Behavioral Sciences

MCAT

Sensory Neurons

Sensory Neurons

Transmit sensory information from receptors to the spinal cord and brain

Motor Neurons

Transmit motor information from the brain and spinal cord to muscles and glands

Interneurons

Found between other neurons; Most numerous; Located predominantly in the brain and spinal cord and are often linked to reflexive behavior

Reflex Arcs

Control reflexive behavior

Central Nervous System (CNS)

Brain and spinal cord

Peripheral Nervous System (PNS)

Nerve tissue and fibers outside the brain and spinal cord; Spinal nerves (Nerves emanating from the spinal cord); Cranial nerves (Nerves emanating from the brain)

Somatic Nervous System

Sensory and motor neurons distributed throughout the skin, joints, and muscles; Sensory neurons transmit information toward the CNS through afferent fibers; Motor impulses travel from the CNS back to the body along efferent fibers

Autonomic Nervous System (ANS)

Regulates heartbeat, respiration, digestion, and glandular secretions; Manages involuntary muscles; Regulates body temperature

Extirpation (Ablation)

Various parts of the brain are surgically removed and the behavioral consequences are observed; Pierre Flourens used this technique to assert that specific parts of the brain had specific functions

Functionalism

Studies how mental processes help individuals adapt to their environments

Paul Broca

Demonstrated that specific functional impairments could be linked with specific brain lesions; Broca’s Area: Area on the left side of the brain that gives us our ability to speak

Parasympathetic Nervous System

Conserves energy; Reduce heart rate and constrict the bronchi; Manage digestion; Acetylcholine; Stimulate flow of saliva; Inhibits release of glucose and adrenaline production; Stimulates bile release; Promotes erection of genitals

Sympathetic Nervous System

Activated by stress; “Fight-or-flight” reactions;

When activated:

• Increases heart rate

• Redistributes blood to muscles

• Increases blood glucose concentration

• Relaxes the bronchi

• Decreases digestion and peristalsis

• Dilates the eyes to maximize light intake

• Releases epinephrine into the bloodstream

Meninges

A thick, three-layered sheath of connective tissues that covers the brain; Resorb cerebrospinal fluid

• Outer Layer: Dura mater

• Middle Layer: Arachnoid mater (Fibrous, weblike structure)

• Inner Layer: Pia mater (Directly connected to brain)

Cerebrospinal fluid

Aqueous solution that nourishes the brain and spinal cord and provides a protective cushion; Produced by ventricles

Brainstem

Formed by hindbrain and midbrain

Forebrain

Complex perceptual, cognitive, and behavioral processes; Emotion and memory

• Cerebral Cortex

• Basal Ganglia

• Limbic System

• Thalamus

• Hypothalamus

Midbrain

Involuntary reflex responses triggered by visual or auditory stimuli

• Inferior and superior colliculi

Hindbrain

Where the brain meets the spinal cord; Balance, motor coordination, breathing, digestion, and general arousal processes like sleeping and walking; Vital functions

• Cerebellum

• Medulla oblongata

• Reticular formation

• Pons

Cerebral cortex

Complex perceptual, cognitive, and behavioral processes; Language processing, problem solving, impulse control, long-term planning; Has numerous bumps and folds called gyri and sulci; Two halves called cerebral hemispheres

Basal Ganglia

Coordinate muscle movement as they receive information from the cortex and relay this information to the brain and the spinal cord

Superior Colliculis

Receives visual sensory input from some nerve fibers after leaving the optic chiasm; Controls some reflex responses to visual stimuli and reflexive eye movements

Inferior Colliculis

Receives sensory information from the auditory system

Cerebellum

Refined motor movements; Posture, balance, coordination

Medulla oblongata

Heart, vital reflexes (vomiting, coughing); Breathing, digestion

Reticular Formation

Arousal and alertness

Pons

Communication within the brain, breathing; Sensory and motor pathways between the cortex and the medulla

Neuropsychology

Study of functions and behaviors associated with specific regions of the brain

Electroencephalogram (EEG)

Involves placing several electrodes on the scalp in order to study electrical activity generated by larger groups of neurons

