PROJECT DiViNe: DIVERSE VOICES IN NEUROSCIENCE: Profiles of Rita Levi-Montalcini, Ricardo Miledi, Simon LeVay, Erich Jarvis, and Steve Ramirez.

In this paper we share the first five of what we hope will be many profiles of neuroscientists from historically underrepresented or marginalized groups. This initial collection of profiles, meant to stake out the general territory for future offerings, takes as its subjects a fairly broad range of individuals from Nobel laureates to early career scientists and educators. The goal of this project is to facilitate the dissemination of materials neuroscience educators can use to highlight the scientific contributions and personal stories of scientists from historically marginalized groups, and has been developed more extensively in the Editorial that accompanies this collection (Frenzel and Harrington, 2021). We believe that by sharing these stories, and highlighting the diversity of those who have and will continue to contribute to the field of neuroscience, we can help to foster a more inclusive discipline for our undergraduate students. Each of these profiles is a testament to the respect these contributors hold for their subjects. We hope that others might see this new feature as an opportunity to share the admiration they have for those who have impacted them as colleagues, mentors, and role models.

Celebrating Diverse Voices in Neuroscience: Introducing Project DiViNe.

Institutions of higher education are meant to provide opportunities for the growth and development of their students. As student bodies have become more diverse it would seem to follow that institutional efforts to satisfy this obligation would likewise need to change. Despite increases in the numbers of historically underrepresented students entering higher education, the proportion of these students who graduate continues to lag behind that of students who are not historically underrepresented. As others have suggested, we believe the disparity between rates of matriculation and graduation parallels a disconnect between diversity and inclusion. Whereas the former is a relatively simple matter of access and demographic accounting, the latter concerns the lived experiences of students within our programs. Evidence suggests that the degree to which students feel valued within their programs can predict students' success, persistence, and graduation from these programs. Here, in an effort to promote greater inclusion, we propose a new pedagogical resource designed to share the personal stories and scientific contributions of neuroscientists from historically underrepresented or marginalized groups. After providing some context for why these interventions are so important, we describe the general expectations of these profiles and, in an accompanying article in this same issue, provide a number of examples. By incorporating these stories into our curricula we would hope to increase the sense of belonging of historically underrepresented or marginalized students and to increase awareness of disciplinary diversity among their peers. Ultimately, by challenging a colorblind approach to science in general and to neuroscience in particular, we hope to change our collective assumptions about who neuroscientists are and can be.

An Instructor's Guide to (Some of) the Most Amazing Papers in Neuroscience.

Although textbooks are still assigned in many undergraduate science courses, it is now not uncommon, even in some of the earliest courses in the curriculum, to supplement texts with primary source readings from the scientific literature. Not only does reading these articles help students develop an understanding of specific course content, it also helps foster an ability to engage with the discipline the way its practitioners do. One challenge with this approach, however, is that it can be difficult for instructors to select appropriate readings on topics outside of their areas of expertise as would be required in a survey course, for example. Here we present a subset of the papers that were offered in response to a request for the "most amazing papers in neuroscience" that appeared on the listserv of the Faculty for Undergraduate Neuroscience (FUN). Each contributor was subsequently asked to describe briefly the content of their recommended papers, their pedagogical value, and the audiences for which these papers are best suited. Our goal is to provide readers with sufficient information to decide whether such articles might be useful in their own classes. It is not our intention that any article within this collection will provide the final word on an area of investigation, nor that this collection will provide the final word for the discipline as a whole. Rather, this article is a collection of papers that have proven themselves valuable in the hands of these particular educators. Indeed, it is our hope that this collection represents the inaugural offering of what will become a regular feature in this journal, so that we can continue to benefit from the diverse expertise of the FUN community.

Use of Whole-Genome Sequencing to Link Burkholderia pseudomallei from Air Sampling to Mediastinal Melioidosis, Australia.

The frequency with which melioidosis results from inhalation rather than percutaneous inoculation or ingestion is unknown. We recovered Burkholderia pseudomallei from air samples at the residence of a patient with presumptive inhalational melioidosis and used whole-genome sequencing to link the environmental bacteria to B. pseudomallei recovered from the patient.

What drives the occurrence of the melioidosis bacterium Burkholderia pseudomallei in domestic gardens?

