Single-neuron mechanism may bridge gap between working memory and long-term memory

Amazing stuff!

"... Researchers ... recently set out to simultaneously investigate the neural underpinnings of both WM and LTM, to determine whether these systems utilize some common mechanisms to store information. ...

The researchers carried out experiments involving 41 patients diagnosed with epilepsy who had electrodes implanted in their brains via an invasive procedure to monitor their brain activity. These electrodes allowed the researchers to record the activity of single neurons in their medial temporal lobe, which includes various brain regions associated with memory encoding and information processing, particularly the hippocampus and amygdala. ..."

From the highlights and abstract:

"Highlights

• Working memory (WM) and long-term memory (LTM) interact in the hippocampus

• Persistent WM activity of category-selective neurons predicts LTM formation

• LTM-selective neurons fire more for items encoded with strong WM activity

• This suggests a single-neuron mechanism linking both WM and LTM systems in humans

Summary

Working memory (WM) and long-term memory (LTM) are often viewed as separate cognitive systems. Little is known about how these systems interact when forming memories.

We recorded single neurons in the human medial temporal lobe while patients maintained novel items in WM and completed a subsequent recognition memory test for the same items.

In the hippocampus, but not in the amygdala, the level of WM content-selective persistent activity during WM maintenance was predictive of whether the item was later recognized with high confidence or forgotten.

By contrast, visually evoked activity in the same cells was not predictive of LTM formation. During LTM retrieval, memory-selective neurons responded more strongly to familiar stimuli for which persistent activity was high while they were maintained in WM.

Our study suggests that hippocampal persistent activity of the same cells supports both WM maintenance and LTM encoding, thereby revealing a common single-neuron component of these two memory systems."

Single-neuron mechanism may bridge gap between working memory and long-term memory

Persistent activity during working memory maintenance predicts long-term memory formation in the human hippocampus (open access)

Graphical abstract