Although premature ejaculation (PE) is a common type of male sexual dysfunction, to date we lack a unified definition of PE. The multidimensional definition of PE has been accepted by more and more clinicians. Intravaginal ejaculatory latency time (IELT) is one of the three important dimensions (time to ejaculation, inability to control or delay ejaculation, and negative consequences) for defining PE. Rapid ejaculation is one of the core symptoms of PE and IELT is an objective measurement as well as an important tool for the evaluation of PE. This article reviews estimated IELT, stopwatch-measured IELT, the correlation between estimated and stopwatch-measured IELT, and the factors affecting IELT in the general male population, PE patients, and those complaining of PE.
Coitus ; Ejaculation ; physiology ; Humans ; Male ; Premature Ejaculation ; etiology ; physiopathology ; Reaction Time ; physiology ; Time Factors

To interpret the flash evoked potential (FVEP) as dynamic high-order responses to natural and experimental stimulation in healthy preterm infants, waveform analysis of FVEP in 36 healthy preterm infants (postconceptional age 28~42 weeks) were performed using an autoregressive analysis. Based on the histogram of damping frequency of different component impulse response waveforms, the waveforms were divided into 4 groups: group I (0 ~ <2 Hz), group II (2 ~ <6.5 Hz), group III (6.5 ~ <12.0 Hz) and group IV (12~25 Hz). The total power, power of component impulse responses (group I~IV), and damping time (group II~IV) changed significantly with increasing postconceptional age (P<0.01 or P<0.05). Identification of an impulse response component with dominant frequency which undergoes a well-identified change with age is considered to be a useful tool for discriminating between normal and abnormal changes in the FVEP with age in healthy preterm infants.
Evoked Potentials, Visual ; physiology ; Female ; Humans ; Infant, Newborn ; Infant, Premature ; physiology ; Male ; Reaction Time ; Sleep ; physiology

The secondary motor cortex (M2) encodes choice-related information and plays an important role in cue-guided actions. M2 neurons innervate the dorsal striatum (DS), which also contributes to decision-making behavior, yet how M2 modulates signals in the DS to influence perceptual decision-making is unclear. Using mice performing a visual Go/No-Go task, we showed that inactivating M2 projections to the DS impaired performance by increasing the false alarm (FA) rate to the reward-irrelevant No-Go stimulus. The choice signal of M2 neurons correlated with behavioral performance, and the inactivation of M2 neurons projecting to the DS reduced the choice signal in the DS. By measuring and manipulating the responses of direct or indirect pathway striatal neurons defined by M2 inputs, we found that the indirect pathway neurons exhibited a shorter response latency to the No-Go stimulus, and inactivating their early responses increased the FA rate. These results demonstrate that the M2-to-DS pathway is crucial for suppressing inappropriate responses in perceptual decision behavior.
Mice ; Animals ; Motor Cortex ; Corpus Striatum/physiology* ; Neostriatum ; Neurons/physiology* ; Reaction Time

OBJECTIVES: To analyze the Nogo-P3 component of event-related potential (ERP) in the process of visual acuity processing, to provide electrophysiological evidence for objective evaluation of visual acuity. METHODS: Twenty-six subjects with no other ocular diseases except for ametropia were recruited, and all subjects had uncorrected visual acuity both eyes 1/10 (evaluated using Monoyer chart). Block letter E with different visual angles and directions were used as graphic stimuli. The Go/Nogo paradigm was used for ERP studies. The visual angle of Go stimulation angle was 1°15', Nogo stimuli were 1°15', 55', 24' and 15'. The visual acuity test was performed on each of the two naked eyes separately in all subjects, and the characteristics of the Nogo-P3 component were analyzed. RESULTS: The latency of Nogo-P3 showed no difference between the stimuli of 1°15' and 55', and between Nogo stimulation angle 24' and 15'. There was significant difference between Nogo stimulation angle 1°15' and 24', and between Nogo stimulation angle 1°15' and 15' (P<0.05). There was significant difference between Nogo stimulation angle 55' and 24', and between Nogo stimulation angle 55' and 15' (P<0.05). No significant differences were observed in the Nogo-P3 amplitude among Nogo stimulation. CONCLUSIONS In the Go/Nogo paradigm, Nogo-P3 can reflect the cognitive response of subjects to Nogo stimulation, which can be used for objective evaluation of visual acuity.
Electroencephalography ; Evoked Potentials/physiology* ; Humans ; Photic Stimulation ; Reaction Time/physiology* ; Refractive Errors ; Visual Acuity

