MCAT Psychology

Neurons

Sensory: Afferent, receptors → spinal cord

Interneurons: Between other neurons. Mainly CNS.

Motor: Efferent, CNS → muscles & glands

Reflex Arc

Interneurons in spinal cord relay info to the source of stimuli while simultaneously routing it to the brain

CNS

Brain and spinal cord

PNS

PNS. Nervous tissue and fibers outside

CNS Somatic: Voluntary Autonomic: Sympathetic = F/F, parasympathetic = R/D.

Neutrotransmitters

Released by neurons to carry a signal

Acetylcholine

Used by somatic nervous system to move muscles. Also used by the parasympathetic and CNS.

Dopamine

Smooth movements and steady posture

Endorphins & Enkephalins

Natural pain killers

Epinephrine & Norepinephrine

Maintain wakefulness and mediate F/F responses. Epinephrine tends to act as a hormone, norepinephrine a neurotransmitter

g-aminobutyric Acid (GABA)

Inhibitory neurotransmitters. Act as brain “stabilizers”. Glycine serves a similar function

Gluamate

Excitatory neurotransmitter

Sertonin

Modulates mood, sleep, eating, and dreaming.

Cortisol

Stress hormone released by the adrenal cortex

Hindbrain

Cerebellum, medulla oblongata, reticular formation

Midbrain

Inferior and superior colliculi

Forebrain

Thalamus, hypothalamus, basal ganglia, limbic system, cerebral cortex.

Methods of study

EEG and regional cerebral blood flow

Thalamus

Relay station for sensory info

Hypothamamus

Homeostasis & the 4 F’s. Integrates with endocrine system. Hypothalamus → hypophyseal portal → anterior pituitary

Basal Ganglia

Smooths movements and helps postural stability

Limbic System

Septal Nuclei: Pleasure and addiction.

Amygdala: Fear and aggression.

Hippocampus: Emotion and memory

Cerebral Cortex

Four lobes

Frontal: Executive function, impulse control, speech, motor.

Parietal: Touch, pressure, temp, pain, spatial processing.

Occipital: Visual

Temporal: Sound, speech perception, memory, emotion

Cerebral hemispheres

Left is dominant and for language, logic, and math.

Right is intuition, creativity, and spatial processing

Neural tubes

Becomes the CNS

Neural crest cells

Spread out of the body with tissue differentiation

Primitive Reflexes

Exist in infants and should disappear with age.

Rooting Reflex: Turns head toward stimulus.

Moro Reflex: Extends arms, response to falling sensation.

Babinski Reflex: Big toe is extended and other toes fan out in response to brushing on sole of foot.

Grasping Reflex: Grabs anything put into hands.

Developmental milestones

• Gross and fine motor abilities progress head to toe and core to periphery

• Social skills shift from parent-oriented to other-oriented

• Language skills become increasingly complex

Sensory receptors

Sensory nerves that respond to stimuli

sensory ganglia

Collection of cell bodies outside CNS

projection areas

Parts of the brain that analyze sensory input

absolute threshold

Min stimulus energy that will activate a sensory system

Threshold of Conscious Perception

The minimum stimulus energy that will create a signal large enough in size and long enough in duration to be brought into awareness.

Difference treashold

Minimum difference in magnitude between 2 stimuli before one can perceive this difference

Weber’s law

Just noticeable difference in a stimulus is proportional to the magnitude of the stimulus

Signal detection theory

Refers to the effects of nonsensory factors, such as experiences, motives, and expectations on perception of stimuli. Accounts for response bias.

Adaptation

Refers to more or less sensitivity in a stimulus

Cornea

Gathers and filters incoming light

Iris

Controls size of pupil. Colored part of eye. Divides front of the eye into the anterior and posterior chamber. Contains the dilator and the constrictor papillae

Lens

Refracts incoming light to focus on the retina

Aqueous humor

Produced by the ciliary body. Nourishes the eye and gives the eye its shape.

Retina

Rods: Detect light / dark. Contain rhodopsin.

Cones: Color. Short / medium / long. Cones are in the fovea, which is part of the macula. Pathway from retina: Rods/Cones → bipolar cells → ganglion cells → optic nerve

Retinal disparity

Space between eyes that add depth and binocular vision

Horizontal and Amacrine Cells

Integrates signals from ganglion cells and performs edge-sharpening

Support

Vitreous on inside. Sclera and choroid on outside

Processing

Parallel Processing: Color, form, and motion at same time. Magnocellular Cells: Motion. High temporal resolution. Parvocellular Cells: Shape. High spatial resolution

Outer ear

Pinna, external auditory canal, tympanic membrane

Middle ear

Connected to nasal cavity by Eustachian tube.

Ossicles: Acronym MIS and HAS.

Malleus: Hammer

Incus: Anvil

Stapes: Stirrup. Footplate of stapes rests in the oval window of cochlea.

Inner ear

Bony Labyrinth: Filled with perilymph.

