Monday, December 31, 2012

Gerald Wiest - Neural and Mental Hierarchies

This is an interesting article from the Frontiers and Psychology open source series, Frontiers in Psychoanalysis and Neuropsychoanalysis. Psychoanalyst and neurologist Gerald Wiest looks in this article at how neural hierarchies are related to mental hierarchies and how this plays out in contemporary psychoanalytic theory.

Neural and mental hierarchies

Gerald Wiest (1,2)*
(1) Department of Neurology, Medical University Vienna, Vienna, Austria
(2) Vienna Psychoanalytical Society, Vienna, Austria

The history of the sciences of the human brain and mind has been characterized from the beginning by two parallel traditions. The prevailing theory that still influences the way current neuroimaging techniques interpret brain function, can be traced back to classical localizational theories, which in turn go back to early phrenological theories. The other approach has its origins in the hierarchical neurological theories of Hughlings-Jackson, which have been influenced by the philosophical conceptions of Herbert Spencer. Another hallmark of the hierarchical tradition, which is also inherent to psychoanalytic metapsychology, is its deeply evolutionary perspective by taking both ontogenetic and phylogenetic trajectories into consideration. This article provides an outline on hierarchical concepts in brain and mind sciences, which contrast with current cognitivistic and non-hierarchical theories in the neurosciences.
Full Citation: 
Wiest, G. (2012). Neural and mental hierarchies. Frontiers and Psychoanalysis and Neuropsychoanalysis, 3:516. doi: 10.3389/fpsyg.2012.00516

Here is the introduction to the article.

The Philosophical and Biological Foundations of a Theory

According to modern biology, the development of hierarchies distinguishes the organic from the anorganic world (Mayr, 1997). Herbert Spencer (1820–1903) was the first who – influenced by Lamarckism – provided a coherent theory on the evolution, structure, and function of the nervous system. In his “Principles of Psychology” (Spencer, 1855), he postulated that the human mind can only be fully understood by considering its phylogenetic development. In his view, the phylogeny of consciousness illustrates a general principle of evolution, namely the development from a simple, undifferentiated homogeneity to a complex, differentiated heterogeneity. This conception implies that the human mind had evolved in the same way from a simple automatic response in lower animals to higher cognitive processes in man.

Spencer envisaged the evolutionary change of neural structures toward higher complexity as a process of stratification or layering of neural formations (Figure 1). Thus, each neural formation of the nervous system not only represents impressions and experiences of the individual’s past, but also those of its ancestors. From a neurological perspective, this would mean that a lesion at a higher cerebral level unveils neural and mental functions from an earlier evolutionary stage.
Figure 1. Herbert Spencer’s concept of the evolutionary change in the nervous system by means of superimpositions (A′) of neural layers exemplified in a neural ganglion (A). Consequently, neural excitation does not proceed anymore from a to b but is rather following new neural formations (d, e, f, g). Image from Spencer H (The Principles of Psychology, 1896, Appleton Press).
The British neurologist John Hughlings Jackson (1834–1911), one of the founding fathers of clinical neurology, was intrigued by the correlations between Spencer’s proposed evolutionary principles of neural functioning and his clinical observations in patients with focal brain lesions. In contrast to Spencer’s interest in evolutionary aspects of brain function, Jackson was more occupied with the reverse effect of evolution, which he coined “dissolution.”

In Jackson’s view, neurological symptoms such as aphasia, hemiparesis, or epileptic seizures, represent a dissolution, i.e., a reversal of the evolution of the nervous system, caused by a cerebral lesion. Jackson found that evolutionary higher cerebral centers inhibit the lower ones and lesions at these higher centers are accompanied by the production of “negative” symptoms (e.g., a palsy due to the absence of function) and of “positive” symptoms (e.g., pyramidal signs), caused by a functional release of the lower centers. Neurological or psychiatric symptoms can in this regard provide a look into the phylogeny of neural function. In his major work entitled “Evolution and Dissolution of the Nervous System” (Taylor, 1931/1932) Jackson outlined his theory of brain function, which still belongs to the foundations of neurology. The validity of a hierarchical organization of the nervous system has subsequently been confirmed by modern neurology and neuroscience for a variety of neural systems (Kennard, 1989; Swash, 1989; Vallbo, 1989; Miller and Cohen, 2001;Greene et al., 2004). The Jacksonian concept contrasts with non-hierarchical models of brain function, such as the theories by Hebb (Brown and Milner, 2003) or Lashley (1958). These models propose that brain function, in particular cortical processing, is based on the distributed processing of cell assemblies, i.e., of neural networks. According to lesion studies, Lashley proposed for example, that memories are not localized but widely distributed across the cortex, which has not been confirmed in subsequent studies. Classical empirical studies as well as recent imaging studies – on the other hand – provide convincing evidence that the rostro-caudal axis of the frontal lobe may indeed be hierarchically organized (Goldstein and Scherer, 1941; Luria, 1966; Mesulam, 2002; Petrides, 2005; Badre and D’Esposito, 2009). However, the Jacksonian concept not only paved the way to the establishment of neurology as a scientific discipline, it also had a profound impact on Sigmund Freud and the development of psychoanalytic metapsychology.
Read the whole article.
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