We examined the prediction that people activate perceptual symbols during language comprehension. Subjects read sentences describing an animal or object in a certain location. The shape of the object or animal changed as a function of its location (e.g., eagle in the sky, eagle in a nest). However, this change was only implied by the sentences. After reading a sentence, subjects were presented with a line drawing of the object in question. They judged whether the object had been mentioned in the sentence (Experiment 1) or simply named the object (Experiment 2). In both cases, responses were faster when the pictured object's shape matched the shape implied by the sentence than when there was a mismatch. These results support the hypothesis that perceptual symbols are routinely activated in language comprehension.

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The prefrontal cortex (PFC) is a brain region that is critically involved in cognitive function and inhibitory control of behavior, and adolescence represents an important period of continued PFC development that parallels the maturation of these functions. Evidence suggests that this period of continued development of the PFC may render it especially vulnerable to environmental insults that impact PFC function in adulthood. Experimentation with alcohol typically begins during adolescence when binge-like consumption of large quantities is common. In the present study, we investigated the effects of repeated cycles of adolescent intermittent ethanol (AIE) exposure (post-natal day 28–42) by vapor inhalation on different aspects of executive functioning in the adult rat. In an operant set-shifting task, AIE exposed rats exhibited deficits in their ability to shift their response strategy when the rules of the task changed, indicating reduced behavioral flexibility. There were no differences in progressive-ratio responding for the reinforcer suggesting that AIE did not alter reinforcer motivation. Examination of performance on the elevated plus maze under conditions designed to minimize stress revealed that AIE exposure enhanced the number of entries into the open arms, which may reflect either reduced anxiety and/or disinhibition of exploratory like behavior. In rats that trained to self-administer ethanol in an operant paradigm, AIE increased resistance to extinction of ethanol-seeking behavior. This resistance to extinction was reversed by positive allosteric modulation of mGluR5 during extinction training, an effect that is thought to reflect promotion of extinction learning mechanisms within the medial PFC. Consistent with this, CDPPB was also observed to reverse the deficits in behavioral flexibility. Finally, diffusion tensor imaging with multivariate analysis of 32 brain areas revealed that while there were no differences in the total brain volume, the volume of a subgroup of regions (hippocampus, thalamus, dorsal striatum, neocortex and hypothalamus) were significantly different in AIE exposed adults compared to litter-matched control rats. Taken together, these findings demonstrate that binge-like exposure to alcohol during early to middle adolescence results in deficits in PFC-mediated behavioral control in adulthood.

We investigated the question of whether comprehenders mentally simulate a described situation even when this situation is explicitly negated in the sentence. In two experiments, participants read negative sentences such as There was no eagle in the sky, and subsequently responded to pictures of mentioned entities in the context of a recognition task. Participants' responses following negative sentences were faster when the depicted entity matched rather than mismatched the negated situation. These results suggest that comprehenders simulate the negated situation when processing a negated sentence. The results thereby provide further support for the experiential-simulations view of language comprehension.