Regional Cerebral Blood Flow (rCBF)

Detects broad patterns of neural activity based on increased blood flow to different parts of the brain; Relies on the assumption that blood flow increases to regions of the brain that are engaged in cognitive function

CT (Computed Tomography/CAT) Scan

Multiple X-rays are taken at different angles and processed by a computer to produce cross-sectional images of the tissue

PET (Positron Emission Tomography) Scan

Radioactive sugar is injected and absorbed into the body, and its dispersion and uptake throughout the target tissue is imaged

MRI (Magnetic Resonance Imaging)

A magnetic field that interacts with hydrogen atoms is used to map out hydrogen dense regions of the body

fMRI (Functional MRI)

Specifically measures changes associated with blood flow; Useful for monitoring neural activity, since increased blood flow to a region of the brain is typically coupled with its neuronal activation

Lateral Hypothalamus (LH)

Hunger center

Ventromedial Hypothalamus (VMH)

Satiety center; Signals to stop eating

Anterior Hypothalamus

Controls sexual behavior; Regulates sleep and body temperature

Posterior Pituitary

The site of release for the hypothalamic hormones antidiuretic hormone (ADH or Vasopressin) and oxytocin

Pineal Gland

Secretes melatonin to regulate circadian rhythms

Extrapyramidal System

Gathers information about body position and carries this information to the central nervous system

Parkinson’s Disease

Chronic illness associated with destruction of portions of the basal ganglia; Characterized by jerky movements and uncontrolled resting tremors

Septal Nuclei

Primary pleasure center in the brain

Anterograde Amnesia

Not able to establish new long-term memories

Retrograde Amnesia

Memory loss of events that transpired before brain injury

Anterior Cingulate Cortex

Regulation of impulse control and decision-making; Emotion and motivation

Frontal Lobe

Two basic regions: Prefrontal cortex and Motor cortex; Contains Broca’s Area

Association Area

Area that integrates input from diverse regions of the brain

Projection Area

Performs more rudimentary perceptual and motor tasks; Sensory processing

Primary Motor Cortex

Initiate voluntary motor movements by sending neural impulses down the spinal cord toward the muscles; Located on the precentral gyrus, just in front of the central sulcus that divides the front and parietal lobes

Broca’s Area

Speech production; Usually found in only one hemisphere, the so-called “dominant” hemisphere (often the left hemisphere)

Parietal Lobe

Located to the rear of the frontal lobe; The somatosensory cortex is located on the postcentral gyrus and is involved in somatosensory information processing; Destination for all incoming sensory signals for touch, pressure, temperature, and pain

Occipital Lobe

At the rear of the brain; Visual cortex

Temporal Lobe

Auditory cortex for sound processing; Wernicke’s area; Memory processing, emotion, and language

Wernicke’s Area

Associated with language reception and comprehension

Contralateral Communication

When one side of the brain communicates with the opposite side of the body

Ipsilateral Communication

When cerebral hemispheres communicate with the same side of the body (i.e. Hearing)

Dominant Hemisphere

Often left; Primarily analytic in function; Language, logic, and math skills; Broca’s and Wernicke’s areas; Analyzes the content of language

Nondominant Hemisphere

Often right; Intuition, creativity, music cognition, and spatial processing; Processes the pieces of a stimulus and assembles them into a holistic image; Interprets the emotional tone of language

Neurotransmitter

Chemical used by neurons to send signals to other neurons

Agonist

Drug that mimics the action of some neurotransmitter

Antagonist

Drug that acts by blocking the action of neurotransmitters

Acetylcholine

Used in the peripheral nervous system to transmit nerve impulses to the muscles; Used by the parasympathetic nervous; In CNS, linked to attention and arousal

Catecholamines

Epinephrine, norepinephrine, dopamine; Important roles in the experience of emotions

Epinephrine (adrenaline) and norepinephrine (noradrenaline)

Control alertness and wakefulness; Primary neurotransmitter of the sympathetic nervous system; Fight-or-flight response

