Bio Bases

Up to Midterm

Factors Contributing to Abnormalities

Hormones, peri/pre-natal experience, early experiences, genes, environment, abuse, neglect, maternal substance abuse

Conceptualizing Behavior

1. What is the manifested behavior? (Behavior occurs → hormones)

2. What triggered the nervous system? (Seconds before? → uncon. sensory processing)

3. What went on secs-mins before and what parts of the brain were prompted? How much were you aware of outside stimulus? (80% of stimulus influences you unknowingly → unconscious processing)

4. What happened in hours/days before behaviors? (hormones come into play here)

5. Days/months before?

6. What does the frontal lobe development look like? → learning hx, base rate of trauma/PTSD

Sensory triggers

• most are subliminal

Fusiform gyrus

Responsible for face recognition; heavily connected to amygdala and wired to go against threats

Interoceptive

the perception and interpretation of signals originating from inside the body, such as heartbeat, hunger, pain, and emotional states

Galen’s understanding of body

fluid/hydraulic driven model wherein cardio and organ systems acted as open-ended network of fluids (like localized factories and aqueducts) rather than a closed, circulatory system.

Golgi’s contributions

staining methods giving greater understanding of cellular structure → revealed neurological networks are a web and not a mosaic

Ablation

the electrical shocks used to map out brain

Cajal’s contributions

every cell has a cell body → axons + dendrites → neurons are building blocks and signaling elements (early understanding of networks) → Neuron doctrine

Neuron Doctrine

individual neurons are the basic building blocks (structural, functional, organizational) of the brain

Harrison’s contribution

axons + dendrites grow from neurons + identified network feasibility → they have an inherent DNA process and function (as observed via growing in petri dish)

Palay’s contributions

synapses identified via electron microscopy images → reaffirmed Neuron Doctrine → discovered synaptic vesicles

The soul (as per Descartes)

internal, unconscious self that we’re unaware of

Flourens’ Contribution

Produced a holistic view of the brain and neural functioning by challenging the view of separate, functional centers of the brain and arguing for more unified, higher cortex processes

Warnecki and Jackson’s contributions

Argued specific parts of the brain do specific things → cellular connection cortex perspective. Proposed the brain is arranged in functional units that are organized and connected in precise ways

Luria’s 3 Functional Units

1. Regulation of cortical tone (mental alertness/wakefulness) → involves the brain stem, reticular activating system. Regulates how much arousal/activation for a particular stimuli. Operates according to the Law of Strength (strong act → strong response)

2. Responsible for receiving/analyzing storing info → asks what sense is this? Operates via simultaneous operation/successive & simultaneous processing. Involves parietal, occipital, and temporal lobe. Operates Law of Sequence (creates sequential/series order)

3. Promotes/regulates intentions/plans. Executes plans/verifies outcome compared to plan → frontal lobe/prefrontal area

Issues w/Luria’s 3 Functional Units

can lead you down mosaic thinking

Neuron cell types

neurons and glia

name for presynaptic terminals

end button (with an accent)

cell body/soma

metabolic center, nucleus, genes, endoplasmic reticulum (extension of nucleus, site of protein synthesis)

end button

releases neurotransmitters on the synaptic cleft and connects w/dendrite of other neurons, at end of presynaptic terminals

purpose of dendritic spines

exposure

purpose of myeline sheath in AP

propagates speed and conduction, keeps electricity inside the axon

nodes of Ranvier

unsheathed and exposure to opposing charge of outside environment here causes propagation of AP down the axon (located in myelin sheath)

electrical signal path

dendrite → cell body → axon → end button → vesicle/release/cleft → post-synaptic cleft → next neuron

Classification of neurons

• unipolar: single primary process, gives rise to many branches

  • highly sensory, efficient, found in ANS of vertebrates

• bipolar: oval soma/cell body

  • 2 distinct processes

  • dendritic structure receiving signals from other neurons

  • axon carries info towards CNS

  • largely sensory

  • short, efficient

• pseudo unipolar: receptor neurons, convey touch/pressure/pain

  • start as bipolar, but extension from soma fuse into one

  • one axon carries sensory info from receptor to spinal cord

• anaxonic

  • absence of axon

  • signals from cell body, doesn’t transmit long distance info

  • modulates to integrate info in short distances

• multipolar

  • multiple dendrites + single extension axon

  • info from multiple sources

  • most abundant

  • vary in size + length + very efficient

Teuber’s Principle

someone help me here

Glial cells

surround cell bodies, axons, dendrites

6 Action Potential (AP) steps

1. Na+ enters cell as cell channels open

2. K+ channels open and exits cell via electrostatic diffusion

3. Na+ channels become refractory = no more Na+ can enter the cell because no more electrical charge is needed for AP

4. K+ channel remains open, K+ continues to leave (polarizing cell)

5. K+ channels close, Na+ channels reset

6. Excess of K+ outside cell are cleaned up by microglia

resting potential is -70/65mv, critical threshold is reached at -55mv.

Graded potential

can hyper-polarize a cell making it more or less likely to fire an AP

astrocytes

• provide nutrition and neuronal signaling to neurons

• irregular, star shaped, large number of processes extending from them

• envelope and support capillaries + CNS blood vessels

• reduce inflammation/toxicity post-injury/disease

• susceptible to diseases

Oligodendrocytes

from the myelin sheath, surround cell bodies, keep things in place

Microglia

• the little pac-men of the brain, eat pathogens/debris

• flexibility in future jobs, 10% derived from progenitor cells

• colonize in early embryonic development and already knows its future job upon leaving yolk sac

• sculpt neurocircuits

• increase in number following injury/disease (brought in to site of damage and bring in lymphocytes)

Anaxonic synapse

have an end button which connects and triggers next cell but no dendrite is involved in process

Longitudinal brain fissure

divides brain into two hemispheres

Corpus callosum

connects the 2 brain hemispheres

White matter

Myelin (surrounding axons)

3 Sources of Arousal/Activation

1. environment (PNS senses it w/somatic markers)

2. Internal (ex. stomach growls, sexually aroused)

3. Intention created by brain (plan + intention + execution + verification)

Central sulcus

separates parietal + temporal lobes

Sulci

Shallow grooves in brain

gyrus

bumps along cerebral cortex

motor strip

in front of central sulcus and part of the front lobe/precentral gyrus, controls + plans + executes voluntary muscle movement

Sensory strip

anterior (front) portion of parietal lobe, posterior (behind) to central sulcus, postcentral gyrus, processes touch/sensation

Internal capsule

• subcortical, white matter structure

• Damage of any kind in this location will affect multiple areas of brain

• mainly composed of myelinated nerve fibers of ascending and descending tracts of the central nervous system

Frontal rectus gyrus

Anatomical directional terms when looking at cerebral cortex

1. superior/dorsal

2. posterior/caudal

3. anterior/rostral

4. ventral/inferior

Anatomical directional terms from spinal cord down

1. rostral/superior

2. ventral/anterior

3. dorsal/posterior

4. caudal/inferior

Horizontal plane

Coronal plane

sagittal plane

Oligodendrocyte vs Scwann cell location

Oligodendrocyte is in CNS myelin sheath, Scwann is in PNS myelin sheath