The Effect of Negative and Positive Emotionality on Associative Memory: An fMRI Study

In general, emotion is known to enhance memory processes. However, the effect of emotion on associative memory and the underling neural mechanisms remains largely unexplored. In this study, we explored brain activation during an associative memory task that involved the encoding and retrieval of word and face pairs. The word and face pairs consisted of either negative or positive words with neutral faces. Significant hippocampal activation was observed during both encoding and retrieval, regardless of whether the word was negative or positive. Negative and positive emotionality differentially affected the hemodynamic responses to encoding and retrieval in the amygdala, with increased responses during encoding negative word and face pairs. Furthermore, activation of the amygdala during encoding of negative word and neutral face pairs was inversely correlated with subsequent memory retrieval. These findings suggest that activation of the amygdala induced by negative emotion during encoding may disrupt associative memory performance

ジョウシン ニ ハッセイシタ タケイ センシュ ノ 1レイ

多形腺腫は唾液腺腫瘍の中で最も発生頻度が高い腫瘍である. 小唾液腺にも発生する多形腺腫の中であるが, 口唇に発生することはまれである. 今回われわれは口唇腺に発生した多形腺腫の1例を経験したので文献的考察を加えて報告する. 患者は52歳女性で, 上唇の腫瘤精査目的に当院皮膚科を受診し, 上唇良性腫瘍と診断され, 当科へ紹介され受診した. 左側上唇粘膜下に11×9 mm大の弾性硬, 可動性良好な腫瘤を認め, 全身麻酔下に摘出術を施行した. 腫瘍は被膜に包まれており, 周囲組織との境界は明瞭であった. 病理組織学的検査所見では, 腫瘍は薄い線維性被膜に覆われ, 大小の腺管構造とその周囲に筋上皮細胞の増殖, および軟骨様組織の形成を認め, 多形腺腫との診断であった. 術後1年6か月経過した現在, 口唇の機能的, 形態的異常はみられず, 腫瘍の再発は認めていない. 多形腺腫には悪性転化の報告もあり, 今後も注意深く経過観察を行う必要があると考えられる.Pleomorphic adenoma is the most common type of salivary gland tumor. The lip is a rare site of onset for pleomorphic adenomas that occur in the minor salivary glands. Here, we report our experience in the treatment of a patient with pleomorphic adenoma of the labial gland along with a review of the literature.The patient was a 52-year-old female who was referred to our department after consultation at the dermatology department of our institution for detailed examinations of a mass in the upper lip and being diagnosed with a benign tumor of the upper lip. A firm, elastic, highly movable mass of 11 × 9 mm was found under the mucosa of the left upper lip, which was excised under general anesthesia. The tumor was surrounded by a capsule, and the boundary of the surrounding tissue was well-delineated. Histopathological examinations revealed a thin fibrous capsule, and the proliferation of myoepithelial cells and formation of cartilage-like tissue were observed in and around the large and small ductal structures. Consequently, the tumor was diagnosed as a pleomorphic adenoma. At present, 1.5 years after surgery, no functional and morphological abnormalities of the lip have been observed, and there has been no recurrence of the tumor. Since there have been reports of malignant transformation of pleomorphic adenomas, careful follow-up will be necessary in the future

Face-Word Association Paradigm.

<p>Subjects were asked to learn pairs of neutral face and emotional (positive or negative) words related to personality-trait by pressing a button. After the control task in which subjects were asked to press one of the target button, each face was shown with 3 words and subjects were asked to indicate, via button press, which word was previously paired with that face. (The picture of one of the authors was used in the Figure instead of that from the database of SOFTPIA JAPAN to protect the privacy of subjects participated in the database).</p

Correlation between activations in regions detected by one sample t-tests and associative memory performances.

<p><i>r</i>, correlation coefficiency; <i>p</i>, p-value;</p><p>*, <i>p</i><0.05.</p

Correlation between amygdala activation and associative memory performance.

<p>A. shows the graph illustrates the inverse correlation between correct response rate of negative word - face pairs and the contrast estimates during encoding of negative word - face pairs in the region of interest shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0024862#pone-0024862-g002" target="_blank">Figure 2A</a>. B. shows the graph illustrates the positive correlation between correct response rate of positive word - face pairs and the contrast estimates during encoding of positive word - face pairs in the region of interest shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0024862#pone-0024862-g002" target="_blank">Fig. 2A</a>.</p

Results of one sample t-test for positive word and neutral face pairs.

<p>BA, Brodmann area; L, Left; R, Right; Z, Z value of the peak activation within the cluster; Coordinates for the peak voxel are listed as MNI coordinates. p, corrected p value for whole brain or region of interest (^a bilateral hippocampus which include 1667 voxels or ^b bilateral amygdala which include 306 voxels); k_E, cluster size (voxels) difined by the same peak-level FWE thresholds and used for cluster level testing.</p

Results of one sample t-test for negative word and neutral face pairs.

<p>BA, Brodmann area; L, Left; R, Right; Z, Z value of the peak activation within the cluster; Coordinates for the peak voxel are listed as MNI coordinates. p, corrected p value for whole brain or region of interest (^a bilateral hippocampus which include 1667 voxels or ^b bilateral amygdala which include 306 voxels); k_E, cluster size (voxels) difined by the same peak-level FWE thresholds and used for the cluster level testing.</p