Characteristics of basolateral amygdala neuronal firing on a spatial memory task involving differential reward.

Abstract

Previous research has shown that spatial, movement, and reward information is integrated within the ventral striatum (VS). The present study examined the possible contribution of the basolateral nuclei of the amygdala (BLA) to this interaction by examining behavioral correlates of BLA neurons while rats performed multiple memory trials on an 8-arm radial maze. Alternate arms consistently held 1 of 2 different amounts of reward. Recorded cells were correlated with motion, auditory input, space, and reward acquisition. Reward-related units were found that anticipated reward encounter, that responded during reward consumption, and that differentiated between high and low reward magnitude. This is consistent with the hypothesis that BLA neurons may provide the VS with reward-related information that could then be integrated with spatial information to ultimately affect goal-directed behavior. Past research into the role of the amygdala in animal behavior has demonstrated that it is an important substrate for the association of cues with their affective significance.

Dopamine gating of glutamatergic sensorimotor and incentive motivational input signals to the striatum

“…Instead, environmentally elicited elevations in mesolimbic and nigrostriatal DA activity gate the input of reward signals to the striatum, just as they gate the throughput of sensorimotor signals to the striatum. As suggested below, striatal reward signals are likely to originate in the orbitofrontal cortex and basolateral amygdala (BLA), regions that contain neurons sensitive to reward magnitude [84,95,106,115] and that project strongly to the striatum [37,47,63].…”

“…The BLA contains neurons that are sensitive to food reward magnitude [95]. Following lesions of the BLA, conditioned stimuli associated with reward lose their ability to control operant behavior [19,20,97].…”

Dopaminergic Regulation of Inhibitory and Excitatory Transmission in the Basolateral Amygdala–Prefrontal Cortical Pathway

“…However, a number of in vivo and in vitro electrophysiological studies have shown that modulation by DA of evoked excitatory responses in the mPFC is dependent on the frequency at which excitatory inputs are activated (Jay et al, 1995;Gurden et al, 1999;Seamans et al, 2001a;Floresco and Grace, 2003;Seamans and Yang, 2004). In light of these data, we assessed the effects of burst stimulation of the VTA on evoked firing when the BLA was stimulated with a higher-frequency train of pulses (five pulses at 20 Hz) in an attempt to mimic the way BLA neurons fire in response to rewarding stimuli (Ono et al, 1995;Pratt and Mizumori, 1998). Analysis of these data with a two-factor ANOVA yielded a significant sample (baseline vs VTA stimulation) by pulse interaction (F (4,20) ϭ 15.49; p Ͻ 0.0001).…”

“…We also assessed whether the effects of VTA stimulation on evoked firing were dependent on the frequency of BLA stimulation. Here, the BLA was stimulated with 20 Hz trains of five pulses, delivered 20 ms after VTA burst stimulation, with this combination of VTA-BLA stimulation delivered every 10 s. The 20 Hz stimulation frequency mimics the way BLA projection neurons fire during reward-related behaviors (Ono et al, 1995;Pratt and Mizumori, 1998). We used a minimum of 25 sweeps to compile the data for all experiments assessing the effects of VTA stimulation on BLA-evoked excitatory responses.…”

Limbic-Cortical-Ventral Striatal Activation during Retrieval of a Discrete Cocaine-Associated Stimulus: A Cellular Imaging Study with γ Protein Kinase C Expression

“…Although presentation of reward-related stimuli increases firing responses in neurons of the BLA complex (Muramoto et al, 1993;Ono et al, 1995;Pratt and Mizumori, 1998), stimulation of glutamatergic BLA afferents elicits excitatory and inhibitory responses in the mPFC, with the latter responses predominating (Perez-Jaranay and Vives, 1991).…”