MCAT Psychology

Neuropsychology

study of the connection between the nervous system and behavior

• most of the field focuses on the functions of various brain regiosn

Organization of the Brain

hindbrain

midbrain

forebrain

• contains thalamus, hypothalamus, basal ganglia, limbic system, and cerebral cortex

Hindbrain

• contains cerebellum, medulla oblongata, and reticular formation

  • cerebellum: refined motor movements,

  • medulla oblongata: vital functioning,

  • Reticular foramtion: arousal and alertness

Midbrain

• contain infereior and superior colliculi

  • inferior: auditory stimuli

  • superior: visual stimuli

• function in sensorimotor refelxes

Feanz Gall

had early theory that behavior, intellect, and eoeribskugt might be linked to antomy

• developed doctrine of phrenology

• could mesaure physiological attributes by feeling/analyzing skull

Brainstem

hindbrain plus midbrain

Pierre Flourens

first to study functions of major brain sections

• performed ablations on animals

Wiliam James

“father of AMerican psychology”

• importance of studying how mind functioned in adapting to environment

  • funcationalism

Functinalism

system of thought that studied how mental processes help individuals adapt to their environments

Paul Broca

added to knowledge of physiology by examining behavioral deficits of peiople with brain damage

• first to demonstrate specific funational impairments could be linked with specific brain lesions

Hermann von Helmholtz

was first to measure speed of a nerve impulse

• measured speed of nerve impulses in terms of reaction time

Charles Sherrington

first inferred the existence of synapses

Meninges

thick sheath of connective tissue protecting the brain and spinal cord

• pia mater

• arachnoid mater

• dura mater

Cerebrospinal Fluid

aqueous solution in which the brain and spinal cord rest

• produced by specialized cells in ventricles (ependymal cells)

Limbic System

a group of nerual structuwes primarily associated with emotion and memory

• septal nuclei : contains one of primary pleasure brain centers

Amygdala

plays an important role in defensive and aggresive behaviors, including fear and rage

Cerebral cortex

outer covering of the cerebral hemisphers

• associated with cognitive processing from language to problem solving

CT (computed tomography)

multiple x-rays are taken at different angles and processed by a computer to cross-sectional slice 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 eimages

MRI (magentic resonance imaging)

uses a magnetic field to interact with hydorgen and map out hydrogen dense regions of the body

fMRI (functional magnetic resonance imaging)

uses the same base technique as MRI, but speicfically measrues changes associted with blood flow

Thalamus

serves as an important relay station for incoming sensory information (except for olfaction)

Hypothalamus

serves homestatic functions and key in emotional experiences during high arousal states, along with endocrine function and control of the ANS

• lateral

• ventromedial

• anterior

Lateral Hypothalamus

referred to as the hunger center becuase of its special receptors thought to detect when the body needs more food or fluids

• triggers eating and drinking

Ventromedial Hypothalamus

identified as the “satiety center” and provides signals to stop eating

Anterior Hypothalamus

controls sexual behavior

• also helps regulate sleep and body temperatuer

Basal Ganglia

coordinate muscle movemetn as they receive information form teh cortex and relay this information

• extrapyramidal system

• destruction of this leasd to parkinson’s disease

Extrapyramidal System

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

Hippocampus

plays a vital role in learning and memory processes, consolidating infroamton to form long-term memories

Anterograde Amnesia

not being able to form long term memories

Retrograde Amnesia

refers to memory loss of events that transpired before brain injury

Broca’s area

located in frontal lobe and is important in speech production

• ……. aphasia: inabilty to produce coherent or speech but can understand speech well

  • may say one or two words at a time

Prefrontal Cortex

area of frontal lobe that acts as an association area, integrating informatoin from different parts of the brain

• manages executive function by superivsing and directing brain operations

Primary Motor Cortex

area of frontal lobe involved on the precentral gyrus initiating voluntary motor movement

Somatosensory Cortex

area of the parietal lobe at the postcentral gyrus involved in processing incoming sensory signals

