Department of Pediatrics, Children's Hospital of Michigan, Wayne State University, Detroit, MI 48201, USA.
Clin Neurophysiol. 2013 Dec;124(12):2368-77. doi: 10.1016/j.clinph.2013.05.030. Epub 2013 Jul 30.
We determined where and when category-preferential augmentation of gamma activity took place during naming of animal or non-animal pictures.
We studied 41 patients with focal epilepsy who underwent measurement of naming-related gamma-augmentation at 50-120 Hz during extraoperative electrocorticography. The assigned task consisted of naming of a visually-presented object classified as either 'animal' or 'non-animal'.
Within 80 ms following the onset of picture presentation, regardless of stimulus type, gamma-activity in bilateral occipital regions began to be augmented compared to the resting period. Initially in the occipital poles (at 140 ms and after) and subsequently in the lateral, inferior and medial occipital regions (at 320 ms and after), the degree of gamma-augmentation elicited by 'animal naming' became larger (by up to 52%) than that by 'non-animal naming'. Immediately prior to the overt response, left inferior frontal gamma-augmentation became modestly larger during 'animal naming' compared to 'non-animal naming'.
Animal category-preferential gamma-augmentation sequentially involved the lower- and higher-order visual areas. Relatively larger occipital gamma-augmentation during 'animal naming' can be attributed to the more attentive analysis of animal stimuli including the face. Animal-preferential gamma-augmentation in the left inferior frontal region could be attributed to a need for selective semantic retrieval during 'animal naming'.
A specific program of cortical processing to distinguish an animal (or face) from other objects might be initiated in the lower-order visual cortex.
我们确定了在命名动物或非动物图片时，类别偏好性伽马活动增强发生的位置和时间。
我们研究了 41 例接受局灶性癫痫手术的患者，在手术期间用电皮质图测量与命名相关的 50-120 Hz 伽马增强。指定的任务包括命名视觉呈现的物体，分为“动物”或“非动物”。
在图片呈现后 80 ms 内，无论刺激类型如何，与静息期相比，双侧枕叶区域的伽马活动开始增强。最初在枕极（140 ms 后），随后在外侧、下侧和内侧枕叶区域（320 ms 后），“动物命名”引起的伽马增强程度（高达 52%）大于“非动物命名”。在明显反应之前，“动物命名”期间左侧下额伽马增强程度稍大于“非动物命名”。
动物类别偏好性伽马增强依次涉及低级和高级视觉区域。在“动物命名”期间，相对较大的枕叶伽马增强可归因于对动物刺激（包括面部）的更细致分析。左侧下额区域的动物偏好性伽马增强可能归因于在“动物命名”期间进行选择性语义检索的需要。
一种特定的皮质处理程序可能在低级视觉皮层中启动，以区分动物（或面部）与其他物体。
