Behavioral neuroscience


Behavioral neuroscience, also known as biological psychology, biopsychology, or psychobiology, is part of the broad, interdisciplinary field of neuroscience, with its primary focus being on the biological and neural substrates underlying human experiences and behaviors, as in our psychology. Derived from an earlier field known as physiological psychology, behavioral neuroscience applies the principles of biology to study the physiological, genetic, and developmental mechanisms of behavior in humans and other animals.
Behavioral neuroscientists examine the biological bases of behavior through research that involves neuroanatomical substrates, environmental and genetic factors, effects of lesions and electrical stimulation, developmental processes, recording electrical activity, neurotransmitters, hormonal influences, chemical components, and the effects of drugs. Important topics of consideration for neuroscientific research in behavior include learning and memory, sensory processes, motivation and emotion, as well as genetic and molecular substrates concerning the biological bases of behavior. Subdivisions of behavioral neuroscience include the field of cognitive neuroscience, which emphasizes the biological processes underlying human cognition. Behavioral and cognitive neuroscience are both concerned with the neuronal and biological bases of psychology, with a particular emphasis on either cognition or behavior depending on the field.

History

Behavioral neuroscience as a scientific discipline emerged from a variety of scientific and philosophical traditions in the 18th and 19th centuries. René Descartes proposed physical models to explain animal as well as human behavior. Descartes suggested that the pineal gland, a midline unpaired structure in the brain of many organisms, was the point of contact between mind and body. Descartes also elaborated on a theory in which the pneumatics of bodily fluids could explain reflexes and other motor behavior. This theory was inspired by moving statues in a garden in Paris.
Other philosophers also helped give birth to psychology. One of the earliest textbooks in the new field, The Principles of Psychology by William James, argues that the scientific study of psychology should be grounded in an understanding of biology.
The emergence of psychology and behavioral neuroscience as legitimate sciences can be traced from the emergence of physiology from anatomy, particularly neuroanatomy. Physiologists conducted experiments on living organisms, a practice that was distrusted by the dominant anatomists of the 18th and 19th centuries. The influential work of Claude Bernard, Charles Bell, and William Harvey helped to convince the scientific community that reliable data could be obtained from living subjects.
Even before the 18th and 19th centuries, behavioral neuroscience was beginning to take form as far back as 1700 B.C. The question that seems to continually arise is: what is the connection between the mind and body? The debate is formally referred to as the mind-body problem. There are two major schools of thought that attempt to resolve the mind–body problem; monism and dualism. Plato and Aristotle are two of several philosophers who participated in this debate. Plato believed that the brain was where all mental thought and processes happened. In contrast, Aristotle believed the brain served the purpose of cooling down the emotions derived from the heart. The mind-body problem was a stepping stone toward attempting to understand the connection between the mind and body.
Another debate arose about localization of function or functional specialization versus equipotentiality which played a significant role in the development in behavioral neuroscience. As a result of localization of function research, many famous people found within psychology have come to various different conclusions. Wilder Penfield was able to develop a map of the cerebral cortex through studying epileptic patients along with Rassmussen. Research on localization of function has led behavioral neuroscientists to a better understanding of which parts of the brain control behavior. This is best exemplified through the case study of Phineas Gage.
The term "psychobiology" has been used in a variety of contexts, emphasizing the importance of biology, which is the discipline that studies organic, neural and cellular modifications in behavior, plasticity in neuroscience, and biological diseases in all aspects, in addition, biology focuses and analyzes behavior and all the subjects it is concerned about, from a scientific point of view. In this context, psychology helps as a complementary, but important discipline in the neurobiological sciences. The role of psychology in this questions is that of a social tool that backs up the main or strongest biological science. The term "psychobiology" was first used in its modern sense by Knight Dunlap in his book An Outline of Psychobiology . Dunlap also was the founder and editor-in-chief of the journal Psychobiology. In the announcement of that journal, Dunlap writes that the journal will publish research "...bearing on the interconnection of mental and physiological functions", which describes the field of behavioral neuroscience even in its modern sense.
In relation to the discipline, Solomon Carter Fuller also aided in the advancement of neurology and psychology with his Alzheimer's research. Dr. Fuller was the first African American psychiatrist and one of the pioneers of Alzheimer's disease. In 1904, Dr. Fuller began working as a research assistant under the founder of Alzheimer's disease, Alois Alzheimer, studying presenile dementia. Later in 1912, Dr. Fuller published the first review on Alzheimer's disease that included information regarding his patient who was the 9th person to ever be diagnosed with the disease. During his time as a researcher and doctor, he worked with black veterans to prevent them from getting misdiagnosed and deemed ineligible for military benefits; he also trained staff to diagnose side effects from sexually transmitted infections. In 1969, an award was established by the American Psychiatric Association called the Solomon Carter Fuller Award to honor black pioneers who worked to help other black people.
Neuroscience is considered a relatively new discipline, with the first conference for the Society of Neuroscience occurring in 1971. The meeting was held to merge different fields focused on studying the nervous system by creating one interdisciplinary field. In 1983, the Journal of Comparative and Physiological Psychology, published by the American Psychological Association, was split into two separate journals: Behavioral Neuroscience and the Journal of Comparative Psychology. The author of the journal at the time gave reasoning for this separation, with one being that behavioral neuroscience is the broader contemporary advancement of physiological psychology. Furthermore, in all animals, the nervous system is the organ of behavior. Therefore, every biological and behavioral variable that influences behavior must go through the nervous system to do so. Present-day research in behavioral neuroscience studies all biological variables which act through the nervous system and relate to behavior.

