Internal Seminar: Wickens Unit and Maruyama Unit

Join us for August's first Internal Seminar Series on August 7, from 17:00 to 18:00 in C210. This month's first seminar features the Neurobiology Research Unit (Jeff Wickens) and the Information Processing Biology Unit (Ichiro Maruyama).

Neurobiology Research Unit (Jeff Wickens)

Speaker : Takashi Nakano

Title : A new way to manipulate the brain

Abstract : The external control over rapid and precise drug delivery and chemical release in the brain would provide a powerful interface for interaction with neural behavior. We have developed a novel drug delivery method using femtosecond laser stimulated liposomes. Briefly, liposomes – lipid capsules packed with the relevant drug, were tethered to gold nanoparticles. They were then stimulated by near-infrared femtosecond laser pulses, which induced the release of drug from the liposomes. We demonstrated the ability to control the temporal profile of drug release with unprecedented temporal resolution. The temporal-profile and the quantity of the released drug can be both independently controlled via the laser power and the stimulation time. Moreover, it is possible to release drug from liposomes repeatedly without destroying them.
We then applied the liposomal drug application to acute brain slice in order to demonstrate the ability of liposome to control neural activities. Liposomes were injected into the brain and exposed to femtosecond laser using a standard 2-photon microscopy setup. Excitatory neural responses were observed when AMPA receptor agonist containing liposomes were stimulated with femtosecond laser pulses. Neural responses were controlled by changing laser stimulation characteristics. Furthermore, we demonstrated epileptic seizure was blocked by stimulating GABA receptor agonist containing liposome.
In conclusion, our drug delivery technique using femtosecond laser stimulated liposomes has the ability to control and directly interface with brain functioning. Our technique is applicable to a wide range of drugs. These would enable investigations of neural mechanisms that have previously been unattainable, and suggests new possibilities to treat neurological disorders.

Information Processing Biology Unit (Ichiro Maruyama)

Speaker : Satomi Ito

Title : Associative learning and memory in Caenorhabditis elegans

Abstract : Sensory neurons perceive information from the environment, which affects animal’s behavior. C. elegans is an excellent model organism for the study of neuronal circuits that regulate the behavior, because of its relatively simple nervous system. The animal can also learn and store memory of non-associative memory like habituation and associative memory of two environmental stimuli. We are interested in molecular mechanisms and cellular networks underlying the associative memory, and have developed protocols for induction of short-term and long-term olfactory appetitive memories, STM and LTM, respectively, in C. elegans. We used 1-nonanol, a weak, volatile aversive chemical to C. elegans, as a conditioned stimulus (CS) and potassium chloride (KCl), a strong attractive substance, as an unconditioned stimulus (US). We conditioned animals with massed and spaced trainings to induce STM and LTM, respectively. Young adult animals in a small plastic tube sealed the bottom with a 30 um-nylon mesh sheet were stimulated with 1-nonanol vapor in a beaker, and then with KCl solution. For the massed training, animals were repeatedly conditioned as described above eight times without an inter-trial interval (ITI) between the conditionings. For the spaced training, on the other hand, animals were conditioned in the similar way to the massed training with ITI, during which animals were rested on an NGM plate. Immediately or hours later after the conditioning, animals were analyzed by chemotaxis assay on an agar plate spotted with 1-nonanol. As results, the trained animals successfully learned and retained the memory by the massed training and the spaced training. We have also examined whether the training induces CS-specific memory by using 2-nonanone as a CS, instead of 1-nonanol. After training with 2-nonanone and KCl, animals formed 2-nonanone-specific, but not 1-nonanol-specific, associative memory. These results demonstrate that the protocols can successfully induce associative STM and LTM in C. elegans. We are currently trying to elucidate neuronal circuits responsible for the learning and memory.