cognitive neuroscience- brain areas and theories

phrenology

activation of brain areas makes them larger (Gall and Spurzheim)

aggregate field theory

behavioural abilities are mediated by interactions of areas from the entire brain (Marie-Jean-Pierre Flourens)

topographic organisation

neighbouring regions of the body or sensory space are represented by neighbouring neurons in the brain (John Hughlings Jackson)

brocas area

responsible for speech production and articulation in the posterior frontal lobe

wernickes area

responsible for speech comprehension in the posterior temporal lobe

brodmann’s cytoarchitectonic areas

52 areas of the brain, differentiated on the basis of cell structure and arrangement (Brodmann)

syncytium

multinucleated cell that forms when individual cells fuse together- believed to be the structure of neurons within the brain in the 19^th century

reticular theory

neurons were not discrete entities but formed a continuous network (reticulum) through which signals flowed directly (Golgi)

neuron doctrine

neurons are separate, specialized cells that communicate through contact (later understood as synapses) but not continuity (Cajal)

behaviourism

learning and conditioning are the sole determinants of all behaviour (Thorndike and Watson)

Glial cells

non-neuronal cells in the nervous system that provide essential support, maintenance, and regulation for neurons

oligodendrocytes

myelinate axons in the brain and spinal cord (CNS)

astrocytes

Maintain the blood-brain barrier by regulating substance exchange between blood and the brain, and clean up ‘waste’ (CNS)

microglial cells

Act as the brain's immune cells, defending against pathogens (CNS)

schwann cells

myelinate axons in the periphery of the body (PNS)

resting potential

baseline electrical charge across a neuron's membrane when it is not transmitting a signal. It is typically around -70 mV (millivolts) in most neurons. Maintained using an ion pump

ion pump

uses energy in the form of ATP to remove 3 Na+ and add K+ into the neuron

action potential

rapid electrical signal that travels along a neuron's axon, enabling communication between neurons or between neurons and muscles

threshold potential

the voltage level that needs to be met to trigger an action potential (around -55mV)

depolarization

When sodium ions rush into the cell, causing the membrane potential to increase. The intercellular space becomes positive

repolarization

Potassium ions flow out of the cell, lowering the membrane potential

hyperpolarization

The outflow of K⁺ overshoots the resting potential, briefly making the membrane potential more negative than -70 mV, ensures the neuron does not immediately fire another action potential (refractory period)

grey matter

neurons arranged in layers forming a sheet of tissue. Located in the cerebral cortex

white matter

axons and glial cells forming tracts interconnecting the brain

cerebral cortex

outer layer of the brain's cerebrum, divided into 4 lobes. comprised of grey matter

frontal lobe

Located at the front of the brain. Responsible for decision-making, problem-solving, planning, voluntary movements, and speech production (via Broca’s area). Key in personality and emotional regulation.

parietal lobe

Located at the top middle part of the brain. Processes sensory information like touch, temperature, and pain. Involved in spatial awareness, navigation, and integrating sensory inputs.

occipital lobe

Located at the back of the brain. Primarily responsible for visual processing, such as recognizing shapes, colours, and motion

temporal lobe

Located on the sides of the brain, near the ears. Handles auditory processing, language comprehension (via Wernicke’s area), and memory formation. Important for recognizing objects and emotions

limbic system

group of interconnected brain structures located deep within the brain, primarily involved in regulating emotion, memory, motivation, and behaviour.

amygdala

Involved in processing emotions, especially fear, anger, and pleasure. Plays a key role in forming emotional memories and threat detection

hippocampus

Crucial for memory formation, particularly converting short-term memory into long-term memory. Also contributes to spatial navigation

thalamus

Acts as a relay station, transmitting sensory and motor signals to the cerebral cortex. Plays a role in regulating consciousness, alertness, and emotional responses.

hypothalamus

Maintains homeostasis by regulating hunger, thirst, temperature, and circadian rhythms. Links the nervous system to the endocrine system through the pituitary gland. Contributes to emotional responses and sexual behaviour.

mammillary bodies

Part of the hypothalamus, these structures are important for memory recall and are connected to the hippocampus.

Posner’s letter matching task

Study acts participants to identify whether a pair of letters are ‘same’ (both vowels/consonants) or different (one vowel, one consonant). Demonstrates the multiple levels of representation we have in our brain using reaction times between different pairs (with physical identity being the quickest representation to identify). This is an example of chronometry.

memory comparison task

Study shows participants a set of one, two or four letters and are asked to memorise them. After a delay, a single probe letter appears, and the participant indicates whether that letter was a member of the memory set. Hypothesised stages are encode, compare, decide and respond. Reaction time increases with set size, indicating that the target letter must be compared with the memory set sequentially.

single cell recording

a microelectrode is stuck into the nervous system and very close to a neuron. This then measures/records the activity of a singular neuron.

