Avian nidopallium caudolaterale mediates decision-making during goal-directed navigation.

Previous work demonstrates that nidopallium caudolaterale, which is considered to be an analog of the mammalian prefrontal cortex, participates in goal-directed navigation in pigeons. However, its role remains unclear. To clarify its role, two goal-directed navigation tasks in plus-maze were designed, in which the goal location of one is random, and the other is fixed, i.e., the random-goal task and the fixed-goal task. The animals were trained to run from the starting location to the goal location in accordance with the cue in the plus-maze. The goal location is variable for the random-goal task but unchanged for the fixed-goal task. The results have demonstrated that the time point of nidopallium caudolaterale neuron response is consistent with decision-making. During the decision-making, the firing rates significantly increased in two tasks, which can also decode the direction of upcoming movement in the random-goal task. However, the location of decision-making is different between the tasks mentioned above. The decision-making window is at the intersection in the random-goal task, which is a departure in the fixed-goal task. In addition, these results also provide evidence that the neural activities obtained from the nidopallium caudolaterale may contain the decision-making information during goal-directed navigation. These results suggest that the avian nidopallium caudolaterale and the mammalian prefrontal cortex may play a similar role in goal-directed spatial decision-making. Additionally, these also may provide some support to understand the neural mechanism of decision-making for different species.

[Comparison of decoding performance between spike and local field potential signals during goal-directed decision-making task of pigeons].

Both spike and local field potential (LFP) signals are two of the most important candidate signals for neural decoding. At present there are numerous studies on their decoding performance in mammals, but the decoding performance in birds is still not clear. We analyzed the decoding performance of both signals recorded from nidopallium caudolaterale area in six pigeons during the goal-directed decision-making task using the decoding algorithm combining leave-one-out and k-nearest neighbor (LOO- kNN). And the influence of the parameters, include the number of channels, the position and size of decoding window, and the nearest neighbor k value, on the decoding performance was also studied. The results in this study have shown that the two signals can effectively decode the movement intention of pigeons during the this task, but in contrast, the decoding performance of LFP signal is higher than that of spike signal and it is less affected by the number of channels. The best decoding window is in the second half of the goal-directed decision-making process, and the optimal decoding window size of LFP signal (0.3 s) is shorter than that of spike signal (1 s). For the LOO- kNN algorithm, the accuracy is inversely proportional to the k value. The smaller the k value is, the larger the accuracy of decoding is. The results in this study will help to parse the neural information processing mechanism of brain and also have reference value for brain-computer interface.

Spatial preference behavior of robo-pigeons induced by electrical stimulus targeting fear nuclei.

BACKGROUND: Numerous studies have confirmed that stimulating the mid-brain motor nuclei can regulate movement forcibly for robo-pigeons, but research on behavior modulation using non-motor nuclei is scarce. OBJECTIVE: In this study, we constructed a spatial preference behavior by stimulating the stratum griseum periventriculare (SGP), a nucleus correlated with fear and escape, for robo-pigeons. METHODS: The study was carried out in a square-enclosed experimental field, with a designated box serving as the 'safe' area for the robo-pigeons. If the robo-pigeon exits this area, the SGP will be stimulated. After a brief training period, the robo-pigeons will have a clear spatial preference for the box. RESULTS: The result from five pigeons has shown that, after simple training, the animals develop a spatial preference for the box. They can quickly return to the box in any situation when the SGP is stimulated, with a success rate exceeding 80% (89.0 ± 6.5%). Moreover, this behavior is highly stable and remains consistent, unaffected by changes in the location of the box or the interference box. CONCLUSION: The results prove that using the electrical stimulus could enable animals to accomplish more complex tasks. It may offer a novel approach to regulating pigeon behavior and further advance the study of cyborg animals.

Wireless-controlled cubic neural stimulator for free-moving animals.

An electrical stimulator transmitting information into selected neural circuits is a promising approach for neural prostheses or animal robots. However, traditional stimulators are based on rigid printed circuit board (PCB) technology; technological limitations hindered the development of stimulators, especially for experiments involving free-moving subjects. Here we described a small (1.6 × 1.8 × 1.6 cm), lightweight (4 g, including a 100 mA h lithium battery) and multi-channel (eight unipolar or four bipolar biphasic channels) cubic wireless electrical stimulator exploiting flexible PCB technology. In comparison with the traditional stimulator, an appliance of both flexible PCB and cube structure makes it smaller and lighter, and enhances its stability. Stimulation sequences can be constructed with 100 selectable current levels, 40 selectable frequency levels and 20 selectable pulse-width-ratio levels. Moreover, the distance of wireless communication can reach approximately 150 m. Both in vitro and in vivo results have demonstrated functionality of the stimulator. The feasibility of remote pigeon's navigation using the proposed stimulator was successfully verified.

Goal-directed behavior elevates gamma oscillations in nidopallium caudolaterale of pigeon.

Avian nidopallium caudolaterale (NCL), a functional analogue of mammalian prefrontal cortex, is thought to be participated to goal-directed behavior. However, few studies so far investigated local field potential (LFP) properties within this area. In this study, we recorded the LFP activity from the NCL of six pigeons when they performed a goal-directed decision-making task in a plus-maze. Spectral analysis revealed a significant LFP-power increase in the gamma-band (40-60Hz) during the decision-making process. Moreover, the LFP activity in the gamma-band was modulated by the behavioral outcomes of pigeons. It could decode effectively the motion directions of animals. These results indicate that the gamma rhythm of LFP recorded from the NCL correlates with the goal-directed behavior of pigeons.