Cerebral hemispheres and Laterality

cerebral hemisphres usually communicate contralaterally (u should know what this means)

• Dominant hemisphere: primarily analytic in function, manging details (usually left)

• nondominant hemisphere: associated with intuition, creativity, music cognition, and spatial processing (usually right)

Acetylcholine

neurotransmitter foudn in both CNS and PNS involved in transmit nerve impulses to muscles

• linked to attention and arousal

• loss associated with Alzheimer’s

Biongenic Amines

• dopamine

• norepinephrine

• epinephrine

Glycine

can serve as inhibitory neurotransmitter, CNS by increasing chloride influx into neuron

Serotonin

important in regulating sleep, mood, eating, sleeping, and dreaming

Endorphins

peptide neurotransmitter that acts as natural painkiller

Innate Behavior

genetically programmed as a result of evolution

• seen in all individuals regardless of environment or experience

Learned Behaviors

behaviors based on expereience and environment

• adaptive value: extent to which a trait or behavior positively benefits a species

Family Studies

rely on the assumption that genetically related individuals are more similar genotypically than unrelated individuals

• limitied due to participants sharing both genetics and environment

Twin studies

compare concordance arates for a trait between monozygotic and dizygotic twins

• concordance rates: refer to likelihood that both twins exhibit the same trait

Adoption Studies

help us understand environmental influences and gneetic influence on behavior

• compare similariets betwen bioglocal relative and adopted children

Neural development

• neuralation: ectoderm overlying neurochord begin to furrow forming neural groove , surrounded by two neural folds

Neural crest

cells at leading edge of neural fold

• will migrate thorughtout thbody to form disparate tissues (dorsal root ganglia, melanocytes etc.)

Neural Tube

remainder of furrow from neural groove

• ultimately forms CNS

• altar plate: diffrentiates into sensory neurons

• basal plate: differentiates into motor neurons

Primitive reflexes

reflexes that dissapear with age

• rooting reflex

• moro reflex

• babinski reflex

• grasping reflex

Rooting Reflex

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

Moro Reflex

infants react to abrupt movements of their head s by flinging out their arms, then slowly retracting and crying

Babinski Reflex

causes the toe to spread apart automatically when the sole of the foot is stimulated

Grasping reflex

occurs when teh infant closes his or her fingers around an object placed in their hand

Stranger and separation anxiety Anxiety

at birth, parental figure beceome’s center of infant’s world; infant develops

• fear and apprehension of unfamilar individuasl

• fear of being separated from parental figure

Sensation

the converison, or transduction, of physical, electromagnetic, auditory and other information from the internal and external environment into electric signals in the nervous system

Perception

the processing of sensory information to make sense of its significance

Sensory Receptors

nerves that respondto stimuli and trigger electrical signals

• associated with sensory ganglia

• transmit to projection areas in the brain

threshold

the minimum stmiulus that cauess a chagne in signal transduction

Common sensory receptors

• photoreceptors

• hair cells

• nociceptors

• thremoreceptors

• osmoreceptors

• olfactory receptors

• taste receptors

Stimuli

trigger sensory neurons and trnasuduced into electrical signals

• pxroximal: directly interact w/ sensory receptors

• distal: originate outside the body

absolute threshold

the minimum stimulus of energy that is needed to activate a sensory system

threshold of conscious perception

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

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

Weber’s Law

states that the jnd, diffrence threshold, for a stimulus is proportional to the magnitude of the stimulus, and that is constant over most of the range of possible stimuli

Signal Detection Theory

the effecs of nonsensory factors, such as experiences, motives, and expectations, on perception of stimuli

• allows us to look at response bias

catch trial: signal is presented

noise trials: signal is not presented

Response Bias

the tendency of subjects to systematically respond to a stimulus in a particular way due to nonsensory factors

