Brain and nerve = Shinkei kenkyū no shinpo
-
Review Case Reports
[Different stages of human memory consolidation system deficits revealed by patients with epileptic amnesia].
Some patients with temporal lobe epilepsy display an atypical memory disorder known as very long-term amnesia or accelerated forgetting. The characteristics of the study patients were as follows: First, they could retain information long after the test was adminstrated; however, several weeks later, they could not remember the information (long-term anterograde amnesia: LAA). Second, they showed dense retrograde amnesia for decades (long-term retrograde amnesia: LRA). ⋯ However, there have been no reports regarding the effects of such drugs on LRA. In this report, we show 2 patients who were in the initial stage of long-term amnesia and epilepsy in late adult life, and the effect of an AED on LAA and LRA. We found that an AED prevented LAA but not LRA, suggesting that LAA and LRA were different memory consolidation system dificits and that accelerated forgetting was treatable, but retrograde amnesia was an irreversible process.
-
Most of our motor skills are acquired through learning. Although the cerebellum is established as the critical site for motor learning, the precise mechanism underlying acquisition and consolidation of motor memory is a topic of on-going debate. We examined the role of the cerebellum in acquisition and storage of motor memory by using adaptations of horizontal vestibulo-ocular reflex (VOR) and optokinetic response (OKR) eye movements in mice and monkeys. ⋯ We further revealed that long-term depression (LTD) of parallel fiber-Purkinje cell synapses plays a critical role in both the day- and week-long adaptations. These results suggest that the trace of motor memory is initially acquired in the cerebellar cortex, and later transferred to the cerebellar/vestibular nuclei for consolidation. LTD plays an essential role in both the acquisition and consolidation of motor memory.