ABSTRACT
The rapid development of silicon microelectrode arrays provides an ideal means for the study of spatio-temporal features of neuronal activity in the brain. The stability of the linear silicon electrode array (LSEA) in recording neuronal potentials and its validity in recording unit activity are investigated. The experimental results showed that during the recording of field potentials in the hippocampal CA1 region of anesthetized rats, upward and downward movements of the recording probe for a distance of 200 ?m did not affect the orthordromic and antidromic evoked potentials significantly. The data indicated that the probe movements caused very small damage to the neurons, and the recording was stable. The contact sites that located in the pyramidal cell layer acquired CA1 neuronal unit activity validly. Different types of unit activity from independent neurons were easily distinguished in epochs of recording from a same recording site. These results demonstrated the features of the LSEA, including the facility of probe manipulation, the stability of recording and the abundance of data acquirement. The data will be helpful to the researchers involved in the application of microelectrode array for neuroscience researches.
ABSTRACT
Objective To explore the behavioral and electrophysiological characteristics of prefrontal executive control in macaca mulatas. Methods Three macaca mulatas were used for behavioral research. Neuronal activities of the prefrontal cortex were recorded in two monkeys while visual discriminated go/no go tasks were being performed. Results ① The response time was (419?18)ms, (376?26)ms and (540?21)ms in three monkeys while performing go/no go tasks; ② A total of 41 tetrodes penetrations were made in the PFC of two monkeys. A total of 92 task related neurons were sampled and categorized as 5 types: visual signal related neurons, decision making related neurons, go movement related neurons, reward related neurons and multi events related neurons; ③ When it was correct, the discharge rate of a neuron to a go signal was significantly higher than that to a no go signal during cue period; the discharge rate of a decision making neuron in a go task was significantly higher than that in a no go task. However, when it was wrong, the situation was on the contrary during delay period. Conclusions ① The prefrontal cortex contains various kinds of neurons; ② There are two types of errors in executing go/no go tasks: cue period error and delay period error.
ABSTRACT
Unit discharges of neurons of the hypothalamic ventromedial nucleus region (HVM) and its surrounding structures including paraventricular nucleus, anterior hypothalamic area,and hypolhalamic dorsomcdial nucleus, were recorded in the ureth-ane-anesthetized and flaxidel-immobilized rats. In HVM,8 of 82 units showed periodical fluctuations in discharge rate, which could be categorized into two types: (1) With alternating active and silent phases 5 (2) with gradually waxing and waning phases. The duration of cach cycle varied from 1 to 5 minutes in different neurons. The periodicity disappeared after intraperitoneal injection of nembutal, while the average discharge rate was raised somewhat. This result suggested that the depressing pha-s of periodical activity of the HVM neuron might probably result from the inhibitory action in certain neuronal circuit, rather than from the intrinsic property of the recorded neurons. The effect of picrotoxin was contradictory. No periodical activity was noted in the 47 recorded neurons outside of the HVM.