Inhibition of the LH Surge by Restraint Stress in Cyclic Rats: Studies on the Role of GABAA and GABAB Receptors

There is evidence that stress can alter the activity in the brain of gamma-aminobutyricacid (GABA), a neurotransmitter that has been implicated in the regulation of LH secretion. In the present study the role of GABA in the restraint stress-induced inhibition of the LH surge was investigated in the intact cyclic rat. Intracerebroventricular (icv) administration of the GABAA receptor agonist muscimol (0.1, 0.5 or 1 μg) 5 min before the presumed onset of the pro-oestrous LH surge (at 0900 h) caused a dose dependent suppression of the surge. A single dose of the GABAB receptor agonist baclofen (1 μg; icv) injected at 0855 h postponed the onset of the LH surge, and repeated injections at 0855 and 1130 h suppressed the surge. These data indicate that GABA-ergic activity in the brain can inhibit the LH surge in the cyclic rat via GABAA and GABAB receptors. Pro-oestrous rats were subjected to 5 hrs of restraint starting at 0855 h. Pretreatment with the GABAA receptor antagonist bicuculine (1 μg; icv) at 0840, 0940 and 1040 h or pretreatment with the GABAB receptor antagonist phaclofen (10 μg; icv) at 0840 h were ineffective in preventing the restraint-induced inhibition of the LH surge. The results suggest that GABAA and GABAB receptors are not involved in the inhibitory effect of restraint stress on the LH surge.     

Are historic years understood as numbers or events? An fMRI study of numbers with semantic associations

While numbers generally cue processing of quantity or order, they can also contain semantic information, as in the case of historic years (e.g., “1492” calls forth associations of Columbus sailing the ocean blue). Whether these dates are processed as quantities or events may depend on the context in which they occur. We examined such “ambiguous number” processing in two different contexts using a paired-comparison task, recording both behavioral responses and brain activity. Participants were either asked to think of all items as numbers and to choose the larger number, or were told to treat the comparators as events and to choose the later event. Behaviorally, all events showed a normal distance effect, establishing that they may be understood and compared in an ordinal sequence. Functional magnetic resonance imaging (fMRI) demonstrated significant differences between years when treated as numbers versus as events. Dates in both contexts shared activity in parietal lobe regions previously implicated in number processing. Dates as numbers showed no extra-numeric activity, while dates thought of as events evoked activity in temporal semantic processing and frontal semantic retrieval areas. These differences suggest that extra-numeric information may be easily accessed and incorporated during processing when supported by even a weak context. This work supports previous studies showing a dissociation between quantity and meaning, and illustrates the brain areas involved in these different aspects.     

Age of acquisition's effect on memory for semantically associated word pairs

This experiment investigated the effects of age of acquisition (AoA) in memory for associated word pairs in a cued recall task. Participants studied a list of frequency-controlled early- and late-acquired words in semantically related pairs and then were asked to recall the second word of the pair when cued with the first. Reaction time effects were found, showing that a late-acquired cue for an early-acquired target word was responded to significantly faster than other combinations. Additionally, late-acquired target words resulted in significantly more accurate responses. As significant differences were found even when frequency was controlled, the effects must therefore stem from the manipulations ofAoA. Given this evidence, the implications for AoA's effects on the organization of semantic memory are explored.     

Tangible words are recognized faster: the grounding of meaning in sensory and perceptual systems

Sensory experience rating (SER), a new variable motivated by the grounded cognition framework of conceptual processing (e.g., Barsalou, 2008 ), indexes the degree to which a word evokes sensory/perceptual experiences. In the present study, SERs were collected for over 2,850 words. While SER is correlated with imageability, age of acquisition, and word frequency, the latter variables (along with seven others) account for less than 30% of the variance in SER. Reanalyses of two large-scale studies demonstrate that SER significantly predicts lexical decision times when other established predictor variables are statistically controlled. These results suggest that conceptual processing is grounded in sensory systems. Additionally, a major benefit of this variable is that it allows psycholinguistic researchers to examine semantic-perceptual links for all word classes with a single rating.     

Interactional patterns of bipolar patients and their spouses

This study examined the interactional patterns of eight bipolar patients (when manic and in remission) and their spouses by videotaping the couples' interactions and then quantifying those interactions using the Marital Interaction Coding system. These couples' interactions were compared to the interactions of eight happily and eight unhappily married nonbipolar psychiatric control patients and their spouses. The purposes were to determine (a) whether the interactional pattern between bipolar patients and their spouses changes or remains the same when the patient is in a manic vs. a nonmanic state and (b) how the interaction patterns of bipolar patients when manic and nonmanic compare to happily and unhappily married nonbipolar psychiatriccontrol patients. Significant differences in interactions were found between manic and nonmanic states, in addition to significant differences between these patients and the control groups. There were also expected differences between happily and unhappily married psychiatric control groups. Implications are discussed for marital therapy for manies that involves problemsolving and communication training.