Melioidosis is an often fatal infectious disease affecting humans and animals in tropical regions and is caused by the saprophytic environmental bacterium Burkholderia pseudomallei. Domestic gardens are not only a common source of exposure to soil and thus to B. pseudomallei, but they also have been found to contain more B. pseudomallei than other environments. In this study we addressed whether anthropogenic manipulations common to gardens such as irrigation or fertilizers change the occurrence of B. pseudomallei. We conducted a soil microcosm experiment with a range of fertilizers and soil types as well as a longitudinal interventional study over three years on an experimental fertilized field site in an area naturally positive for B. pseudomallei. Irrigation was the only consistent treatment to increase B. pseudomallei occurrence over time. The effects of fertilizers upon these bacteria depended on soil texture, physicochemical soil properties and biotic factors. Nitrates and urea increased B. pseudomallei load in sand while phosphates had a positive effect in clay. The high buffering and cation exchange capacities of organic material found in a commercial potting mix led to a marked increase in soil salinity with no survival of B. pseudomallei after four weeks in the potting mix sampled. Imported grasses were also associated with B. pseudomallei occurrence in a multivariate model. With increasing population density in endemic areas these findings inform the identification of areas in the anthropogenic environment with increased risk of exposure to B. pseudomallei.

Can You Change a Student's Mind in a Course about the Brain? Belief Change Following an Introductory Course in Biological Psychology.

Undergraduate courses in the neurosciences, including biological psychology, often appeal to students because they offer perspectives on human behavior and experience that are so different from those students arrive with or are exposed to elsewhere on campus. Consider, for example, this passage from Crick's, Astonishing Hypothesis: "You, your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behaviour of a vast assembly of nerve cells and their associated molecules." Unfortunately, because this perspective is at such odds with those many students arrive with, the very thing that makes these classes so interesting is also likely to engender resistance. With Crick's hypothesis serving as the theme of my introductory course in biological psychology, we explore the ways in which complex experiences and behaviors can be explained by lower-level, biological phenomena. Historically, and for a host of valid reasons, class assessment tends to focus on whether students understand the course material (e.g., Can you explain the role of Ca(2+) in synaptic transmission?), rather than whether students believe what they have been introduced to (e.g., Do you believe that the mind exists as something separate from the body?). For a number of years, however, I have also been collecting pre- and post-test data from students enrolled in three formats of the class in an effort to measure changes in beliefs. One format was a conventional standalone class, whereas the other two were more intensive and involved parallel coursework in the Philosophy of Mind with a second instructor. The full assessment, identical at both test intervals, was comprised of 56 items and included 16 items from a Theoretical Orientation Scale (TOS; Coan, 1979), several of which addressed whether human behavior was predictable; 14 items that addressed dualism, the veracity of our perceptions, personal responsibility, and other topics; and 26 items from the Organicism-Mechanism Paradigm Inventory (OMPI; Germer et al., 1982). Unlike most of the other test items, which addressed class topics specifically, the OMPI addressed general worldviews between two poles of mechanism and organicism. Mechanistic explanations, common in Neuroscience, tend to be highly reductive and treat organisms as more passive and reactive, whereas organismic explanations treat organisms as more active and the systems that give rise to their behaviors as non-reductive. Overall, analyses revealed statistically significant changes on a wide range of items that were generally, though not always, consistent with course objectives. The results of the OMPI indicated that the average student began the term closer to the organismic end of the scale, and became slightly more organismic by the end of the term. And yet, on a number of items related more specifically to the relationship between brain and behavior, students became more willing to endorse reductive and mechanistic positions. Although student beliefs can be very resistant to persuasion, change can occur.

Spatial sensitivity of neurons in the anterior, posterior, and primary fields of cat auditory cortex.

We assessed the spatial-tuning properties of units in the cat's anterior auditory field (AAF) and compared them with those observed previously in the primary (A1) and posterior auditory fields (PAF). Multi-channel, silicon-substrate probes were used to record single- and multi-unit activity from the right hemispheres of alpha-chloralose-anesthetized cats. Spatial tuning was assessed using broadband noise bursts that varied in azimuth or elevation. Response latencies were slightly, though significantly, shorter in AAF than A1, and considerably shorter in both of those fields than in PAF. Compared to PAF, spike counts and latencies were more poorly modulated by changes in stimulus location in AAF and A1, particularly at higher sound pressure levels. Moreover, units in AAF and A1 demonstrated poorer level tolerance than units in PAF with spike rates modulated as much by changes in stimulus intensity as changes in stimulus location. Finally, spike-pattern-recognition analyses indicated that units in AAF transmitted less spatial information, on average, than did units in PAF-an observation consistent with recent evidence that PAF is necessary for sound-localization behavior, whereas AAF is not.

