains a similarly abundant protein of molecular mass 43 kDa (TM43). When purified to homogeneity, these proteins induce ion-conducting pores in lipid bilayers. Antibodies raised against TM43 abolish channel activity. Pore formation in epithelial cell membranes may facilitate invasion of the host gut by Trichuris and enable the parasite to maintain its syncytial environment in the caecal epithelium. The observation that this activity may be inhibited by antibody opens a possible avenue for drug and vaccine development.

Protection against membrane-mediated cytotoxicity by calcium and zinc

Injection of S. aureus alpha toxin or ultraviolet-inactivated Sendai virus into the mammary gland of lactating mice leads to cytopathic changes in the alveolar cells compatible with a breakdown of their permeability barrier. Simultaneous administration of Ca2+ or Zn2+ prevents such changes, as it does when added to alveolar cells in vitro. It is concluded that increased levels of Zn2+ (and under certain conditions of Ca2+) may exert a protective role that is clinically significant.