Abstract
BACKGROUND: Predicting adverse events from past experience is fundamental for many biological organisms.
However, some individuals suffer from maladaptive memories that impair behavioral control and well-being, e.g., after
psychological trauma. Inhibiting the formation and maintenance of such memories would have high clinical relevance.
Previous preclinical research has focused on systemically administered pharmacological interventions, which cannot
be targeted to specific neural circuits in humans. Here, we investigated the potential of noninvasive neural stimulation
on the human sensory cortex in inhibiting aversive memory in a laboratory threat conditioning model.
METHODS: We build on an emerging nonhuman literature suggesting that primary sensory cortices may be crucially
required for threat memory formation and consolidation. Immediately before conditioning innocuous somatosensory
stimuli (conditioned stimuli [CS]) to aversive electric stimulation, healthy human participants received continuous
theta-burst transcranial magnetic stimulation (cTBS) to individually localized primary somatosensory cortex in either
the CS-contralateral (experimental) or CS-ipsilateral (control) hemisphere. We measured fear-potentiated startle to
infer threat memory retention on the next day, as well as skin conductance and pupil size during learning.
RESULTS: After overnight consolidation, threat memory was attenuated in the experimental group compared with the
control cTBS group. There was no evidence that this differed between simple and complex CS or that CS identifi-
cation or initial learning were affected by cTBS.
CONCLUSIONS: Our results suggest that cTBS to the primary sensory cortex inhibits threat memory, likely by an
impact on postlearning consolidation. We propose that noninvasive targeted stimulation of the sensory cortex may
provide a new avenue for interfering with aversive memories in humans.
Ojala, Karita E