MCAT Behavioral Sciences Chapter 1

Franz Gall

Phrenology, thought the brain part that is more active enlarges

Pierre Fluorens

Ablated parts of brain to observe behaviour effects

William James

How minds adapt to their environments, origin of fundamentalism

John Dewey

Saw organism as a whole in how it adapts to environment, orignated fundamentalism

Paul Broca

Found specific impairments can occur from lesions in specific parts of the brain

Hermann von Helmholtz

Measured nerve impusle speed, reaction time, linked physiology and psychology

Sir Charles Sherrington

Theorized about synapses

Meninges

Connective tissue to protect, anchor brain, absorbs CSF

Meninges layers

Dura connects to skull, arachinoid is fibrous web, pia is connects to brain

Cerebrospinal fluid, CSF

Nourishes, protects brain and spinal cord, from cells that line brain ventricles

Brain stem

Primitive, hind brain and midbrain, developed earlier evolutionary

Limbic system

Forebrain, for emotions and memory

Cerebral cortex

Cerebral hemispheres, most recent evolutionary development

Prenatal brain development

Neural tube has 3 swellings, hind brain that splits into 2, midbrain, and forebrain that splits into 2

Hindbrain

Rhombencephalon, controls basic survival functions, splits into myencephalon and metencephalon

Myencephalon

Becomes medulla oblongata, regulates HR, breathing, digestion

Metencephalon

Develops into pons and cerebellum

Pons

Above medulla, has sensory and motor pathways between medulla and cortex

Cerebellum

Mantains posture, balance, body coordination

Midbrain

Mesencephalon, reflexes from visual, auditory stimuli, contains colliculi

Superior colliculus

Gets visual input, in midbrain

Inferior colliculus

Gets auditory input, reflex reactions, in midbrain

Forebrain

Prosencephalon, controls complex processes, divides into telencephalon and diencephalon

Telencephalon

Becomes cerebral cortex, basal ganglia, limbic system

Diencephalon

Becomes thalamus, hypothalamus, posterior pituitary, pineal gland

Extirpation

Make lesions in the brain to study neuropsychology

Cortical maps

Electrode stimulates a part of the brain and elicits a response

Electroencephalogram, EEG

Measures electrial activity from large neuron groups via scalp electrodes

regional Cerebral bloood flow, RCBF

Measures blood flow to parts of brain to assess neural activity via radioactive gas

Brain imaging

CT or cross-sectional x-rays, PET measures radioactivity, magnetic MRI and fMRI which measures neural activty via blood flow

Thalamus

Relays and sorts all sensory input except smell

Hypothalamus

Lateral, ventromedial, anterior with endocrine, autonomic function, drives hunger thirst and sexual behavior

Lateral hypothalamus, LH

Hunger center, detects when the body needs to eat or drink more

Ventromedial hypothalamus, VMH

Satiety center, signals to stop eating

Anterior hypothalamus

Control sexual behavior, sleep, body temp

Pineal gland

Releases melatonin based on retina signals

Basal ganglia

Coordinates muslce movement, posture via extrapyramidal system input on body position

Basal ganglia pathology

Loss of dopaminergic neurons in Parkinson’s, can influence schizophrenia and OCD

Limbic system components

Septal nuclei, amygdala, hippocampus, anterior cingulate cortex

Septal nuclei

Main pleasure center, involved in addiction

Amygdala

Controls fear and rage, lesions lead to hypersexuality and less fear, rage

Hippocampus

Learning, long term memory formation and redistribution, connects to limbic system via fornix

Anterograde amnesia

Cannot make long term memories, but memories before injury are intact

Retrograde amnesia

Memory loss of events right before injury

Anterior cingulate cortex

Regulates impulse control and decision making

Cerebral cortex

Gyri bumps, sulci folds, with frontal, parietal, occipital, temporal lobes in hemispheres

Frontal lobe

Prefrontal cortex and motor cortex, Broca’s area

Prefrontal cortex

Regulates attention, perception, memory, alertness, impulse control, long term planning

Association area

Integrates multiple inputs, like prefrontal cortex

Projection area

Can do basic perceptual and motor tasks, like somatosensory, motor cortex

Primary motor cortex

Starts voluntary movements, in precentral gyrus in front of central sulcus between frontal and parietal lobes

Broca’s area

In dominant hemisphere, produces speech

Parietal lobe

Spacial processing and manipulation, and somatosensory cortex input for pain, teperarure, pressure, touch,

Occipital lobe

Visual or striate cortex, assocaited with learning and motor control

Temporal lobe

Auditory cortex that processes sound, Wernicke’s area for language comprehension, and involved in memory, emotion, language

Contralateral communication

Cerebral hemispheres control movement of opposite side of body

Ipsilateral communication

Cerebral hemisphers get sensory info from same side of body

Dominant hemisphere

Usually left, analytic and detail oriented, has Broca and Wernicke’s area

Non dominant hemisphere

Creative, intuition, spatial processing, analyzes body language, tone

Agonist

Drug mimics action of neurotransmitter

Antagonist

Drug blocks action of neurotransmitter

Acetylcholine, ACh

Used in PNS to move muscles and sweat, excitatory in CNS for attention and arousal

Alzheimers physiology

Loss of cholinergic neurons in hippocampus

Monoamines

Epi, norepi, dopamine

Epinephrine and norepinephrine

SNS fight or flight, control alertness

Epinephrine

From adrenal medulla, acts systemically as a hormone

Norepinephrine

Acts locally as a neurotrasmitter, low in depression, high in mania and anxiety

Dopamine

High in basal ganglia, imblanced in schizophrenia due to too much/hypersensitivity theory

Serotonin

Monoamine, regulates mood, eating, sleeping, dreaming, high in mania and low in depression

GABA

Inhibitory, hyperpolarizes postsynaptic membrane

Glycine

Inhibitory, increases Cl influx to hyperpolarize postsynaptic membrane

Glutamate

Excitatory

Neuropeptides

Slow, long effects on post synaptic cell, endorphins

Pituitary

Master gland, especially anterior

Adrenal glands

Atop kidneys, medulla makes epi and norepi, cortex makes corticosteroids and androgens

Gonads

Sex grands, make sex hormones for maitng, libido, sexual function

Behaviors origin

Innate from genes, learned from environment

Adaptive value

Lelvel that a trait or behavior positively benefits fitness

Concordance rates

Likelihood both twins show the same trait

Critical period

Times when development is more susceptible to environmental effects

Neuralation

Ectoderm over notochord forms neural groove and 2 neural folds, 2 neural crests and neural tube

Neural tube

Forms CNS, alar plate forms sensory neurons, basal plate forms motor neurons

Primitive reflexes

In infants, disappear with age, rooting, Moro, Babinski, grasping, can reappear in demyelination diseases

Rooting reflex

Head turns towards stimulus that touches cheek

Moro relfex

Arms fling out when moved abruptly, disappears after 4 months

Babinski reflex

Toes spead when sole is touched

Grasping reflex

Fingers wrap aorund anything placed in palm

Motor skils

Gross are whole body motion, fine are finger, toe, and eye movements

Developmental milestones

Kids motor skills develop from core out, and socially from parents to self to others