Cross-Sensory Visual Evoked Activity in Human Auditory Cortex
Kaisu Lankinen, Jyrki Ahveninen, Mainak Jas, Tommi Raij, and Seppo P. Ahlfors
(see article e1119232024)
Sensory cortices, which process external and internal sensory information, are influenced by inputs from other brain regions. These connections can be feedforward (FF) or feedback (FB). In nonhuman primates, the early auditory cortex, which processes sound, has mostly FF characteristics for auditory stimulation. However, visual evoked activity in the auditory cortex is FB. To investigate whether this is the case in humans, Lankinen and colleagues used magnetoencephalography to record neural activity elicited from auditory or visual stimuli. They found evidence of cross-sensory visual evoked activity in the auditory cortex. They used the Human Neocortical Neurosolver to model FF and FB connections through auditory cortex layers to determine whether their experimentally derived responses in the auditory cortex were mediated by FF or FB connections. They found that auditory evoked responses were driven by an FF input and a subsequent FB input while visual evoked responses were driven by a sole FB input. This extends the relevance of nonhuman primate auditory cortex imaging findings to humans and is informative for the auditory cortex field.
Maps of the model's estimate for evoked activity in the auditory cortex (top left and right) and occipital cortex (bottom left and right) at the time of the largest peak in response to visual stimuli. These data were used to confirm that visual evoked responses in the auditory cortex were not due to artifactual spread from the visual cortex.
Emotions May Shape Our Expectations, and Thus Our Experience, of Pain
Hsin-Yun Tsai, Kulvara Lapanan, Yi-Hsuan Lin, Cheng-Wei Huang, Wen-Wei Lin, Min-Min Lin, Zheng-Liang Lu, Feng-Sheng Lin, and Ming-Tsung Tseng
(see article e1627232024)
When we feel pain, we integrate our previous expectations with the sensory experience. Expecting something to hurt ahead of time enhances the painful experience by evoking anxiety, whereas more positive expectations alleviate pain by reducing the aversiveness of the painful stimulation. These influential expectations are linked to activation of brain structures involved in emotion processing, suggesting that there is an emotional component to the interaction between expectations and sensory information. In this issue, Tsai and colleagues investigated this interaction more directly. They used fMRI to measure emotional reactions in healthy human participants as they expected and perceived an incoming painful stimulus. The authors discovered that when participants voluntarily reduced anticipatory emotions, it reduced the magnitude of pain modulation by both negative and positive expectations. For negative expectations, they found that expectations were integrated with sensory inputs by anxiety-processing brain regions, where the updating of negative expectations by prediction errors was suppressed. On the other hand, positive expectations were integrated with sensory inputs by brain structures that underlie positive emotion processing and threat response inhibition. These findings provide new insights into the critical role of emotions in pain modulation by stimulus expectancy.
Footnotes
This Week in The Journal was written by Paige McKeon