Dopamine

Neurotransmitter that plays important role in movement and posture

Dopamine Hypothesis of Schizophrenia

Argues that delusions, hallucinations, and agitation associated with this illness arise from either too much dopamine or from an oversensitivity to dopamine in the brain

Serotonin

Regulating mood, eating, sleeping, and dreaming; Oversupply thought to produce manic states, undersupply thought to produce depression

GABA (Gamma-Aminobutyric Acid)

Produces inhibitory postsynaptic potentials; Stabilizing neural activity in the brain; Causes hyperpolarization of the postsynaptic membrane

Glycine

Inhibitory neurotransmitter in the CNS by increasing chloride influx into the neuron; Hyperpolarizes the postsynaptic membrane

Glutamate

Excitatory neurotransmitter in CNS

Neuromodulators

Relatively slow and have longer effects on the postsynaptic cell than neurotransmitters; I.e. Endorphins

Endorphins

Natural painkillers produced in the brain

Endocrine System

Uses hormones and is somewhat slower than the nervous system because hormones travel to their target destination through the bloodstream

Pituitary Gland

Releases hormones that regulate activities of the endocrine glands elsewhere in the body; Controlled by the hypothalamus

Adrenal Glands

Located on top of the kidneys

• Adrenal Medulla: Releases epinephrine and norepinephrine as part of the sympathetic nervous system

• Adrenal Cortex: Produces many hormones called corticosteroids, including the stress hormone cortisol; Also produces the sex hormones testosterone and estrogen

Gonads

Sex glands of the body —ovaries in females and testes in males; Produce sex hormones that increase libido

Innate Behavior

Result of evolution

Learned Behaviors

Based on experience and environment

Adaptive Value

Extent to which a trait or behavior positively benefits and species by influencing the evolutionary fitness of the species, leading to adaptation through natural selection

Family Studies

Rely on the fact that genetically related individuals are more similar genotypically than unrelated individuals

Twin Studies

Compare concordance rates for a trait between monozygotic (identical) and dizygotic (fraternal) twins; Better able to distinguish the relative effects of shared environment and genetics; Concordance rates refer to the likelihood that both twins exhibit the same trait

Adoption Studies

Compare the similarities between biological relatives and the child who was adopted to similarities between adoptive relatives and the child

Critical Periods

Specific periods in development where children are particularly susceptible to environmental factors

Neurulation

Occurs when the ectoderm overlying the notochord begins to furrow, forming a neural groove surrounded by two neural folds

Umbilical Cord

Attaches the fetus to the uterine wall and placenta

Placenta

Transmits food, oxygen, and water to the fetus while returning water and waste to the mother

Primitive Reflex

Reflex that disappears with age

Rooting Reflex

The automatic turning of the head in the direction of a stimulus that touches the cheek

Moro Reflex

Infants react to abrupt movement of their heads by flinging out their arms, then slowly retracting their arms and crying

Babinski Reflex

Causes the toes to spread apart automatically when the sole of the foot is stimulated

Grasping Reflex

Occurs when infants close their fingers around an object placed in the hand

Gross Motor Skills

Incorporate movement from large muscle groups and whole body motion

Fine Motor Skills

Involve the smaller muscles of the fingers, toes, and eyes, providing more specific and delicate movement

Stranger Anxiety

Fear and apprehension of unfamiliar individuals; Develops at 7 months

Separation Anxiety

Fear of being separated from parental figure; Develops at 1 year

Parallel Play

Children will play alongside each other without influencing each other’s behavior; Develops at 2 years

Transduction

Taking the physical, electromagnetic, auditory, and other information from our internal and external environment and converting this information into electrical signals in the nervous system

Distal Stimuli

Physical objects outside of the body

Proximal Stimuli

Sensory-stimulating byproducts (i.e. Photons, sounds waves, heat, pressure, etc.); Directly interact with and affect the sensory receptors, and thereby inform the observer about the presence of distal stimuli

Ganglia

Collections of neuron cell bodies found outside the CNS; Once transduction from these occurs, the electrochemical energy is sent along neural pathways to various projection areas in the brain, which further analyze the sensory input