Neural representations of visual memory in inferotemporal cortex reveal a generalizable framework for translating between spikes and field potentials

Translating neurophysiological findings requires understanding the relationship between common measures of brain activity in animals (spiking activity) and humans (local field potentials, LFP). Prior work suggests alignment between population spiking and high-gamma activity (HGA, 50-150 Hz) of the LFP; however, this is not always observed and is consequently debated. Here, we show that this alignment and prior failures depend on the underlying coding scheme. First, we examined neural representations of variables related to visual memory in macaque inferotemporal cortex. We found that spikes and HGA were strikingly aligned for variables encoded as population response magnitude (novelty, recency, and memorability). However, a variable encoded as a distributed pattern of activity (category) was misaligned. Next, we showed that these insights generalize across many published studies, accounting for prior alignment successes and failures. These results provide a framework for translating between spikes and LFPs, highlighting the scenarios likely to be fruitful for translation.