Lennart Heimer (11 March 1930 – 12 March 2007), was a Swedish-American

neuroscientist A neuroscientist (or neurobiologist) is a scientist who has specialised knowledge in neuroscience, a branch of biology that deals with the physiology, biochemistry, psychology, anatomy and molecular biology of neurons, Biological neural network, n ...

and

professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who pr ...

at the

Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...

and the

University of Virginia The University of Virginia (UVA) is a Public university#United States, public research university in Charlottesville, Virginia. Founded in 1819 by Thomas Jefferson, the university is ranked among the top academic institutions in the United S ...

. He was most noted for mapping circuits of the brain in the

limbic lobe The limbic lobe is an arc-shaped region of cortex on the medial surface of each cerebral hemisphere of the mammalian brain, consisting of parts of the frontal, parietal and temporal lobes. The term is ambiguous, with some authors including the p ...

and

basal ganglia The basal ganglia (BG), or basal nuclei, are a group of subcortical nuclei, of varied origin, in the brains of vertebrates. In humans, and some primates, there are some differences, mainly in the division of the globus pallidus into an extern ...

, structures that play central roles in emotion processing and movement.

Background

Heimer was born in

Östersund Östersund (; sma, Staare) is an urban area (city) in Jämtland in the middle of Sweden. It is the seat of Östersund Municipality and the capital of Jämtland County. Östersund is located at the shores of Sweden's fifth-largest lake, Storsjön, ...

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

. He completed his medical training at the

University of Gothenburg The University of Gothenburg ( sv, Göteborgs universitet) is a university in Sweden's second largest city, Gothenburg. Founded in 1891, the university is the third-oldest of the current Swedish universities and with 37,000 students and 6000 st ...

. In 1965, Heimer was recruited to join the faculty at the MIT Department of Psychology and Brain Science.

Research

Heimer's first notable achievement was the development of the Fink-Heimer silver stain for mapping the smallest ends of

axons An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see American and British English spelling differences#-re, -er, spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, th ...

in the brain. With this and other tract-tracing techniques, he made his most well known contribution: a new structural framework for the

striatum The striatum, or corpus striatum (also called the striate nucleus), is a nucleus (a cluster of neurons) in the subcortical basal ganglia of the forebrain. The striatum is a critical component of the motor and reward systems; receives glutamate ...

. Heimer identified the

nucleus accumbens The nucleus accumbens (NAc or NAcc; also known as the accumbens nucleus, or formerly as the ''nucleus accumbens septi'', Latin for "nucleus adjacent to the septum") is a region in the basal forebrain rostral to the preoptic area of the hypotha ...

and the

olfactory tubercle The olfactory tubercle (OT), also known as the tuberculum olfactorium, is a multi-sensory processing center that is contained within the olfactory cortex and ventral striatum and plays a role in reward cognition. The OT has also been shown to ...

as striatal structures and termed them the "

ventral striatum The striatum, or corpus striatum (also called the striate nucleus), is a nucleus (a cluster of neurons) in the subcortical basal ganglia of the forebrain. The striatum is a critical component of the motor and reward systems; receives glutamate ...

." The traditional striatal structures, the

caudate nucleus The caudate nucleus is one of the structures that make up the corpus striatum, which is a component of the basal ganglia in the human brain. While the caudate nucleus has long been associated with motor processes due to its role in Parkinson's di ...

and

putamen The putamen (; from Latin, meaning "nutshell") is a round structure located at the base of the forebrain (telencephalon). The putamen and caudate nucleus together form the dorsal striatum. It is also one of the structures that compose the basal n ...

are, strictly speaking, now termed the 'dorsal' striatum, though in practice the term "

" without qualification generally refers just to the dorsal striatum. Heimer is also known for helping to elaborate the anatomical concept of the

extended amygdala The extended amygdala is a macrostructure in the brain that is involved in reward cognition and defined by connectivity and neurochemical staining. It includes the central medial amygdala, sublenticular substantia innominata, and the bed nucleus o ...

, first proposed by his collaborator, Jose de Olmos.Elias WJ, Ray DK, Jane JA
Lennart Heimer: concepts of the ventral striatum and extended amygdala.
Neurosurg Focus. 2008;25(1):E8.

References

{{DEFAULTSORT:Heimer, Lennart 1930 births 2007 deaths People from Östersund University of Gothenburg alumni American neuroscientists Massachusetts Institute of Technology School of Science faculty Swedish emigrants to the United States