思维盲点：病感失认症
《决策大脑》思维盲点：病感失认症,页面无弹窗的全文阅读!
我们在生活中的成功主要取决于两种能力：洞察我们内心世界的能力和洞察他人内心世界的能力。这两种能力是紧密相关的，都受到额叶的控制。一旦额叶受伤或者发育不良，两种能力都会受影响，引发某种临床综合征。在本书的第7章，我们讨论了额叶在形成有关他人思维的看法方面发挥的作用，并揭示了额叶损伤对该能力的影响。现在是时候思考额叶在形成对自身认知世界的看法方面所起的作用了。
弗拉基米尔的案例同样对此有启发意义。弗拉基米尔的例子最让人惊讶的莫过于他对自己的障碍和自身情况的巨大变化一无所知。弗拉基米尔患有病感失认症，这是一种让患者意识不到自身所患疾病的严重情况。病感失认症患者可能受过严重的损伤，但是对损伤一无所知，还认为自己一切都好。这和“讳疾忌医”是完全不同的，讳疾忌医指的是患者有能力认识自身的缺陷，但不承认。而额叶受损后，人会完全丧失对自身情况的洞察能力。
病感失认症可能有若干表现形式。出于人们尚未完全理解的某种原因，右半脑损伤比左半脑损伤更容易导致病感失认症。一些科学家认为，这是由于内省能够感知到的只有受语言调节的认知，或者说内省本身就是一种基于语言的过程。因此，根据该观点，脑损伤引起的所有受语言调节的认知过程的变化能够被内省感知到，而脑损伤引起的所有非语言认知的变化则不会被内省感知到。这样一来，内省的范围就仅限于受左半脑调节的心理过程了。
不过，我总是觉得病感失认症与右半脑（而不是左半脑）损伤之间的联系反映的是左右半脑更广泛的功能差异。右半脑的认知过程的常规化程度更低，对稳定代码的依赖程度更低，在全新运算方面的参与程度更高。这意味着右半脑认知过程所操作的内容不太容易为内省所用，甚至对健康的个体来说也更模糊。由于个体对右半脑的认知操作一开始就是模糊的，脑损伤给其带来的变化也不够明显。
不论采用何种解释，一个右半脑严重中风的成功的国际企业家的案例总是让人难以忘怀。他在语言任务中的表现丝毫不受影响，这表明他的左半脑没有受影响。但是，他在视觉空间任务（要求他绘制或摆弄一些没有意义的视觉图形）中的表现糟透了，这表明他的右半脑受损严重。他的空间感极差，完全记不住我狭小办公室的陈设，一直分不清检查室、接待室和厕所。但他坚持认为自己已经痊愈了，一点儿毛病都没有，他必须立即飞往开罗敲定一笔生意。他绝对不可能抵达开罗。他在肯尼迪国际机场一下出租车就完全找不着北了。他的妻子和女儿对此非常了解，在他强烈反对的情况下，她们还是明智地给他办理了住院手续。
即便是这种程度的病感失认症，也无法与严重的额叶损伤的临床表现相提并论。至少，这个经常出差的企业家承认他生过病。而弗拉基米尔丝毫不认为疾病给他的生活带来了灾难性的、无法逆转的改变。严重额叶损伤引起的病感失认症也是最彻底、最顽固的。
病感失认症背后的机制目前尚不清楚。广义上，它可能与额叶的编辑功能受损有关，即将人的操作结果与其意图进行比较。或者说它反映的是更严重的额叶疾病：额叶完全失去了自身的意向性。有机体没有了渴望、目的和目标，因而无法感知到失败。要想改善患者的状况，首先必须让患者意识到自身的缺陷。病感失认症患者感知不到自身的不足和缺陷，因此不会有纠正它们的想法。患者的配合是治疗成功的关键，而病感失认症让治疗变成了一场艰苦卓绝的战役，进而导致额叶疾病的后果极其严重。
和所有的临床症状一样，不同严重程度的病感失认症也有不同的表现形式。弗拉基米尔对自身状况的一无所知是最严重的一种情况。比较轻的病感失认症可能表现为无法监控自己的行为或无法意识到自身的错误。从严谨的研究角度来说，揭示具体任务中的自我监控和错误检测背后的大脑机制是一项比较容易完成的工作。理查德·里德林霍夫及其同事在大量文献综述的基础上得出了如下结论：后内侧前额叶皮质（包括前扣带回皮质）对于错误的监控以及对行为不良后果的检测尤其重要。前扣带回皮质似乎在检测任务情境中的矛盾方面也发挥着重要的作用。前扣带回皮质通过某种方式给外侧前额叶皮质发送信号，后者会根据该信号调整行为。弗拉基米尔的额叶受损严重，其前额叶皮质的内外侧都出现了损伤。在不太严重的额叶损伤的案例中，错误检测能力与生成差距（想要实现的结果和实际行为结果之间的差距）信号的能力之间可能会出现轻微的分离。
A.Damasio, Descartes’ Error; Emotion, Reason, and the Human Brain (New York:Putnam Publishing Group, 1994).
