Reward Contingency Modulates Neuronal Activity in Rat Septal Nuclei during Elemental and Configural Association Tasks

Abstract

It has been suggested that septal nuclei are important in the control of behavior during various reward and non-reward situations. In the present study, neuronal activity was recorded from rat septal nuclei during discrimination of conditioned sensory stimuli (CSs) of the medial forebrain bundle associated with or without a reward (sucrose solution or intracranial self-stimulation, ICSS). Rats were trained to lick a spout protruding close to the mouth just after a CS to obtain a reward stimulus. The CSs included both elemental and configural stimuli. In the configural condition, the reward contingency of the stimuli presented together was opposite to that of each elemental stimulus presented alone, although the same sensory stimuli were involved. Of the 72 responsive septal neurons, 18 responded selectively to the CSs predicting reward (CS+-related), four to the CSs predicting non-reward (CS0-related), nine to some CSs predicting reward or non-reward, and 15 non-differentially to all CSs. The remaining 26 neurons responded mainly during the ingestion/ICSS phase. A multivariate analysis of the septal neuronal responses to elemental and configural stimuli indicated that septal neurons encoded the CSs based on reward contingency, regardless of the stimulus physical properties and were categorized into three groups; CSs predicting the sucrose solution, CSs predicting a non-reward, and CSs predicting ICSS. The results suggest that septal nuclei are deeply involved in discriminating the reward contingency of environmental stimuli to manifest appropriate behaviors in response to changing stimuli.

Rat Paraventricular Neurons Encode Predictive and Incentive Information of Reward Cues

“…Finally, the rats were trained in both regular and modified cue-induced licking tasks, as in the recording sessions (see section "Electrophysiological Recordings"). In this well-trained state, individual lick latencies to the 2-s CSs associated with sucrose were less than 300-500 ms in response to 2-s cues, consistent with previous studies (Oyoshi et al, 1996;Takenouchi et al, 1999;Toyomitsu et al, 2002;Matsuyama et al, 2011). The total number of trials per day in the training session was 200-250.…”

“…Task paradigms and training were essentially similar to our previous studies (Oyoshi et al, 1996;Takenouchi et al, 1999;Toyomitsu et al, 2002;Matsuyama et al, 2011). Briefly, while the heads of the rats were painlessly fixed in a stereotaxic instrument, the rats were trained to lick a tube, which was protruded close to their mouths for 2 s after 2-s CSs, to obtain the 0.3-M sucrose solution or water ( Figure 1A).…”

“…However, it remains unknown how these two types of information are represented in the PVT. The present study investigated the neural representation of this information in the rat PVT by recording PVT neuronal activity in a cue-induced licking task (Oyoshi et al, 1996;Takenouchi et al, 1999;Toyomitsu et al, 2002;Matsuyama et al, 2011). The CSs consisted of both elemental (auditory or visual cues) and configural (simultaneous presentation of the auditory and visual cues) cues.…”

Remote-Controlled Fully Implantable Neural Stimulator for Freely Moving Small Animal

“…Cortical stimulation can be delivered by either a percutaneous connection or a wirelessly controlled stimulator. While a wired percutaneous connection of arrays and an external stimulator represents a simpler approach [13][14][15][16][17], this method limits the movement of the animals and impedes natural behavior. It is also subject to a potential risk of infection at the percutaneous wound site and the mechanical failure of the device due to animal grooming or an external impact.…”

Third Ventricular Glioblastoma Multiforme: Case Report and Literature Review

“…Radiographically, GBMs characteristically present as a heterogeneous mass with necrosis and ring enhancement. 12 22 23 The ring enhancement appearance is due to the presence of dense cellularity and neovascularization in the outer viable margin of the tumor, encompassing the T2-hyperintense necrotic region. 23 …”