See Also: Book Notes, (me), Notes on Consciousness, Seth: Being You, Happiness Hypothesis, LeDoux: Deep History of Conscious Brains, Consciousness and the Brain, Barrett:HEAM, 7.5 Brain Lessons, Allostasis, Neuroscience of Human Relationships, Thinking, Fast and Slow

Entangled Brain Cover

The Entangled Brain:

How Perception, Cognition, and Emotion Are Woven Together
Luiz Pessoa

The MIT Press

p.30 "... the central thesis of the book: Brain areas don't compute specific functions—they are not segregated "organs of the mind," as Brodmann put it. The brain is not a modular system that can be understood a region at a time. Instead, we need to unravel how collections of cortical, subcortical, and brainstem regions work together to support complex behaviors."

Luiz Pessoa has been studying emotions for a long time, which him to study the subcortical structures, especially the amygdala. This book is aptly named, for it is about the complex system that is our brain and the many, many moving parts, each of which plays a complicated and multifaceted role. He covers, the hippocampus, hypothalamus, thalamus, basal ganglia, nuclues accumbens, striatum, PAG, and several cortical regions. Pessoa is also a huge proponent of the Large Scale Brain Networks, as in the what weaves together all of the brain regions and the subtitle: How Perception, Cognition, and Emotion Are Woven Together. What follows a somethings that I want to be able to refer back to.

Subcortical Structures

p.201 "hippocampus ... attuned to the spatial and temporal properties during an animal's navigation through its environment. But the more these cells are studied, the clearer it becomes that their activity is very nuanced. Hippocampal firing to places, borders, direction, speed, and so on is influenced by a gamut of factors, including the presence or absence of objects, the presence of a stimulus previously paired with aversive outcomes (as in conditioning paradigms), as well as generally factors such as novelty, attention, and even an animal's internal state (is it hungry?). Other motivational information also plays a role, as cells fire more vigorously near "task goal" locations, including places where an animal receives reward. ... researchers try to understand how the hippocampus interacts with neighboring areas in the temporal lobe (the so-called medial temporal lobe), as well as how it participates in broader interactions with regions across the brain. Episodic memory and spatial navigation are not carried out by single regions—no mental process is. "

p.70 "hypothalamus ... participates in complex homeostatic mechanisms and contributes to neuroendocrine outputs affecting brain and body glands. And it contributes to wide-ranging processes: circadian rhythms, wakefulness and sleep, stress responses, temperature regulation, food intake, thirst, sexual behaviors, and defensive behaviors. ... In all these processes, the region works in concert with a multitude of other sites ... the hypothalamus has robust projections contacting multiple brainstem sites, including the periaqueductal gray (PAG), and even parts of the spinal cord; some of these areas have rather direct somatic and visceral effects on the body (Somatic refers here to the skin and skeletal muscles; visceral refers to the internal organs.) ... the hypothalamus is also bidirectionally connected with large sectors of the cortex ... instead of outflow or inflow, it's best to characterize areas in terms of integration and distribution of signals: the more it has incoming pathways, the more it can integrate signals; the more it has outgoing pathways, the more it can distribute them."

p.88 "Although accumbens neurons are strongly influenced by dopamine, this chemical is not endogenous to this region. Projections from the substantia nigra release it there. The dopamine-containing neurons or the substantial nigra form a continuous band that extends into adjacent parts of the midbrain (called the ventral tegmental area, which also synthesize this molecule. Collectively, this "dopaminergic midbrain" is the origin of anatomical pathways that play key roles in motivated behaviors."

p.204 " In the early 1980s, investigators managed to record from neurons in the orbitofrontal cortex while monkeys actively performed tasks. ... Some neurons fired vigorously when the monkey saw a syringe used to deliver black currant juice. But when the contents of the syringe now contained saline (which is mildly aversive, especially in comparison with a favored juice), the monkey's activity declined sharply on seeing the syringe. ... it became increasingly clear that it encodes value ... Reinforcing the notion of value coding, neurons in the orbitofrontal cortex integrate information about the magnitude and the probability of reward..... Even more broadly, neuronal activity in the orbitofrontal cortex represents the expectation of the value of the outcome." image Pessoa_Figure10_8.jpg


p.184 "Network science has additional tools that can help. One of them is to think of nodes as having a spectrum of computational properties. Both how well connected a node is and how vastly distributed its links are matter. Nodes that are particularly well connected are called hubs (with a meaning similar to that in "airport hub"), a property that is formally captured by a mathematical measure called centrality. Hubs come in many different flavors, such as connector hubs that have links to many communities and provincial hubs that are well connected within their particular community. We can thus think of connector hubs as nodes that are more "central" in the overall system than provincial nodes."

p.187 "There's a second, more radical way in which networks are dynamic. That's when they are viewed not as fixed collections of regions but instead as coalitions that form and dissolve to meet computational needs. For instance, at time t1, regions R1, R2, R7, and R9 might form a natural cluster; at a later time t2, regions R2, R7, and R17 might coalesce. This shift in perspective challenges the notion of a network as a coherent unit, at least for longer periods of time. "

p.105 "Early hints that viscerosensory signals reach the cortex go back to the 1950s. when researchers stimulated the vagus, a large nerve exiting the brain that innervates the heart, the stomach, and intestines. When investigators stimulated the vagus nerve in monkeys and other animals, they noted activation of a "vagal receptive cortex" corresponding to the insular cortex. The role of the insula in the conscious appreciation of visceral sensation was vividly demonstrated in the studies by Penfield and colleagues, as they electrically stimulated the cortex of patients during neurosurgery. As Penfield moved the electrode down along the primary sensory cortex, he identified a region extending just beyond the tongue in the homunculus, where electrical stimulation produced taste sensation. When he moved the electrode further into the insula, the patients reported oropharyngeal, esophageal, or even gastrointestinal sensation. Whereas the patients volunteered a variety of descriptions about their experiences, none of them reported emotional responses they were more of a sensory nature."

