About

Andrew Bass is the Horace White Professor of Neurobiology and Behavior at Cornell University. His work focuses on behavioral and evolutionary neuroscience, aiming to explain how phenotypic variation in vertebrate brain organization leads to adaptive behavioral phenotypes. He communicates these ideas through teaching, seminars, and symposia both nationally and internationally. His research projects utilize sound-producing and vocalizing teleost fish as model systems to establish the operating principles of the vocal and auditory systems of vertebrates. His laboratory's research concentrates on two main projects: the characterization and hormonal influences on sex differences in the morphology of physiologically-identified neurons, and the temporal and spectral encoding of acoustic communication signals. These studies involve a multidisciplinary, neuroethological approach that combines field studies of vocal communication with laboratory investigations using neurophysiology, anatomical tract tracing, neuroendocrinology, electron microscopy, immunocytochemistry, and in situ hybridization. His contributions significantly advance understanding of the neural mechanisms underlying vocal communication and social behaviors in fish, with broader implications for vertebrate neurobiology.

Research topics

• Biology
• Zoology
• Neuroscience
• Psychology
• Genetics
• Fishery
• Anatomy
• Evolutionary biology
• Developmental psychology
• Geology
• Physics
• Ecology
• Paleontology
• Optics

Selected publications

• Comparative neuroscience: A tale of two fishes

  Current Biology · 2025-07-01

  articleSenior author
  PublisherDOI

• Label‐Free Multiphoton Imaging Reveals Volumetric Shifts Across Development in Sensory‐Related Brain Regions of a Miniature Transparent Vertebrate

  The Journal of Comparative Neurology · 2025-04-01 · 2 citations

  articleOpen accessSenior authorCorresponding

  Animals integrate information from different sensory modalities as they mature and perform increasingly complex behaviors. This may parallel differential investment in specific brain regions depending on the changing demands of sensory inputs. To investigate developmental changes in the volume of canonical sensory regions, we used third harmonic generation imaging for morphometric analysis of forebrain and midbrain regions from larval through juvenile and adult stages in Danionella dracula, a transparent, miniature teleost fish whose brain is optically accessible throughout its lifespan. Relative to whole-brain volume, increased volume or investment in the telencephalon, a higher order sensory integration center, shows the most dramatic increases between 30-60 days postfertilization (dpf) and again at 90 dpf as animals reach adulthood. The torus longitudinalis (TL), a midbrain visuomotor integration center, also significantly increases between 60 and 90 dpf. In contrast, investment in the midbrain optic tectum (TeO), a retinal-recipient target, progressively decreases from 30 to 90 dpf, whereas investment is relatively consistent across all stages for the midbrain torus semicircularis (TS), a secondary auditory and mechanosensory lateral line center, and the olfactory bulb (OB), a direct target of the olfactory epithelium. In sum, increased investment in higher-order integration centers (telencephalon, TL) occurs as juveniles reach adulthood (60-90 dpf) and exhibit more complex cognitive tasks, whereas investment in modality-dominant regions occurs earlier (TeO) or is relatively consistent across development (TS, OB). Complete optical access throughout Danionella's lifespan provides a unique opportunity to investigate how changing brain structure over development correlates with changes in connectivity, microcircuitry, or behavior.

  PublisherOA PDFDOI

• Label‐free, whole‐brain in vivo mapping in an adult vertebrate with third harmonic generation microscopy

  The Journal of Comparative Neurology · 2024-04-01 · 6 citations

  articleOpen accessSenior authorCorresponding

  Comprehensive understanding of interconnected networks within the brain requires access to high resolution information within large field of views and over time. Currently, methods that enable mapping structural changes of the entire brain in vivo are extremely limited. Third harmonic generation (THG) can resolve myelinated structures, blood vessels, and cell bodies throughout the brain without the need for any exogenous labeling. Together with deep penetration of long wavelengths, this enables in vivo brain-mapping of large fractions of the brain in small animals and over time. Here, we demonstrate that THG microscopy allows non-invasive label-free mapping of the entire brain of an adult vertebrate, Danionella dracula, which is a miniature species of cyprinid fish. We show this capability in multiple brain regions and in particular the identification of major commissural fiber bundles in the midbrain and the hindbrain. These features provide readily discernable landmarks for navigation and identification of regional-specific neuronal groups and even single neurons during in vivo experiments. We further show how this label-free technique can easily be coupled with fluorescence microscopy and used as a comparative tool for studies of other species with similar body features to Danionella, such as zebrafish (Danio rerio) and tetras (Trochilocharax ornatus). This new evidence, building on previous studies, demonstrates how small size and relative transparency, combined with the unique capabilities of THG microscopy, can enable label-free access to the entire adult vertebrate brain.

