Lennart Heimer
Encyclopedia
Lennart Heimer was a Swedish-American neuroscientist
and educator most noted for mapping circuits of the brain in the limbic lobe
and basal ganglia
, structures that play central roles in emotion processing and movement.
Neuroscientist
A neuroscientist is an individual who studies the scientific field of neuroscience or any of its related sub-fields...
and educator most noted for mapping circuits of the brain in the limbic lobe
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...
and basal ganglia
Basal ganglia
The basal ganglia are a group of nuclei of varied origin in the brains of vertebrates that act as a cohesive functional unit. They are situated at the base of the forebrain and are strongly connected with the cerebral cortex, thalamus and other brain areas...
, structures that play central roles in emotion processing and movement.
Research
Heimer's first notable achievement was the development of the Fink-Heimer silver stain for mapping the smallest ends of axons in the brain. With this technique, he made his most well known contribution: a new structural framework for the striatumStriatum
The striatum, also known as the neostriatum or striate nucleus, is a subcortical part of the forebrain. It is the major input station of the basal ganglia system. The striatum, in turn, gets input from the cerebral cortex...
. Heimer identified the nucleus accumbens
Nucleus accumbens
The nucleus accumbens , also known as the accumbens nucleus or as the nucleus accumbens septi , is a collection of neurons and forms the main part of the ventral striatum...
and the olfactory tubercle
Olfactory tubercle
The olfactory tubercle is a structure involved in Olfaction.It is present in humans, but much smaller than it is in some other animals.It is a frequent subject of research.-External links:...
as striatal structures and termed them the "ventral striatum
Ventral striatum
The ventral striatum is generally considered that part of the striatum that is connectionally associated with limbic structures, such as the amygdala, hippocampus, midline thalamus, and certain regions of the prefrontal cortex...
." The traditional striatal structures, the caudate nucleus
Caudate nucleus
The caudate nucleus is a nucleus located within the basal ganglia of the brains of many animal species. The caudate nucleus is an important part of the brain's learning and memory system.-Anatomy:...
and putamen
Putamen
The putamen is a round structure located at the base of the forebrain . The putamen and caudate nucleus together form the dorsal striatum. It is also one of the structures that comprises the basal ganglia. Through various pathways, the putamen is connected to the substantia nigra and globus pallidus...
are, strictly speaking, now termed the 'dorsal' striatum, though in practice the term "striatum
Striatum
The striatum, also known as the neostriatum or striate nucleus, is a subcortical part of the forebrain. It is the major input station of the basal ganglia system. The striatum, in turn, gets input from the cerebral cortex...
" without qualification generally refers just to the dorsal striatum. Heimer is also known for helping to elaborate the anatomical concept of the extended amygdala
Extended amygdala
Extended amygdala refers to a composite structure of the endbrain that is defined by connectivity and neurochemical staining. It includes the central amygdalar nucleus and a portion of the corticomedial nuclear group of the amygdala, the portion of substantia innominata ventral to the globus...
, first proposed by his collaborator, Jose de Olmos.