Neuroscience: Language Centers, Circadian Rhythms, and Memory

Vocabulary flashcards covering the brain language centers (Broca's and Wernicke's areas), circadian rhythms, the suprachiasmatic nucleus (SCN), and memory types and consolidation.

Aphasia

A condition characterized by trouble with understanding or producing speech, typically resulting from damage to language regions of the brain.

Broca’s area

A brain area typically located in the left cerebral hemisphere (in $\sim 90\%$ of people) that determines how to move the mouth, tongue, lips, and lungs to make sounds and how to write letters to form words associated with a thought.

Expressive aphasia

A condition resulting from damage to Broca’s area where individuals can understand what other people are saying, but cannot express in language what they themselves want to say.

Wernicke’s area

A brain area typically located in the left cerebral hemisphere (in $\sim 90\%$ of people) that determines what sound combinations or letter combinations correspond with different thoughts and ideas.

Receptive aphasia

A condition resulting from damage to Wernicke’s area where individuals can express thoughts and speak effortlessly, but cannot understand what other people are saying, often producing nonsensical speech (a 'word salad').

Circadian rhythm

An internal biological clock with an approximately $24\text{-hour}$ cycle (derived from the Latin 'circa diem', meaning 'about a day') that regulates physiological variables including hormone levels, ion concentrations, temperature, and digestive function.

Melatonin

A hormone produced by the pineal gland that decreases during the day to promote wakefulness and increases as night approaches to boost blood levels and cause drowsiness.

Pineal gland

The endocrine gland in the brain responsible for producing the sleep-regulating hormone melatonin.

Suprachiasmatic nucleus (SCN)

The internal clock of the body located in the hypothalamus directly above the optic chiasm, which regulates circadian rhythms through a negative feedback loop of time-keeping proteins.

Optic chiasm

The anatomical crossing point of portions of the optic nerves, situated directly beneath the suprachiasmatic nucleus (SCN).

Time-keeping proteins

Proteins produced in SCN neurons that accumulate, enter the nucleus to block their own coding genes, degrade over roughly $24\text{ hours}$, and modulate neuronal signaling throughout the cycle.

Free-running state

The state of an individual's internal circadian clock when functioning in the complete absence of external environmental cues or stimuli (such as light or noise), like living alone deep in a cave.

Memory

The brain's ability to store, retain, and recall information.

Short-term memory

A memory system that holds information for a brief duration, such as a few seconds or minutes.

Long-term memory

A memory system that stores information for extended periods, divided into declarative and non-declarative memory.

Declarative memory

A form of long-term memory that involves the conscious recall of facts and events.

Non-declarative memory

A form of long-term memory that involves unconscious recall, such as learning a skill (procedural memory).

Consolidation

The process of moving information from short-term memory into long-term memory when it is important or repeated frequently.

Hippocampus

A brain structure that is vital to the process of memory consolidation.

Synaptic strengthening ('Neurons that fire together, wire together')

The cellular basis of memory storage in which simultaneous activation of interconnected neurons leads to pronounced increases in synaptic strength between those neurons.

Amnesia

The pathological inability to remember or recall memories.

Retrograde amnesia

A type of amnesia in which an individual cannot remember certain things or events that occurred in the past.

Anterograde amnesia

A type of amnesia in which an individual cannot transfer new short-term memories into long-term memory.