Brain reward circuitry: four circuit elements "wired" in apparent series.

Area of Science:

• Neuroscience
• Neurobiology
• Reward System Research

Background:

• Activation of specific central nervous system sites induces rewarding states.
• Four key phenomena demonstrate central reward: amphetamine in nucleus accumbens, morphine in ventral tegmental area, and electrical stimulation of both ventral tegmental area and medial forebrain bundle.

Purpose of the Study:

• To investigate the common neural circuit underlying diverse rewarding stimuli.
• To identify the series-connected elements within this central reward circuit.

Main Methods:

• The study reviews existing evidence on central reward phenomena.
• It proposes a model of a common reward circuit based on anatomical and functional connections.

Main Results:

• Four key elements of a common reward circuit are identified: medial forebrain bundle fibers, opioid peptide afferents to the ventral tegmental area, dopaminergic projections from the ventral tegmental area to the nucleus accumbens, and dopaminoceptive cells within the nucleus accumbens.
• These elements are suggested to be connected in series, forming a functional pathway.

Conclusions:

• Diverse rewarding stimuli converge on a common neural circuit.
• This circuit involves a sequential activation of specific neuronal populations and pathways, including dopaminergic signaling.