Memory Circuits of Memory Circuits of the Cortex and the Cortex and Limbic SystemsLimbic Systems

BDNF upregulation during BDNF upregulation during declarative memory declarative memory formation in monkey formation in monkey

inferior temporal cortexinferior temporal cortexTokuyama et alTokuyama et al

The BasicsThe Basics The inferior temporal cortex stores visual The inferior temporal cortex stores visual

pair association memory.pair association memory. Tested the hypothesis that BDNF would be Tested the hypothesis that BDNF would be

upregulated in IT cortex during formation upregulated in IT cortex during formation of visual pair-association memory.of visual pair-association memory.

Found BDNF was upregulated selectively Found BDNF was upregulated selectively in area 36 of IT cortex during PA learning, in area 36 of IT cortex during PA learning, but not in areas involved in earlier stages but not in areas involved in earlier stages of visual processing. of visual processing.

Suggests that BDNF contributes to Suggests that BDNF contributes to reorganization of neural circuits for visual reorganization of neural circuits for visual long-term memory formation in the long-term memory formation in the primateprimate

Methods:Three Methods:Three experimental strategiesexperimental strategies

Intra-animal comparison of mRNA Intra-animal comparison of mRNA expressionexpression

A visual memory task as the control vs. A visual memory task as the control vs. a no-task conditiona no-task condition

Trained the monkeys to first learn a Trained the monkeys to first learn a “rule” or “strategy” component of the “rule” or “strategy” component of the tasks with training stimulus sets; a test tasks with training stimulus sets; a test stimulus was then introduced for new stimulus was then introduced for new learning of declarative components.learning of declarative components.

Increased BDNF and trk-B mRNA Increased BDNF and trk-B mRNA expression in cortical and limbic expression in cortical and limbic regions following formation of a regions following formation of a

social recognition memorysocial recognition memory Kevin D. Board et Kevin D. Board et

alal

The BasicsThe Basics

Sheep recognition: olfactory Sheep recognition: olfactory evolving to visualevolving to visual

Investigate BDNF & trk-B mRNA Investigate BDNF & trk-B mRNA expression 4.5 hours post partum in expression 4.5 hours post partum in olfactory/visual systemsolfactory/visual systems