MCAT Behavioral Science -- Chapter 1

Franz Gall

thought that the area of a brain linked to a specific trait will increase in size as that trait is used more

Pierre Flourens

performed extirpation (surgically removed parts of brain) to observe behavioral consequences

William James

foundation of functionalism, which studies how mental processes help individuals adapt to environments

John Dewey

thought that psychology should focus on study of organism as a whole as it adapts to environment

Paul Broca

examined behavioral deficits of people with brain lesions; found Broca's area was associated with inability to speak

Hermann von Helmholtz

first to measure speed of nerve impulse and correlate it to reaction time

Sir Charles Sherrington

inferred existence of synapses (thought they were electrical, but turns out they were chemical)

Sensory neurons (afferent)

sends signals from body to the brain (Ascends to brain)

Motor neurons (efferent)

Sends motor info from brain to muscles (Exits brain)

Interneurons

Most numerous type of neuron; associated with reflexive behavior and bypasses motor neurons to send impulses to muscles directly to reflexively act (signal still sent to motor neurons, so motor neurons still involved)

Central Nervous System

brain and spinal cord

Peripheral Nervous System

nerve tissue and fibers outside of brain and spinal cord, including olfactory and optic nurves

Somatic Nervous System

sensory and motor neurons

Automatic Nervous System

regulates heartbeat, respiration, digestion, glandular secretions, etc (involved with involuntary muscles of internal organs); also helps regulate body temp

Parasympathetic Nervous System

Rest and Digest; constrict pupil, stimulate flow of saliva, slow heartbeat, constrict bronchi, contracts bladder, promotes erection of genitals

Sympathetic Nervous System

Fight or Flight; increased heart rate, stimulates glucose production, dilates pupils, inhibitis peristalsis and secretion; opposite effects of parasympathetic

Meninges

thick, three layered sheath of connective tissue surrounding brain that also helps absorb cerebrospinal fluid

Dura Mater

outer layer of meninges; connected directly to skull

Arachnoid mater

middle meninges, a fibrous, weblike structure

Pia mater

inner layer, connected directly to brain

Neural Tube

Composed of three swellings (hindbrain, midbrain, forebrain), but hindbrain and forebrain later divide into two swellings to make 5 total swellings

Forebrain

Prosencephalon; Divides into telencephalon and diencephalon; made up of cerebral cortex, basal ganglia, limbic system, thalamus, hypothalamus

Midbrain

Mesencephalon; associated with sensorimotor reflexes; has colliculi

Hindbrain (1)

Rhombencephalon; Divides into metencephalon (becomes pons and cerebellum) and medulla oblongata (myelencephalon); contains cerebellum, medulla oblongata, reticular formation, and pons

Hindbrain (2)

Controls balance, motor coordination, breathing, digestion, sleeping, and waking (vital functions for survival)

Medulla oblongota

Regulates vital functionsl ike breathing, heart rate, and digestion

Pons

Contains sensory and motor pathways between cortex and medulla

Cerebellum

Helps maintain posture and balance and coordinates body movements; alcohol impairs function

Superior colliculus

Visual sensory input

Inferior colliculus

Auditory sensory input

Telencephalon

forms cerebral cortex, basal ganglia, limbic system

Diencephalon

forms thalamus, hypothalamus, posterior pituitary, pineal gland

Brain Lesions

helps to study functions of the brain by examining behavioral consequences of the loss

Cortical maps

Use electrical stimulation directly on the brain and ask awake and alert patient about effects

Electroencephalogram (EEG)

place electrodes on scalp to detect broad patterns of electrical activity (can use ultrasensitive equipment to detect individual neural activity)

Regional cerebral blood flow (rCBF)

Detects broad patterns of neural activity based on increased blood flow to different parts of brain; operates on assumption that increased blood flow is associated with increased brain activity; patient inhales radioactive gas and device measures radioactivity levels in bloodstream

Computed tomography (CT) and computed axial tomography (CAT)

X-rays at different angles to produce cross-sectional images of brain

Positron emission tomography (PET)

radioactive sugar injected and absorbed by body, and its dispersion and uptake throughout body is imaged

Magnetic resonance imaging (MRI)

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

Functional magnetic resonance imaging (fMRI)

same as MRI, but specifically measures changes associated with blood flow, so very useful for neural activity

Thalamus

Sensory relay station

Hypothalamus

Serves homeostatic functions and is key player in emotional experiences; also helps control endocrine functions and automatic nervous system; links endocrine and nervous systems and regulates hormonal function of pituitary gland

Lateral Hypothalamus (LH)

hunger center; when removed, one Lacks Hunger

Ventromedial Hypothalamus (VMH)

satiety center that provides signals to stop eating; when removed, one is Very Much Hungry

Anterior Hypothalamus

controls sexual behavior

Posterior Pituitary

Releases hypothalamic hormones antidiuretic hormone and oxytocin

Pineal Gland

key player in several biological rhythms; most notably, releases melatonin to help regulate circadian rhythm

