We have proposed previously a kinetochore motor-polar ejection model for chromosome congression to the metaphase plate where forces generated at the kinetochore are antagonized by away-from-the pole forces generated within each half-spindle on the chromosome arms. This model was based in large part on observations of the behavior of chromosomes on monopolar spindles. In these cells chromosomes ...

BACKGROUND Meiotic spindles in living human oocytes can be visualized by the Polscope. This study investigated the relationship between the presence/location of the spindle in metaphase II (MII) oocytes and developmental competence of embryos in vitro. METHODS The spindles in 626 MII oocytes were examined by the Polscope and divided into six groups (A-F) based on the presence or absence of th...

A spindle detection method was developed that: (1) extracts the signal of interest (i.e., spindle-related phasic changes in sigma) relative to ongoing "background" sigma activity using complex demodulation, (2) accounts for variations of spindle characteristics across the night, scalp derivations and between individuals, and (3) employs a minimum number of sometimes arbitrary, user-defined para...

OBJECTIVE To examine the effects of different thermodynamic control systems on the temperature stability of human eggs during in vitro manipulation, with the integrity of meiotic spindles imaged using the LC-PolScope (Cambridge Research & Instrumentation, Inc., Woburn, MA). DESIGN We performed intracytoplasmic sperm injection (ICSI) and/or imaging of eggs with the temperature regulated by thr...

We used fluorescent speckle microscopy to probe the dynamics of the mitotic kinesin Eg5 in Xenopus extract spindles, and compared them to microtubule dynamics. We found significant populations of Eg5 that were static over several seconds while microtubules flux towards spindle poles. Eg5 dynamics are frozen by adenylimidodiphosphate. Bulk turnover experiments showed that Eg5 can exchange betwee...

Sleep spindles are bursts of 11-15 Hz that occur during non-rapid eye movement sleep. Spindles are highly synchronous across the scalp in the electroencephalogram (EEG) but have low spatial coherence and exhibit low correlation with the EEG when simultaneously measured in the magnetoencephalogram (MEG). We developed a computational model to explore the hypothesis that the spatial coherence spin...

Sleep spindles have been connected to memory processes in various ways. In addition, spindles appear to be modulated at the local cortical network level. We investigated whether cueing specific memories during sleep leads to localized spindle modulations in humans. During learning of word-location associations, words presented in the left and right visual hemifields were paired with different o...

Mitotic spindles are microtubule-based structures, but increasing evidence indicates that filamentous actin (F-actin) and F-actin-based motors are components of these structures. ADD1 (adducin-1) is an actin-binding protein that has been shown to play important roles in the stabilization of the membrane cortical cytoskeleton and cell-cell adhesions. In this study, we show that ADD1 associates w...