Chapter 6, The Hidden Spring, The source Flashcards
What is the basic assumption of neuropsychology and why does that invalidate the notion that the cortex is the seat of consciousness?
The basic assumption of neuropsychology is that if a lesion occurs in a particular brain region, then that regions function is lost. However, if lesions occur in the cortex, then how can someone retain consciousness? This understanding invalidates that assumption
What is the name of the core structure in the brainstem where consciousness arises, according to both solms and Panksepp?
The reticular activating system in the brainstem. This is what Solms refers to when he says the hidden spring
Why is the reticular core system a site that Solms believes is the hidden spring of consciousness?
Because in it are the sources of neurotransmitters that govern our consciousness. Dopamine, serotonin, and norepinephrine neurons are located in this dense bundle and these sites are the target to much psychopharmacology, whose intent is to alter consciousness to a more favorable state.
If the RAS in the brain stem is the site of consciousness, what must it also be the original site for?
Affect
Since affect and consciousness originate from the same place, what does that imply about feelings?
Feelings are the primary source of consciousness, and without access/understanding to them people become separated from reality
What does Solms believe is the most accurate way to describe the level of activity within the RAS?
Arousal. The level of arousal will indicate how activated the RAS is
What wave pattern is most correlated with consciousness? Describe the wave pattern and its hz
Gamma wave patternsLow wave patterns with higher amplitudes (25-100hz)
What does the cortex’s level of consciousness depend on?
The level of activation in the brain stem
What is the least arousing wave pattern seen in cortical activity?
The delta wave pattern, at a frequency of 2hz. This may be a good sound to get into to turn down arousal, especially prior to something like sleep
Briefly describe the notion of synaptic transmission
The way neurons within a circuit communicate to each other is through synaptic transmission. This communication between synapses is facilitatedthrough either excitatory or inhibitory neurotransmitters. If an abundance of neurotransmitters exists, then those molecules will continue to be passed down to other neurons in the circuit, or they will be taken back into the presynaptic neuron (uptake)
Neurons in circuit–> Neurotransmitters (inhibitory or excitatory)–> Continued transmission or reuptake
What is the other form of synaptic transmission that takes place? Briefly describe how it works
Post synaptic modulation. It arises endogenously in the reticular activating system and has everything do with arousal
Who are the central players in post synaptic modulation and how do they govern activity in the brain?
The central players are neuromodulators and they act on whole regions of the brain, rather than through individual synapses. Because they don’t operate through specific channels, and influence whole networks, they end up regulating the whole state of the cortex. This influences experience according to the state one is in.
Ex- If someone is approaching a stranger, their response to them will change according to state the cortex has been put in through neuromodulation. If they are in a seeking state they may strike up a conversation, if in fear they will hope to avoid
What is the difference between channel and state and how can that help you understand the different ways in which neurons communicate with one another?
The state of the cortex alters the strength of the message passing between channels. The state governs how loudly the channels communicate with one another.
How does arousal (state) influence synaptic transmission (channel)?
Arousal will govern which synaptic impulses will be transmitted, and the strength to which they will
How do neuromodulators vary in their function, relative to neurotransmitters?
How do neuromodulators exert greater influence on neuroplasticity than neurotransmitters?
Neuromodulators are slow acting and longer lasting, because the chemicals last longer and therefore continuously influence the frequency of firing of nerve channels. Neuromodulators are also not as binary and neurotransmitters.
Since neuromodulators last for longer periods of time, the network they act in will stay boosted until the neuromodulators down modulate, therefore contributing to extended neuroplasticity between channels during that time.
Where do neuromodulators come from in the body? In the brain?
Body- pituitary, adrenals, thyroid, sex glands
Brain- Hypothalamus, RAS (the brains central source of arousal)
What are the 5 main neuromodulators responsible for arousal that originate in the reticular brain stem and where do they release from?
Dopamine- ventral tegmental area and substantial nigra
Noradrenaline- locus coreleus
Acetylcholine- mesopontine tegmentum and basal forebrain nuclei
Histamine- tuberomamillary hypothalamus
Serotonin- Raphe nuclei
Neuromodulators can only affect cells if they contain what?
Receptors or receptor subtypes
Can neuromodulators create states on their own?
No, they can only modulate signals that already exist. If a circuit is active already, the neuromodulation will either enhance its existing function or inhibit it
To review, where does arousal originate from and how does it arise physiologically?
Arousal originates primarily in the brain stem and hypothalamus and arouses the forebrain through modulating neurotransmission
Where is the site in the brain where all the affective circuits converge? Where is it located and what does it’s integrity indicate?
The periacqueductal grey. It’s integrity is what governs the shifting from vegetative wakefulness to affective arousal. It’s location is a set of tightly packed neurons in the midbrain
What lies at the basis of conscious behavior, and what does Solms believe is not an accurate description of consciousness?
Arousal governs ones intentionality, which forms the basis of conscious behavior. SOlms believe wakefulness is not an accurate description of consciousness, as one can be vegetatively awake
How do the RAS and PAG differ in the direction of information they send to the forebrain?
The RAS sends information upwards into the cortex, while the PAG receives downward communication from the cortex.
RAS—> Forebrain—> PAG
What role does the PAG play in survival, and how does it receive its information to guide behavior?
The PAG orchestrates coping behaviors in response to threatened survival by integrating afferent information from the periphery and higher thinking centers.
It’s as if the subcortical information communicated to the cortex what is happening to someone and whether their survival is threatened, and if so, the cortex communicates to the PAG the threat, and the PAG organizes the survival response.
THE PAG IS THE BRAINS MAIN OUTPUT FOR FEELINGS AND EMOTIONAL BEHAVIORS