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Sensory and Working Memory Representations of Small and Large Numerosities in the Crow Endbrain.
J Neurosci. 2016 11 23; 36(47):12044-12052.JN

Abstract

Neurons in the avian nidopallium caudolaterale (NCL), an endbrain structure that originated independently from the mammalian neocortex, process visual numerosities. To clarify the code for number in this anatomically distinct endbrain area in birds, neuronal responses to a broad range of numerosities were analyzed. We recorded single-neuron activity from the NCL of crows performing a delayed match-to-sample task with visual numerosities as discriminanda. The responses of >20% of randomly selected neurons were modulated significantly by numerosities ranging from one to 30 items. Numerosity-selective neurons showed bell-shaped tuning curves with one of the presented numerosities as preferred numerosity regardless of the physical appearance of the items. The resulting labeled-line code exhibited logarithmic compression obeying the Weber-Fechner law for magnitudes. Comparable proportions of selective neurons were found, not only during stimulus presentation, but also in the delay phase, indicating a dominant role of the NCL in numerical working memory. Both during sensory encoding and memorization of numerosities in working memory, NCL activity predicted the crows' number discrimination performance. These neuronal data reveal striking similarities across vertebrate taxa in their code for number despite convergently evolved and anatomically distinct endbrain structures.

SIGNIFICANCE STATEMENT

Birds are known for their capabilities to process numerical quantity. However, birds lack a six-layered neocortex that enables primates with numerical competence. We aimed to decipher the neuronal code for numerical quantity in the independently and distinctly evolved endbrain of birds. We recorded the activity of neurons in an endbrain association area termed nidopallium caudolaterale (NCL) from crows that assessed and briefly memorized numerosities from one to 30 dots. We report a neuronal code for sensory representation and working memory of numerosities in the crow NCL exhibiting several characteristics that are surprisingly similar to the ones found in primates. Our data suggest a common code for number in two different vertebrate taxa that has evolved based on convergent evolution.

Authors+Show Affiliations

Animal Physiology Unit, Institute of Neurobiology, University of Tübingen, 72076 Tübingen, Germany.Animal Physiology Unit, Institute of Neurobiology, University of Tübingen, 72076 Tübingen, Germany andreas.nieder@uni-tuebingen.de.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

27881787

Citation

Ditz, Helen M., and Andreas Nieder. "Sensory and Working Memory Representations of Small and Large Numerosities in the Crow Endbrain." The Journal of Neuroscience : the Official Journal of the Society for Neuroscience, vol. 36, no. 47, 2016, pp. 12044-12052.
Ditz HM, Nieder A. Sensory and Working Memory Representations of Small and Large Numerosities in the Crow Endbrain. J Neurosci. 2016;36(47):12044-12052.
Ditz, H. M., & Nieder, A. (2016). Sensory and Working Memory Representations of Small and Large Numerosities in the Crow Endbrain. The Journal of Neuroscience : the Official Journal of the Society for Neuroscience, 36(47), 12044-12052.
Ditz HM, Nieder A. Sensory and Working Memory Representations of Small and Large Numerosities in the Crow Endbrain. J Neurosci. 2016 11 23;36(47):12044-12052. PubMed PMID: 27881787.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Sensory and Working Memory Representations of Small and Large Numerosities in the Crow Endbrain. AU - Ditz,Helen M, AU - Nieder,Andreas, PY - 2016/05/10/received PY - 2016/09/09/revised PY - 2016/09/12/accepted PY - 2016/11/25/entrez PY - 2016/11/25/pubmed PY - 2017/8/19/medline KW - corvid songbird KW - endbrain KW - number KW - single-unit recordings SP - 12044 EP - 12052 JF - The Journal of neuroscience : the official journal of the Society for Neuroscience JO - J. Neurosci. VL - 36 IS - 47 N2 - : Neurons in the avian nidopallium caudolaterale (NCL), an endbrain structure that originated independently from the mammalian neocortex, process visual numerosities. To clarify the code for number in this anatomically distinct endbrain area in birds, neuronal responses to a broad range of numerosities were analyzed. We recorded single-neuron activity from the NCL of crows performing a delayed match-to-sample task with visual numerosities as discriminanda. The responses of >20% of randomly selected neurons were modulated significantly by numerosities ranging from one to 30 items. Numerosity-selective neurons showed bell-shaped tuning curves with one of the presented numerosities as preferred numerosity regardless of the physical appearance of the items. The resulting labeled-line code exhibited logarithmic compression obeying the Weber-Fechner law for magnitudes. Comparable proportions of selective neurons were found, not only during stimulus presentation, but also in the delay phase, indicating a dominant role of the NCL in numerical working memory. Both during sensory encoding and memorization of numerosities in working memory, NCL activity predicted the crows' number discrimination performance. These neuronal data reveal striking similarities across vertebrate taxa in their code for number despite convergently evolved and anatomically distinct endbrain structures. SIGNIFICANCE STATEMENT: Birds are known for their capabilities to process numerical quantity. However, birds lack a six-layered neocortex that enables primates with numerical competence. We aimed to decipher the neuronal code for numerical quantity in the independently and distinctly evolved endbrain of birds. We recorded the activity of neurons in an endbrain association area termed nidopallium caudolaterale (NCL) from crows that assessed and briefly memorized numerosities from one to 30 dots. We report a neuronal code for sensory representation and working memory of numerosities in the crow NCL exhibiting several characteristics that are surprisingly similar to the ones found in primates. Our data suggest a common code for number in two different vertebrate taxa that has evolved based on convergent evolution. SN - 1529-2401 UR - https://www.unboundmedicine.com/medline/citation/27881787/Sensory_and_Working_Memory_Representations_of_Small_and_Large_Numerosities_in_the_Crow_Endbrain_ L2 - http://www.jneurosci.org/cgi/pmidlookup?view=long&pmid=27881787 DB - PRIME DP - Unbound Medicine ER -