Terminal stria
Encyclopedia
The stria terminalis is a structure in the brain
consisting of a band of fibers running along the lateral margin of the ventricular surface of the thalamus
. Serving as a major output pathway of the amygdala
, the stria terminalis runs from its corticomedial division to the ventral medial nucleus of the hypothalamus
.
as seen upon gross dissection of the ventricles
of the brain, viewed from the superior aspect.
The stria terminalis extends from the region of the interventricular foramen to the temporal horn
of the lateral ventricle, carrying fibers from the amygdala
to the septal nuclei
, hypothalamic
, and thalamic areas of the brain. It also carries fibers projecting from these areas back to the amygdala.
and regulate its activity in response to acute stress
. It is also thought to promote behavioral inhibition in response to unfamiliar individuals, by input from the orbitofrontal cortex
. Bilateral disruption of this pathway has been shown to attentuate reinstatement of drug seeking behaviour in rodents.
neurons. A sample of six male-to-female transsexuals taking estrogen were found to have female-typical number of cells in the BSTc, whereas a female-to-male transsexual taking testosterone was found to have a male-typical number. The authors also examined subjects with hormone-related disorders and found no pattern between those disorders and the BSTc while the single untreated male-to-female transsexual had a female-typical number of cells. They concluded that the BSTc provides evidence for a neurobiological basis of gender identity disorder
and proposed that such was determined before birth. Criticisms of the former statement suggest the study used an unrepresentative sample and did not adequately control for hormone replacement therapy
which has been shown to influence hypothalamic size. The latter statement has been brought to question, though not refuted, by a follow up study by the same group which found that the sexual dimorphism of the BSTc is not present before adulthood (approximately 22 years of age) even though transsexuals report being aware of their gender identity since childhood.
Reduction of bed nucleus of the stria terminalis is observed in pedophilic male perpetrators, in addition to reductions in the right amygdala, hypothalamus and abnormalities in related structures. The authors propose that childhood deficits in the BNST and medial amygdala may cause inhibition of sexual maturity.
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
consisting of a band of fibers running along the lateral margin of the ventricular surface of the thalamus
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...
. Serving as a major output pathway of the amygdala
Amygdala
The ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...
, the stria terminalis runs from its corticomedial division to the ventral medial nucleus of the hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
.
Anatomy
The stria terminalis covers the thalamostriate vein, marking a line of separation between the thalamus and the caudate nucleusCaudate 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:...
as seen upon gross dissection of the ventricles
Ventricular system
The ventricular system is a set of structures containing cerebrospinal fluid in the brain. It is continuous with the central canal of the spinal cord.-Components:The system comprises four ventricles:* right and left lateral ventricles* third ventricle...
of the brain, viewed from the superior aspect.
The stria terminalis extends from the region of the interventricular foramen to the temporal horn
Inferior horn of lateral ventricle
The inferior cornu , the largest of the horns of the lateral ventricle, traverses the temporal lobe of the brain, forming in its course a curve around the posterior end of the thalamus....
of the lateral ventricle, carrying fibers from the amygdala
Amygdala
The ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...
to the septal nuclei
Septal nuclei
The septal area are structures that lie below the rostrum of corpus callosum in front of lamina terminalis , composed of medium-size neurons grouped into medial, lateral, and posterior groups...
, hypothalamic
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
, and thalamic areas of the brain. It also carries fibers projecting from these areas back to the amygdala.
Functions
The activity of the bed nucleus of the stria terminalis correlates with anxiety in response to threat monitoring. It is thought to act as a relay site within the hypothalamic-pituitary-adrenal axisHypothalamic-pituitary-adrenal axis
The hypothalamic-pituitary-adrenal axis , also known as thelimbic-hypothalamic-pituitary-adrenal axis and, occasionally, as the hypothalamic-pituitary-adrenal-gonadotropic axis, is a complex set of direct influences and feedback interactions among the hypothalamus, the pituitary gland ,...
and regulate its activity in response to acute stress
Stress (biology)
Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...
. It is also thought to promote behavioral inhibition in response to unfamiliar individuals, by input from the orbitofrontal cortex
Orbitofrontal cortex
The orbitofrontal cortex is a prefrontal cortex region in the frontal lobes in the brain which is involved in the cognitive processing of decision-making...
. Bilateral disruption of this pathway has been shown to attentuate reinstatement of drug seeking behaviour in rodents.
Bed nucleus of the stria terminalis
The central subdivision of the bed nucleus of the stria terminalis (BSTc) is sexually dimorphic. On average, the BSTc is twice as large in men as in women and contains twice the number of somatostatinSomatostatin
Somatostatin is a peptide hormone that regulates the endocrine system and affects neurotransmission and cell proliferation via interaction with G-protein-coupled somatostatin receptors and inhibition of the release of numerous secondary hormones.Somatostatin...
neurons. A sample of six male-to-female transsexuals taking estrogen were found to have female-typical number of cells in the BSTc, whereas a female-to-male transsexual taking testosterone was found to have a male-typical number. The authors also examined subjects with hormone-related disorders and found no pattern between those disorders and the BSTc while the single untreated male-to-female transsexual had a female-typical number of cells. They concluded that the BSTc provides evidence for a neurobiological basis of gender identity disorder
Gender identity disorder
Gender identity disorder is the formal diagnosis used by psychologists and physicians to describe persons who experience significant gender dysphoria . It describes the symptoms related to transsexualism, as well as less severe manifestations of gender dysphoria...
and proposed that such was determined before birth. Criticisms of the former statement suggest the study used an unrepresentative sample and did not adequately control for hormone replacement therapy
Hormone replacement therapy
Hormone replacement therapy may refer to:*Hormone replacement therapy *Hormone replacement therapy *Hormone replacement therapy *Androgen replacement therapy -See also:...
which has been shown to influence hypothalamic size. The latter statement has been brought to question, though not refuted, by a follow up study by the same group which found that the sexual dimorphism of the BSTc is not present before adulthood (approximately 22 years of age) even though transsexuals report being aware of their gender identity since childhood.
Reduction of bed nucleus of the stria terminalis is observed in pedophilic male perpetrators, in addition to reductions in the right amygdala, hypothalamus and abnormalities in related structures. The authors propose that childhood deficits in the BNST and medial amygdala may cause inhibition of sexual maturity.
External links
- Photo at University of PennsylvaniaUniversity of PennsylvaniaThe University of Pennsylvania is a private, Ivy League university located in Philadelphia, Pennsylvania, United States. Penn is the fourth-oldest institution of higher education in the United States,Penn is the fourth-oldest using the founding dates claimed by each institution...
- Overview at Everything2Everything2Everything2, Everything2, or E2 for short is a collaborative Web-based community consisting of a database of interlinked user-submitted written material. E2 is moderated for quality, but has no formal policy on subject matter...
