Intentionality and "free-will" from a neurodevelopmental perspective

Abstract

The nature of free-will as a subset of intentionality and probabilistic and deterministic function is explored with the indications being that human behavior is highly predictable which in turn, should compromise the notion of free-will. Data supports the notion that age relates to the ability to progressively effectively establish goals performed by fixed action patterns and that these FAPs produce outcomes that in turn modify choices (free-will) for which FAPs need to be employed. Early goals require behaviors that require greater automation in terms of FAPs that lead to goals being achieved or not; if not, then one can change behavior and that in turn is free-will. Goals change with age based on experience which is similar to the way in which movement functions. We hypothesize that human prefrontal cortex development was a natural expansion of the evolutionarily earlier developed areas of the frontal lobe and that goal-directed movements and behavior, including choice and free-will, provided for an expansion of those areas. The same regions of the human central nervous system that were already employed for better control, coordination, and timing of movements, expanded in parallel with the frontal cortex. The initial focus of the frontal lobes was the control of motor activity, but as the movements became more goal-directed, greater cognitive control over movement was necessitated leading to voluntary control of FAPs or free-will. The paper reviews the neurobiology, neurohistology, and electrophysiology of brain connectivities developmentally, along with the development of those brain functions linked to decision-making from a developmental viewpoint. The paper reviews the neurological development of the frontal lobes and inter-regional brain connectivities in the context of optimization of communication systems within the brain and nervous system and its relation to free-will.

Keywords: electrophysiology; fixed-action patterns; free-will; frontal-lobe; functional connection; goal direction; self-regulation.

Figure 1

Mean log 6–8 Hz power for the resting baseline period in the left and right frontal and parietal regions for criers (N = 6) and non-criers (N = 7). (Decreases in 6–8 Hz power are indicative of increases in activation. Error bars indicate standard errors of the mean). (From Davidson and Fox, 1989).

Figure 2

Cytoarchitecture of the cortex with reference to the frontal lobes according to Broadmann. Areas 1, 2, and 3, Primary Somatosensory Cortex; Area 4, Primary Motor Cortex; Area 5, Somatosensory Association Cortex; Area 6, Pre-Motor and Supplementary Motor Cortex (Secondary Motor Cortex); Area 7, Somatosensory Association Cortex; Area 8, Includes Frontal eye fields; Area 9, Dorsolateral prefrontal cortex; Area 10, Frontopolar area (most rostral part of superior and middle frontal gyri); Area 11, Orbitofrontal area (orbital and rectus gyri, plus part of the rostral part of the superior frontal gyrus); Area 12, Orbitofrontal area (used to be part of BA11, refers to the area between the superior frontal gyrus and the inferior rostral sulcus); Area 17, Primary Visual Cortex (V1); Area 18, Visual Association Cortex (V2); Area 19, (V3); Area 20, Inferior Temporal gyrus; Area 21, Middle Temporal gyrus; Area 22, Superior Temporal Gyrus, of which the rostral part participates to Wernicke's area; Area 23, Ventral Posterior cingulate cortex; Area 24, Ventral Anterior cingulate cortex; Area 25, Subgenual cortex; Area 26, Ectosplenial area; Area 28, Posterior Entorhinal Cortex; Area 29, Retrosplenial cingular cortex; Area 30, Part of cingular cortex; Area 31, Dorsal Posterior cingular cortex; Area 32, Dorsal anterior cingulate cortex; Area 34, Anterior Entorhinal Cortex (on the Parahippocampal gyrus); Area 35, Perirhinal cortex (on the Parahippocampal gyrus); Area 36, Parahippocampal cortex (on the Parahippocampal gyrus); Area 37, Fusiform gyrus; Area 38, Temporopolar area (most rostral part of the superior and middle temporal gyri); Area 39, Angular gyrus, part of Wernicke's area; Area 40, Supramarginal gyrus part of Wernicke's area; Areas 41 and 42, Primary and Auditory Association Cortex; Area 43, Subcentral area (between insula and post/precentral gyrus); Area 44, pars opercularis, part of Broca's area; Area 45, pars triangularis Broca's area; Area 46, Dorsolateral prefrontal cortex; Area 47, Inferior prefrontal gyrus.

Figure 3

Compared to other parts of the brain, frontal lobe development is on a delayed timetable. As frontal lobes mature throughout childhood and adolescence, the ability to think through, inhibit, and plan actions as well as executive functions of governing emotions, judgment, planning, organization, problem solving, impulse inhibition, abstraction, analysis/synthesis, self-awareness and self-concept, and identity gradually develops.

Figure 4

Brain cells develop connections over the first two years of the infant's life. These connectivities are formed, altered, and actively sculpted over the first 20 + years of life.

Figure 5

Cerebral metabolic rate as a function of age. Elevated CMRGlc during 3–10 years corresponds to era of exuberant connectivity needed for energy needs of neuronal processes which is greater by a factor of 2 in childhood as compared to adults. PET shows relative glucose metabolic rate. We see the complexity of dendritic structures of cortical neurons consistent with expansion of synaptic connectivities and increases in capillary density in frontal cortex.

Figure 6

The corticolimbic system consists of several brain regions that include the rostral anterior cingulate cortex, hippocampal formation, and basolateral amygdala. The anterior cingulate cortex has a central role in processing emotional experiences at the conscious level and selective attentional responses. Emotionally related learning is mediated through the interactions of the basolateral amygdala and hippocampal formation and motivational responses are processed through the dorsolateral prefrontal cortex (from Benes, 2010).