E. Goldberg, “Introduction: the frontal lobes in neurological and psychiatric conditions,”Neuropsychiatry Neuropsychol Behav Neurol 5 (1992):231–2.
E. Goldberg, “Introduction: the frontal lobes in neurological and psychiatric conditions,”Neuropsychiatry Neuropsychol Behav Neurol 5 (1992):231–2.
A. Lilja, S. Hagstadius, J. Risberg, L. G. Salford, and G. J. W. Smith, “Frontal lobe dynamics in brain tumor patients: a study of regional cerebral blood f iow and affective changes before andafter surgery,” J Neuropsychiatry Neuropsychol Behav Neurol 5, n4(1992):294–300.
M. S. Nobler, H. A. Sakheim, I. Prohovnik, J. R. Moeller, S. Mukherjee, D. B. Schur,J. Prudic, and D. P. Devanand, “Regional cerebral blood f iow in mood disorders: III.Treatment and clinical response,” Arch Gen Psychiatry 51 (1994): 884–97.
J. Risberg, “Regional cerebral blood f iow measurements by 133Xe-inhalation: methodology and applications in neuropsychology and psychiatry,” Brain Lang 9 (1980): 9–34.
W. G. Honer, I. Prohovnik, G. Smith, and L. R. Lucas, “Scopolamine reduces frontal cortex perfusion,” J Cereb Blood Flow Metab 8 (1988): 635–41.
E. Goldberg, A. Kluger, T. Griesing, L. Malta, M. Shapiro, and S. Ferris, “Early diagnosis of frontal-lobe dementias,” presented at the Eighth Congress of the International Psychogeriatric Association, August, 17–22, 1997, Jerusalem, Israel.
E. Goldberg, “Introduction: the frontal lobes in neurological and psychiatric conditions,”Neuropsychiatry Neuropsychol, Behav Neurol 5 (1992): 231–2.
J. H. Jackson, “Evolution and dissolution of the nervous system,” Croonian Lecture. Selected Papers 2 (1884).
A. R. Luria, Higher Cortical Functions in Man (New York: Basic Books, 1966).
E. Goldberg and L. D. Costa, “Qualitative indices in neuropsychological assessment:an extension of Luria’s approach to executive def icit following prefrontal lesion,” in Neuropsychological Assessment of Neuropsychiatric Disorders, eds.I.Grantand K. M.Adams(New York: Oxford University Press, 1985), 48–64.
See K. Heilman and E. Valenstein, eds., Clinical Neuropsychology (New York: Oxford University Press, 1993).
E. Moniz, “Essai d’un traitement chirurgical de certaines psychoses,” Bull Acad Natl Med 115 (1936): 385–92.
See K. Heilman and E. Valenstein, eds., Clinical Neuropsychology (New York: Oxford University Press, 1993).
Dr. Robert Iacono, personal communication, January 2000.
C. S. Carter, M. M. Botvinick, and J. D. Cohen, “The contribution of the anterior cingulate cortex to executive processes in cognition,” Rev Neurosci 10 (1999): 49–57.
A. Ploghaus, I. Tracey, J. S. Gati, S. Clare, R. S. Menon, P. M. Matthews, and J. N. Rawlings,“Dissociating pain from its anticipation in the human brain,” Science 284(5422) (1999):1979–81.
T. D. Wager, J. K. Rilling, E. E. Smith, A. Sokolik, K. L. Casey, R. J. Davidson,S. M. Kosslyn, R. M. Rose, and J. D. Cohen, “Placebo-induced changes in fMRI in the anticipation and experience of pain,” Science 303 (2004): 1162–7.
T. D. Wager, J. K. Rilling, E. E. Smith, A. Sokolik, K. L. Casey, R. J. Davidson,S. M. Kosslyn, R. M. Rose, and J. D. Cohen, “Placebo-induced changes in fMRI in the anticipation and experience of pain,” Science 303 (2004): 1162–7.
T. Singer, B. Seymour, J. O’Doherty, H. Kaube, R. J. Dolan, and C. D. Frith, “Empathy for pain involves the affective but not sensory components of pain,” Science 303 (2004):1157–62.
N. I. Eisenberger, M. D. Lieberman, and K. D. Williams, “Does rejection hurt? An fMRI study of social exclusion,” Science 302 (2003): 290–2.
N. Fujii and A. M. Graybiel, “Representation of action sequence boundaries by macaque prefrontal cortical neurons,” Science 301 (2003): 1246–9.
