Olfaction as a model system for the neurobiology of mammalian short-term habituation

Olfaction represents an ideal model system for the study of mammalian habituation given that it is an anatomically relatively simple system with strong reciprocal connections to the limbic system, driving both reflexive and non-reflexive (motivated) behaviors that are easily quantifiable. Data are reviewed here demonstrating short-term habituation of the odor-evoked heart-rate orienting reflex described according to the criteria for habituation outlined by Thompson and Spencer [Thompson, R. F., & Spencer, W. A. (1966). Habituation: A model phenomenon for the study of neuronal substrates of behavior. Psychological Reviews, 73(1), 16–43]. A necessary and sufficient mechanism of short-term habituation is then described, which involves a metabotropic glutamate receptor mediated depression of afferent input to the piriform (primary olfactory) cortex. Finally, evidence for, and a mechanisms of, dishabituation of the orienting reflex and cortical adaptation are described.     

Time and direction preparation of the long latency stretch reflex

This study investigated time and direction preparation of motor response to force load while intending to maintain the finger at the initial neutral position. Force load extending or flexing the index finger was given while healthy humans intended to maintain the index finger at the initial neutral position. Electromyographic activity was recorded from the first dorsal interosseous muscle. A precue with or without advanced information regarding the direction of the forthcoming force load was given 1000 ms before force load. Trials without the precue were inserted between the precued trials. A long latency stretch reflex was elicited by force load regardless of its direction, indicating that the long latency stretch reflex is elicited not only by muscle stretch afferents, but also by direction-insensitive sensations. Time preparation of motor response to either direction of force load enhanced the long latency stretch reflex, indicating that time preparation is not mediated by afferent discharge of muscle stretch. Direction preparation enhanced the long latency stretch reflex and increased corticospinal excitability 0–20 ms after force load when force load was given in the direction stretching the muscle. These enhancements must be induced by preset of the afferent pathway mediating segmental stretch reflex.     

宫颈癌根治术前预处理减少输尿管损伤及下肢静脉血栓临床观察

通过对术前考虑盆腔粘连可能比较严重的宫颈癌根治术（RH）术中穿着医用弹力袜行双下肢弹力加压,并经膀胱镜放置输尿管导管作预处理,减少下肢静脉血栓及输尿管损伤的临床效果。回顾性研究在我院行手术治疗的术前考虑盆腔粘连可能比较严重的宫颈癌患者364例,其中182例接受广泛子宫切除及盆腔淋巴结清扫术,术中穿着医用弹力袜行双下肢弹力加压,作为研究组,另182例单纯接受广泛子宫切除及盆腔淋巴结清扫术,未作预处理,作为对照组。结果研究组无一例损伤输尿管,对照组2例发生输尿管损伤（P ＜0．05）。因此,术前考虑盆腔粘连可能比较严重的 RH 术中穿着医用弹力袜行双下肢弹力加压,并经膀胱镜放置输尿管导管常规作预处理,可明显减少下肢静脉血栓、尿潴留及输尿管损伤,值得临床推广应用。     

Parental perception and interpretation of infant emotions: psychological and physiological processes

To study parental experience and perception of infant emotional expressions parents' responses to infant pictures depicting positive, neutral and negative emotions were assessed on the level of affective judgments (perceived and experienced valence and arousal), of mimic responses (facial muscle activity) and of the eyelid reflex (using the startle paradigm). In general, while parents were able to appropriately perceive infant emotions and were clearly affected by them, they exhibited a bias for positive interpretation. This was obvious from their subjective evaluations which, e.g. were more positive for experienced than for perceived valence, as well as from their mimic responses indicating positive responses in general. In addition, infant pictures including the negative ones lead to an inhibition of the startle reflex, indicating a positive evaluation of infant emotions on the sub‐cortical level. These effects were most prominent when parents were faced with pictures of their own infants as compared to unfamiliar ones. The way parents process information about infant emotions may facilitate appropriate responsiveness to infants' needs. Copyright © 2005 John Wiley & Sons, Ltd.     

The intelligent reflex

ABSTRACT

The seeming distinction between motor and cognitive skills has hinged on the fact that the former are automatic and non-propositional (knowing-how), whereas the latter are slow and deliberative (knowing-that). Here, the physiological and behavioral phenomenon of long-latency stretch reflexes is used to show that “knowing-that” can be incorporated into “knowing-how,” either immediately or through learning. The experimental demonstration that slow computations can, with practice, be cached for fast retrieval, without the need for re-computation, dissolves the intellectualist/anti-intellectualist distinction: All complex human tasks, at any level of expertise, are a combination of intelligent reflexes and deliberative decisions.