Membranous Labyrinth: Filled with endolymph. Membranous labyrinth consists of cochlea (sound), utricle & saccule (linear acceleration) and semicircular canals (rotational acceleration & balance).

Projection areas

Superior Olive: Localizes sound. Located in brain stem.

Inferior Colliculus: Startle reflex. Also used by both eyes and ears in the vestibulo-ocular reflex which keeps the eyes fixed on a single point as the head rotates.

Visual pathway

eye → optic nerves → optic chiasm → optic tracts → lateral geniculate nucleus → visual radiations → visual cortex

Auditory pathway

cochlea → vestibulocochlear nerve → medical geniculate nucleus → auditory cortex

Smell

The detection of volatile or aerosolized chemicals by the olfactory chemoreceptors (olfactory nerves) in the olfactory epithelium. Smell info bypasses the thalamus.

Pheromones

Chemicals given off by animals that have an effect on social foraging and sexual behavior

Taste

Sweet/salty/sour/bitter/umani

Somatosenation

Presse, vibration, pin, and temp

2-point threshold

Minimum distance necessary between 2 points of stimulation on the skin such that points will be felt as 2 distant stimuli

Physiological zero

Normal temp of skin which objects are compared to

Nociceptors

Pain reception. Gate theory of pain

Kinesthetic sense

Proprioception

Top-down processing

Recognition by memories and expectations. Don’t look at the details

Bottom-up processing

Details → whole. Recognition via similarity

Gestalt Principles

Proximity, similarity, continuity, closure. All are governed by the Law of Prägnanz. Whole

Habiation

Getting used to a stimulus

Dishabituation

2nd stimulus causes resensitization of original

Associative Learning

Pairing together stimuli/behavior

Operant conditioning

Behavior is changed through the use of consequences.

Reinforcement: Increases likelihood of behavior.

Punishment: Decreases likelihood of behavior.

Schedule: The schedule of reinforcement can be based on an amount of time or a ratio of behavior / reward, and can be either fixed or variable.

Positive Response: Adding something.

Negative Response: Removing something

Extinction

Behavior stops when no longer reinforced

Shaping

Getting closer and closer to target behavior

Classical conditioning

With repeating, a neural stimulus becomes conditioned stimulus that produces a conditioned response

Observational Learning

Learning behavior by observing others

Encoding

Processing new info into memory. Semantic encoding is stronger than acoustic and visual

Sensory Memory

Transient and based on neurotransmitter activity (few seconds)

Working Memory

Requires short term memory, attention, and executive function to manipulate information

Long term memory

Requires elaborate rehearsal and is the result of increased neuronal connectivity.

Explicit (declarative) Memory: Accounts for memories that we must consciously recall with effort and focus.

Implicit (nondeclaritive) Memory: Accounts for acquired skills and conditioned responses to circumstances and stimuli.

Sematic networks

Stores facts. Links close concepts together

Retrieval

Recognition of info stronger than recall. Retrieval is based on priming interconnected nodes of the semantic network.

Korsakoff’s syndrome

Memory loss caused by thiamine shortage in brain. Causes amnesia. Fabricates memories

Agnosia

Loss of ability to recognize objects, people, or sounds. Usually caused by physical damage to brain.

Retroactive inerferance

New memories make you forget old

Proactive interference

Old memories interfere with learning new memories

Information Processing Model

The brain encodes, stores, and retrieves info much like a computer.

Piaget’s stages

Trial-and-Error

Algorithms

Deductive Reasoning: Form conclusions from rules. Inductive Reasoning: Form conclusions from evidence.

Mental Set

A pattern of approach for a given problem.

Functional Fixedness

The tendency to use objects only in the way they are normally utilized. Creates barriers to problem-solving.

Heuristics

Rule of thumb

Availability Heuristic

When we make our decisions based on how easily similar instances can be imagined.

Representative heuristic

The tendency to make decisions about actions / events based on our standard representations of the events.

Confirmation bias

The tendency to focus on information that fits an individual’s beliefs, while rejecting information that goes against those beliefs.

Gardner’s theory of multiple intelligenes

7 areas of intelligence: Linguistic, logicalmathematical, musical, visual-spatial, bodilykinesthetic, interpersonal, intrapersona

Alertness

Sleep

More info on right

Hypnosis

Individuals appear to be in normal control of their faculties but are in a highly suggestible state. Used for pain control, psychological therapy, memory enhancement.

Meditation

Quieting of the mind and used for relief of anxiety.

Depressants

Alcohol, barbiturates, benzodiazepines. Increase GABA

Stimulants

Opiates

Heroin, morphine, opium, oxycodone & hydrocodone. Can cause death by respiratory depression

Hallucinogens

LSD, peyote, mescaline, ketamine

Mesolimbic pathway

Mediates drug addiction. Includes nucleus accumbens, medial forebrain bundle, and ventral tegmental area. Dopamine is the main neurotransmitter

Phonology

Actual sound of speech

Morphology

Building blocks of works