Greer Tracy L, Trivedi Madhukar H, Thompson Lucien T
Department of Psychiatry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9119, USA.
J Affect Disord. 2005 Jun;86(2-3):235-45. doi: 10.1016/j.jad.2005.02.006.
Preliminary evidence obtained in our lab has revealed that depressive symptoms impair associative learning, as measured by acquisition of eyeblink classical conditioning (EBCC) tasks. The current study assesses EBCC acquisition in individuals with major depressive disorder (MDD).
The 17-item Hamilton Rating Scale for Depression (HAM-D(17)) and the 30-item Inventory for Depressive Symptomatology, Self-Report (IDS-SR(30)) were used to quantify severity of depressive symptoms. Participants received 60 trials each in delay 500, trace 500, and trace 1000 conditioning paradigms. A 150-ms, 5-7 psi air puff served as the unconditioned stimulus (US), and an 80-dB, 1-kHz tone as the conditioned stimulus (CS). Mean percent conditioned responses (CRs) served as the primary measure of task acquisition.
The MDD group generated significantly fewer CRs on delay 500 and trace 500 tasks, and approached significance on the trace 1000 task compared to healthy controls. Furthermore, presentation of successive trials did not increase CR production in the depressed group, in contrast to progressive increases observed in the control group.
The presentation of multiple EBCC tasks precludes some detailed analyses of task-specific performance. Future studies may also benefit from including sufficient numbers of subjects to assess differential characteristics of depression (e.g., length of episode, depressive subtype) and treatment effects.
These data suggest that MDD impairs acquisition of EBCC, providing behavioral support for cerebellar and hippocampal dysfunction in depression. Delineating the neural substrates involved in MDD may aid in future treatment approaches for this pervasive disorder.
我们实验室获得的初步证据表明，抑郁症状会损害联想学习，这通过眨眼经典条件反射（EBCC）任务的习得情况来衡量。本研究评估了重度抑郁症（MDD）患者的EBCC习得情况。
使用17项汉密尔顿抑郁评定量表（HAM-D(17)）和30项抑郁症状自评量表（IDS-SR(30)）来量化抑郁症状的严重程度。参与者在延迟500、痕迹500和痕迹1000条件反射范式下各接受60次试验。150毫秒、5 - 7磅/平方英寸的空气喷射作为无条件刺激（US），80分贝、1千赫兹的音调作为条件刺激（CS）。平均条件反应百分比（CRs）作为任务习得的主要衡量指标。
与健康对照组相比，MDD组在延迟500和痕迹500任务中产生的CRs显著减少，在痕迹1000任务中接近显著水平。此外，与对照组中观察到的逐渐增加相反，连续试验的呈现并未增加抑郁组的CR产生。
多个EBCC任务的呈现妨碍了对特定任务表现的一些详细分析。未来的研究可能也会受益于纳入足够数量的受试者，以评估抑郁症的不同特征（如发作时长、抑郁亚型）和治疗效果。
这些数据表明，MDD会损害EBCC的习得，为抑郁症中小脑和海马功能障碍提供了行为学支持。描绘MDD中涉及的神经基质可能有助于针对这种普遍疾病的未来治疗方法。
