Abstract
Emotional content/context enhances declarative memory through modulation of encoding and retrieval mechanisms. At encoding, neurophysiological data have consistently demonstrated the subsequent memory effect in theta and gamma oscillations. Yet, the existing studies were focused on the emotional content effect and let the emotional context effect unexplored. We hypothesized that theta and gamma oscillations show higher evoked/induced activity during the encoding of visual stimuli when delivered in an emotionally arousing context. Twenty-five healthy volunteers underwent evoked potentials (EP) recordings using a 21 scalp electrodes montage. They attended to an audiovisual test of emotional declarative memory being randomly assigned to either emotionally arousing or neutral context. Visual stimulus presentation was used as the time-locking event. Grand-averages of the EP and evoked spectral perturbations were calculated for each volunteer. EP showed a higher negative deflection from 80 to 140 ms for the emotional condition. Such effect was observed over central, frontal and prefrontal locations bilaterally. Evoked theta power was higher in left parietal, central, frontal, and prefrontal electrodes from −50 to 300 ms in the emotional condition. Evoked gamma power was higher in the emotional condition with a spatial distribution that overlapped at some points with the theta topography. The early theta power increase could be related to expectancy induced by auditory information processing that facilitates visual encoding in emotional contexts. Together, our results suggest that declarative memory enhancement for both emotional content and emotional context are supported by similar neural mechanisms at encoding, and offer new evidence about the brain processing of relevant environmental stimuli.
Highlights
Arousing events are better remembered than neutral ones (Dolan, 2002; LaBar and Cabeza, 2006; McGaugh, 2006)
Functional neuroimaging and electroencephalographic (EEG) recordings during the encoding of the stimuli have revealed some brain structures and mechanisms that are critical for the episodic memory formation
Our group has extensively used an emotional memory test (Cahill and McGaugh, 1995) in which visual and auditory information is delivered simultaneously (Frank and Tomaz, 2000; Gasbarri et al, 2005, 2006; Uribe et al, 2008). With this methodology we demonstrated that the emotional content enhances the episodic memory formation
Summary
Arousing events are better remembered than neutral ones (Dolan, 2002; LaBar and Cabeza, 2006; McGaugh, 2006). If someone is asked about what they were doing when they found out about the death of a loved relative, everyone remembers about the central fact (the notice), and whom they were with, where, and what were they doing in that moment Such clear evidence, from the everyday experience, demonstrates the effect of emotion over memory. From the everyday experience, demonstrates the effect of emotion over memory Both the content of the information and the context in which the information is embedded enhance memory formation (LaBar and Cabeza, 2006; Barrett et al, 2007; Pastor et al, 2008). Some evidence do not agree, the consensus is that during the encoding of episodic memories the activity of left hemisphere is increased, especially at the medial temporal lobe, the parietal lobe, and the prefrontal cortex (Sederberg et al, 2003, 2007; Osipova et al, 2006)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
