Neuro Question....?

Question

I get that the dif areas of the brain send messages to and from down the spinal cord, what I dont get is the midbrain...

Couple spec questions:

1) What exactly is a nuclei?

2) Is there a rule that the sensory pathways do something in the midbrain (and motor too)?

3) Thanks for help, alot of the texts, etc are great, but wanted clarrification

Answer 1

A nuclei is a cluster of nerve cell bodies. Where you find them in the brain means that you are in a an area of the brain that can process information and learn. They usually receive information from several sensory and motor channels but that is a general statement. There are exceptions. Ganglia are basically the same thing.

The second question isn't phrased well, but if I get your meaning. The midbrain has many very important structures for motor and sensory processes. You need to look up the anatomy of the midbrain to get a list. But they do not work alone, they all connect to either the cerebrum and/or cerebellum.

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The red nuclei are involved in the motor pathway that controls the large muscles of the arm. It probably orginally developed (evolutionarily) as part of the controls for quadrpedal motion (forelimbs). It helps babies crawl and is responsibly for arm swinging while walking. It is probably also involved in coordinated movements of the whole arm like pitching and punching.

The guy below me also knows what he is talking about. I am a little rusty on this stuff but I was trained as a neuroscientist.

Answer 2

Cell nucleus, the control center of a cell, which contains the cell's chromosomal DNA

Nucleus (neuroanatomy), a central nervous system structure composed mainly of gray matter

Answer 3

You've got a good answer upstairs. I'm just gonna add to it.

Nuclei, as you''ve heard are clusters of cell bodies, usually with a common function/neurotransmitter. The midbrain in the grand scheme of things is not THAT important (though you still need it). In terms of decending pathways, the corticospinal travels through the crus cerebri of the midbrain.

The edginger-westerphal (parasympathetic to cilary ganglion), occulomotor, and trochlear nuclei are all in the midbrain, and are important decending pathways.

The other major thing in the midbrain is the suprior and inferior colliculi. The Superior carries vision and allows the information to interact with the brainstem nuclei (for things like balance through the medial longtitudinal fasciculus). The inferior colliculus is integral to sound from the ears travelling up to the brain.

The sensory neurones go through specific tracts/phases in the midbrain. The Spinothalamic/spinoreticularthalamic go through the spinal leminiscus. The Dorsal coloumns go through the medial leminiscus pathway. And sound incidentally, goes through the lateral leminiscus.

The magnocellular red nucleus, is a motor nucleus linked to the cerebellum (Majorly) and the motor cortex. It predominantly controls flexor muscle tone and is extrapyramidal. It may be a decending path of the cerebellum to control motion (as a result of error reporting from spino-olivio cerebellar pathways). The pathway undergoes a ventral tegmental decussation.

There's a lot of info here... I hope it's helpful!