Spatial sensitivity in the dorsal zone (area DZ) of cat auditory cortex.

We compared the spatial sensitivity of neural responses in three areas of cat auditory cortex: primary auditory cortex (A1), the posterior auditory field (PAF), and the dorsal zone (DZ). Stimuli were 80-ms pure tones or broadband noise bursts varying in free-field azimuth (in the horizontal plane) or elevation (in the vertical median plane), presented at levels 20-40 dB above units' thresholds. We recorded extracellular spike activity simultaneously from 16 to 32 sites in one or two areas of alpha-chloralose-anesthetized cats. We examined the dependence of spike counts and response latencies on stimulus location as well as the information transmission by neural spike patterns. Compared with units in A1, DZ units exhibited more complex frequency tuning, longer-latency responses, increased prevalence and degree of nonmonotonic rate-level functions, and weaker responses to noise than to tonal stimulation. DZ responses also showed sharper tuning for stimulus azimuth, stronger azimuthal modulation of first-spike latency, and enhanced spatial information transmission by spike patterns, compared with A1. Each of these findings was similar to differences observed between PAF and A1. Compared with PAF, DZ responses were of shorter overall latency, and more DZ units preferred stimulation from ipsilateral azimuths, but the majority of analyses suggest strong similarity between PAF and DZ responses. These results suggest that DZ and A1 are physiologically distinct cortical fields and that fields like PAF and DZ might constitute a "belt" region of auditory cortex exhibiting enhanced spatial sensitivity and temporal coding of stimulus features.

Location coding by opponent neural populations in the auditory cortex.

Although the auditory cortex plays a necessary role in sound localization, physiological investigations in the cortex reveal inhomogeneous sampling of auditory space that is difficult to reconcile with localization behavior under the assumption of local spatial coding. Most neurons respond maximally to sounds located far to the left or right side, with few neurons tuned to the frontal midline. Paradoxically, psychophysical studies show optimal spatial acuity across the frontal midline. In this paper, we revisit the problem of inhomogeneous spatial sampling in three fields of cat auditory cortex. In each field, we confirm that neural responses tend to be greatest for lateral positions, but show the greatest modulation for near-midline source locations. Moreover, identification of source locations based on cortical responses shows sharp discrimination of left from right but relatively inaccurate discrimination of locations within each half of space. Motivated by these findings, we explore an opponent-process theory in which sound-source locations are represented by differences in the activity of two broadly tuned channels formed by contra- and ipsilaterally preferring neurons. Finally, we demonstrate a simple model, based on spike-count differences across cortical populations, that provides bias-free, level-invariant localization-and thus also a solution to the "binding problem" of associating spatial information with other nonspatial attributes of sounds.

Tinnitus in hamsters following exposure to intense sound.

Hamsters were trained with a conditioned suppression/avoidance procedure to drink in the presence of a broadband noise and/or a tone and to stop drinking in the absence of sound. A variety of tones and loudspeaker locations were used during training so that the animals would respond to a sound regardless of its frequency or location. Four groups of animals then had their left ears exposed to a 10-kHz tone at 124 or 127 dB for 0.5, 1, 2 or 4 h. They were then tested for tinnitus by comparing their performance with that of unexposed animals to determine if they behaved as if they perceived a sound when no external sound was present. The groups exposed for 2 and 4 h tested positive for tinnitus whereas those exposed for 0.5 and 1 h did not. The degree of hearing loss produced by the tone exposure was assessed using behavioral and auditory brainstem response (ABR) procedures. A partial dissociation was found between the hearing loss, as estimated by the ABR, and the results of the tinnitus test in that animals exposed for 1 h had the same hearing loss as the 2- and 4-h exposed animals, but did not test positive for tinnitus. This suggests that the positive scores on the tinnitus test were not due to hearing loss. These results are discussed along with those of previous behavioral studies of tinnitus in animals.