Impairments in negative patterning, but not simple discrimination learning, in rats with 192 IgG-saporin lesions of the nucleus basalis magnocellularis.

Rats with 192 IgG-saporin lesions of the nucleus basalis magnocellularis (NBM) and sham-operated rats were trained in either a simple discrimination paradigm assessing simple association learning or a negative patterning paradigm assessing configural association learning. In the simple discrimination task, rats were reinforced for responding to a light but were not reinforced for responding to a tone. In the negative patterning discrimination task, rats were reinforced for responding to either a light or a tone presented alone but were not reinforced for responding to both stimuli presented simultaneously. Simple discrimination learning was not affected, whereas acquisition of negative patterning was impaired by NBM lesions. Impaired configural association learning may reflect a loss in the ability of rats with NBM lesions to attend to multiple sensory stimuli or to cope with conflicting response strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increased rates of events that activate or deactivate the behavioral approach system, but not events related to goal attainment, in bipolar spectrum disorders.

Research indicates that life events involving goal attainment and goal striving trigger hypomania/mania and that negative life events trigger bipolar depression. These findings are consistent with the behavioral approach system (BAS) dysregulation model of bipolar disorders, which suggests that individuals with bipolar disorders are hypersensitive to cues signaling opportunity for reward and cues signaling failure and loss of rewards. However, no studies to date have investigated whether individuals with bipolar spectrum disorders experience increased rates of these BAS-relevant life events, which would place them at double risk for developing bipolar episodes. The present study found that individuals with bipolar II disorder and cyclothymia experience increased rates of BAS-activating and BAS-deactivating, but not goal-attainment, life events. Finally, for bipolar spectrum individuals only, BAS-activating events predicted BAS-deactivating events' rates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)