21 research outputs found
Motor control by precisely timed spike patterns
A fundamental problem in neuroscience is to understand how sequences of
action potentials ("spikes") encode information about sensory signals and motor
outputs. Although traditional theories of neural coding assume that information
is conveyed by the total number of spikes fired (spike rate), recent studies of
sensory and motor activity have shown that far more information is carried by
the millisecond-scale timing patterns of action potentials (spike timing).
However, it is unknown whether or how subtle differences in spike timing drive
differences in perception or behavior, leaving it unclear whether the
information carried by spike timing actually plays a causal role in brain
function. Here we demonstrate how a precise spike timing code is read out
downstream by the muscles to control behavior. We provide both correlative and
causal evidence to show that the nervous system uses millisecond-scale
variations in the timing of spikes within multi-spike patterns to regulate a
relatively simple behavior - respiration in the Bengalese finch, a songbird.
These findings suggest that a fundamental assumption of current theories of
motor coding requires revision, and that significant improvements in
applications, such as neural prosthetic devices, can be achieved by using
precise spike timing information.Comment: 48 pages, 16 figure
Cross-species parallels in babbling: animals and algorithms
A key feature of vocal ontogeny in a variety of taxa with extensive vocal repertoires is a developmental pattern in which vocal exploration is followed by a period of category formation that results in a mature species-specific repertoire. Vocal development preceding the adult repertoire is often called ‘babbling’, a term used to describe aspects of vocal development in species of vocal-learning birds, some marine mammals, some New World monkeys, some bats and humans. The paper summarizes the results of research on babbling in examples from five taxa and proposes a unifying definition facilitating their comparison. There are notable similarities across these species in the developmental pattern of vocalizations, suggesting that vocal production learning might require babbling. However, the current state of the literature is insufficient to confirm this suggestion. We suggest directions for future research to elucidate this issue, emphasizing the importance of (i) expanding the descriptive data and seeking species with complex mature repertoires where babbling may not occur or may occur only to a minimal extent; (ii) (quasi-)experimental research to tease apart possible mechanisms of acquisition and/or self-organizing development; and (iii) computational modelling as a methodology to test hypotheses about the origins and functions of babbling
Own Song Selectivity in the Songbird Auditory Pathway: Suppression by Norepinephrine
Like human speech, birdsong is a learned behavior that supports species and individual recognition. Norepinephrine is a catecholamine suspected to play a role in song learning. The goal of this study was to investigate the role of norepinephrine in bird's own song selectivity, a property thought to be important for auditory feedback processes required for song learning and maintenance.Using functional magnetic resonance imaging, we show that injection of DSP-4, a specific noradrenergic toxin, unmasks own song selectivity in the dorsal part of NCM, a secondary auditory region.The level of norepinephrine throughout the telencephalon is known to be high in alert birds and low in sleeping birds. Our results suggest that norepinephrine activity can be further decreased, giving rise to a strong own song selective signal in dorsal NCM. This latent own song selective signal, which is only revealed under conditions of very low noradrenergic activity, might play a role in the auditory feedback and/or the integration of this feedback with the motor circuitry for vocal learning and maintenance
SQL B068
SQL data file of developmental song features of individual B068. Feature extraction was conducted with Sound Analysis Pro 2011
SQL B002
SQL data file of developmental song features of individual B002. Feature extraction was conducted with Sound Analysis Pro 2011
SQL B047
SQL data file of developmental song features of individual B047. Feature extraction was conducted with Sound Analysis Pro 2011
SQL B022
SQL data file of developmental song features of individual B022. Feature extraction was conducted with Sound Analysis Pro 2011
SQL B010
SQL data file of developmental song features of individual B010. Feature extraction was conducted with Sound Analysis Pro 2011