Graduating seniors 2017

This year we bid goodbye to a record number of graduating seniors: Nisha, Nisha, Joseph, Jonathan, Rebecca, and Tracy. And to our AuD student Jeni, who completed her capstone research project and is off to an externship next year. Thanks to all of you for your contributions to the lab over the past few years! You'll be missed!

New paper: concept representation and the dynamic multilevel reactivation framework (Reilly et al.)

I'm fortunate to have as a collaborator Jamie Reilly, who over the past decade has been spearheading an effort to deepen our understanding about how the brain represents concepts (i.e., semantic memory). Our review paper out in Psychonomic Bulletin and Review (Reilly et al., 2016) puts forth the current version of the dynamic multilevel reactivation framework. (It's part of a special issue on concept representation that contains a number of interesting articles.) 

Recent years have seen increasing interest in the idea that concept representations depend in part on modality-specific representation in or near sensory and motor cortex. For example, our concept of a bell includes something about the acoustic sound of a bell ringing, which this view suggests is supported by regions coding auditory information. Information from different modalities would also need to be bound together, perhaps in heteromodal regions such as the angular gyrus (Bonner et al., 2013; Price et al., 2015). (Interestingly, Wernicke proposed much the same thing well over 100 years ago, as related in Gage & Hickok 2005. Smart guy!)

A distributed semantics view has intuitive appeal for many aspects of concrete concepts for which we can easily imagine sensory details associated with an object. However, it is much more difficult to apply this distributed sensorimotor approach to abstract concepts such as "premise" or "vapid". Similar challenges arise for encyclopedic (verbal) knowledge. These difficulties suggest that distributed sensorimotor representations are not the only thing supporting semantic memory. An alternative view focuses more on amodal semantic "hub" regions that integrate information across modalities. The existence of hub regions is supported by cases such as semantic dementia (i.e., the semantic variant of primary progressive aphasia), in which patients lose access to concepts regardless of how those concepts are tested. Reconciling the evidence in support of distributed vs. hub-like representations has been one of the most interesting challenges in contemporary semantic memory research.

In our recent paper, we suggest that concepts are represented in a high dimensional semantic space that encompasses both concrete and abstract concepts. Representations can be selectively activated depending on task demands. Our difficult-to-pronounce but accurate name for this is the "dynamic multilevel reactivation framework" (DMRF).

Although the nature of the link between sensorimotor representations and linguistic knowledge needs to be further clarified, we think a productive way forward will be models of semantic memory that parsimoniously account for both "concrete" and "abstract" concepts within a unified framework.

References:

Bonner MF, Peelle JE, Cook PA, Grossman M (2013) Heteromodal conceptual processing in the angular gyrus. NeuroImage 71:175-186. doi:10.1016/j.neuroimage.2013.01.006 (PDF)

Gage N, Hickok G (2005) Multiregional cell assemblies, temporal binding and the representation of conceptual knowledge in cortex: A modern theory by a "classical" neurologist, Carl Wernicke. Cortex 41:823-832. doi:10.1016/S0010-9452(08)70301-0

Price AR, Bonner MF, Peelle JE, Grossman M (2015) Converging evidence for the neuroanatomic basis of combinatorial semantics in the angular gyrus. Journal of Neuroscience 35:3276-3284. doi:10.1523/JNEUROSCI.3446-14.201 (PDF)

Reilly J, Peelle JE, Garcia A, Crutch SJ (2016) Linking somatic and symbolic representation in semantic memory: The dynamic multilevel reactivation framework. Psychonomic Bulletin and Review. doi:10.3758/s13423-015-0824-5 (PDF)

New paper: The neural consequences of age-related hearing loss

I'm fortunate to have stayed close to my wonderful PhD supervisor, Art Wingfield. A couple of years ago Art and I hosted a Frontiers research topic on how hearing loss affects neural processing. One of our goals was to follow the effects from the periphery (i.e. effects in the cochlea) through higher-level cognitive function.

We've now written a review article that covers these topics (Peelle and Wingfield, 2016). Our theme is one Art has come back to over the years: given the numerous age-related declines in both hearing and cognition, we might expect speech comprehension to be relatively poor in older adults. The fact that it is, in fact, generally quite good speaks to the flexibility of the auditory system and compensatory cognitive and neural mechanisms.

A few highlights:

  • Hearing impairment affects neural function at every level of the ascending auditory system, from the cochlea to primary auditory cortex. Although frequently demonstrated using noise induced hearing loss, many of the same effects are seen for age-related hearing impairment.

