Dissociations between appetitive and consummatory responses by pharmacological manipulations of reward-relevant brain regions.
Appetitive behaviors of rats were monitored in a runway situation following central infusions of neuroactive substances into brain areas implicated in electrical self-stimulation. Microinjections of the dopamine antagonist cis-flupentixol or the cholinergic antagonist atropine into the nucleus accumbens (Acb) severely reduced the approach speed and anticipatory shuttlebox activity while leaving the consumption of the 20% sucrose reward intact. Microinjections of GABA into the ventral tegmental area (VTA), pedunculopontine tegmental nucleus (PPTg), and oral pontine reticular nucleus (PnO) also severely disrupted approach without decreasing consumption. The highest doses of atropine into the VTA, PPTg, and PnO disrupted both consummatory and approach responses equally. The results indicate that modulation of various neurochemistries along the trajectory of the self-stimulation system has stronger effects on appetitive approach than consummatory motivation. The implications for understanding appetitive-approach motivation in the brain are discussed.
Ikemoto
S
S
Department of Psychology; Bowling Green State University, Ohio 43402, USA.
Panksepp
J
J
D000109:Acetylcholine / Q000502:physiology; D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects / Q000502:physiology*; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D001931:Brain Mapping; D003259:Consummatory Behavior / Q000187:drug effects / Q000502:physiology*; D018492:Dopamine Antagonists / Q000494:pharmacology; D004558:Electric Stimulation; D005475:Flupenthixol / Q000494:pharmacology; D008297:Male; D008845:Microinjections; D009042:Motivation; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D018377:Neurotransmitter Agents / Q000502:physiology*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000502:physiology; D011149:Pons / Q000187:drug effects / Q000502:physiology; D051381:Rats; D012154:Reticular Formation / Q000187:drug effects / Q000502:physiology; D012653:Self Stimulation / Q000187:drug effects / Q000502:physiology*; D013681:Tegmentum Mesencephali / Q000187:drug effects / Q000502:physiology; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology / Q000502:physiology
D018492:Dopamine Antagonists; D018377:Neurotransmitter Agents; D005680:gamma-Aminobutyric Acid; D005475:Flupenthixol; D000109:Acetylcholine