A Labeled-Line Code for Small and Large Numerosities in the Monkey Prefrontal Cortex

Abstract

How single neurons represent information about the magnitude of a stimulus remains controversial. Neurons encoding purely sensory magnitude typically show monotonic response functions ("summation coding"), and summation units are usually implemented in models of numerosity representation. In contrast, cells representing numerical quantity exhibit nonmonotonic tuning functions that peak at their preferred numerosity ("labeled-line code"), but the restricted range of tested quantities in these studies did not permit a definite answer. Here, we analyzed both behavioral and neuronal representations of a broad range of numerosities from 1 to 30 in the prefrontal cortex of monkeys. Numerosity-selective neurons showed a clear and behaviorally relevant labeled-line code for all numerosities. Moreover, both the behavioral and neuronal tuning functions obeyed the Weber-Fechner Law and were best represented on a nonlinearly compressed scale. Our single-cell study is in good agreement with functional imaging data reporting peaked tuning functions in humans, demonstrating neuronal precursors for human number competence in a nonhuman primate. Our findings also emphasize that the manner in which neurons encode and maintain magnitude information may depend on the precise task at hand as well as the type of magnitude to represent and memorize.

Basic mathematical rules are encoded by primate prefrontal cortex neurons

“…Because carrying information across delays is thought to reflect working memory, a hallmark function of PFC (40), this finding is particularly surprising and in striking contrast to those of many studies using delayed response tasks (44) as well as our previous recordings from the PFC. There, about one-third of randomly selected PFC neurons were significantly tuned to numerosity during a delayed matching task (11)(12)(13)(14). Neurophysiological differences between individuals are unlikely to account for this discrepancy, because one of the monkeys participating in the current study (monkey B) also exhibited the typical high proportion of numerosity-selective PFC neurons in a previous delayed match to numerosity study (14).…”

“…Neurons in macaque IPS (8)(9)(10) and prefrontal cortex (PFC) (11)(12)(13)(14) readily encode numerosities from visual displays and memorize them during delay periods. In humans, the detection of nonsymbolic numerosities and symbolic number information activates these sites in functional imaging studies (7,(15)(16)(17).…”

Konstruktywizm Jeana Piageta i koncepcja zmysłu liczby a edukacja matematyczna

“…Samo pojęcie zmysłu liczby jest pewnego rodzaju metaforą opisującą różne procesy związane z szacowaniem wielkości (Hornung i in., 2014; Szűcs i in., 2014), przetwarzaniem symbolicznych i niesymbolicznych informacji liczbowych (Pina, Castillo, neuronów liczbowych (number neurons) w obrębie tylnej kory przedczołowej i bruzdy śródciemieniowej, selektywnie reagujących na określone liczebności zbiorów (Nieder, 2005;Nieder i Merten, 2007;Nieder i Miller, 2003;2004). Wyspecjalizowane neurony liczbowe wykryto także u krukowatych (Ditz i Nieder, 2015).…”

Algebraic Models of Mental Number Axes: Part II

“…According to data presented in Miller 2003, 2004;Nieder and Merten 2007), neurons in the brains of macaque monkeys may react centrally or peripherally to a given non-symbolic numeral stimulus. This means that the same neuron may react to many, but not all, of the different cardinalities of non-symbolic numerals.…”