We discuss

We discuss this area much more fully later; it is the most important region of the entire brain for higher intellectual function because almost all such intellectual functions are language based. Area for Initial Processing of Visual Language Reading. Posterior to the language comprehension area, lying mainly in the anterolateral region of the occipital lobe, is a visual association area that feeds visual information conveyed by words read from a book into Wernickes area, the language comprehension area. This socalled angular gyrus area is needed to make meaning out of the visually perceived words. In its absence, a person can still have http://www.roozegarphoto.ir/ excellent language comprehension through hearing but not through reading. Area for Naming Objects. In the most lateral portions of the anterior occipital lobe and posterior temporal lobe is an area for naming objects. The names are learned mainly through auditory http://mosaicnet.ie/ input, whereas the physical natures of the objects are learned mainly through visual input. In turn, the names are essential for both auditory and visual language comprehension functions performed in Wernickes area located immediately superior to the auditory names region and anterior to the visual word processing area. Prefrontal Association Area. In Chapter , we learned that the prefrontal association area functions in close association with the motor cortex to plan complex Chapter Cerebral Cortex, Intellectual Functions of the Brain, Learning and Memory Figure Map of specific functional areas in the cerebral cortex, showing especially Wernickes and Brocas areas for language comprehension and speech production,which in per cent of all people are located in the left hemisphere.http://www.flyturizam.com/v2/index.php/component/k2/itemlist/user/

One of

One of the mechanisms for this is to excite serotonergic neurons; these in turn secrete the inhibitory neurohormone serotonin at crucial points in the brain; we will discuss this in more detail later . Unit XI The Nervous System: C. Motor and Integrative Neurophysiology Neurohormonal http://anellioriginals.com/ Control of Brain Activity Aside from direct control of brain activity by specific transmission of nerve signals from the lower brain areas to the cortical regions of the brain, still another physiologic mechanism is very often used to control brain activity. This http://ip-67-205-105-209.static.privatedns.com/ is to secrete excitatory or inhibitory neurotransmitter hormonal agents into the substance of the brain. These neurohormones often persist for minutes or hours and thereby provide long periods of control, rather than just instantaneous activation or inhibition. Figure shows three neurohormonal systems that have been mapped in detail in the rat brain: a norepinephrine system, a dopamine system, and a serotonin system. Norepinephrine usually functions Cerebellum Olfactory region Frontal cortex Basal brain areas NOREPINEPHRINE JCingulate cortex Caudate nucleus Brain stem Locus cerulus DOPAMINE Midline nuclei SEROTONIN Figure Three neurohormonal systems that have been mapped in the rat brain: a norepinephrine system, a dopamine system, and a serotonin system. Adapted from Kelly, after Cooper, Bloom, and Roth, in Kandel ER, Schwartz JH: Principles of Neural Science, nd ed. New York: Elsevier, as an excitatory hormone, whereas serotonin usually is inhibitory, and dopamine is excitatory in some areas but inhibitory in others.http://vipaccommodation-online.com/

Intermediate LongTerm

Intermediate LongTerm Memory Intermediate longterm memories may last for many minutes http://www.spartateck.com/ or even weeks. They will eventually be lost unless the memory traces are activated enough to become more permanent; then they are classified as longterm memories. Experiments in primitive animals have demonstrated that memories of the intermediate longterm type can result from temporary chemical or physical changes, or both, in either the synapse presynaptic terminals or the synapse postsynaptic membrane, changes that can persist for a few minutes up to several weeks. These mechanisms are so important that they deserve special description. Memory Based on Chemical Changes in the Presynaptic Terminal or Postsynaptic Neuronal Membrane Figure shows a mechanism of memory studied especially by Kandel and his colleagues that can cause memories lasting from a few minutes up to weeks in the large snail Aplysia. In this figure, there are two synaptic terminals. One terminal is from a sensory input neuron and terminates directly on the surface of the neuron that is to be stimulated; this is called the sensory terminal. The other terminal is a presynaptic ending that lies on the surface of the sensory terminal, and it is called the facilitator terminal. When the sensory terminal is stimulated repeatedly but without stimulation of the facilitator terminal, signal transmission at first is great, but it becomes less and less intense with repeated stimulation until transmission almost ceases. This phenomenon is habituation, as was http://www.josif.edu.rs/ explained previously.http://asopdias.gr/chessleague/index.php/component/k2/itemlist/user/

The hippocampus

The hippocampus is http://www.kosvoyannis.gr/ the most medial portion of the temporal lobe cortex, where it folds first medially underneath the brain and then upward into the lower, inside surface of the lateral ventricle. The two hippocampi have been removed for the treatment of epilepsy in a few patients. This procedure does not seriously affect the persons memory for information stored in the brain before removal of the hippocampi. However, after removal, these people have virtually no capability thereafter for storing verbal and symbolic types of memories declarative types of memory in longterm memory, or even in intermediate memory lasting longer than a few minutes. Therefore, these people are unable to establish new longterm memories of those types of information that are the basis of intelligence. This is called anterograde amnesia. But why are the hippocampi so important in helping the brain to store new memories? The probable answer is that the hippocampi are among the most important output pathways from the reward and punishment areas of the limbic system, as explained in Chapter Sensory stimuli or thoughts that cause pain or aversion excite the limbic punishment centers, and stimuli that cause pleasure, happiness, or sense of reward excite the limbic reward centers http://www.qualitour.co.za/heritagesa.co.za/ . All these together provide the background mood and motivations of the person. Among these motivations is the drive in the brain to remember those experiences and thoughts that are either pleasant or unpleasant. The hippocampi especially and to a lesser degree the dorsal medial nuclei of the thalamus, another limbic structure, have proved especially important in making the decision about which of our thoughts are important enough on a basis of reward or punishment to be worthy of memory.http://turtledreams.ca/index.php/component/k2/itemlist/user/