Basic Brain Anatomy
Neurons
Neurotransmitters
Dopamine


The Brain

brizain

In this section we will present you with the structures of the brain that are implicated in schizophrenia and amphetamine psychosis.  We hope you gain an understanding of these complex systems, so that you will know more about what areas of the brain the research in this website will  focus on.   This page will focus on three systems in the brain:  the basal ganglia, limbic system and tegmentum.



Basal Ganglia

cortex and hindbrain
The basal ganglia is a collection of subcortical (beneath the cortex) nuclei in the forebrain (front area of the brain).  The cortex is the brain matter that makes up the outside of the brain; cortex literally means "bark," so you can think of it as the bark of the brain.  The parts of the brain beneath the cortex are referred to as subcortical and include the midbrain and hindbrain, as well as structures not a part of the midbrain and hindbrain.  Nuclei are groups of neurons of similar shape.



Basal GangliaThe major parts of the basal ganglia consist of the caudate nucleus, the putamen and the globus pallidus.

The basal ganglia is involved in the control of movement.  The nucleus accumbens contains neurons that are part of the basal ganglia.  Thus, this structure may play a role in the regulation of movement, including the control of complex motor activity and the cognitive aspects of motor control.  In addition, this structure has been found to possibly be the area that becomes activated in situations that involve reward and punishment.

The nucleus accumbens is a nucleus of the basal forebrain.  It receives dopamine-secreting terminal buttons from neurons of the VTA and is thought to be involved in reinforcement and attention.




limbic systemLimbic System

This system consists of a couple of brain structures.  First it includes several regions of one form of cortex called the limbic cortex; this cortex is also known as the cingulate cortex as shown in the picture.

Besides the limbic cortex, the most important parts of the limbic system are the hippocampus and the amygdala.  The fornix and mammilary bodies are also parts of the limbic system.

 The limbic system has been implicated in learning and memory and emotions.  The implication in emotions involves feelings and expressions of emotions, emotional memories and recognition of emotions in other people.




Tegmentum

tegmentumThe tegmentum consists of an area of the midbrain.  It includes the bottom end of the reticular formation, the periaqueductal gray matter, the red nucleus, the substantia nigra and the ventral tegmental area.

The reticular formation is a large structure consisting of many nuclei.  It is also characterized by a diffuse, interconnected network of neurons with complex dendritic and axonal processes.  The reticular formation receives sensory information and projects axons to the cerebral cortex, thalamus and spinal cord.

The periaqueductal gray matter (PAG) is so called because it consists mostly of cell bodies of neurons (these appear gray as opposed to axons which appear white) that surround an area of the brain called the cerebral aqueduct.  The PAG has been implicated in pain systems as well as behaviors such as fighting and mating.

The red nucleus contains a bundle of axons; this is one of the two major fiber systems that bring motor information from the cerebral cortex and cerebellum to the spinal cord.

The substantia nigra contains neurons whose axons project to the caudate nucleus and putamen parts of the basal ganglia, this is known as the nigrostriatal system.  The ventral tegmental area (VTA) is a group of dopamine neurons in the  midbrain whose axons form the mesolimbic and mesocortical systems; this area plays a critical role in reward and reinforcement.

VTA




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Pictures contained in the web page courtesy of

www.mhhe.com/socscience/ intro/ibank/set1.htm

www.ablongman.com/carlson8e