B&B B1 - Cognitive Neuroscience Definitions, themes and approaches

cognition

a set of processes that allow humans and many other animals to perceive external stimuli, extract key info and hold it in memory, and ultimately generate thoughts and actions that help reach desired goals

behaviorism

emphasis on highly controlled experiments that matched objective external stimuli to measurable behavior, rejects subjective work on mental functions being outside range of scientific inquiry

B.F. Skinner

operant conditioning rats with food

behaviorism uses

applied to treatment of addiction, challenges in education and criminal rehabilitation but started to ignore other cognitive functions

operationalism

psychological concepts could be discussed only in terms of the experimental manipulations that evoked them

psychophysics

focused on basic perceptual tasks

Miller

memory processes must ‘recode’ complex stimuli into smaller parts

Noam Chomsky

claimed that inferences drawn by behaviorists couldn’t eliminate psychological states or account for simple elements of real-world behavior

cognitive science

unifies research on mental processes regardless of the specific topic/approach

cognitive models

predict how sensory input leads to some behavioral output

neuroscience

how the nervous system in humans and other animals are organized and how they function

Franz Joseph Gall

differences among individuals in their cognitive function and personality traits were associated with diff sizes of cerebral cortex mapped through bumps on the skull (phrenology)

localization of function

diff parts of the brain contribute to diff sorts of info processing

neurons

signals transmitted along neuronal axons by action potentials, neurotransmitters released by the terminals of neuronal axons at synapses

Penfield

attempted to examine the cerebral cortex to reduce damage when removing a tumor or during epileptic seizures

neural correlates

mapping the brain regions that activate during a certain psychological process

studies of individual differences

understanding how and why people differ in their cognitive abilities

convergence

combining results from multiple experimental paradigms to illuminate a single theoretical concept

meta-analysis techniques

methods for combining info across multiple studies

clinical-pathological correlations

correlating a patient’s signs/symptoms with the location of brain lesions, can arise from stroke/injury/tumor/disease, not under control of experimenter and distribution of brain regions varies among adults so difficult to generalize results

diaschisis

mammalian brain is highly interconnected therefore lesioning one part of the brain may lead to other parts of the brain that are innervated by the damaged area to cease functioning normally

dopamine system

plays a major role in reward evaluation

computerized tomography

moveable x-ray tube that rotates around patient’s head and acquires intensity info

MRI

protons in the brain are aligned with magnetic fields, radio waves at precise frequency of protons

diffusion tensor imaging

quantifies the relative diffusivity of the water molecules in each voxel into directional components

agonists

drugs that bind to and activate receptors in a similar way to neurotransmitters

antagonists

drugs that bind to and block receptors

intracranial brain stimulations

electrodes placed onto or into the brain during a neurosurgical procedure to assess function of individual or groups of neurons as subject carries out a task

transcranial magnetic stimulation

creates a reversible brain ‘lesion’ limited to a specific area (rTMS)

optogenetics

stimulates neural circuits far more specifically, combines genetics and laser light

EEG

measures electrical brain waves that can be detected at the scalp, signal derives from dendritic field potentials, sensitive to neuronal activity in both cortical gyri and sulci

event-related potentials

small voltage fluctuations in an ongoing EEG triggered by sensory/cognitive events

MEG

magnetic counterpart of EEG, sensitive to neuronal activity in the cortical valleys/sulci

PET

measures changes in metabolism and blood flow to visualize active areas of the brain, same technique as fMRI

functional connectivity

how the activity in one brain region varies in comparison to the brain activity in another

coactivation

when multiple brain regions respond similarly to a condition

psychophysiological interaction analysis

time course of activity in one region to predict activity in another

optical brain imaging

active brain tissue transmits/reflects light differently than inactive brain tissue

three philosophical positions on relationship between mind and brain

mind is responsible for intellectual function and independent to brain, mind controls higher cognitive function and only interacts w brain to control physical processes and all function of. themind result from neural processes in the brain

Galen and gladiators

treated the gladiators and noticed that brain damage affected behavior, linked the mind and brain, discovered nerve fibres from the brain (animal spirits)

