Alteration of gene activity in response to early life stress

Review written by Rebekah Rashford (PNI)

There is much consensus that negative stressful early life experiences impact the development of an individual. Numerous studies in humans have linked childhood adversity (e.g., loss of a caregiver, abuse, natural disaster, etc.) to an increased risk for depression and other psychiatric disorders in adulthood. In other words, the more an individual has experienced negative stressors in childhood, the more likely that individual is to develop depression or anxiety when they experience mild stressors in adulthood. This heightened sensitization and increased risk of mood disorders in humans has a parallel observation in rodents, specifically mice, which are used as model organisms in the discussed study. Principal Investigator Catherine Jensen Peña and colleagues at the Icahn School of Medicine at Mount Sinai were interested in exploring the epigenetic effects of such early life stressors on reward circuitry in the brain. Throughout this work the authors posit, as does much of the early life stress (ELS) field, that there could be epigenetic mechanisms at work leading to the aforementioned risk of mood disorder development. 

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Alignment of brain activity leads to increased learning in the classroom

Alignment of brain activity leads to increased learning in the classroom

Review written by Jess Breda (PNI)

Have you ever wondered how information is transferred from one brain to another? This process can occur in a variety of ways, from verbal storytelling to simple hand gestures, and across different backgrounds, such as a flight attendant instructing a first time flyer, or a casual conversation with a friend. We gain information from others on a daily basis. However, to study this on a biological level requires the complicated task of recording from two brains experiencing the same stimuli and aligning their activity in time.

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How do our previous choices inform our future decisions?

Constantinople graphical abstract

Review written by Renee Waters (PSY) 

Humans tend to make individual choices based on a series of past experiences, decisions, and outcomes. Just think about the last time you had some terrible take out: you might decide not to eat at that particular restaurant again based on your previous experience. Maybe, you take the same route to work every day because, in the past, there is less traffic on this particular route. The effects that past experiences have on choices are often termed sequential biases. These biases are present everywhere, especially in value-based decision making. You might wonder, what are the neural mechanisms driving this phenomenon? Christine Constantinople, a former postdoc at Princeton University and now an assistant professor at NYU, began to explore this question along with colleagues in the Brody Lab at Princeton.

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Learning to control the brain

Review written by Eleni Papadoyannis (PNI)

How do humans control a complex system like the brain? Over the years, neuroscientists have discovered numerous methods to do exactly that. Applying chemicals, such as muscimol, can drive inhibition to shut down a brain region. Alternatively, shining light can selectively activate certain cell types through the photo-sensitive protein channelrhodopsin. Sending electrical impulses via electrodes in deep brain stimulation (DBS) can also control regional activity in humans. Causal manipulation of the brain not only offers incredible insight into hypotheses relating neural activity to behavior, but also serves as a clinical tool. Electrical and magnetic stimulation methods have been used as therapies for treating patients with a variety of diseases and disorders, such as using DBS to control motor disruption in Parkinson’s. A major limitation with many stimulation methods, however, is that the protocol is static while the brain is plastic—over time, brain responses to stimulation may no longer elicit what was intended as the brain naturally changes. 

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Understanding visual navigation

Understanding visual navigation using cue cells

Review written by Sara Camilli (QCB) and Adelaide Minerva (PNI)

As we go about our daily lives, we often do not consciously think about all the real-world landmarks that we use to position ourselves in space. Yet, as we walk to our local coffee shop or go for a jog in the park, our brain is continuously updating its internal representation of our location, which is critical to our ability to navigate the world. However, we also know that humans and a number of animals can update this internal representation of their position in space even in the absence of external cues. This phenomenon, known as path integration, involves interaction between the parietal cortex, medial entorhinal cortex (MEC), and hippocampus regions of the brain. Prior work has shown that grid cells in the MEC have firing fields that are arrayed in a hexagonal lattice, tiling an environment. Further, there is evidence of inputs to the MEC that encode the velocity at which an animal is moving, which can be used to update the animal’s internal representation of its position. Together, these features support a role of the MEC in path integration. 

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