The latency change detection of EPs is of special interest in many clinical applications such as diagnosis of the injury and pathological changes in the nervous system. This paper reviews the adaptive latency change detection approaches under stable noise conditions, based on the fractional lower order statistics. It also evaluates and compares the performances of the presented algorithms.
Algorithms ; Animals ; Brain ; physiology ; Electroencephalography ; methods ; Evoked Potentials ; physiology ; Humans ; Reaction Time ; physiology ; Signal Processing, Computer-Assisted

OBJECTIVETo explore the working mechanism and age-related change of the conflict processing system of the frontal cortex.

METHODSFifteen normal elderly people and 15 youth were performed a modified Eriksen flanker paradigm, while event-related potential (ERPs), which include 32 systerm electroencephalography, reaction time and correct rate were recorded.

RESULTSThe elderly group showed a distinct effect of reaction time and effect of conflict in the respond level compared with the youth group. The elderly group had a longer time window of N380 and same amplitude as the youth group. Low resolution brain electromagnetic tomography (LORETA) showed the bilateral temporal lobe and the dorsolateral prefrontal cortex (especially right) were activated in the youth group, while the left temporal lobe, the left dorsolateral prefrontal cortex and left medial frontal gyrus were activated in the elderly group.

CONCLUSIONWhen conflict stimuli existed in the response level, old people showed frontal interference control hypofunction. N380 reflected the activation of the left dorsolateral prefrontal cortex and the left temporal lobe during response selection and executive control processing in older people.

Adolescent ; Aged ; Aging ; Electroencephalography ; Evoked Potentials ; Frontal Lobe ; physiology ; Humans ; Prefrontal Cortex ; physiology ; Reaction Time ; Temporal Lobe ; physiology

OBJECTIVETo explore the feasibility to evaluate objectively auditory temporal resolution using the iso-modulation depth temporal modulation transfer function (TMTF) derived from the amplitude of evoked response to sinusoidally modulated signals.

METHODSChronic electrodes were implanted in inferior colliculus and auditory cortex of guinea pigs. We recorded the evoked response to sinusoidally modulated tones with modulation frequency being varied from 20 to 400 Hz and modulation depth fixed at 100%. The response amplitude in uV was converted into relative amplitude using the fast Fourier transform (FFT) function provided by Biosig software, and then the iso-modulation depth TMTF was plotted with the relative amplitude changed with modulation frequency. Then we recorded the evoked response to the sinusoidally modulated tones with modulation depth being varied from 100% to 10% and derived the iso-amplitude TMTF comparable to conventional modulation depth threshold TMTF. The derived iso-amplitude TMTF was compared to iso-modulation depth TMTF to determine the validity of iso-modulation depth TMTF.

RESULTSThe iso-modulation-depth TMTF and iso-amplitude TMTF in inferior colliculus and auditory cortex of guinea pigs represented respectively bandpass and lowpass characteristic. The cut-off frequency calculated from the two TMTF methods didn't differ significantly and the cut-off frequency derived from auditory cortex iso-modulation depth TMTF was consistent with behavioral results.

CONCLUSIONSThe TMTF plotted with the response amplitude to sinusoidally modulated tones with the modulation depth fixed at 100% and the modulation frequency was a valid method to evaluate objectively auditory temporal resolution.

Animals ; Auditory Cortex ; physiology ; Electrodes ; Evoked Potentials, Auditory ; physiology ; Fourier Analysis ; Guinea Pigs ; Inferior Colliculi ; physiology ; Reaction Time

OBJECTIVETo explore the effects of high altitude on cognitive flexibility.

METHODSSimulated hypoxia at an altitude of 3 600 m was performed in a hypobaric chamber. Twenty-three volunteers without hypoxic experience were selected and the mean age was about 25.1 years. The physiological parameters (heart rate, blood pressure and oxygen saturation) were measured. Task switch paradigm was used to explore the cognitive flexibility in each phase, and the changing anxiety state was evaluated simultaneously.