  PublisherOA PDFDOI

• A tale of two males: Behavioral and neural mechanisms of alternative reproductive tactics in midshipman fish

  Hormones and Behavior · 2024-03-12 · 3 citations

  review1st authorCorresponding
  PublisherDOI

• Label-free multiphoton imaging reveals volumetric shifts across development in sensory-related brain regions of a miniature transparent vertebrate

  bioRxiv (Cold Spring Harbor Laboratory) · 2024-07-22

  preprintOpen accessSenior authorCorresponding

  ABSTRACT Animals integrate information from different sensory modalities as they mature and perform increasingly complex behaviors. This may parallel differential investment in specific brain regions depending on the demands of changing sensory inputs. To investigate developmental changes in the volume of canonical sensory integration brain regions, we used third harmonic generation imaging for morphometric analysis of forebrain and midbrain regions from 5 to 90 days post fertilization (dpf) in Danionella dracula , a transparent, miniature teleost fish whose brain is optically accessible throughout its lifespan. Relative to whole brain volume, increased volume or investment in telencephalon, a higher order sensory integration center, and torus longitudinalis (TL), a midbrain visuomotor integration center, is relatively consistent from 5 to 30 dpf, until it increases at 60 dpf, followed by another increase at 90 dpf, as animals reach adulthood. In contrast, investment in midbrain optic tectum (TeO), a retinal-recipient target, progressively decreases from 30-90 dpf, whereas investment is relatively consistent across all stages for the midbrain torus semicircularis (TS), a secondary auditory and mechanosensory lateral line center, and the olfactory bulb (OB), a direct target of the olfactory epithelium. In sum, increased investment in higher order integration centers (telencephalon, TL) occurs as juveniles reach adulthood and exhibit more complex cognitive tasks, whereas investment in modality-dominant regions occurs in earlier stages (TeO) or is relatively consistent across development (TS, OB). Complete optical access throughout Danionella ’s lifespan provides a unique opportunity to investigate how changing brain structure over development correlates with changes in connectivity, microcircuitry, or behavior.

  PublisherOA PDFDOI

• Midbrain node for context-specific vocalisation in fish

  Nature Communications · 2024-01-02 · 7 citations

  articleOpen accessSenior author

  Vocalizations communicate information indicative of behavioural state across divergent social contexts. Yet, how brain regions actively pattern the acoustic features of context-specific vocal signals remains largely unexplored. The midbrain periaqueductal gray (PAG) is a major site for initiating vocalization among mammals, including primates. We show that PAG neurons in a highly vocal fish species (Porichthys notatus) are activated in distinct patterns during agonistic versus courtship calling by males, with few co-activated during a non-vocal behaviour, foraging. Pharmacological manipulations within vocally active PAG, but not hindbrain, sites evoke vocal network output to sonic muscles matching the temporal features of courtship and agonistic calls, showing that a balance of inhibitory and excitatory dynamics is likely necessary for patterning different call types. Collectively, these findings support the hypothesis that vocal species of fish and mammals share functionally comparable PAG nodes that in some species can influence the acoustic structure of social context-specific vocal signals.

  PublisherOA PDFDOI

• Author response for "Label‐free, whole‐brain in vivo mapping in an adult vertebrate with third harmonic generation microscopy"

  2024-02-16

  peer-reviewSenior author
  PublisherDOI

• Danionella fishes

  Nature Methods · 2024-10-01 · 8 citations

  article1st authorCorresponding
  PublisherDOI

• California singing fish

  Current Biology · 2023-03-01 · 4 citations

  articleOpen access1st authorCorresponding
  PublisherOA PDFDOI

• :<i>Neuroendocrine Regulation of Animal Vocalization: Mechanisms and Anthropogenic Factors in Animal Communication</i>

  The Quarterly Review of Biology · 2023-05-18

  review1st authorCorresponding
  PublisherDOI

Recent grants

• Midbrain Motor Coding of Vocal Behavior

  NSF · $830k · 2017–2022

• NIH Grant R01DC000092

  NIH · $5.6M · 2012

• DISSERTATION RESEARCH: Melatonin Regulation of Vocal Behavior

  NSF · $19k · 2014–2016

• Molecular-neural basis for motor patterning of vocal-acoustic signals

  NSF · $850k · 2015–2021

• Behavioral Neuroendocrinology of Vocal Communication

  NSF · $629k · 2005–2011

Frequent coauthors

• Margaret A. Marchaterre

  Cornell University

  47 shared

• R. Baker

  45 shared

• Paul M. Forlano

  36 shared

• Edwin Gilland

  Howard University

  34 shared

• Carl D. Hopkins

  24 shared

• Matthew S. Grober

  Florida Aquarium

  24 shared

• Richard K. Brantley

  University of Virginia

  22 shared

• Ni Y. Feng

  Nanjing Agricultural University

  19 shared

Labs

• Bass LabPI

Awards & honors

• Mong fellowship