MCAT Behavioral Sciences Chapter 1

Neuropsychology

Study of the connection between the nervous system and behavior

Sensory (afferent) neurons

Neurons that carry incoming information from the sensory receptors to the brain and spinal cord

Motor (efferent) neurons

Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

Interneurons

Central nervous system neurons that internally communicate and intervene between the sensory inputs and motor outputs

Reflex arcs

Ability of the interneurons in the spinal cord to replay information to the source of stimuli while simultaneously routing it to the brain

Central nervous system (CNS)

Brain and spinal cord

Peripheral nervous system (PNS)

Most cranial and spinal nerves. Divided into somatic (voluntary) and autonomic (automatic) divisions. Autonomic nervous system is further divided into parasympathetic (rest and digest) and sympathetic (fight or flight)

Hindbrain

Contains the cerebellum, medulla oblongata, and reticular formation

Midbrain

Contains inferior and superior colliculi

Forebrain

Contains thalamus, hypothalamus, basal ganglia, limbic system, and cerebral cortex

Thalamus

Relay station for sensory information

Hypothalamus

Maintains homeostasis and integrates with the endocrine system through the hypophyseal portal system that connects it to the anterior pituitary

Basal ganglia

Smoothen movements and help maintain postural stability

Limbic system

Contains septal nuclei, amygdala, and hippocampus, controls emotion and memory.

Septal nuclei

Involved with feelings of pleasure, pleasure-seeking behavior, and addiction

Amygdala

Controls fear and aggression

Hippocampus

Consolidates memories and communicates with other parts of the limbic system through and extension called the fornix

Cerebral cortex

Divided into four lobes

- Frontal: controls executive functioning, impulse control, long-term planning, motor function, and speech production

- Parietal: Controls sensations of touch, pressure, temperature, and pain; spatial processing; orientation; and manipulation

- Occipital: Controls visual processing

- Temporal: Controls sound processing, speech perception, memory and emotion

Brain is divided into two cerebral hemispheres

Left and right. Left is often dominant hemisphere for language

Neurotransmitters

Released by neurons and carry a signal to another neuron or effector (a muscle fiber or a gland)

Acetylcholine (ACh)

Used by somatic nervous system to move muscles, the PNS and CNS for alertness

Dopamine

Maintains smooth movements and steady posture.

Endorphins and enkephalins

Act as natural painkillers

Epinephrine and norepinephrine

Maintains wakefulness and alertness and mediate fight or flight responses. Epinephrine tends to acts a hormone and norepinephrine acts as a neurotransmitter.

y-aminobutyric acid (GABA) and glycine

Act as brain stabilizers

Glutamate

Acts as an excitatory transmitter in the brain

Serotonin

Modulates mood, sleep patterns, eating patterns, and dreaming

Cortisol

Stress hormone released by the adrenal cortex

Testosterone and esrogen

Mediate libido; testosterone also increases aggressive behavior. Both are released by the adrenal cortex. In males, the testes also produce testosterone. Females, the ovaries produce estrogen

Epinephrine and norepinephrine

Released by the adrenal medulla and cause physiological changes associated with the sympathetic nervous system

Nature vs. Nurture

Genetics = nature

Environment = nurture

- Study using family studies: relative frequency of a trait within a family compared to the general population; twin studies: compare concordance rates between monozygotic (identical) and dizygotic (fraternal) twin; adoption studies: compare similarities between adopted children and their adoptive parents, relative to similarities with their biological parents

Neurulation

Process by which nervous system develops, where notochord stimulates overlying ectoderm to fold over, creating a neural tube topped with neural crest cells. Neural tube becomes CNS, neural crest cells spread throughout the body, differentiating into many different tissues.

Primitive reflexes

Exist in infants and should disappear with age. Most primitive reflexes served a protective role. They can reappear in certain nervous system disorders.

Rooting reflex

Infant turns head toward anything that brushes the cheek

Moro reflex

Infant extends the arms, and slowly retracts them and cries in response to sensation of falling

Babinksi reflex

Big toe is extended and the other toes fan in response to the brushing of the sole of the foot.

Grasping reflex

Infant grabs anything put into his or her hands

Developmental milestones give an indication of what skills and abilities a child should have at a given age. Most children adhere closely t these milestones, deviating by only one or two months.

Gross and fine motor abilities progress from head to toe and core to periphery. Social skills shift from parent-oriented to self-oriented to other-oriented. Language skills become increasingly complex.