Measuring Response Bias in Trials

• miss: subject fails to perceive the signal

• hits: subject correctly perceives the signal

• false alarms: subject seems to perveive a signal when none was present

• correct negatives: subject correctly identifies that no signal was given

Adaptation

refers to a decrease in response to a stimulus over time

cornea

gathers and filters oncoming light

iris

divides the fron of the eye into the anterior and posterior chambers

• contains dilator and constrictor pupillae (open and close the pupillae)

Lens

refracts incoming light to focus it on retina

• held in place by suspensory ligaments

• connected to ciliary muscle

Aqueous humor

produced by ciliary body and drains throught the canal of Schlemm

Eye vasculature

supplement nutrients to the eye

• choroidal vessels

• retinal vessels

Retina

innermost layer of the eye

• contains the actual photoreceptors that transduce light into electrical infomation

Ciliary muscle

portion of the ciliary body that is under parasympathetic control

• contraction pulls on suspensory ligaments and causes the lens to accomodate

Vitreous Humor

transparent gel behind lens that supports the retina

Duplicity Theory of Vision

retina contain two kindsof photoreceptors

• rods: specialized for light and dark light

• cones: specialized for color detection, birght light

Macula

has a high concentration of cones

• fovea: centermost point with only cones

Bipolar Cells

highlight gradients between adjacent rods or cones

• synapse with ganglion cells

Ganglion cells

group together to form the optic nerve

• each cell represents the combined activity of many rods and cones

Resolution at Ganglion Cells

as the numebr of receptors that converge through bipolar neurons onto one ganglion cell increases, the resolution decreases

• # of cones converging onto single ganglion is greater than rods so cones have greater fine detail sensitivity

Connection Between Rods and Cones

several leyers of neurons

1. bipolar cells

2. Amocrine and Horizontal cells

3. Ganglion Cells

Amacrine and Horizontal cells

receive input from multiple retinal cells in the same area before the informatio is passed on to ganlgion cells

• amocrine = motion detection

• horizontal = enhances contrast/edges

Visual Pathway

1. Eye (retina)

2. Optic Nerves

3. optic chiasm

4. optic tracts

5. Lateral geniculate nucleus (LGN)

6. Visual Cortex through visual radiations

Visual Radiations

run through the temporal and parietal lobe to transmit visual stimuli to the visual cortex

parallel processing

the ability to simultaneously analyze and combine information regarding color, shape, and motion

Parvocellular cells

detect shape

• have high spatial resolution and low temporal resolution

Magnocellular cells

detect motion

• low spatial resolution and high temporal resolution

Outer Ear

consists of the pinna, external auditory canal, and tympanic membrane

Middle Ear

conssists of ossicles….

• malleus: affixed to tympanic membrane

• incus

• stapes: rests on oval window of cochlea

connected to the nasal cavity via the Eustachian tube

Inner Ear

contain the bony labyrinth with the membranous labyrinth winthin it

Bony Labyrinth

contains the membranous labyrinth

• filled with perilymph, which transmits vibrations from outside world

Membranous Labyrinth

filled with potassium rich endolymph and consists of the …..

• cochlea: detects sound

• uticle and saccule: detect linear accelration

• semicircualr canals: detect rotational acceleration

Projection of Auditory Stimuli

projects to superior oliive to be localized and inferior colliculus which is involved in the starle reflex

Pinna

directs sound waves to the to external auditory canal which moves those soudnwavs to the tympanic membrane

Cochlea

divided into 3 parts called sclae

• middla scala holds ogan of Corti

  • composed of thoursands of hairs and rests on thin flexible basilar membrane

• round window

  • membrane covered hole that permits perilymph to move within

Ogan of Corti

• composed of thoursands of hairs and rests on thin flexible basilar membrane

  • hairs are bathed in perilymph and convery physcial stimlus into electrosignal to be sent through auditory (vestibulocochlear nerve)

Vestibule

refers to the poriton of the bony labyrinth that contain the utricle and ssaccule

Semicircular Canals

lie within the utricle and saccule and are sensitive to rotational acceleration

• ampulla: where hair cells are located