Electroencephalogram

electrodes are attached to the heard to measure electrical activity in the brain. non-invasive but lacks spatial validity

Alzheimers disease

A progressive neurodegenerative disorder that primarily affects memory, thinking, and behaviour

Stroke

A sudden disruption of blood flow to the brain, causing brain cell damage or death

Traumatic brain injury

Damage to the brain caused by an external force, such as a blow, jolt, or penetration

event related potential

the accumulation of multiple EEG recordings to measure the brain activity during a certain task

functional neurosurgery

aims to restore or enhance neurological function by targeting specific brain or nervous system structures

optogenetics

uses light to control the activity of specific neurons genetically modified to express light-sensitive proteins

transcranial magnetic stimulation

low level currents are introduced into the brain through anodes, that result in action potentials

functional magnetic resonance imaging

non-invasive imaging technique used to measure and map brain activity by detecting changes in blood flow

retinotopic mapping

the orderly representation of external space in our visual areas

Dorsal posterior parietal pathway

pathway in the primary visual cortex that deals with motion and depth (MT/v5)

Ventral inferior temporal pathway

pathway in the primary visual cortex that deals with colour and form (v4)

Feature maps

spatially organized patterns of neural activity in the brain where neurons with similar response properties are grouped together. These maps allow the brain to process complex information efficiently

Attentional networks

System of brain regions and neural mechanisms that work together to control and regulate attention

Attentional Control network

System of brain regions and neural mechanisms that work together to control and regulate attention

Attentional Control network

areas activated during the ‘delay’ stage of the spatial cuing paradigm, that holds attention to a certain area/stimulus.

 Dorsal frontal cortex (Includes the FEF)

 Inferior parietal lobule (includes the TPJ)

 Superior temporal sulcus

 Posterior cingulate

 Medial frontal

Top down fronto-parietal attention network

controls voluntary attention control. More medial parts of the frontal and parietal lobes, and includes:

 Inferior parietal sulcus (SPL)

 Frontal eye field

bottom-up attention network

for novelty and attentional reorientating. More lateral parts of the frontal and parietal cortex

 Temporoparietal junction

 Ventral frontal cortex

monkey attentional network

 Frontal eye field (motor eye movements)

 Posterior parietal cortex (attention)

 Primary visual cortex (sensory)

midbrain attentional network

involves the superior colliculus

superior colliculus

involved in directing attention and controlling eye movements

neglect

results from damage to your parietal cortex. Means that you are unable to perceive something in your field. Often unilateral, and the brain areas implicated involve:

 Temporoparietal junction- spatial neglect

 Angular gyrus (IPL) -spatial neglect

 Supramarginal gyrus (IPL) – spatial neglect

 Superior temporal gyrus (object neglect)

spatial neglect

mediated by the inferior parietal lobule (specifically angular and supramarginal gyrus) and the tempoparietal junction

object neglect

mediated by the superior temporal gyrus

extinction

results from damage to your parietal cortex. Means that the presence of another competing stimuli prevents the perception of another stimulus (usually the left perceptual stimuli that is ignored)

left angular gyrus

patient E.E demonstrated that this area was related to short term memory deficits

central executive

type of memory stored in the prefrontal cortex

visuospatial sketchpad

type of memory stored in the parietal lobe

phonological loop

type of memory stored in the supramarginal gyrus and the BA44 in the frontal lobe

episodic memory

type of memory strongly associated with the hippocampus. Found in the mammillary bodies and MTL

semantic memory

type of memory found in the medial temporal lobe, middle diencephalon and neocortex

perirhinal cortex

where the ‘what’ of an episodic memory is processed

parahippocampal cortex

where the ‘where’ of an episodic memory is processed

procedural memory

type of memory found in the basal ganglia and skeletal muscle

perceptual priming

type of memory found in the perceptual and association neocortex

classical conditioning

type of memory associated with the cerebellum

non-associative learning

type of memory associated with reflex pathways

H.M

suffered anterograde amnesia due to the removal of their hippocampus

Korsakoff syndrom

damage to the dorsomedial nucleus of the thalamus and the mammillary bodies causes anterograde amnesia

E.E

selective short term memory deficits because of the removal of the left angular gyrus

entorhinal cortex

where familiarity memory is stored

hippocampus and fusiform gyrus

where source memory activates

modality-specific cortices

where episodic memories are stored

apperceptive agnosia

patients cannot accurately perceive an object and are unable to construct sensory representations of stimuli, but they are able to verbally identify them, but caused by lesions in the temporal lobe

associative agnosia

patients cannot interpret, understand or assign meaning to objects. Sensory representation is created normally but cannot be associated with any meaning- it cannot be verbally identified. Also caused by lesions in the temporal lobe

left frontal cortex

has a lot of activation during episodic encoding and semantic retrieval

right frontal cortex

has a lot of activation during episodic retrieval