Brain-derived neurotrophic factor genetic polymorphism rs6265 and creativity

The protein brain-derived neurotrophic factor (BDNF) promotes neural plasticity of the central nervous system and plays an important role for learning and memory. A single nucleotide polymorphism (rs6265) at position 66 in the pro-region of the human BDNF gene, resulting in a substitution of the amino acid valine (val) with methionine (met), leads to attenuated BDNF secretion and has been associated with reduced neurocognitive function. Inhomogeneous results have been found regarding the effect of the BDNF genotype on behavior. We determined the BDNF genotype and performance on the Compound Remote Associate (CRA) task as a common measure of creativity in 76 healthy university students. In our main analyses, we did not find significant differences between met-carriers (n = 30) and non-met carriers (n = 46). In a secondary analysis, we found that met-carriers had a slower solution time (medium effect size) for items of medium difficulty. Our results suggest that met-carriers and non-met-carriers do not generally differ regarding their creativity, but non-met-carriers may have a certain advantage when it comes to moderately difficult problems. The wider literature suggests that both genetic variants come with advantages and disadvantages. Future research needs to sharpen our understanding of the disadvantages and, potentially, advantages met allele carriers may have.

Sleep Strengthens but does Not Reorganize Memory Traces in a Verbal Creativity Task

STUDY OBJECTIVES

Sleep after learning promotes the quantitative strengthening of new memories. Less is known about the impact of sleep on the qualitative reorganization of memory content. This study tested the hypothesis that sleep facilitates both memory strengthening and reorganization as indexed by a verbal creativity task.

METHODS

Sixty healthy university students (30 female, 30 male, 20-30 years) were investigated in a randomized, controlled parallel-group study with three experimental groups (sleep, sleep deprivation, daytime wakefulness). At baseline, 60 items of the Compound Remote Associate (CRA) task were presented. At retest after the experimental conditions, the same items were presented again together with 20 new control items to disentangle off-line incubation from online performance effects.

RESULTS

Sleep significantly strengthened formerly encoded memories in comparison to both wake conditions (improvement in speed of correctly resolved items). Offline reorganization was not enhanced following sleep, but was enhanced following sleep-deprivation in comparison to sleep and daytime wakefulness (solution time of previously incubated, newly solved items). Online performance did not differ between the groups (solution time of new control items).

CONCLUSIONS

The results support the notion that sleep promotes the strengthening, but not the reorganization, of newly encoded memory traces in a verbal creativity task. Future studies are needed to further determine the impact of sleep on different types of memory reorganization, such as associative thinking, creativity and emotional memory processing, and potential clinical translations, such as the augmentation of psychotherapy through sleep interventions.

Carcinoma of the testis

Patients with Stage I or II malignant testis germ cell tumors underwent a randomized prospective study at Walter Reed Hospital, Washington, D.C., from 1968 to 1973. Pure cell lines of seminoma or choriocarcinoma were excluded. Forty patients had inguinal orchiectomy followed by irradiation to the inguinal, iliac, lumbar para-aortic, mediastinal and supraclavicular lymph nodes. Thirty-four patients (85%) in this group are alive and free of tumor a minimum of 3 years. Fifty-one patients received pre- and postoperative irradiation to primary lymphatic pathways in association with bilateral retroperitoneal lymphadenectomy as well as elective irradiation to the mediastinum and supraclavicular regions. Forty-six patients (90%) in this second group are alive and free of tumor a minimum of three years. Both treatment methods represent marked improvement in cure rates compared to lymphadenectomy and postoperative irradiation utilized prior to 1968, but no statistically significant difference from each other.