The genome can also be manipulated experimentally for example, mice can be engineered to lack a particular gene, or a gene can be expressed in a strain that normally does not (the “transgenic”). Advanced techniques can also allow the expression or deletion of a gene that is produced by injecting some regulatory chemical. Organisms, often mice, can be selectively bred among inbred strains to create a recombinant congenital strain. This could be done to isolate an experimentally interesting stretch of DNA derived from one strain in the background genome of another strain to allow stronger inferences about the role of that stretch of DNA. The influence of a gene on some behaviors can be statistically inferred by studying inbred strains of some species, most often mice. Recent genome sequencing of many species, especially mice, has facilitated this technique. ![]() It shows the functioning of the human brain through the measurement of electromagnetic activity. Measurement of the magnetic fields created by electrical current flowing within neurons identifies brain activity associated with various human functions in real time, with millimeter spatial precision. Doctors can obtain data non-invasively to help them assess neurological disorders and plan surgical treatments. Functional neuroanatomyĪ more complex counterpart to phrenology, the expression of an anatomical marker is taken to reflect neuronal activity. For example, immediate early gene expression is thought to be caused by vigorous neuronal activity. Technique most frequently applied in human subjects, in which changes in cerebral blood flow can be detected on an MRI machine and taken to indicate relative activity of larger-scale brain regions (i.e., on the order of hundreds of thousands of neurons). ![]() The use of a set of fine electrodes to record the simultaneous activity of up to hundreds of neurons. Single unit recordingĪ method by which an electrode is inserted into the brain of a living animal to detect the electrical activity generated by neurons adjacent to the tip of the electrode. This is normally done with sedated animals but is sometimes done on awake animals participating in a behavioral event. Optical methods for recording neuronal activity rely on methods that modify the optical properties of neurons in response to cellular events associated with action potentials or neurotransmitter release. Neural activity measurement Optical techniques ![]() Optogenetic excitationĪ light-activated excitatory protein is expressed in selected cells. Channelrhodopsin-2 (ChR2), a light-activated cation channel, was the first bacterial opsin shown to excite neurons in response to light, although several excitatory optogenetic tools have now been generated enhancing and imparting novel properties. In some cases (for example, studies of the motor cortex), this technique can be analyzed as having a stimulating effect (rather than as a functional injury). They can be used to modulate cell function by innervating brain regions such as Hippocampus. This innervation results in amplification of γ rhythms, which increases motor activity. History is an important part of modern scientific psychology. The study of biological psychology can be traced back to Avicenna, a physician who in The Canon of Medicine recognized physiological psychology in the treatment of diseases involving emotions and developed a system for associating changes in pulse rate with internal feelings, which are seen as a preview of the word association test.Īvicenna also gave psychological explanations for certain somatic illnesses, and always related physical and psychological illnesses. He explained that the “humidity” inside the head can contribute to mood disorders, and acknowledged that this occurs when the amount of breath changes, happiness increases respiration, which increases the humidity inside the brain, but if this humidity goes beyond its limits, the brain would lose control over its rationality and it would lead to mental disorders.
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