COMMENTS: anticipation of reward and novelty rely on separate circuits within the larger reward circuit. Combined activation amplifies the excitement signals, and wires the experience into the brain. Internet porn = anticipation of novelty.
Neuroimage. 2011 Sep 15;58(2):647-55. doi: 10.1016/j.neuroimage.2011.06.038. Epub 2011 Jun 24.
Department of Experimental Psychology, Ghent University, 9000 Ghent, Belgium. [email protected]
Reward and novelty are potent learning signals that critically rely on dopaminergic midbrain responses.
Recent findings suggest that although reward and novelty are likely to interact, both functions may be subserved by distinct neuronal clusters.
We used high-resolution functional magnetic resonance imaging (fMRI) to isolate neural responses to reward and novelty within the human substantia nigra/ventral tegmental area (SN/VTA) complex to investigate the spatial delineation and integration of reward- and novelty-related activity clusters.
We demonstrate that distinct clusters within the caudal portion of the medial SN/VTA and the lateral portion of the right SN are predominantly modulated by the anticipation of reward, while a more rostral part of the medial SN/VTA was exclusively modulated by novelty.
In addition, the caudal medial SN/VTA cluster embodied an interaction between novelty and reward where novelty selectively increased reward-anticipation responses. This interaction, in turn, was paralleled by differences in the functional-connectivity patterns of these SN/VTA regions.
Specifically, novel as compared to familiar reward-predictive stimuli increased the functional connectivity of the medial SN/VTA with mesolimbic regions, including the nucleus accumbens and the hippocampus, as well as with the primary visual cortex.
This functional correlation may highlight how afferents of the medial SN/VTA provide integrative information about novelty and reward, or, alternatively, how medial SN/VTA activity may modulate memory processes for novel events associated with rewards.