Relationship to other fields of psychology and biology

In many cases, humans may serve as experimental subjects in behavioral neuroscience experiments; however, a great deal of the experimental literature in behavioral neuroscience comes from the study of non-human species, most frequently rats, mice, and monkeys. As a result, a critical assumption in behavioral neuroscience is that organisms share biological and behavioral similarities, enough to permit extrapolations across species. This allies behavioral neuroscience closely with comparative psychology, ethology, evolutionary biology, and neurobiology. Behavioral neuroscience also has paradigmatic and methodological similarities to neuropsychology, which relies heavily on the study of the behavior of humans with nervous system dysfunction.

Research methods

The distinguishing characteristic of a behavioral neuroscience experiment is that either the independent variable of the experiment is biological, or some dependent variable is biological. In other words, the nervous system of the organism under study is permanently or temporarily altered, or some aspect of the nervous system is measured.

Disabling or decreasing neural function

  • Lesions – A classic method in which a brain-region of interest is naturally or intentionally destroyed to observe any resulting changes such as degraded or enhanced performance on some behavioral measure. Lesions can be placed with relatively high accuracy "Thanks to a variety of brain 'atlases' which provide a map of brain regions in 3-dimensional" stereotactic coordinates.
  • *Surgical lesions – Neural tissue is destroyed by removing it surgically.
  • * Electrolytic lesions – Neural tissue is destroyed through the application of electrical shock trauma.
  • * Chemical lesions – Neural tissue is destroyed by the infusion of a neurotoxin.
  • * Temporary lesions – Neural tissue is temporarily disabled by cooling or by the use of anesthetics such as tetrodotoxin.
  • Transcranial magnetic stimulation – A new technique usually used with human subjects in which a magnetic coil applied to the scalp causes unsystematic electrical activity in nearby cortical neurons which can be experimentally analyzed as a functional lesion.
  • Synthetic ligand injection – A receptor activated solely by a synthetic ligand or Designer Receptor Exclusively Activated by Designer Drugs, permits spatial and temporal control of G protein signaling in vivo. These systems utilize G protein-coupled receptors engineered to respond exclusively to synthetic small molecules ligands, like clozapine N-oxide, and not to their natural ligand. RASSL's represent a GPCR-based chemogenetic tool. These synthetic ligands upon activation can decrease neural function by G-protein activation. This can with Potassium attenuating neural activity.
  • Optogenetic inhibition – A light activated inhibitory protein is expressed in cells of interest. Powerful millisecond timescale neuronal inhibition is instigated upon stimulation by the appropriate frequency of light delivered via fiber optics or implanted LEDs in the case of vertebrates, or via external illumination for small, sufficiently translucent invertebrates. Bacterial Halorhodopsins or Proton pumps are the two classes of proteins used for inhibitory optogenetics, achieving inhibition by increasing cytoplasmic levels of halides or decreasing the cytoplasmic concentration of protons, respectively.