EMOTIONCOG · Exploring the Effects of Emotion on Human Cognition

Exploring the Effects of Emotion on Human Cognition

Determining how emotions influence human cognition is critical for our understanding of psychiatric disease. The EmotionCog project has led to a number of discoveries that will advance this understanding. The most significant finding pertains to the properties of the amygdala – a brain structure critical for emotional processing. Specifically, a fast, subcortical pathway to the amygdala is thought to have evolved to enable rapid detection of threat. This pathway’s existence is fundamental for understanding non-conscious emotional responses, but has been challenged due to lack of evidence for short-latency fear-related responses in primate amygdala, including humans. During the course of EmotionCog, we recorded human intracranial electrophysiological data from patients with epilepsy. We demonstrate fast amygdala responses, beginning ~70ms post-stimulus onset, to fearful, but not neutral or happy, facial expressions. These responses have considerable shorter latency than fear responses we observe in visual cortex. Critically, fast amygdala responses are limited to low spatial frequency components of fearful faces, as predicted by theorised fast inputs to amygdala. Furthermore, fast amygdala responses are not evoked by photographs of arousing scenes, indicating selective early reactivity to socially-relevant visual information conveyed by fearful faces. These data therefore support the existence of a phylogenetically old subcortical pathway providing fast, but coarse, threat-related signals to human amygdala. This pathway, and its functional properties, may also constitute an important neural substrate for models of non-conscious processing in anxiety disorders and the generalization of fear responses to coarsely defined cues in pathological conditions. In a subsequent experiment, we show that these responses cannot be observed with magnetoencephalography (MEG) recordings, a non-invasive electrophysiological technique for recordings in healthy volunteers. The amygdala is a structure located deep in the brain, thus we confirm a view that amygdala responses cannot be observed with scalp recordings. The amygdala is also involved in upregulation of memory for emotional events. Our intracranial recordings also provide the first evidence for successful encoding-related responses in amygdala, specifically for emotional stimuli, at a latency of ~200ms. Neutral events that occur in temporal proximity to an emotional stimulus can also show memory enhancement or even impairment, and studies conducted within this project have further illuminated the neurobiological mechanisms mediating this effect. Memory enhancement for emotional stimuli is known to depend on the adrenergic system in the brain. In the context of this project, we have also discovered that this system also upregulates memory for stimuli requiring a motor response, an observation that may have important implications for developing methods to improve learning in healthy individuals and patients with memory disorders. The scientific advances made through EmotionCog are of interest to the general public, as indicated by numerous articles in the popular press written about the work from this project thus far. Moreover, these advanced have a direct impact on understanding human disease and in designing future therapies. Please visit www.thestrangelab.org for more information, or contact Dr. Bryan Strange MRCP MBBS PhD Laboratory for Clinical Neuroscience, Centro de Tecnología Biomédica, Universidad Politecnica de Madrid bryan.strange@upm.es

Data: CORDIS, © European Union