Muscle-specific movement-phase-dependent modulation of corticospinal excitability during upper-limb motor execution and motor imagery combined with virtual action observation.

Corticospinal excitability in humans can be facilitated during imagination and/or observation of upper-limb motor tasks. However, it remains unclear to what extent facilitation levels may differ from those elicited during execution of the same tasks. Twelve able-bodied individuals were recruited in this study. Motor evoked potentials (MEPs) in extensor carpi radialis (ECR) and flexor carpi radialis (FCR) muscles were elicited through transcranial magnetic stimulation of the primary motor cortex during: (i) rest; (ii) wrist extension; and (iii) wrist flexion. Responses were compared between: (1) motor imagery combined with virtual action observation (MI + AO; first-person virtual wrist movements shown on a computer display, while participants remained at rest and imagined these movements); and (2) motor execution (ME; participants extended or flexed their wrist). During MI + AO, ECR MEPs were facilitated during the extension phase but not the flexion phase, while FCR MEPs were facilitated during the flexion phase but not extension phase, compared to rest. During the ME condition, same, but greater, modulations were shown as those during MI + AO, while background muscle activities were similar in the rest phase as during extension and flexion phase in the MI + AO condition. Our results demonstrated that kinesthetic MI that included imagination and observation of virtual hands can elicit phase-dependent muscles-specific corticospinal facilitation of wrist muscles, consistent to those during actual hand extension and flexion. Moreover, we showed that MI + AO can contribute considerably to the overall corticospinal facilitation (∼20 % of ME) even without muscle contractions. These findings support utility of computer graphics-based motor imagery, which may have implications for rehabilitation and development of brain-computer interfaces.

Design and synthesis of ß-strand-fixed peptides inhibiting aggregation of amyloid ß-protein.

Aggregation of 42-residue amyloid ß-protein (Aß42) can be prevented by ß-sheet breaker peptides (BSBps) homologous to LVFFA residues, which are included in a ß-sheet region of Aß42 aggregates. To enhance the affinity of BSBps to the Aß42 aggregates, we designed and synthesized ß-strand-fixed peptides (BSFps) whose side chains were cross-linked by ring closing metathesis. Conformation analysis verified that the designed peptides could be fixed in ß-strand conformation. Among the synthesized pentapeptides, 1 and 12, whose side chains of 2nd and 4th residues were cross-linked, significantly inhibited the aggregation of Aß42. This suggested that ß-strand-fixation of BSBps could enhance their inhibitory activity against the Aß42 aggregation. However, pentapeptides 1 and 12 had little effect on morphology of Aß42 aggregates (fibrils) and neurotoxicity of Aß42 against SH-SY5Y cells.

Validity of Psammoperca datnioides Richardson 1848 and redescriptions of P. waigiensis Cuvier in Cuvier Valenciennes 1828 and Hypopterus macropterus (Günther 1859) in the family Latidae (Perciformes) from the Indo-West Pacific.

Psammoperca datnioides Richardson 1848, long considered a synonym of P. waigiensis (Cuvier in Cuvier Valenciennes 1828), is redescribed as a valid species of Psammoperca Richardson 1848. The species is likely to be endemic to Australia, where it was formerly considered to be P. waigiensis, but differs from P. waigiensis in having the following characters: more slender body (mean depth 28.9% of SL vs. mean depth 36.7% of SL in P.  waigiensis), pored lateral-line scales 49-54 (vs. 46-48 in P. waigiensis), scale rows above and below lateral line 6½ / 10½-11½ (vs 4½ / 9½-10½ in P. waigiensis), and vertical at hind margin of maxilla posterior/behind center of eye (vs. vertical at hind margin of maxilla anterior to/in front of hind margin of eye in P. waigiensis). Live specimens of Psammoperca datnioides have a uniformly dense black or brownish body, with this dark colour on body scales and pored lateral-line scales persisting even in preserved specimens. Live specimens of Psammoperca waigiensis have a brownish body, often golden in colour, and pored lateral-line scales that are yellow-edged. The COI sequence (cytochrome c oxidase subunit I, 612 bp) of P. datnioides also is distinct from P. waigiensis, and the related and poorly known Hypopterus macropterus (Günther 1859). The latter species is redescribed and diagnosed with eight indistinct dark bands on the head and body, and dorsal-fin rays VII-I, 14-15 (vs. no dark bands and dorsal-fin rays VII-I, 12-13 in Psammoperca). Nominal species in the genus Psammoperca are discussed and Cnidon chinensis Müller Troschel 1849 (type locality: Manila, Philippines) is included as a junior synonym of P. waigiensis. Psammoperca vaigiensis Boulenger 1895 is an unneeded emendation and thus an invalid name. Psammoperca macroptera Günther 1859 is retained in the monotypic genus Hypopterus Gill 1861 in the family Latidae, although the species has been overlooked in most studies on the Latidae and/or Centropomidae. A key to the Latidae is provided.

Amamiichthys, a new genus for the sparid fish Cheimerius matsubarai Akazaki 1962, and redescription of the species, with designation of a neotype.

A new genus, Amamiichthys, is proposed for the sparid fish Cheimerius matsubarai Akazaki 1962. This genus differs from all other genera in the family Sparidae by the following combination of characters: both jaws with an outer row of small molariform teeth and an inner row of similar, even smaller teeth; frontal bone flat, coarse and porous; strongly bifurcate protuberance of upper ethmoid just beneath mid-region of anteriormost portion of frontal bone; head and body pinkish, gradually becoming silvery toward abdomen, with many small blue spots, some pairs overlapping. The type species, Amamiichthys matsubarai, is redescribed and a neotype designated.