Active avoidance recruits the anterior cingulate cortex regardless of social context in male and female rats.

Actively avoiding danger is necessary for survival. Most research has focused on the behavioral and neurobiological processes when individuals avoid danger alone, under solitary conditions. Therefore, little is known about how social context affects active avoidance. Using a modified version of the platform-mediated avoidance task in rats, we investigated whether the presence of a social partner attenuates conditioned freezing and enhances avoidance learning compared to avoidance learned under solitary conditions. Rats spent a similar percentage of time avoiding during the tone under both conditions; however, rats trained under social conditions exhibited greater freezing during the tone as well as lower rates of darting and food seeking compared to solitary rats. Under solitary conditions, we observed higher levels of avoidance in females compared to males, which was not present in rats trained under social conditions. To gain greater mechanistic insight, we optogenetically inactivated glutamatergic projection neurons in the anterior cingulate cortex (ACC) following avoidance training. Photoinactivation of ACC neurons reduced expression of avoidance under social conditions both in the presence and absence of the partner. Under solitary conditions, photoinactivation of ACC delayed avoidance in males but blocked avoidance in females. Our findings suggest that avoidance is mediated by the ACC, regardless of social context, and may be dysfunctional in those suffering from trauma-related disorders. Furthermore, sex differences in prefrontal circuits mediating active avoidance warrant further investigation, given that females experience a higher risk of developing anxiety disorders.

Knowledge-based intervention improves older adult recognition memory for novel activity, but not event segmentation or temporal order memory.

Although episodic memory declines with age, older adults are often able to make use of relevant knowledge to support episodic memory. More specifically, prior knowledge may support the perception of meaningful events through the process of event segmentation. We sought to test whether increasing older adults' knowledge for novel activities (i.e., Tai chi, making gyozas) would improve segmentation and memory. We conducted an online, pre-registered intervention in which eighty older adults were recruited based on being novices in each of the targeted activities. Participants completed segmentation and memory tests before and after being randomly assigned to one of two interactive virtual workshops (learning how to practice Tai chi or make gyozas). Each workshop consisted of two one-hour sessions during which an expert provided information about the activity and demonstrated it in a step-by-step fashion. We found that the intervention led to increased learning and recognition memory for the trained activity; however, there were no significant improvements in segmentation behavior, free recall, or memory of sequential information. These findings indicate that either more knowledge training is necessary to affect segmentation, or that segmentation is guided by perceptual features in the environment rather than one's conceptual understanding of the activity.

Local geometric properties do not support reorientation in hippocampus-engaged homing pigeons.

It is generally accepted that the geometry of an environment is a reliable source of information for spatial navigation used by most vertebrate species. However, there is a continuing debate on which geometrical properties of space are the ones that matter for reorientation. In this study, pigeons were trained to find a food reward hidden in 2 opposite corners in a rectangular arena. The animals were then tested in a kite-shaped environment similar to Pearce, Good, Jones, and McGregor (2004). We found that pigeons, unlike rats, were not able to identify the correct corner in the kite arena even though elements clearly preserved the correct long wall-short wall geometric configuration and the local aspect of the trained goal. This behavioral study was followed by a c-Fos, IEG analysis of brain activation that contrasted pigeons exposed to the trained, familiar rectangular environment with pigeons that were exposed to an unfamiliar, trapezoid arena. The hippocampal formation (HF) displayed greater c-Fos expression in the animals exposed to the familiar, training arena, which further supports the conclusion that pigeons do not substantially rely on local geometric features for reorientation. (PsycINFO Database Record (c) 2019 APA, all rights reserved).