Basal Ganglia

Coordinates muscle movement; destruction is associated with Parkinson's disease

Limbic System

Associated with emotion and memory; includes septal nuclei, amygdala, hippocampus, anterior cingulate cortex

Septal nuclei

Primary pleasure center

Amygdala

Important role in defensive and aggressive behaviors; lesion results in docility and hypersexual states

Hippocampus

Vital role in learning and long-term memory, communicates with rest of limbic system through fornix

Anterior Cingulate Cortex

Higher order cognitive processes, including regulation of impulse control and decision making

Cerebral Cortex

outer surface of brain, has numerous gyri (bumps) and sulci (folds)

Frontal Lobe

Composed of prefontal cortex and motor cortex

Prefrontal Cortex

Association area that integrates input from diverse regions of the brain; supervises operations of other brain regions

Primary Motor Cortex

Projection area that performs perceptual and motor tasks; initiates voluntary movements

Broca's area

vitally important for speech production; found in the dominant hemisphere, which is the left hemisphere for most people

Parietal Lobe

Somatosensory cortex; closely associated with motor cortex, so sometimes described as sensorimotor complex

Occipital Lobe

Contain visual cortex

Temporal Lobe

auditory cortex for sound processing and Wernicke's area for language reception and comprehension; also contains hippocampus

Contralateral

One side of brain communicates with opposite side of body (motor neurons of left hemisphere activate movement on right side of body)

Ipsilateral

One side of brain communicates with same side of body (hearing)

Dominant Hemisphere

Usually left; analytic in function, so recognizes language, logic, math, and complex voluntary movement

Nondominant Hemisphere

Associated with intuition, creativity, music cognition, and spacial processing (faces, music, emotional tone, geometry, sense of direction)

Agonist

Drug that mimics action of some neurotransmitter

Antagonist

Drug that inhibits action of some neurotransmitter

Acetylcholine

found in both CNS and PNS; used in PNS to transmit nerve impulses to muscles, used in CNS to attention and arousal, and its loss in CNS has been associated with Alzheimer's

Catecholamines

epinephrine, norepinephrine, and dopmaine; all play roles in experience of emotions

Epinephrine (adrenaline) and Norepinephrine (noradrenaline)

primary neurotransmitter of sympathetic nervous system; promote fight or flight response

Norepinephrine

local neurotransmitter; low levels associated with depression and high levels associated with anxiety and mania

Dopamine

Important role in movement and posture; high levels found in basal ganglia; imbalances found to be associated with schizophrenia and Parkinson's disease

Serotonine

Regulating mood, eating, sleeping, and dreaming; oversupply leads to manic states, undersupply leads to depression

GABA

inhibitory postsynaptic potentials, stabilizes neural activity; causes hyperpolarization of postsynaptic membrane

Glycine

similar to GABA; inhibitory neurotransmitter in CNS

Glutamate

opposite of glycine; excitatory neurotransmitter

Endorphins

Painkillers

Hypophyseal Portal System

directly connects hypothalamus and pituitary gland to help maintain control over endocrine release of hormones

Pituitary Gland

sometimes called 'master' gland; divided into anterior and posterior; secretes various hormones into bloodstream

Anterior Pituitary Gland

true 'master' because it releases hormones that regulate activities of endocrine glands elsewhere; actually controlled by hypothalamus

Adrenal Glands

located on top of kidneys; divided into adrenal medulla and adrenal cortex

Adrenal medulla

releases epinephrine and norepinephrine as part of sympathetic nervous system

Adrenal cortex

produces many hormones called corticosteroids, including cortisol; also contributes to sexual functioning by producing estrogen and testosterone

Gonads

sex glands of body (ovaries and testes), produces sex hormones in higher concentrations

Neuralation

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

Neural crest

Cells at leading edge of neural fold; will migrate throughout body to form disparate tissues

Neural tube

Remainder of furrow closes to form this, and neural tube ultimately becomes CNS

Alar Plate

Neural tube contains this, and this will differentiate into sensory neurons

Basal plate

Neural tube contains this, and this will differentiate into motor neurons

Primitive reflexes

Reflexes common in infants that disappear with age; adults with neurological disorders may still exhibit these behaviors, especially if their disorders cause demyelination

Rooting reflex

Automatic turning of head in direction of stimulus that touches the cheek

Moro reflex

Infants react to abrupt movement of their heads by flinging out their arms, then slowly retracting them and crying (disappears after four months; continuation after one year is suggestion of developmental difficulties)

Babinski reflex

Toes spread out automatically when sole of foot is stimulated

Grasping reflex

Infants close their fingers around object placed in hand

Gross motor skills

development progresses from head to toe; incorporates movement from large muscle groups and whole body motion (crawling, sitting, walking)

Fine motor skills

development progresses from core to extremities; involves smaller muslces of fingers, toes, and eyes

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 play alongisde each other without influencing each other's behavior; develops at 2 years