cannabis, ethanol, opioids, and stimulants such as nicotine, amphetamine, or cocaine.

caffeine is the most widely consumed psychoactive substance in the world

d, but you just need to remember that agonist drugs increase and antagonist drugs decrease whatever the typical effect is at a particular synapse,

neurotransmitters across the synapse

the study of how drugs affect the brain and behavior, is a relatively new science, although people have probably been taking drugs to change how they feel from early in human history

Endocrine glands in the brain include the pituitary gland (located at the base of the brain), the hypothalamus (immediately above the pituitary gland), and the pineal gland (near the center of the brain). The pituitary gland is controlled by the hypothalamus, to which it is connected by a thin stalk (the infundibulum).

eural messages can travel only to destinations along existing nerve tracts. Hormonal communication, on the other hand, is like traveling in a car. You can drive to many more destinations than train travel allows because there are many more roads than railroad tracks. Similarly, hormonal messages can travel anywhere in the body via the circulatory system; any cell receiving blood is potentially able to receive a hormonal message.

the fastest nerve impulses travel at speeds greater than 100 meters per second!

Sensory neurons in the autonomic system detect internal body conditions and send messages to the brain. Motor nerves in the autonomic system function by controlling the contractions of smooth or cardiac muscle or glandular tissue.

controls voluntary activities for which decisions and commands come from the cerebral cortex of the brain.

It serves as a communication relay, going back and forth between the CNS and muscles, organs, and glands throughout the body. Figure 4.5.14.5.1\PageIndex{1} illustrates both the central and peripheral nervous systems, including many representative spinal nerves.

hippocampus is essential for forming memories and storing them long-term and is located deep in the temporal lobe. Lastly, the amygdala (also called the amygdaloid body, colored blue in the figure) is connected to the anterior end of the hippocampus and is involved in multiple aspects of emotion, including encoding memories related to highly emotional states.

The brainstem, the spinal cord, and the PNS all send information to the cerebrum through the diencephalon, and output from the cerebrum then passes back through the diencephalon.

with executive functions such as attention, self-control, planning, problem-solving, reasoning, abstract thought, language, and personality. Another important function of the frontal lobes is movement- as mentioned above, the precentral gyrus (indicated on Figure 4.4.64.4.6\PageIndex{6}) contains the primary motor cortex.

It controls conscious, intellectual functions, such as reasoning, language, memory, sight, touch, and hearing.

The term differentiation also encompasses the formation of different types of neurons (Stiles & Jernigan, 2010), or gaining the features that distinguish one type of neuron from another.

the forebrain (including the cerebrum, thalamus, hypothalamus, and limbic system structures), the midbrain, and the hindbrain (including the medulla, pons, and cerebellum)

a sperm cell and an egg cell fuse to become a fertilized egg.

The CNS includes the brain and spinal cord, and the PNS consists of all other nervous tissue in the body. The nerves of the PNS connect the CNS to the rest of the body. The PNS is further divided into the autonomic and somatic nervous systems. The somatic nervous system (SNS) is responsible for activities that are under voluntary control and awareness. The autonomic nervous system (ANS) controls involuntary activities.

sympathetic nervous system controls the "fight-or-flight" response during emergencies, and the parasympathetic nervous system controls the routine “housekeeping” functions of the body

Cephalic/Caudal–

Frontal (or coronal) plane—A vertical cut that separates the front from the back of the individual/structure. Transverse (or horizontal) plane—A horizontal cut that separates the top from the bottom of the individual/structure. (May also be called cross-sections.) Sagittal plane—A vertical cut that separates the left half from the right half of the individual/structure.

include motor neurons (see functional classification below), which carry commands from the brain and spinal cord to muscles and glands, and interneurons (see functional classification below), which constitute the majority of neurons.

heir function is to receive messages (excitatory and inhibitory post-synaptic potentials, EPSPs/IPSPs- see the nervous system communication chapter) from other cells and carry them to the cell body

It is the axon that propagates the nerve impulse (also called an action potential), which is communicated to one or more cells. The other processes of the neuron are dendrites, which receive information from other neurons across specialized areas called synapses.

Ongoing research pursues an expanded role that glial cells might play in signaling, but neurons are still considered the basis of this function. Neurons are important, but without glial support they would not be able to perform their function.

It then usually sends signals encoding this information to the brain, which processes the information to determine an appropriate response. Finally, the brain sends signals to muscles, organs, or glands to bring about the necessary response.

The most serious consequences of prenatal drug or alcohol exposure involve newborn addiction and fetal alcohol syndrome (FAS). Fetal alcohol syndrome affects both physical and mental development, damaging neurons within the brain and often leading to cognitive impairment and below-average weight.

the mind is a collection or bundle of information processing "organs" or "modules" each of which has evolved, over our evolutionary history as a species, to process particular kinds of information from the environment in quite specific ways to help us to survive and reproduce our genes.

The following quote from Steven Pinker (1997) expresses these ideas eloquently:

Brain development is more rapid during this critical or sensitive period than at any other, with more than 700 neural connections created each second. Herein, complex gene –environment interactions (or genotype–environment interactions, G×E) serve to increase the number of possible contacts between neurons, as they hone their adult synaptic properties and excitability.

Nutrients can reverse or change DNA methylation and histone modifications, thereby modifying the expression of critical genes associated with physiologic and pathologic processes, including embryonic development, aging, and carcinogenesis.

