Lecture 8 - Central Nervous System

What are the various roles of the midbrain? What important structures/nuclei are found there and what are the roles of these structures/nuclei?

-contains nuclei (substantia nigra) that communicate with primary motor cortex to control voluntary movement -contains ventral tegmental area that contains dopaminergic neurons that send projections to the limbic system structures that play an important role in reward system -superior colliculi- nuclei that act in visual reflexes -inferior colliculu- nuclei that act in reflexive response to sound -also contains pyramidal tracks that start in primary motor cortex- the cerebral peduncles is where the tracks run through.

What are the various roles of the hypothalamus?

-control of emotional responses and behavior -main visceral control center of the body (controls most of ANS functions) -regulates ANS centers in medulla and pons -regulates body temp -regulates hunger and thirst sensations (chemoreceptors, osmoreceptors) -regulates sleep-wake cycles -communicates with the pituitary gland (therefore, controlling the endocrine system)

What are major roles of the cerebellum that were discussed in class?

-receives input from proprioceptors and participates in the coordination of voluntary movement -cerebellum is needed for motor learning (new motor skills) and for coordinating movement of different joints during movement -recieves info from pre motor area re: planned movement -integrates info about future movement, current movement -gets info from vestibular apparatus in inner ear, where head is in space -takes all of the info together, integrates, to make proper movements

What type of matter is the cerebral cortex composed of? What is found in that matter?

Cerebral cortex is composed of gray matter; cell bodies and dendrites of neurons, short unmylineated interneurons

What are the three MAIN regions of the brain and what brain structures are found in each region?

Forebrain- cerebrum, thalamus & hypothalamus Midbrain- midbrain Hindbrain- cerebellum, pons, medulla oblongata

What are the five (paired) lobes of the cerebrum?

Frontal lobe parietal lobe occipital lobe temporal lobe insula

What are the various roles of the medulla oblongata? What cranial nerves arise at the medulla?

Has nuclei involved in: -visceral and skeletal motor control of muscles and glands in the neck/head region -gives rise to axons within cranial nerves; IX, X = innervates smooth muscle of abdominal organs, thoracic organs and cardiac muscle XI, XII = just innervate skeletal muscles -vagus nuclei give rise to vagus nerve (X) which carries sensory information from the viscera to the brain and sends autonomic motor signals from the brain to these viscera -contains neurons required for regulation of breathing respiratory center -cardiovascular responses in vasomotor center (blood vessel dilation and constriction) and cardiac control center (heart rate and contractility of heart)

What is memory consolidation? What brain regions are responsible for memory consolidation?

Memory consolidation is the conversion of short term memory to long term memory -requires activation of genes, production of new proteins and formation of new synapses and dendritic spines -is a function of the medial temporal lobe, particularly the hippocampus and amygdala

What is neurogenesis and which region of the brain can it occur in?

Neurogenesis is the formation of new neurons from neural stem cells in the subgranular zone of the hippocampus

Does the hippocampus store long term memories?

No, the hippocampus is critical for acquiring new memories of facts and events for the consolidation of short term into long term memory -no longer needed one the memory has become consolidated into a more stable long term form. -long-term memory is stored in various areas of the cerebral cortex.

What are the various functions of the occipital lobes? What functional cortices are found there?

Occipital lobe contains the primary visual cortex and visual association cortices. -primary area responsible for vision and the coordination of eye movements

Based on the body maps of these cortices which body regions have the highest density of sensory receptors? Which have the highest density of motor innervation?

Sensory receptors: highest in face/lips and hands motor innervation: in face and hands

What type of responses is the amygdala important for?

The amygdala is important in the memory of fear responses -visual processing of fearful

What is the corpus callosum composed and what is its job?

The corpus callosum connects the two hemispheres of the cerebrum and is a large major tract of axons (white matter)

What brain areas does the limbic system span? What are the functions of the limbic system?

The limbic system consists of a group of structures in the medial aspects of the temporal, parietal and frontal cortical areas. Plus parts of insula, and certain parts of the diencephalon -responsible for the emotional impact that actions and situations and behaviors have on us (our feelings) -directs responses to these emotions (regulates) -also functions to create, store and retrieve memories, especially those that elicit strong emotions (such as fear)

What is the main role of the thalamus?

The nuclei in the thalamus act as a relay stations for incoming sensory messages -every part of brain communicating with cerebral cortex relays signals through the thalamic nuclei -gateway to cerebral cortex (sends axons to regions of the cerebral cortex) -nuclei organize and either amplify or tone down signals

What is one role of the pons that we discussed? What two important centers are found there?

The pons works with the medulla oblongata to regulate breathing and breathing rate -respiratory control centers are: -apneustic center -pneumotaxic centers

What are gyri and sulci?

They are convolutions of the cerebral cortex that increase the surface area. gyri are the elevated areas sulci are the depressions

What three regions is the brain stem composed of?

midbrain, pons, medulla oblongata

What are the various roles of the prefrontal cortex?

performs higher order cognitive functions; -thinking -planning -decision making -working memory -responsible for our personalities (regulates limbic system, our emotional brain)

Which cerebral lobes are the precentral and postcentral gyri found in?

precentral gyri is found in the frontal lobe postcentral gyri is found in the parietal lobe

What functional cortex does the precentral gyrus contain? What is the function of this cortex? What is the name of the interneurons found in this cortex?

precentral gyrus contains the primary motor cortex -it is involved in voluntary movement initiation and control -cell bodies of interneurons here are called pyramidal neurons because of their role in skeletal muscle regulation (also called upper motor neurons)

What functional cortex does the postcentral gyrus contain? What is the SPECIFIC function of this cortex?

primary somatosensory cortex is in the postcentral gyrus. -responsible for the perception of somatesthetic sensations (somatic sensory) -perception of cutaneous, muscle, tendon, bone, joint sensation

What type of neurons found (mostly in the spinal cord) do these primary motor neurons synapse with? What effector organs are these neurons ultimately in control of?

synapse with somatic motor neurons in the spinal cord which innervate skeletal muscle (they release acetylcholene)

What are the various functions of the temporal lobes? What functional cortices are found there?

temporal lobe contains auditory centers recieve sensory input from cochlea of ear -primary auditory cortex -auditory association area -also involved in the interpretation and association of auditory and visual information

What is the diencephalon composed of?

thalamus, hypothalamus, epithalamus

What are important roles of the vagus nerves (CN X)?

the vagus nerve is a regulator of our autonomic nervous system -regulates our viscera- smooth muscle within visceral organs, cardiac muscle in the heart, and glands in visceral organs -CN X carries sensory info from visceral organs, and sends autonomic motor signals from the brain to these viscera