2 research outputs found
General anesthesia reduces complexity and temporal asymmetry of the informational structures derived from neural recordings in Drosophila
We apply techniques from the field of computational mechanics to evaluate the
statistical complexity of neural recording data from fruit flies. First, we
connect statistical complexity to the flies' level of conscious arousal, which
is manipulated by general anesthesia (isoflurane). We show that the complexity
of even single channel time series data decreases under anesthesia. The
observed difference in complexity between the two states of conscious arousal
increases as higher orders of temporal correlations are taken into account. We
then go on to show that, in addition to reducing complexity, anesthesia also
modulates the informational structure between the forward- and reverse-time
neural signals. Specifically, using three distinct notions of temporal
asymmetry we show that anesthesia reduces temporal asymmetry on
information-theoretic and information-geometric grounds. In contrast to prior
work, our results show that: (1) Complexity differences can emerge at very
short timescales and across broad regions of the fly brain, thus heralding the
macroscopic state of anesthesia in a previously unforeseen manner, and (2) that
general anesthesia also modulates the temporal asymmetry of neural signals.
Together, our results demonstrate that anesthetized brains become both less
structured and more reversible.Comment: 14 pages, 6 figures. Comments welcome; Added time-reversal analysis,
updated discussion, new figures (Fig. 5 & Fig. 6) and Tables (Tab. 1
Enhancing quantum transport in a photonic network using controllable decoherence
Transport phenomena on a quantum scale appear in a variety of systems,
ranging from photosynthetic complexes to engineered quantum devices. It has
been predicted that the efficiency of quantum transport can be enhanced through
dynamic interaction between the system and a noisy environment. We report the
first experimental demonstration of such environment-assisted quantum
transport, using an engineered network of laser-written waveguides, with
relative energies and inter-waveguide couplings tailored to yield the desired
Hamiltonian. Controllable decoherence is simulated via broadening the bandwidth
of the input illumination, yielding a significant increase in transport
efficiency relative to the narrowband case. We show integrated optics to be
suitable for simulating specific target Hamiltonians as well as open quantum
systems with controllable loss and decoherence.Comment: 6 pages, 3 figure