Unit 2: High Functions and Neurodevelopment Beginning Flashcards
Retinal ganglion cells
Important retinal detectors of light for circadian rhythms are ganglion cells that contain melanopsin and are depolarized by light.
Retinohypothalamic tract
Retinal ganglion cell → suprachiasmatic nucleus of the hypothalamus → paraventricular nucleus of the hypothalamus → preganglionic sympathetic neurons in the thoracic spinal cord → pineal gland.
What is the function of the pineal gland?
The brain structure that produces melatonin from tryptophan.
What is the function of the suprachiasmatic nucleus (SCN)?
The master clock of the circadian rhythm in the anterior hypothalamus.
How is the circadian rhythm controlled at a cellular level?
The circadian rhythm is regulated by gene expression and transcription of different proteins. Negative feedback leads to the self-regulation of this cycle.
The transcription and translation portions of this cycle take time so that is what allows the circadian rhythm to stay about the same without any light cues.
What is the cellular circadian rhythm?
Light-dependent degradation of Per which inhibits gene transcription of Clk and Bmal1 genes → Clk and Bmal1 acting as promoting transcription factors for Cry, Ccg, Per, and Rev-erb⍺ genes → Cry + Per2 dimers and Rev-erb⍺ inhibit Clk and Bmal1 activity.
What is EEG’s ⍺ rhythm associated with?
Associated with alertness; linked with the visual system.
What is EEG’s 𝛽 rhythm associated with?
Associated with mental activity and attention.
What are EEG’s theta and δ rhythm associated with?
Associated with drowsiness and sleep.
What is the interaction between aminergic and cholinergic systems with the circadian rhythm?
The aminergic system is most active while awake. Both aminergic and cholinergic systems decrease activity during non-REM sleep but aminergic systems decrease more leading to the cholinergic system becoming dominant.
What are sleep spindles and where do they come from?
Sleep spindles = high-frequency spike clusters that appear while we sleep.
Come from activity between thalamic and cortical neurons.
What are zeitgebers ?
Anything that can entrain that circadian rhythm.
What activity is required for wakefulness?
Being awake requires activation and tonic activity of thalamocortical systems.
Noradrenergic neurons of the locus coeruleus, serotonergic neurons of the DRN, and histamine neurons of the tuberomamillary nucleus (TMN) of the hypothalamus help increase wakefulness.
The TMN is activated by orexin/hypocretin which is produced by the lateral hypothalamus.
Cholinergic activity in the reticular activating system activates the thalamus leading to desynchronization between the thalamus and cortex.
Desynchronization of the cortex is necessary for wakefulness.
Why do anti-histamines make people drowsy?
Anti-histamines inhibit TMN activity which is why they make people drowsy.
What leads to REM sleep?
Monoamine systems are inactive while cholinergic systems are active.
Cholinergic neurons inhibit somatosensory input and motorneurons.
What is the function of the ventrolateral preoptic nucleus (VLPO)?
Part of the hypothalamus that inhibits wakefulness systems causing drowsiness.
What is learning and memory?
Experientially induced changes in the nervous system that may alter future behavior.
Have we ever observed a memory?
No, we have only ever infrared memories by changes in behavior.
What is priming?
A change in the processing of a stimulus due to a previous encounter with a similar stimulus.
What happens in the brain when reward motivates our behavior to increase memory?
Motivation increases our ability to remember relevant stimuli.
When reward motivates our behavior, the VTA is active and sends dopamine projections to the hippocampus. This aids in memory as the VTA is expecting a reward for the ability to recall this memory.
What are place cells, what do they need to fire, and do they adapt?
Place cells = cells in the hippocampus that fire only when the animal is in a particular location.
The responses of place cells depend on sensory information about that location and about where the animal thinks it is.
They can adapt to new environments and change/expand the location they respond to.
Where are place cells located in the hippocampus?
On the dorsal side.
What are grid cells and what do they need to fire?
Grid cells = entorhinal cortex cells that activate when the animal is at multiple locations that form a hexagonal grid.
Activity is dependent on where an animal thinks it is.
