帕金森病患者诱发电位研究

目的 :研究帕金森病 (PD)患者脑干听觉诱发电位 (BAEP)和视觉诱发电位 (VEP)的变化及其与临床症状的关系。方法 :检测 70例PD患者BAEP和VEP ,并设正常对照组 6 0例作对照。结果 :PD组BAEP异常 31例 (44 % ) ,正常对照组异常 11例 (18% ) ,P <0 0 1。VEPN75、P10 0、N135的潜伏期分别为 93 2± 15 1ms、12 5 2± 12 .4ms和 15 7 2± 19 5ms ,均较正常对照组 83 1± 14 8ms、10 4 2± 7 3ms和139 4± 14 4ms明显延长 ,P <0 0 1;PD患者VEP的P10 0潜伏期与UPDRS评分呈正相关 ,r =0 6 1,P <0 0 1。结论 :BAEP和VEP可客观地反映PD患者听觉和视觉通路电生理的变化。     

The Effect of Small Variation of the Frequent Auditory Stimulus on the Event-Related Brain Potential to the Infrequent Stimulus

We investigated whether the mismatch process between a rare stimulus and the trace of frequent stimulus, which generates the mismatch-negativity component of the event-related potential, can tolerate a small variation in the intensity of the frequent stimulus. Series of short tone pips were presented to 10 subjects while they were reading a book and ignoring the auditory stimuli. The intensity (mean 80dB) of the frequent stimulus (600 Hz) varied within a range that was different in different blocks. The probability of the infrequent stimuli which were, in different blocks, either intensity deviants (600 Hz/70dB) or frequency deviants (650 Hz/80dB) was 10%. Both deviant stimuli elicited mismatch negativity even when the intensity of the frequent stimulus varied, although the amplitude of this component decreased with the increasing variability of the frequent stimulus. These results show that the generator process of mismatch negativity tolerates some variation in the repetitive stimulus, thus indicating that this process is also activated in ecologically more valid conditions. This is crucial to the interpretation of the generator process of mismatch negativity as a biologically vital warning mechanism.     

Development of behavioral audition in the kitten

The present study reports the maturation of behavioral responses to several classes of auditory stimulation and defines both natural and artificial stimuli to which kittens respond. This development is discussed relative to the physical maturation of the external auditory canal and the pinna and the extant electrophysiological and neuroanatomical literature. The external auditory canal did not reach its maximum depth until 12 ± 3 days of age and this was followed by a gradual deepening of the external concavity resulting in the complex adult pinna being formed at around 31 days of age. All but two of the animals showed diffuse pinna movements to tactile, visual and olfactory stimulation on the first post-natal day. The kittens showed a definite response to auditory stimuli by 5 ± 1.5 days. In all cases, the early responses consisted of a general arousal, bouts of pinna movements and facial squints. In general the earliest responses were seen to the tape recorded natural stimuli. Seventy-five percent of the animals responded to all stimulus presentations by 7 days of age, but showed adult latencies only at 14 days. Some degree of spatial localization appeared as early as 10 days, but 75% of the subjects showed this at 16 days with adult latencies coming in at 26 days. It was within this latter period that the animals began to show habituation to the non-animal sounds. These results demonstrate, by using a battery of both natural and artificial auditory stimuli, a diffuse reactivity in the neonatal kitten which suggests that the immature auditory system is quite capable of mediating simple behaviors before central connections are either electrophysiologically or anatomically mature.     

Rapid and highly resolving associative affective learning: Convergent electro- and magnetoencephalographic evidence from vision and audition

Various pathway models for emotional processing suggest early prefrontal contributions to affective stimulus evaluation. Yet, electrophysiological evidence for such rapid modulations is still sparse. In a series of four MEG/EEG studies which investigated associative learning in vision and audition using a novel MultiCS Conditioning paradigm, many different neutral stimuli (faces, tones) were paired with aversive and appetitive events in only two to three learning instances. Electrophysiological correlates of neural activity revealed highly significant amplified processing for conditioned stimuli within distributed prefrontal and sensory cortical networks. In both, vision and audition, affect-specific responses occurred in two successive waves of rapid (vision: 50–80 ms, audition: 25–65 ms) and mid-latency (vision: >130 ms, audition: >100 ms) processing. Interestingly, behavioral measures indicated that MultiCS Conditioning successfully prevented contingency awareness. We conclude that affective processing rapidly recruits highly elaborate and widely distributed networks with substantial capacity for fast learning and excellent resolving power.     

Electrophysiological correlates of the retention of tones differing in timbre in auditory short-term memory

We examined the electrophysiological correlates of retention in auditory short-term memory (ASTM) for sequences of one, two, or three tones differing in timbre but having the same pitch. We focused on event-related potentials (ERPs) during the retention interval and revealed a sustained fronto-central ERP component (most likely a sustained anterior negativity; SAN) that became more negative as memory load increased. Our results are consistent with recent ERP studies on the retention of pitch and suggest that the SAN reflects brain activity mediating the low-level retention of basic acoustic features in ASTM. The present work shows that the retention of timbre shares common features with the retention of pitch, hence supporting the notion that the retention of basic sensory features is an active process that recruits modality-specific brain areas.     