P. Mychack, J. H. Kramer, K. B. Boone, and B. L. Miller, “The inf iuence of right frontotemporal dysfunction on social behavior in frontotemporal dementia,” Neurology 56 (2001):11S-15S.
D. H. Ingvar, “‘Memory of the future: an essay on the temporal organization of conscious awareness,” Hum Neurobiol 4 (1985): 127–36.
P. H. Rudebeck, M. J. Buckley, M. E. Walton, and M. F. Rushworth, “A role for the macaque anterior cingulate gyrus in social valuation,” Science 313 (2006): 1310–2.
S. M. McClure, D. I. Laibson, G. Loewenstein, and J. D. Cohen, “Separate neural systems value immediate and delayed monetary rewards,” Science 306 (2004): 503–7.
R. N. Cardinal, D. R. Pennicott, C. L. Sugathapala, T. W. Robbins, and B. J. Everitt,“Impulsive choice induced in rats by lesions of the nucleus accumbens core,” Science 292(2001): 2499–501.
From E. Goldberg and L. D. Costa, “Qualitative indices in neuropsychological assessment:an extension of Luria’s approach to executive def icit following prefrontal lesion,”in Neuropsychological Assessment of Neuropsychiatric Disorders, eds.I. Grantand K. M. Adams (New York: Oxford University Press, 1985), 55.
F. Lhermitte, “Utilization behavior and its relationship to lesions of the frontal lobes,” Brain 106 (1983): 237–55.
更多详细描述，请参阅M. D. Lezak, Neuropsychological Assessment, 3rd ed. (New York:Oxford University Press, 1995)。
P. Goldman-Rakic, personal communication, February 1991.
K. Brodmann, “Neue Ergebnisse über die vergleichende histologische Lokalisation der Grosshirnrinde mit besonderer Berücksichtigung des Stirnhirns,” Anat Anz 41 (1912;Suppl): 157–216.Cited in J. M.Fuster, The Prefrontal Cortex: Anatomy, Physiology, and Neuropsychology of the Frontal Lobe, 3rd ed. (Philadelphia: Lippincott–Raven, 1997).
R. A. Barkley, ADHD and the Nature of Self-Control (New York: Guilford Press, 1997).
J. W. de Fockert, G. Rees, C. D. Frith, and N. Lavie, “The role of working memory in visual selective attention,” Science 291 (2001): 1803–6.
S. L. Rauch, M. A. Jenike, N. M. Alpert, L. Baer, H. G. Breiter, C. R. Savage, and A. J. Fischman, “Regional cerebral blood f iow measured during symptom provocation in obsessive-compulsive disorder using oxygen 15–labeled carbon dioxide and positron emission tomography,” Arch Gen Psychiatry 51 (1994): 62–70.
A. R. Luria, Higher Cortical Functions in Man (New York: Basic Books, 1966).
E. Goldberg and D. Tucker, “Motor perseverations and long-term memory for visual forms,”J Clin Neuropsychol 1 (1979): 273–88.
J. B. Rowe, I. Toni, O. Josephs, R. S. Frackowiak, and R. E. Passingham, “The prefrontal cortex: response selection or maintenance within working memory?” Science 288 (2000):1656–60.
H. Tomita, M. Ohbayashi, K. Nakahara, I. Hasegawa, and Y. Miyashita, “Top-down signal from prefrontal cortex in executive control of memory retrieval,” Nature 401 (1999):699–703.
D. A. Grant and E. A. Berg, “A behavioral analysis of degree of reinforcement and ease of shifting to new responses in a Weigl-type card-sorting problem,” J Exp Psychol 38 (1948):404–11.
K. Nakahara, T. Hayashi, S. Konishi, and Y. Miyashita, “Functional MRI of macaque monkeys performing a cognitive set-shifting task,” Science 295 (2002): 1532–6.
For review see K. Heilman and E. Valenstein, eds., Clinical Neuropsychology (New York:Oxford University Press, 1993).
E. Goldberg and W. B. Barr, “Three possible mechanisms of unawareness def icit,” in Awareness of Deficit after Brain Injury, eds. G. Prigatano and D. Schacter (New York:Oxford University Press, 1991), 152–75.
E. Goldberg and W. B. Barr, “Three possible mechanisms of unawareness def icit,” in Awareness of Deficit after Brain Injury, eds. G. Prigatano and D. Schacter (New York:Oxford University Press, 1991), 152–75.
K. R. Ridderinkhof, M. Ullsperger, E. A. Crone, and S. Nieuwenhuis, “The role of the medial frontal cortex in cognitive control,” Science 306 (2004): 443–7.
A. W. MacDonald, 3rd, J. D. Cohen, V. A. Stenger, and C. S. Carter, “Dissociating the role of the dorsolateral prefrontal and anterior cingulate cortex in cognitive control,” Science 288 (2000): 1835–8.