From Neurons to Distributed Processing (Lecture 2)

Vocabulary flashcards covering key terms and concepts from the lecture notes.

Polarized neurons

Neurons are asymmetrical cells with directional, selective information flow from dendrites to the axon.

Synapse

Point of contact through which information is transferred between neurons; term coined by Sherrington in 1906.

Principle of Dynamic Polarization

Neurons exhibit directional information flow: dendrite → soma → axon.

Dendrite

Branching structures that receive inputs from other neurons.

Apical dendrites

Dendrites extending from the apex of certain neurons toward the cortical surface.

Basal dendrites

Dendrites emerging from the base of the neuron’s soma.

Axon initial segment

Region at the start of the axon where action potentials are often initiated.

Node of Ranvier

Gaps in the myelin sheath along a myelinated axon that enable saltatory conduction.

Myelin sheath

Insulating layer around axons that speeds up electrical conduction.

Presynaptic terminal

Axon terminal that releases neurotransmitter into the synapse.

Postsynaptic dendrite

Dendrite (or dendritic spine) that receives neurotransmitter at the synapse.

Axon hillock

Conical region of the neuron where the axon emerges and action potentials are initiated.

Lamellipodia

Sheet-like cellular protrusions that support neurite outgrowth during development.

Neurite

Developing projection that will become an axon or dendrite.

Axon

Long projection that transmits signals away from the cell body.

Dendrite

Branching process that receives synaptic inputs.

Growth cone

Dynamic structure at the tip of a growing neurite that seeks synaptic partners.

Dendritic spine

Tiny protrusion on a dendrite where a synapse forms.

Brainbow

Imaging approach labeling neurons with many colors to trace connections in brain tissue.

Electron microscopy (EM)

High-resolution imaging used to reveal synapses and fine neural structure.

Intracellular recording

Measuring electrical potentials inside a neuron to study activity and connectivity.

Hodgkin and Huxley

Pioneering researchers who demonstrated the intracellular recording of action potentials.

Electrophysiology

Study of the electrical properties of neurons and synapses to infer connectivity.

Diffusion Tensor Imaging (DTI)

MRI-based method mapping white-matter tracts by measuring water diffusion.

Serial block-face scanning electron microscopy (SBF-SEM)

3D electron microscopy technique for large-volume ultrastructure imaging.

Brodmann areas

Cortical regions defined by cytoarchitecture; Brodmann mapped 52 areas, still influential.

Nissl stain

Histological stain highlighting neuronal cell bodies to reveal cytoarchitecture.

Cytoarchitecture

Organization of cells into layers and patterns in cortex.

Broca's area

Frontal language area involved in speech production; lesions cause Broca's aphasia.

Wernicke's area

Temporal-parietal language area involved in language comprehension; lesions cause Wernicke's aphasia.

Angular gyrus

Parietal region involved in language and a variety of cognitive processes; part of language network.

Aphasia

Language impairment due to brain damage, including Broca’s and Wernicke’s types.

Phrenology

Historical theory relating skull bumps to faculties; now discredited.

Franz Joseph Gall

Early advocate of phrenology and brain localization concepts.

Lashley

Critic of strict localization; argued for holistic, distributed processing in the cortex.

Principle of Distributed Processing

Idea that complex functions arise from interactions among distributed modules rather than single areas.

Functional modules

Interconnected brain subunits specialized for particular processing tasks.