Villablanca J R, Carlson-Kuhta P, Schmanke T D, Hovda D A
Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles 90024, USA.
Brain Res Dev Brain Res. 1998 Feb 10;105(2):309-24. doi: 10.1016/s0165-3806(97)00187-9.
Groups of cats with resection of the neocortex of the left cerebral hemisphere at postnatal (P) ages (in days) 5-15 (P10), 30 (P30), 60 (P60), 90 (P90), 120 (P120), and in adulthood, were compared using a comprehensive battery of 16 neurobehavioral tests administered when they were at least 6 months post-lesion. For all behaviors, except 3 (including the paw contact placing reaction which never recovered), the performance was significantly better for the cats lesioned between P10 and P30 compared to cats lesioned at older ages. For 10 of the behaviors, the transition from age-at-lesion P30 to P60 was rather abrupt and characterized by a significant increment in impairments. However, cats with the resection at ages P90 and P120 still showed some behavioral advantage over the adult-lesioned animals. Overall, for most of the behaviors tested, there was a significant linear trend for an increase in the magnitude of impairments across the entire age-at-lesion range. We previously reported that cats with a unilateral frontal cortical lesion sustained during the late fetal life showed substantial behavioral impairments, while animals with a similar resection sustained early postnatally exhibited minimal abnormalities. These findings, together with the present results, indicate that the long-term behavioral outcome of neocortical injury is best when the lesion is sustained during a discrete period of the life of the cat. This period extends from about fetal age 55 days (the oldest lesion age in our fetal studies) to about P60, as shown in the present paper. For these reasons, we propose that there is a Critical Maturational Period (CMP) for optimal post injury brain and behavioral restoration. We hypothesize that this span of reduced vulnerability is linked to specific developmental morphological events which occur during the same time period. Since, as discussed, such ontogenetic events also occur in other mammal species (albeit at different chronological ages), we further propose that the timing of the CMP as delineated in cats, can be extrapolated to other higher mammals species including humans.
对出生后（P）5 - 15天（P10）、30天（P30）、60天（P60）、90天（P90）、120天（P120）以及成年期时左脑半球新皮质被切除的几组猫，在损伤至少6个月后使用16种神经行为测试的综合组进行比较。对于所有行为，除了3种行为（包括从未恢复的爪接触放置反应）外，与年龄较大时损伤的猫相比，P10至P30期间损伤的猫表现明显更好。对于10种行为，从损伤年龄P30到P60的转变相当突然，其特征是损伤显著增加。然而，P90和P120年龄时切除的猫与成年期损伤的动物相比仍显示出一些行为优势。总体而言，对于大多数测试行为，在整个损伤年龄范围内，损伤程度的增加存在显著的线性趋势。我们之前报道，胎儿后期单侧额叶皮质损伤的猫表现出严重的行为损伤，而出生后早期类似切除的动物表现出最小的异常。这些发现与当前结果一起表明，当损伤发生在猫生命的一个离散时期时，新皮质损伤的长期行为结果最佳。如本文所示，这个时期从大约胎儿期55天（我们胎儿研究中最大的损伤年龄）延伸到大约P60。基于这些原因，我们提出存在一个关键成熟时期（CMP）以实现最佳的损伤后脑和行为恢复。我们假设这个易损性降低的时间段与同一时期发生的特定发育形态学事件有关。如前所述，由于这种个体发育事件也发生在其他哺乳动物物种中（尽管在不同的时间年龄），我们进一步提出，猫中所描述的CMP时间可以外推到包括人类在内的其他高等哺乳动物物种。