  • Functional brain imaging in humans routinely shows that when speech is acoustically degraded, listeners engage more regions outside the core speech network, suggesting this activation may play a compensatory role in making up for the reduced acoustic information. (An important caveat is that task effects have to be considered).

  • Moving forward, an important effort will be understanding how individual differences in both hearing and cognitive abilities affect the brain networks listened use to process spoken language.


We had fun writing this paper, and hope it's a useful resource!


References:

Peelle JE, Wingfield A (2016) The neural consequences of age-related hearing loss. Trends in Neurosciences 39:486–497. doi:10.1016/j.tins.2016.05.001 (PDF)

 

Psychology Research Assistant Opening - Washington University in Saint Louis

We have an exciting research project and are looking to hire a full-time research assistant. This is a joint project between Jonathan Peelle, Kristin Van Engen, and Mitch Sommers  at Washington University in Saint Louis. We are looking at the cognitive and neural systems involved in understanding speech, especially when it is acoustically degraded (due to background noise or hearing loss). If you got the job you would be located in the Sommers lab in the psychology department on the main campus.

Accurately measuring individual differences in cognitive abilities typically requires a lot of data; your primary responsibility would be to collect behavioral data from our research participants (on average 1-2 participants per day). This includes scheduling participants over the phone, running the study, and transferring the data and paperwork afterwards. This is a tall order, and requires someone who is naturally very organized and good with people.

By "naturally organized" we don't need someone who understands what being organized means, or who can file and alphabetize paperwork. That's true of most of the applicants for this job. We are looking for the kind of person who intuitively designs systems to organize things in life outside of work because that's how their mind works.

It also requires being able to work independently, but in the context of our team: you’ll need to be able to move ahead on projects without asking for input from others. It is highly unlikely that you will have all of the required skills already, so being able to prioritize tasks and learn skills on your own is critical.

As one example of this, you’ll be programming experiments using EPrime and/or PsychoPy. Experience with any kind of programming, especially experiment presentation, is a big plus. If you don’t have experience then a willingness and ability to learn quickly is absolutely essential.

It is also very important that you are comfortable interacting with a range of people. First, because our university research team is spread out, you'll need to be able to coordinate and communicate with all of us. Second, and more importantly, you'll need to be able to be engaging and friendly with both undergraduates and older adults who come in for our study. It is imperative that they feel valued and enjoy their experience, but that you are also able to keep them on task. If you are highly introverted you'll need to consider whether you can keep up a high level of interaction with participants for a long period of time.

On a related note, engaging our participants in scientific communication is also a big part of the job: Compensation for participating in our experiments is usually modest, but our participants are willing go out of their way to take part in our project because they are genuinely interested in the work that we do. Therefore, you will need to communicate the purpose and eventual applications of our work to participants during their visit.

Although not required, we anticipate that having some post-undergraduate experience will be really helpful in developing the skills necessary for the job. Although research experience would be great, it's more the overall level of maturity and life experience we think would be useful.

We are asking for a minimum of a 2-year commitment—there will be a significant training period, and we want to make sure you're around to benefit from the environment, and to contribute to the project. If you are considering further education we are confident that the experience (and potential publications) you gain from this time will serve you well. We have a 5-year grant and if all goes well we would love to have you stay part of the team for a long time.

A background in psychology or cognitive neuroscience—including research design, data collection, and/or programming—will be extremely useful in understanding the project and being able to contribute to the interpretation of the results.

If you're not familiar with Saint Louis, it's a great city. None of the main investigators on the grant are natives but we all like the area: the culture, food, and beer scenes are all excellent, and the overall cost of living relatively low. Wash U is a great academic institution with good benefits and a good place to work.

In summary, we are really excited about this project and want to find the right person for the job! We think the most successful candidates will be naturally organized, excited about the project, and have excellent interpersonal skills.

For informal inquiries, please send a CV to Jonathan Peelle. In your email let us know why you think you'd be a good fit, and what might set you apart from other candidates.

We are looking for the best person for the job, not the person with the "right" background or CV. If you are interested and think you'd do well we really encourage you to apply. We won't be able to interview everyone and we may not interview you, but let us be the ones to make this decision.

An official job posting will be available shortly (we hope). We won't be able to respond personally to all inquiries so please keep an eye on the Wash U human resources page and apply officially if you are interested.