DaVinci

drew the ventricles, thought fluids are most important thing

Descartes

believed in dualism, brain and mind separate, mind separates humans from animals

equipotentiality

direct challenge to functional localization, size of lesions were more important than location and revealed behavioral deficits

motor aphasia

deficit in ability to produce language, affected Broca’s area

Golgi

discovered a way to look at neurons by staining them, supports idea that brain works to connect everything, challenged by Cajal who claimed discrete brain cells rather than connected fibers (neuron doctrine)

prospagnosia

inability or immense difficulty to recognise faces

electroencephalography

record from electrodes that are on the surface of theb rain, records action potentials that occur after a stimulus is presented

magnetoencephalography

measures the magnetic field assoc with electrical field, isn’t distorted like electronic signals

fMRI process

inc brain activity → inc blood flow → inc fMRI signal

neuroglial cells

support and hold together nervous tissue

cell body

contains nucleus and organelles

axon

extends from cel body and conveys info in form of electrical impulses

dendrites

receive info from axonal endings of other nerve cells

neural circuits

the interconnection of nerve cells that forms intricate signaling pathways

neurotransmitters

mediate transfer of into between neurons, released from synapses, change electrical potential across membrane of neuron they contact

axon hillock

the point of origin of the axon from the cell body

action potential

the mechamisms that carries signals to additional target cells, a self-regenerating wave of electrical activity that begins at the axon hillock and propagates to the synaptic endings

ion channels and ion pumps

support action potential propagation

synaptic cleft

intervening space between neurons, where neurotransmitters travel to the connecting dendrites

neurotransmitter receptors

proteins in the membrane of the postsynaptic specialisation

synaptic vesicles

the secretory organelles in the presynaptic terminal, filled with neurotransmitters

afferent neurons

neurons that carry into the CNS

efferent neurons

neurons that carry info away from the CNS

interneurons

participate only in local aspects of the cirtuits, serve as a modulatory function

spinal reflex arc

‘knee jerk’ response

sensory neurons

bipolar in this arc, comprises the afferent limb of this reflex, peripheral axons terminate in sensory receptors in the relevant muscles

motor neurons

bipolar afferent neurons run centrally to contact these neurons in the spinal cord

ion channel

selective on what they let through, allow the selective movement of ions

concentration force

thins move from high concentraiton to low concentration

electrical force

positive attracts to negative

combination of concentration and electrical forces

act to even out, when they’re conflicting they reach a resting membrane potential, no net movement of the ion

sodium potassium pump

actively swaps Na and K across the membrane, moves 3 Na to the outside and 2 K to the inside, higher concentrations of Na outside the neuron and higher concentration of K inside neuron, inside of the neuron is more negatively charged as a result → electrical current

stimulate electrode

injects the current

record electrode

measures membrane potential

resting → depolarize → repolarize → hyperpolarize → resting

when at rest only leak K channel is open → depolarization causes Na to be pulled in by electrical and chemical forces, neuron will become more positive as a result, causes rising of action potential → Na gated ion channels close and K gated ion channels start to open, concentration force will pull K out as well as electrical force → neuron becomes more negative again → refractory period is when K balance recovers, hyperpolarization occurs bc K gated ion channels are slow to close causing briefly negative membrane potential

vesicle process

calcium ion channel opens when the action potential arrives → Ca2+ enters the axon at the synapse → causes the vesicle to fuse with ends of the axon and release into synaptic cleft → neurotransmitter receptors open when neurotransmitters bind to them

removal of neurotransmitter

by reuptake, neurotransmitter recycled, glial cells uptake excess and recycle them back into the axon, can be broken down by enzymes

inhibitory input

neuron is less likely to fire an action potential, causes neurons to become more negative, eventually dissipates

excitatory and inhibitory at the same time?

cancels out

position terms

superior (above), inferior (below), anterior (in front of), posterior (behind)

frontal lobe

decision making, personality

parital lobe

spatial awareness, motor function

occipital and temporal

occipital is vision, temporal is speech/auditory

nuclei

relatively compact accumulations of neurons that have functionally related inputs and outputs

subcortical level

components of the brain that lie beneath the cerebral cortex

gray and white matter

gray matter is nuclei and/or cortices, white matter are axon tracts

sensory ganglia

lie adjacent to either the spinal cord (dorsal root) or brainstem (cranial nerve)

autonomic ganglia

in sympathetic nervous system, control involuntary functions

sympathetic division

send axons to a variety of peripheral targets, prepares the organism for expenditure of metabolic energy (fight or flight)

parasympathetic division

receive input from sympathetic division as well, conserves or stores energy (freeze)

brainstem

medulla pons and midbrain, reflex functions like HR and blood pressure, reticular formation which is core of brainstem where many nuclei mediate these functions

forebrain

diencephalon and cerebral hemispheres

spinal cord

interior formed by gray matter, surrounded by white matter

basal ganglia

receive input from the cerebral cortex and organize/guide complex motor functions

ischemia

brief loss of blood supply, leads to cellular changes/cell death

astrocyte

chemical balance in the brain is maintained like reuptake of neurotransmitters

oligodendrocyte

produce myelin

microglial

become active when there’s an infection in the brain

grey matter

cell bodies and dendrites, makes up cerebral cortex

white matter

axons