RESULTSReaction time (RT) switch cost in hypoxia phase showed a significant increase compared with the baseline; anxiety level in hypoxia phase was higher than the adaptation phase; a remarkable negative correlation between anxiety level and RT switch cost was found in adaptation phase, whereas a positive correlation was found in landing phase.

CONCLUSIONHigh altitude (3 600 m) affects cognitive flexibility and anxiety state. Anxiety before the hypoxia exposure improves the cognitive flexibility performance, while anxiety after the hypoxia exposure hampers the performance because of the post-hypoxia effect.

Adult ; Altitude ; Anxiety ; Cognition ; physiology ; Humans ; Hypoxia ; psychology ; Male ; Reaction Time

BACKGROUNDPrior research about N400 has been mainly based on English stimuli, while the cognitive processing of Chinese characters is still unclear. The aim of the present study was to further investigate the semantic processing of Chinese idioms.

METHODSEvent related potentials (ERP) component N400 was elicited by 38 pairs of matching (congruent) and mismatching (incongruent) ended Chinese idioms: ending words with same phoneme but different shape and meaning (sPdSdM), with similar shape but different phoneme and meaning (sSdPdM), with same meaning but different phoneme and shape (sMdPdS), and words with different phoneme, shape and meaning (dPdSdM) and recorded by Guangzhou Runjie WJ-1 ERP instruments. In 62 right-handed healthy adults (age 19 - 50 years), N400 amplitudes and latencies were compared between matching and mismatching conditions at Fz, Cz and Pz.

RESULTSN400 showed a midline distribution and could be elicited in electrodes Fz, Cz and Pz. The mean values of N400 latencies and amplitudes were obtained for matching and mismatching ending words in healthy adults. Significant differences were found in N400 latencies and amplitudes in matching and mismatching ending-words idioms in healthy adults (P < 0.05). Compared with matching ending-words idioms, N400 latencies were prolonged and the amplitudes were increased in mismatching ones. N400s elicited by different types of stimuli showed different latencies and amplitudes, and longest N400 latency and largest N400 amplitude were elicited by ending-words with dPdSdM. No gender difference was found of N400 latency and amplitude in this study (P > 0.05).

CONCLUSIONSCompared with English stimuli, Chinese ideographic words could provide more flexible stimuli for N400 research in that the words have 3-dimension changes - phoneme, shape and meaning. Features of N400 elicited by matching and mismatching ending words in Chinese idioms are mainly determined by the meaning of the word. Some issues of N400 elicited by Chinese characters deserve further research.

Adult ; Cognition ; Evoked Potentials ; physiology ; Female ; Humans ; Male ; Middle Aged ; Reaction Time ; Reading ; Semantics ; Sex Characteristics

OBJECTIVE: To explore the effect of stimulus intensity on auditory event-related potentials (AERP) evoked by tone stimuli and speech stimuli respectively. METHOD: Normal young participants were tested by both tone and speech stimulus with different intensity levels. Range of the intensity for the typical AERP to tone stimuli and speech stimuli were compared. Whether the effect of intensity on,speech stimuli AERP test is the same as that of the tone stimuli were analyzed. RESULT: When intensity level ranged from 40 dBSL to 70 dBSL, typical AERP were recorded more easily with speech stimuli than with tone stimuli (P < 0.01). When stimulated by speech stimuli or by tone stimuli, the latency of P300 decreased with higher intensity, the influences of intensity to P300 latency have significant difference (P < 0.01), but not to P300 peak amplitude. CONCLUSION The effect of stimulus intensity on AERP evoked by speech stimuli is the same to the tone stimuli, but intensity range for typical AERP of speech stimuli was wider than tone stimuli. It may be resulted from that information contained in speech stimulus is more abundant than that contained in tone stimulus, or subjects were more familiar with speech stimulus than tone stimulus.
Acoustic Stimulation ; methods ; Adult ; Evoked Potentials, Auditory ; physiology ; Female ; Humans ; Male ; Reaction Time ; Speech ; Young Adult