These activate multiple times when the animal enters different hotspots in the grid. They help align measurements for the space that the place cells can use for directionality.
What areas are involved in consolidating and retrieving non-declarative memories?
The amygdala, PFC, basal ganglia, sensory association cortices, and cerebellum.
What areas are used for complex motor learning?
The basal ganglia and PFC are influential for complex motor learning.
What is stimulus-response (S-R) learning and who was behind that idea?
Organisms learn habits in response to a stimulus in the environment.
Clark Hull
What is the law of effect?
A particular behavior by an organism is likely to occur more often if it produces a desirable outcome.
What were E.C. Tolman’s arguments for learning?
Learning involves making associations between stimuli. No response to the stimuli is required.
No biologically significant effect was necessary for learning.
No reinforcement or punishment was necessary for learning.
What is stimulus-stimulus (S-S) learning and who was behind that idea?
Learning involves making associations between stimuli. It is more flexible than S-R learning.
E.C. Tolman.
What is the distinction between performance and learning?
Performance is more rote reaction to something. It’s like putting down answers memorized for a test without actually understanding the material.
Learning is more flexible and can be used in several contexts and be remembered for longer.
Why did Karl Lashley’s lesions studies not find much evidence for memory?
The rats could perform the tasks using multiple different memory systems. Thus, without lesioning all those areas, the rat could still perform the task.
What kind of learning is the caudate of the basal ganglia associated with?
Response learning.
How do learning responses occur?
First, many cognitive processes in the hippocampus are involved.
After much training, and it becomes a much more rote response, the caudate takes over. This frees other cognitive resources.
Then, the task can be performed without even consciously thinking about it.
What is the perforant pathway?
Hippocampus: Entorhinal cortex → dentate gyrus (DG)
What is the mossy fiber pathway?
Hippocampus: DG → CA3
What is the Schaffer collaterals?
Hippocampus: CA3 → CA1
What processing does the ventral hippocampus do?
Emotional processing.
Is the hippocampus only involved in spatial learning?
No. Hippocampal cells encode relationships. Some cells only care about directional relationships while others focus on temporal relationships.
Can animals respond accurately if there is a delay between the stimulus and reaction?
No. The longer the delay is, the less accurate animals can respond. The hippocampal cells have a broader response as the delay increases.
Where are grid cells located?
In the medial entorhinal cortex.
What information does the lateral entorhinal cortex encode?
Provides the “what” information for objects and stimuli in the environment.
Where are retrograde and long-term memories stored?
They become stored in the cortex and rely less on hippocampal activity.
Does retrieval of episodic memories require hippocampus activity?
It is currently thought yes because temporal relationships are important for episodic memories.
Does retrieval of semantic memories require hippocampus activity?
No
What happens to episodic memories over time?
They become more like discrete scenes and not as much mental time travel.
So, it is like looking through a photography book jumping between different captured images instead of going through a video reel.
What is reinforcement learning?
Desirable outcomes to actions that make you more likely to perform the action.
What part of the basal ganglia is involved in the reinforcement of memories/learning?
Ventromedial areas and NAc shell.
What part of the basal ganglia is involved in goal-directed behavior?
Dorsal striatum and the NAc core.
How is the amygdala involved in memory?
Especially with emotional-laden memories, it can help increase the consolidation of the memory.
What are neuronal ensembles?
A set of neurons that encode a particular memory/percept/behavior.
What is Hebb’s idea for neuronal activity?
Neurons that fire together wire together.
What are some synaptic changes in LTP?
Larger synapses.
Increased AMPA responsiveness.
Greater axon terminals on a postsynaptic cell.
What sort of memories is REM better at consolidating?
Memories with emotional content.
Why is sleep important for memory?
Memories are replayed. They are done at a faster rhythm and this helps synaptic changes to occur.
There is coordinated brain activity that helps consolidate memories throughout the cortex as well.
Grammar
A set of rules for language production
Syntax
Placing the words in a meaningful order
Prosody
The rhythm, stress, and tonal variation that gives language its emotional meanings.
Semantics
Meanings of words.
