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“Intense fatigue or illness may also weaken the control of the cortex. Hence we find tired or sick persons responding to threats with a greater degree of undifferentiated anxiety. In psychoanalytic terms, we would speak of this as regression.”
― Rollo May, The Meaning of Anxiety

“We must consider what we mean when we say that the spiking activity of a neuron 'encodes' information. We normally think of a code as something that conveys information from a sender to a recipient, and this requires that the recipient 'understands' the code. But the spiking activity of every neuron seems to encode information in a slightly different way, a way that depends on that neuron's intrinsic properties. So what sense can a recipient make of the combined input from many neurons that all use different codes? It seems that what matters must be the 'population code' - not the code that is used by single cells, but the average or aggregate signal from a population of neurons.
In a now classic paper, Shadlen and Newsome considered how information is communicated among neurons of the cortex - neurons that typically receive between 3,000 and 10,000 synaptic inputs.They argued that, although some neural structures in the brain may convey information in the timing of successive spikes, when many inputs converge on a neuron the information present in the precise timing of spikes is irretrievably lost, and only the information present in the average input rate can be used. They concluded that 'the search for information in temporal patterns, synchrony and specially labeled spikes is unlikely to succeed' and that 'the fundamental signaling units of cortext may be pools on the order of 100 neurons in size.' The phasic firing of vasopressin cells is an extreme demonstration of the implausibility of spike patterning as a way of encoding usable information, but the key message - that the only behaviorally relevant information is that which is collectively encoded by the aggregate activity of a population - may be generally true.”
― Gareth Leng, The Heart of the Brain: The Hypothalamus and Its Hormones

“Purkinje cells are among the most elaborate of all neurons; the cerebellum maps the body and outside space onto its tens of billions of neurons. Yet none of this seems sufficient to generate consciousness. Why not?
Important hints can be found within its highly stereotyped, crystalline-like circuitry. First, the cerebellum is almost exclusively a feedforward circuit. That is, one set of neurons feeds the next one that , in turn, influences a third one. There are few recurrent synapses that amplify small responses or lead to tonic firing that outlasts the initial trigger. While there are no excitatory loops in the cerebellum, there is plenty of negative feedback to quench any sustained neuronal response. As a consequence, the cerebellum has no reverberatory, self-sustaining activity of the type seen in cortex. Second, the cerebellum is functionally divided into hundreds or more independent modules. Each one operates in parallel, with distinct, nonoverlapping inputs and outputs.
What matters for consciousness is not so much the individual neurons but the way they are wired together. A parallel and feedforward architecture is insufficient for consciousness.”
― Christof Koch, The Feeling of Life Itself: Why Consciousness Is Widespread but Can't Be Computed

“The proportion of the brain occupied by the prefrontal cortex is larger in human than in any other species, reflecting our advanced ability to make long-term rational decisions. Unlike most regions of the brain, the prefrontal cortex continues to grow and develop well into the mid-twenties --and so do its cautionary functions.”
― Avi Tuschman, Our Political Nature: The Evolutionary Origins of What Divides Us

“Compared with other animals, our huge cortex also has many more regions specialized for particular functions, such as associating words with objects or forming relationships and reflecting on them. The cortex is what makes us human.”
― John J. Ratey, M. D.