Attention & Cognition in the Visual Cortex

p.117 "Attention is also believed to involve the frontal cortex. In the example described above, one of the regions influencing visual responses in V4 is an area in the frontal cortex called the "frontal eye field," which was originally known to control eye movements (hence the name) but contributes to attention, too. Anatomical pathways from the frontal eye field to the visual cortex allow the former to direct the latter so as to favor the processing of task-relevant information - the one the animal is instructed to pay attention to."

p.221 "In another breakthrough study, researchers used calcium imaging to record from more than 10,000 neurons in the visual cortex of the mouse, ... They found that information in visual cortical neurons reflected over a dozen features of motor information (related to facial movements, including whiskers and other facial features), ... according to traditional thinking, motor and visual signals are only merged later in so-called higher-order cortical areas ... information about the animal's behavior ... was observed nearly everywhere they recorded. ... behaving effectively depends on the combination of sensory data, ongoing motor actions, and internal-state variables. "

p.122 - cognitive control "When certain actions are practiced over and over, they become habitual, a process of habit formation that's important for making them efficient — that is, more automatic. Now, once the behavior is performed in a fairly automatic fashion, it can be rather difficult to break it: Once triggered, it's executed. But if a habitual action is uncalled for, It should be possible to recalibrate it, modify it, or call it off completely. That's when cognitive control comes into play. As a simple example, consider the act of stepping on the gas pedal when the light turns green at an intersection. For those of us who have been driving for many years, this action is completely habitual. But upon spotting a child crossing the street on a bicycle, one should be able to step on the brake pedal immediately (hopefully). Seeing both the green light and the child triggers the conflict ... It has been proposed that the key function of the prefrontal cortex is to enable and ensure adopting and following the "rules of the game." ... at a rather coarse level, we can distinguish three broad segments associated with the lateral, medial, and orbital surfaces. "

p.89 "Operant learning requires the subject's own action, otherwise no reward will come and no learning will occur, just as Olds and Milner's rats needed to lever-press to receive electrical stimulation. Both Pavlovian and operant learning are related to "prediction errors," as we'll see. What type of information is useful during learning? Imagine a comparison mechanism between a predicted and an actual reward; say, a rat anticipates its preferred food morsel and receives a much less pleasant one (figure 5.11). Logically speaking, one of three cases must be true: The reward is better than, equal to, or worse than its prediction. "

p.158 "It is only possible to obtain motivationally relevant items by engaging in behavior that brings them closer or makes their occurrence more likely. In fact, because animals are usually separated from reinforcing items by a long distance or by various obstacles, effective behaviors require work, such as foraging for food. Animals must thus allocate considerable resources toward "seeking behaviors," which vary In terms of speed, persistence and overall level of "output." Although the exertion of effort can be relatively brief at times (for example, a predator pouncing on a prey), under many circumstances it must be sustained over login periods of time... ventral striatum is a motivational hub that helps relate the amount of vigor expended."

p.142 Quick summary of complex systems: interaction between parts, levels of analysis, time, process, decentralization, hetarchy, emergence, complexity.

p.227 "Conrad Waddington: biology does not study things; it studies processes occurring at various timescales ... thinglike entities don't necessarily need to be excluded; they can be considered "processes" stable and sustained enough to have substance — think of a person, an organ, or a cell. But embracing such a process-oriented mindset — a process philosophy—naturally leads to new ways of formulating and answering scientific questions. And whereas this view obviously helps with phenomena such as hurricanes, streams, and vortices, it encourages describing biological phenomena in terms of context-dependent, dynamic processes. For one, the compulsion of neuroscientists to define areas and subareas recedes, giving way to the goal of deciphering how processes involving multiple parts of the brain unfold temporally to support behaviors. "

p.191 Emotion "Emotions mobilize the body through autonomic, neuroendocrine, and musculoskeletal systems, in part through functionally integrated systems that have access to the hypothalamus and to structures in the brainstem and medulla that are linked to the body. Emotions also mobilize disparate brain responses, influencing attention, memory, and decision making. The engagement of body and brain, ... including massive combinatorial anatomical connectivity and distributed functional connectivity. ... Emotion is at times likened to a "biasing" mechanism, such as directing perception to focus on a particularly relevant object, or shifting cognition from one type of information to another. Emotion is not adequately captured by this idea — it's much more. Emotion dynamically influences the properties of large-scale networks, including those that are described as perceptual, motor, motivational, or cognitive. ... Ultimately, emotion — insofar as it is meaningful to speak of "emotion" — like every other mental domain, is a large-scale network property of the nervous system. "

Luiz Pessoa also wrote: The Cognitive-Emotional Brain: From Interactions to Integration 2023-01-23 jch