具有正常听力的年青人乳突气化面积的研究

目的研究具有正常听力的中国汉族年青人乳突气化面积.方法选择年龄在18～24岁间的汉族青年45人90耳,听力正常,排除耳鼻咽喉科疾病,对左右耳分别进行乳突劳氏位及伦氏位拍片,用自动求积仪(日本产PLANIXT求积仪)直接在X线片上计算出乳突气化面积.结果左耳劳氏位乳突气化面积x±s为15.976±5.755cm2,伦氏位乳突气化面积x±s为16.38±6.222cm2;右耳劳氏位乳突气化面积x±s为15.898±4.938cm2,伦氏位乳突气化面积x±s为16.377±5.931cm2.其中气化良好型占96.7%,气化不良型占3.3%.结论乳突气化面积的测量结果可供耳科临床参考.     

Probing the lifetimes of auditory novelty detection processes

Auditory novelty detection can be fractionated into multiple cognitive processes associated with their respective neurophysiological signatures. In the present study we used high-density scalp event-related potentials (ERPs) during an active version of the auditory oddball paradigm to explore the lifetimes of these processes by varying the stimulus onset asynchrony (SOA). We observed that early MMN (90-160 ms) decreased when the SOA increased, confirming the evanescence of this echoic memory system. Subsequent neural events including late MMN (160-220 ms) and P3a/P3b components of the P3 complex (240-500 ms) did not decay with SOA, but showed a systematic delay effect supporting a two-stage model of accumulation of evidence. On the basis of these observations, we propose a distinction within the MMN complex of two distinct events: (1) an early, pre-attentive and fast-decaying MMN associated with generators located within superior temporal gyri (STG) and frontal cortex, and (2) a late MMN more resistant to SOA, corresponding to the activation of a distributed cortical network including fronto-parietal regions.     

Multisensory contributions to the perception of motion

The ability to process motion is crucial for coherent perception and action. While the majority of studies have focused on the unimodal factors that influence motion perception (see, for example, the other chapters in this Special Issue), some researchers have also investigated the extent to which information presented in one sensory modality can affect the perception of motion for stimuli presented in another modality. Although early studies often gave rise to mixed results, the development of increasingly sophisticated psychophysical paradigms are now enabling researchers to determine the spatiotemporal constraints on multisensory interactions in the perception of motion. Recent findings indicate that these interactions stand over-and-above the multisensory interactions documented previously for static stimuli, such as the oft-cited 'ventriloquism' effect. Neuroimaging and neuropsychological studies are also beginning to elucidate the network of neural structures responsible for the processing of motion information in the different sensory modalities, an important first step that will ultimately lead to the determination of the neural substrates underlying these multisensory contributions to motion perception.     

Automatic time perception in the human brain for intervals ranging from milliseconds to seconds

Time perception in everyday life deals with various intervals. Here we investigated whether an automatic duration-discrimination mechanism in audition operates even for intervals of an order of seconds, by using the mismatch negativity (MMN), an index of automatic change detection in audition. In Experiment 1, occasional decrements of the duration of a repetitive "standard" tone elicited an MMN in subjects ignoring auditory stimulation, even with the standard-stimulus durations over a second. Nevertheless, the MMN amplitude was significantly diminished with standard-stimulus durations of 800 ms and above, despite the fact that a constant deviant versus standard duration ratio was used. Complementary experiments varying the interstimulus interval (Experiment 2) and the magnitude of duration change (Experiment 3) yielded corroborating results. The present results suggest that automatic duration discrimination in audition operates even for durations of the order of seconds; yet its optimum time scale might be of the order of milliseconds.     

Cross-modal performance: behavioural processes, phylogenetic considerations and neural mechanisms

Issues relating to cross-modal performance (CMP) are examined from various points of view, with major emphasis on phylogenetic comparisons and neurological mechanisms. Although it now seems likely that certain distinctions that were made based on training procedures (i.e., among transfer, matching, and recognition) have no functional significance, research on this topic has demonstrated how the level of performance is affected by certain task variables (such as number of trials in the first modality). It has not yet been shown that these relationships differ from ones that would be seen in comparable within-modal studies. Overall phylogenetic differences specific to CMP cannot be sustained from the data for humans, apes, monkeys, and non-primates. However, two possible differences - one phylogenetic and one ontogenetic — require further study. Metaphorical matching has not been demonstrated in nonhumans, and it may be the case that ‘categorical’ CMP appears earlier in development than ‘specific’ CMP. Efforts to establish that CMP is mediated by representations localized in regions of polysensory neural convergence have not provided convincing evidence, so that ‘leakage’ between perceptual/memory systems previously considered to be modality-specific is proposed as the mechanism for CMP. Based primarily upon findings from a study using 2-DG, the suggestion is made that one pathway for such leakage is through the ventral claustrum. Polysensory areas of cortex may play a special role during the initial formation of a multisensory engram.