The Secondary Motor Cortex-striatum Circuit Contributes to Suppressing Inappropriate Responses in Perceptual Decision Behavior / 神经科学通报·英文版

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.

Influence of Recent Trial History on Interval Timing / 神经科学通报·英文版

Interval timing is involved in a variety of cognitive behaviors such as associative learning and decision-making. While it has been shown that time estimation is adaptive to the temporal context, it remains unclear how interval timing behavior is influenced by recent trial history. Here we found that, in mice trained to perform a licking-based interval timing task, a decrease of inter-reinforcement interval in the previous trial rapidly shifted the time of anticipatory licking earlier. Optogenetic inactivation of the anterior lateral motor cortex (ALM), but not the medial prefrontal cortex, for a short time before reward delivery caused a decrease in the peak time of anticipatory licking in the next trial. Electrophysiological recordings from the ALM showed that the response profiles preceded by short and long inter-reinforcement intervals exhibited task-engagement-dependent temporal scaling. Thus, interval timing is adaptive to recent experience of the temporal interval, and ALM activity during time estimation reflects recent experience of interval.

EEG changes and stress reactions in rat induced by millimeter wave / 生物医学工程学杂志

The present paper is aimed to study the processes of stress reaction and their judgment bases in rat induced by 35 GHz millimeter wave quantitatively. The relative change in the average energy of each EEG frequency band decomposed by wavelet analysis was calculated for extracting the stress indicator for the purpose. The rat would experience quiet period, guarding period, deadlock period and prostrating period in sequence. The judgment bases of different stress periods in rat induced by millimeter wave were obtained by analyzing the skin temperature, skin injury and changes of blood biochemical indexes during each stress period. The stress period changed from quiet period to guarding period when the skin temperature of irradiated area reached the thermal pain threshold. It was from guarding period to deadlock period when the skin had gotten serious injury. Then the rat reaction sensitivity decreased, and injury of its visceral organs occurred. The rat got to prostrating period when the sustained irradiation caused the rat's visceral organs to get more serious injury. The further sustained irradiation finally induced death of the rat.

Comparison of digital filter and wavelet transform for extracting electroencephalogram rhythm / 生物医学工程学杂志

It is very important to extract electroencephalogram (EEG) rhythm in clinical diagnoses. Digital filter and wavelet transform are used to extract the rhythm from a piece of EEG at the sampling rate of 2 kHz. The Daubechies order 4 wavelet (db4) was used to decompose the EEG at 8 levels. According to the filter characteristic of wavelet decomposition, the reconstructions of aS, d8, d7, d6 and d5 component are nearly corresponding to the rhythms of delta, theta, alpha, gamma separately. The 6 order ellipse infinite impulse response (IIR) filter is also used to decompose the EEG. As the quality factor of wavelet decomposition filter is constant, the wavelet transform obtains better extracted rhythm than the digital filter. Furthermore, the wavelet transform method can be used to extract the low frequency rhythm from wide frequency band.