1. Methods SUBJECTS. SUBJECTS. Ten participants with damage to medial temporal lobe, including the amygdala, consequence to neurosergical temporal lobectomy for the treatment of epilepsy (1 bilateral lobectomy, 3 left lobectomy, and 6 right lobectomy; 3 males, 7 females; mean age=45.3 years, SD=10.3, mean years of education=14.5, SD=2.4), and 11 healthy control participants (2 males, 9 females; mean age=42 years, SD=10.8, mean years of education=15, SD=1.9) matched for age and level of education, were assigned to either the immediate test condition or delayed test condition. MATERIALS. MATERIALS. In a pilot study words were rated for arousal and familiarity, and Skin Conductance Responses (SCRs) were recorded.  Familiarity ratings: on a scale from 1 (not at all familiar) to 7 (very much familiar). Neutral words: (M = 5.7, SD = 0.62), arousing words:(M = 5.5, SD = 0.39), p >.05.  Arousal ratings: on a scale from 1 (not at all arousing) to 7 (very much arousing). Neutral words had lower arousal ratings (M = 1.96, SD = 0.42), than arousing words (M = 3.62, SD = 0.49), p <.001.  Subjects also produced larger SCRs to the arousing words than to the neutral, p <.05, one-tailed.  All words were 4-6 letters (size on screen: 5cm*1cm)PROCEDURE. Subjects sat 57cm from a computer screen. There were 16 trials in which:  Subjects were asked to fixate on the neutral word at the center of screen.  Either a neutral word or an arousing word at random appeared at one of the corners of screen 5cm from the center.  To engage attention at the center, subjects were asked to indicate how often they encounter the central word in the English language on a scale from 1 (rarely) to 5 (often).  A surprise two alternative forced choice recognition test for all words was given either immediately or after a 24 hours delay. Subjects were shown two words on screen, matched for frequency and arousal, and were asked to indicate which of the two appeared in the first part of the study. Modulation of Memory by Arousal when Attention is Controlled: The role of the Medial Temporal Lobe Tali Sharot & Elizabeth A. Phelps - New York University Rational Emotional arousal may strengthen memory both by altering perception and attention during encoding and by enhancing memory retention. Animal and human studies reveal a key role for the amygdala in permitting emotionally arousing content to change encoding efficiency 1, as well as to strengthen its post-encoding hippocampal dependant consolidation into memory 2. Previous studies have revealed impaired emotional memory in patients with bilateral damage to the medial temporal lobe, findings from studies of unilateral patients are less conclusive 3. In these studies the effects of emotion on attention and retention were entangled, and thus may not indicate whether the medial temporal lobe holds a significant role in both modulation processes. In order to examine the influence of emotion on memory retention separately from its influence on attention, we tested temporal-lobectomy patients and matched controls at two time points for recognition of arousing and neutral words in a paradigm that manipulates attention during encoding.Conclusion Arousal can support better long-term memory for emotional stimuli compared to neutral stimuli, and slower forgetting rates, even when modulation of attention by emotional arousal is minimized. There is no evidence that subjects with unilateral MTL damage are impaired in recognition memory of arousing words after a delay. These finding may hold true for right unilateral MTL damaged patients only, and are in accord with past studies that have reported a deficit of long-term memory for emotional stimuli in left, but not right, unilateral temporal lobectomy subjects 3,4. At this time we can not reach conclusions regarding left MTL damaged subjects, as only one such subject was examined in the delay condition. The bilateral MTL damaged patient however, did not show a boost for memory of emotional words at delay. The right medial-temporal lobe structures may not be critical for the strengthening effect of arousal on memory retention of verbal material when attention is controlled during encoding. Results: Results: Recognition rates for words in the periphery Selected References 1. Anderson, A.K., & Phelps, E.A. (2001).Nature,411, (6835). 2. McGaugh,J.L.(2000). Science.14, 287(5451):248-51. 3. Adolphs, R, Tranel D., & Denburg N. (2000). Learn Mem. May-Jun;7(3):180- 6. 3. Buchaman,T.W., Denburg, N.L., Tranel D., & Adolph, R.(2001) Learn Mem. May-Jun;7(3):180-6. Learn Mem. May-Jun;8(6):326-35. Acknowledgment We thank Marisa Carrasco for her assistance in the design of the experiment. This study was supported by the National Institute of Health, MH62104 to EAP.  Recognition scores were characterized by a reliable interaction of word type by time p<0.01.  At delay, recognition of arousing words was significantly higher than for neutral words p<0.01.  A trend for recognition of neutral words to be better at immediate test than at delay test p=0.81.  There was no significant effect of subject group (control vs. unilateral patients), nor any significant interaction of subject group by time and/or by word type.  Bilateral patient showed normal memory for neutral words at delay test, but no enhancement for memory of emotional words, as indicated by Z scores (using means and SDs of controls). 293.13 293.13 X How often do you encounter the central word in the English language? X 16 trials 250 ms 10,000 ms 250 ms Encoding Phase: desk desk truck truck slut clock Test Phase: Either immediately or 24 hours later 2AFC: Which word appeared in the first part of the experiment? clock fabric rape slut Controls Unilateral Patients Bilateral Patient