Quantifying Morphology of a Differentiating Neuroblastoma Cell Line.

SH-SY5Y neuroblastoma cells are a subclone cell line of SK-N-SH cells derived from neural crest that were originally taken from human bone marrow during a biopsy. Research has shown that these cells can be cultured in vitro to differentiate into mature, neuronal phenotypes such as dopaminergic neurons. Here, we added to these discoveries by establishing a quantitative profile for the SH-SY5Y cells of morphometric features including neurite length, branchpoint numbers, and soma area over the span of 18 days. Overall, we showed that in SH-SY5Y cells neurite length initially decreased followed by a dramatic increase of both neurite length and branching. In contrast, soma area for the SH-SY5Y cells initially increased and then stabilized; followed by a small decrease in size. By determining these morphological changes along various timepoints of SH-SY5Y cell development during the programmed cell differentiation process, we provide a set of baseline data for future mechanistic studies in human-derived neuronal cultures.

Striatum supports fast learning but not memory recall.

Animals learn to carry out motor actions in specific sensory contexts to achieve goals. The striatum has been implicated in producing sensory-motor associations, yet its contribution to memory formation or recall is not clear. To investigate the contribution of striatum to these processes, mice were taught to associate a cue, consisting of optogenetic activation of striatum-projecting neurons in visual cortex, with forelimb reaches to access food pellets. As necessary to direct learning, striatal neural activity encoded both the sensory context and outcome of reaching. With training, the rate of cued reaching increased, but brief optogenetic inhibition of striatal activity arrested learning and prevented trial-to-trial improvements in performance. However, the same manipulation did not affect performance improvements already consolidated into short- (within an hour) or long-term (across days) memories. Hence, striatal activity is necessary for trial-to-trial improvements in task performance, leading to plasticity in other brain areas that mediate memory recall.

Strain-dependent sex differences in a long-term forced swim paradigm.

Women are twice as likely as men to suffer from trauma- and stressor-related disorders. The development of improved therapeutic interventions is contingent upon a more complete grasp of both the neural and behavioral dynamics of the stress response in females. The rodent forced swim test (FST) is a valuable animal model for exploring the neurobiological mechanisms responsible for selection of active and passive responses to inescapable stressors, but it is often neglected in 2-day FST studies is the dissociation of innate (Day 1) versus learned (Day 2) coping responses. Here, we used a modified, long-term (4-week) FST paradigm and immunohistological analysis to study the interactions of sex, strain, and housing arrangement on selection of active and passive coping strategies in Sprague Dawley (SD) and Long Evans (LE) rats. We observed significant strain × sex interactions in both forced swim sessions with respect to both passive (immobility) and active (climbing and headshakes) responses. In immobility measures, we observed stable sex differences in SD rats and a stable lack of sex differences in LE rats across tests. In addition, both SD and LE females displayed significantly more headshakes than males during Test 1 and more climbing in Test 2. Most notably, males, but not females, exhibited a cross-test increase in immobility, suggesting that males and females may engage different learning processes in a 2-day FST. These sex differences corresponded to c-fos expression in the medial prefrontal cortex (mPFC), indicating that the mPFC may contribute to sexually dimorphic behavior in the FST. (PsycINFO Database Record