Since the child is being raised by parents who are genetically different from his or her biological parents, the influence of the environment shows in how similar the child is to his or her adoptive parents or adoptive siblings vs. how similar the child is to his or her biological parents and siblings.

Common abnormalities include Down syndrome (caused by an extra chromosome #21), Klinefelter syndrome (caused by an extra X chromosome), and Turner syndrome (caused by a missing X chromosome). Genetic counseling is available for families in order to determine if any abnormalities exist that may be passed along to offspring

it is shaped like a double helix, made of sequences of nucleic acids attached to a sugar phosphate backbone. Genes are subsections of DNA molecules linked together that encode a particular characteristic.

"Fit" in this context does not mean the healthiest or the strongest, rather it is a reference to the ability to pass one's genes on to the next generation.

In this way, evolution is not random as some who don't understand the process are apt to claim--natural selection gives it direction.

The minds and behavior of organisms have been shaped by evolutionary forces over millions of years, just like their anatomical and physiological features.

refinement

So, it is extremely difficult to determine what exactly each cell does through single cell recordings. Recording from one area ignores what is happening everywhere else in the brain.

This magnetic field travels through the skull and scalp and affects neurons near the surface of the brain. When the magnetic field is rapidly turned on and off, a current is induced in the neurons, leading to depolarization or hyperpolarization, depending on the number of magnetic field pulses. Single- or paired-pulse TMS depolarizes site-specific neurons in the cortex, causing them to fire.

This allows researchers to construct a three-dimensional image of the areas of the brain that have the highest metabolic needs, typically those that are most active.

Electroencephalography (EEG) is one technique for studying brain activity.

Computed (or computerized) tomography (CT) is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal small details about structures in the body.

In 1895, Röntgen made the first durable record of the internal parts of a living human: an “X-ray” image (as it came to be called) of his wife’s hand. Scientists around the world quickly began their own experiments with X-rays, and by 1900, X-rays were widely used to detect a variety of injuries and diseases.

Functional imaging techniques allow researchers to learn about the brain activity during various tasks by creating images based on the electrical activity or the absorption of various substances that occurs while a subject is engaging in a task.

Even though each cell has identical copies of all of the same genes, different cells express or repress different genes.

the opposite is likely true: the extent that people differ in arm number is likely the result of accidents and, therefore, environmental.

no other question has caused so much controversy and offense: We are so concerned with nature–nurture because our very sense of moral character seems to depend on it.

It focuses primarily on psychological adaptations: mechanisms of the mind that have evolved to solve specific problems of survival or reproduction.

doing something like offering a gift might represent more than a nice gesture. Just as chimpanzees will give food to mates to show they can provide for them, when you offer gifts to your dates, you are communicating that you have the money or “resources” to help take care of them.

Bipedalism, or upright walking, was the first morphological trait on the road to humanity. Human bipedalism is the primary form of moving around (this is called habitual bipedalism).

The mechanisms of the origin of life on Earth are a particularly difficult problem because it occurred a very long time ago, and presumably it just occurred once.

An individual may carry a very beneficial genotype with a resulting phenotype that, for example, increases the ability to reproduce (fecundity), but if that same individual also carries an allele that results in a fatal childhood disease, that fecundity phenotype will not be passed on to the next generation because the individual will not live to reach reproductive age.

Over time, only long-necked tortoises would be present in the population, as short-necked animals failed to survive and reproduce.

It encompasses the branch of biology that deals with the anatomy, biochemistry, molecular biology, and physiology of neurons and neural circuits. It also encompasses cognition (thinking) and human behavior.

And here was the main point of this curious story: Gage became irritable, irreverent, rude and profane, aspects that were not part of his way of being. His mind had changed radically. His transformation was so great that everyone said that “Gage is no longer himself.”

One of the most important questions given Cajal's neuron doctrine was the mechanism for communication between neurons. The role of electricity in nerves and electrical communication between neurons was first observed in dissected frogs by Luigi Galvani. In 1780, he showed that an electrical stimulus applied to the motor nerve of a frog's nerve cell produced a twitch. This experiment suggested that electricity was an important functional element of the nervous system (Klein and Thorne, 2006).

Measuring the skull by using a technique called cranioscopy would allow the scientist to detect deformation and bumps on the skull which would outline the person's personality (Elias and Saucier,

wo neuroanatomists, Herophilos and Erasistratos, contributed to our knowledge of the human brain. Herophilos distinguished the cerebellum (at the very base of the back of the brain) and the cerebrum (the two cerebral hemispheres). He hypothesized that since the cerebellum was denser than the other parts of the brain, it must control the muscles (a guess of impressive accuracy). And he provided the first clear description of the cavities within the brain known as ventricles (Figure 1.2.1). Erasistratos continued the work of Herphilos and proposed that human intelligence was related to the number of convolutions (ridges) in the brain; the more convolutions an individual's brain had, the more intelligent that person would be.

Using this fundamental assumption of the modern scientific view of the universe, this means that the mind is entirely material, dependent upon the physical activities of an entirely material organ, the brain.

We may not be using our brains as efficiently as possible at all times, but we are using the entirety of our brain as each part contributes to our daily functioning.

Key areas of focus within the field include sensation and perception; motivated behavior (such as hunger, thirst, and sex); control of movement; learning and memory; sleep and biological rhythms; and emotion.