Fear conditioning and brain activity : a positron emission tomography study in humans.

• Regional cerebral blood flow (rCBF) was measured with H2 (15)O positron emission tomography in 8 healthy women before and after fear conditioning (i.e., paired shocks) and unpaired shocks to videotape cues. Conditioning was supported by enhanced peripheral nervous system recordings and subjective ratings. Fear conditioning increased rCBF in the central gray of the midbrain; bilaterally in the hypothalamus, the thalamus, and the left striatum; and in the right and left anterior cingulate and right prefrontal cortices. Regional CBF was attenuated bilaterally in the right and left prefrontal, temporal (including the amygdala), parietal, and occipital cortices, and in the left orbitofrontal cortex. When compared with unpaired shock presentations, fear conditioning resulted in elevated rCBF in the left cerebellum. Hence, in the present paradigm, only neural activity in the left cerebellum solely reflected processes associated with true Pavlovian conditioning.

Keyword

Adult

Arousal/physiology

Brain/blood supply/*radionuclide imaging

Brain Mapping

Cerebellum/physiology/radionuclide imaging

Conditioning; Classical/*physiology

Dominance; Cerebral/physiology

Fear/*physiology

Female

Humans

Regional Blood Flow/physiology

Research Support; Non-U.S. Gov't

Tomography; Emission-Computed

Publication and Content Type

vet (subject category)

art (subject category)