Cutting edge Seminar

 

 

Speaker:　Yoshikazu Isomura  (Professor, Isomura Laboratory, Tamagawa University Brain Science Institute)

Title:  What happens in the brain during a reward-seeking behavior?

 

 

 

 

Date&Time:  24 May. (Wed.) 2017, 12:00- 13:00
Venue: Conference Room(1F), IMEG

 

Abstract:

What happens in the brain when an animal performs a reward-seeking behavior? To address this issue, we established a behavioral task in which head-fixed rats must manipulate (push, hold, and pull) a lever correctly with their forelimb for reward acquisition (e.g., Kimura, 2012). Then, we performed electrophysiological recordings to examine functional (task-related) spike activity in the motor cortex, striatum, and hippocampus of the behaving rats. In the motor cortex, we showed that excitatory pyramidal cells and inhibitory fast-spiking interneurons were differently activated in relation to their task performance (Isomura, 2009; Saiki, 2014). The spiking activity was phase-locked to slow/fast gamma and theta oscillations of local field potentials in a layer-specific manner (Igarashi, 2013), and often synchronous among nearby neurons (Kimura, 2017). In the striatum, we analyzed functional spike activity of striatal projection neurons, which were identified juxtacellularly with in situ hybridization for dopamine D1 receptors, during their reward-seeking behaviors, and suggested that striatal projection neurons for the direct (D1-positive) and indirect (D1-negative) pathways may work cooperatively to integrate motor and reward information (Isomura, 2013). In the hippocampus, we found two types of sharp-wave ripples occurring differently depending on the reward expectation during their task performance (Samura, unpublished). These functionally active neurons in the cortex, striatum, and hippocampus may participate in controlling the reward-seeking behavior. Our Multi-Linc analysis (Saiki, 2017) will unveil functional spike communication among these brain areas in the future.

 

References:

Isomura et al. (2009) Nat. Neurosci. 12: 1586-1593.

Kimura et al. (2012) J. Neurophysiol. 108: 1781-1792.

Isomura et al. (2013) J. Neurosci. 33: 10209-10220.

Igarashi et al. (2013) J. Neurosci. 33: 18515-18530.

Saiki et al. (2014) PLoS ONE 9: e98662.

Kimura et al. (2017) J. Physiol. 595: 385-413.

Saiki et al. (2017) Cereb. Cortex (in press).

 

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